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WO2023128849A1 - Cell selection during operation in unlicensed spectrum - Google Patents

Cell selection during operation in unlicensed spectrum Download PDF

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Publication number
WO2023128849A1
WO2023128849A1 PCT/SE2022/051151 SE2022051151W WO2023128849A1 WO 2023128849 A1 WO2023128849 A1 WO 2023128849A1 SE 2022051151 W SE2022051151 W SE 2022051151W WO 2023128849 A1 WO2023128849 A1 WO 2023128849A1
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WO
WIPO (PCT)
Prior art keywords
cell
cca
drx
function
cycle length
Prior art date
Application number
PCT/SE2022/051151
Other languages
French (fr)
Inventor
Zhixun Tang
Muhammad Kazmi
Santhan THANGARASA
Chunhui Zhang
Original Assignee
Telefonaktiebolaget Lm Ericsson (Publ)
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
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Application filed by Telefonaktiebolaget Lm Ericsson (Publ) filed Critical Telefonaktiebolaget Lm Ericsson (Publ)
Publication of WO2023128849A1 publication Critical patent/WO2023128849A1/en

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Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W48/00Access restriction; Network selection; Access point selection
    • H04W48/16Discovering, processing access restriction or access information
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W76/00Connection management
    • H04W76/20Manipulation of established connections
    • H04W76/28Discontinuous transmission [DTX]; Discontinuous reception [DRX]
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W48/00Access restriction; Network selection; Access point selection
    • H04W48/20Selecting an access point
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W74/00Wireless channel access
    • H04W74/08Non-scheduled access, e.g. ALOHA
    • H04W74/0808Non-scheduled access, e.g. ALOHA using carrier sensing, e.g. carrier sense multiple access [CSMA]
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02DCLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00Reducing energy consumption in communication networks
    • Y02D30/70Reducing energy consumption in communication networks in wireless communication networks

Definitions

  • Embodiments of the present disclosure relate generally to wireless communication networks, and more specifically to improving operation of such networks based on techniques for user equipment (UEs) to select cells operating in shared or unlicensed spectrum.
  • UEs user equipment
  • NR New Radio
  • 3GPP Third-Generation Partnership Project
  • eMBB enhanced mobile broadband
  • MTC machine type communications
  • URLLC ultra-reliable low latency communications
  • D2D side-link device-to-device
  • Rel-15 3GPP Release 15
  • NR uses CP-OFDM (Cyclic Prefix Orthogonal Frequency Division Multiplexing) in the downlink (DL) from network to user equipment (UE), and both CP-OFDM and DFT-spread OFDM (DFT-S-OFDM) in the uplink (UL) from UE to network.
  • CP-OFDM Cyclic Prefix Orthogonal Frequency Division Multiplexing
  • DFT-S-OFDM DFT-spread OFDM
  • NR DL and UL time-domain physical resources are organized into equal-sized 1-ms subframes. A subframe is further divided into multiple slots of equal duration, with each slot including multiple OFDM-based symbols.
  • time-frequency resources can be configured much more flexibly for an NR cell than for an LTE cell.
  • NR SCS can range from 15 to 240 kHz, with even greater SCS considered for future NR releases (e.g., in higher frequency bands).
  • Figure 1 shows an exemplary configuration of NR user plane (UP) and control plane (CP) protocol stacks between a UE (110), a gNodeB (gNB, e.g., base station, 120), and an access and mobility management function (AMF, 130) in the 5G core network (5GC).
  • UP user plane
  • CP control plane
  • PHY Physical
  • MAC Medium Access Control
  • RLC Radio Link Control
  • PDCP Packet Data Convergence Protocol
  • the PDCP layer provides ciphering/deciphering, integrity protection, sequence numbering, reordering, and duplicate detection for CP and UP.
  • the non-access stratum (NAS) layer is between UE and AMF and handles UE/gNB authentication, mobility management, and security control.
  • the RRC layer sits below NAS in the UE but terminates in the gNB rather than the AMF.
  • RRC controls communications between UE and gNB at the radio interface as well as the mobility of a UE between cells in the NG-RAN.
  • RRC also broadcasts system information (SI) and establishes, configures, maintains, and releases DRBs and Signaling Radio Bearers (SRBs) used by UEs.
  • SI system information
  • SRBs Signaling Radio Bearers
  • RRC controls addition, modification, and release of carrier aggregation (CA) and dual-connectivity (DC) configurations for UEs.
  • CA carrier aggregation
  • DC dual-connectivity
  • RRC also performs various security functions such as key management.
  • a UE After a UE is powered ON it will be in the RRC IDLE state until an RRC connection is established with the network, at which time the UE will transition to RRC_CONNECTED state (e.g. , where data transfer can occur). The UE returns to RRC IDLE after the connection with the network is released.
  • RRC IDLE state the UE’s radio is active on a discontinuous reception (DRX) schedule configured by upper layers.
  • DRX discontinuous reception
  • an RRC_IDLE UE receives SI broadcast in the cell where the UE is camping, performs measurements of neighbor cells to support cell reselection, and monitors a paging channel on physical DL control channel (PDCCH) for pages from 5GC via gNB.
  • PDCCH physical DL control channel
  • a UE in RRC IDLE state is not known to the gNB serving the cell where the UE is camping.
  • NR RRC includes an RRC INACTIVE state in which a UE is known by the serving gNB.
  • NR networks In addition to providing coverage via cells as in LTE, NR networks also provide coverage via “beams.”
  • a downlink (DL, i.e., network to UE) “beam” is a coverage area of a network-transmitted reference signal (RS) that may be measured or monitored by a UE.
  • RS can include any of the following: synchronization signal/PBCH block (SSB), channel state information RS (CSI-RS), tertiary reference signals (or any other sync signal), positioning RS (PRS), demodulation RS (DMRS), phase-tracking reference signals (PTRS), etc.
  • SSB is available to all UEs regardless of the state of their connection with the network, while other RS (e.g., CSI-RS, DM-RS, PTRS) are associated with specific UEs that have a network connection.
  • a UE performs measurements on DL RS (e.g., beams) of one or more cells in different RRC states.
  • Each cell measured by a UE may operate on the same carrier frequency as the UE’s serving cell (e.g., an intra-frequency carrier) or it may operate on a different carrier frequency than the UE’s current serving cell (e.g., non-serving carrier frequency).
  • the non-serving carrier is often referred to as an inter-frequency carrier if the serving and measured cells belong to the same RAT bit different carrier frequencies, or as an inter-RAT carrier if the serving and measured cells belong to different RATs.
  • Examples of UE cell measurements include cell identification (e.g., PCI acquisition, PSS/SSS detection, cell detection, cell search, etc), RS Received Power (RSRP), RS Received Quality (RSRQ), secondary synchronization RSRP (SS-RSRP), SS-RSRQ, SINR, RS-SINR, SS-SINR, CSI-RSRP, CSI-RSRQ, received signal strength indicator (RSSI), acquisition of system information (SI) and/or cell global ID (CGI), RS Time Difference (RSTD), UE RX-TX time difference measurement, and Radio Link Monitoring (RLM, including out-of-sync and insync detection).
  • cell identification e.g., PCI acquisition, PSS/SSS detection, cell detection, cell search, etc
  • RSRP RS Received Power
  • RSSRQ secondary synchronization RSRP
  • SS-RSRP secondary synchronization RSRP
  • SS-RSRP secondary synchronization RSRP
  • the network typically provides the UE (e.g., via RRC) a measurement configuration and a measurement reporting configuration.
  • These configurations can include parameters such as measurement gap pattern (MGP), carrier frequency information, types of measurements (e.g., RSRP), higher-layer filtering coefficient, time-to-trigger report, and reporting mechanism (e.g., periodic, event triggered, etc).
  • MGP measurement gap pattern
  • RSRP types of measurements
  • time-to-trigger report e.g., periodic, event triggered, etc.
  • reporting mechanism e.g., periodic, event triggered, etc.
  • the UE performs the measurements for various purposes including mobility (e.g., cell change, cell selection, cell reselection, handover, RRC connection re-establishment etc), positioning, self-organizing network (SON) support, minimization of drive tests (MDT), operation and maintenance (O&M), network planning and optimization, etc.
  • SON self-organizing network
  • MDT minimization of drive tests
  • LAA License Assisted Access
  • LAA is a feature of LTE that leverages the unlicensed 5 GHz band in combination with licensed spectrum to deliver a performance boost for mobile device users. It uses DL CA to combine LTE in licensed and unlicensed bands to provide better data rates and a better user experience.
  • LAA the UE’s PCell is in a licensed band while the UE’s SCells can be in an unlicensed band. Since LAA operates in the 5-GHz band where Wi-Fi operates, it must be able to co-exist with Wi-Fi by avoiding channels that are being used by WiFi users.
  • LAA uses a concept called Listen-before-talk (LBT) that dynamically selects 5-GHz- band channel(s) that is(are) not being used, i.e., a “clear channel.” If no clear channel is available, LAA will share a channel fairly with others. As such, LBT is often referred to as clear channel assessment (CCA).
  • CCA clear channel assessment
  • NR Rel-16 includes a feature similar to LTE LAA, referred to as NR- Unlicensed or “NR-U”.
  • a UE operating in RRC_IDLE receives SI broadcast in the cell where the UE is camping and performs measurements of serving and neighbor cells to support cell reselection. If the UE in RRC_IDLE has not found any suitable cells after 10 seconds of searches and measurements using the intra-frequency, inter-frequency and inter-RAT information indicated in the broadcast SI, the UE is required to initiate a cell selection procedure.
  • the network can only transmit signals to be measured by the UE when the channel is available as determined by the transmitting node’s CCA procedure. This can cause various problems, issues, and/or difficulties for UEs. For example, given the 10-second limit discussed above, a UE may need to initiate cell selection even if the UE hasn’t finished serving cell evaluation or neighbor cell detection due to CCA failures. This may cause the UE to select a cell that is sub-optimal for camping because the UE’s search ended before it could find a cell with better radio conditions.
  • Embodiments of the present disclosure provide specific improvements to operation of UEs in unlicensed or shared spectrum, such as by providing, enabling, and/or facilitating solutions to overcome exemplary problems summarized above and described in more detail below.
  • Embodiments include methods (e.g., procedures) for a UE (e.g, wireless device, loT device, etc.) configured for operation in a wireless network.
  • a UE e.g, wireless device, loT device, etc.
  • These exemplary methods can include performing a search for a suitable cell while operating in DRX and in a non-connected state with respect to the wireless network.
  • the search includes performing measurements of at least one cell, of the wireless network, that is subject to a CCA requirement.
  • These exemplary methods can also include initiating one or more cell selection procedures in response to performing the search for at least a minimum period without identifying a suitable cell.
  • the minimum period is a function of one or more CCA-related parameters for the at least one cell.
  • the minimum period is also a function of one or more DRX-related parameters.
  • the at least one cell includes the UE’s serving cell and the DRX includes periodic DRX cycles, each having a cycle length of TDRX.
  • the measurements are performed on the serving cell every Jth DRX cycle.
  • J is a function of the following: the cycle length TDRX, a periodicity of a signal being measured, and a maximum number of DRX cycles between measurements.
  • performing the search includes evaluating results of the measurements every Jth DRX cycle against one or more cell reselection criteria, wherein the minimum period comprises a number of consecutive DRX cycles.
  • the number of consecutive DRX cycles is a function of the cycle length TDRX and the periodicity of the signal being measured.
  • the number of consecutive DRX cycles is also a function of one or more of the following: UE power class, and whether the UE uses receive beam sweeping to measure the signal.
  • the number of consecutive DRX cycles is also a function of a number of DRX cycles during which the signal being measured is not available to be measured by the UE on at least one occasion due to a CCA failure.
  • the UE can perform different operations when the number of DRX cycles during which the signal is not available to be measured by the UE, within a time period, exceeds a maximum number of unavailable DRX cycles for the time period.
  • the UE can initiate the one or more cell selection procedures based on this condition.
  • these exemplary methods can include, based on this condition, restarting the search for a suitable cell in relation to the minimum period.
  • these exemplary methods can also include obtaining, via the serving cell, information about a plurality of neighbor cells.
  • the information includes CCA- related information.
  • initiating one or more cell selection procedures includes ranking the neighbor cells based on the CCA-related information and initiating the cell selection procedures on the neighbor cells in order of ranking.
  • ranking the neighbor cells is further based on measurements of the neighbor cells made by the UE while performing the search.
  • the CCA-related information for each neighbor cell includes one or more of the following:
  • the neighbor cells are ranked (i.e., based on the received CCA-related information) in order of one of the following: decreasing likelihood of CCA success during the subsequent time interval; increasing likelihood of CCA failure during the subsequent time interval; decreasing CCA success rate during the previous time interval; or increasing CCA failure rate during the subsequent time interval.
  • the DRX includes periodic DRX cycles having a cycle length of TDRX and the minimum period is a function of the following: a duration (PICCA) required for the UE to evaluate or detect the at least one cell subject to the CCA requirement; the cycle length TDRX; and a periodicity of a signal (e.g., SSB) being measured in the at least one cell.
  • the minimum period is also a function of one or more of the following: UE power class, number of UE antennas used to perform the measurements, frequency range of the at least one cell subject to CCA requirement, and whether the UE uses receive beam sweeping to perform the measurements.
  • the duration is a function of one or more of the following:
  • one or more of the following is also a function of the cycle length TDRX:
  • the DRX includes extended periodic DRX cycles, each having an extended cycle length T eDRX and including one or more DRX cycles.
  • the extended cycle length TCDRX is greater than the cycle length TDRX.
  • the minimum period is a function of the extended cycle length T eDRX instead of or in addition to being a function of the cycle length TDRX.
  • these exemplary methods can also include obtaining the minimum period, or the CCA-related parameters of which the minimum period is a function, via one or more of the following:
  • inventions include exemplary methods (e.g., procedures) for a network node (e.g, base station, eNB, gNB, ng-eNB, etc., or component thereof) configured to serve at least one cell that is subject to a CCA requirement in a wireless network.
  • a network node e.g, base station, eNB, gNB, ng-eNB, etc., or component thereof
  • these embodiments are complementary to the UE embodiments summarized above.
  • These exemplary methods can include transmitting one of the following via the at least one cell: a minimum period for UEs to search for a suitable cell during UE DRX operation in a nonconnected state with respect to the wireless network, before UE initiation of one or more cell selection procedures; or • one or more CCA-related parameters for the at least one cell, of which the minimum period is a function.
  • the minimum period is also a function of one or more parameters related to the DRX operation.
  • the DRX includes periodic DRX cycles having a cycle length of TDRX and the minimum period is a function of the following: a duration (PICCA) required for the UE to evaluate or detect the at least one cell subject to the CCA requirement; the cycle length TDRX; and a periodicity of a signal (e.g., SSB) being measured by the UE in the at least one cell subject to a CCA requirement.
  • the minimum period is also a function of one or more of the following: UE power class, number of UE antennas used to perform the measurements, frequency range of the at least one cell subject to CCA requirement, and whether the UE uses receive beam sweeping to perform the measurements.
  • the duration can be a function of any of the parameters that were summarized above in relation to corresponding UE embodiments and variants.
  • various other parameters can also be a function of the cycle length TDRX, including certain parameters (of which the minimum period is a function) that were summarized above in relation to UE embodiments.
  • the DRX includes extended periodic DRX cycles, each having an extended cycle length T eDRX and including one or more DRX cycles.
  • the extended cycle length TCDRX is greater than the cycle length TDRX.
  • the minimum period is a function of the extended cycle length T eDRX instead of or in addition to being a function of the cycle length TDRX.
  • these exemplary methods can also include transmitting, via the at least one cell, information about a plurality of neighbor cells.
  • the information includes CCA- related information, which in various embodiments can include any of the CCA-related information summarized above in relation to UE embodiments.
  • UEs e.g., wireless devices
  • network nodes e.g., base stations, eNBs, gNBs, ng-eNBs, etc., or components thereof
  • Other embodiments include non-transitory, computer-readable media storing program instructions that, when executed by processing circuitry, configure such UEs or network nodes to perform operations corresponding to any of the exemplary methods described herein.
  • Embodiments described herein provide flexible and efficient techniques for cell selection by a UE operating in a non-connected state (e.g., RRC IDLE or RRC IN ACTIVE) and configured with DRX and at least one carrier frequency that is subject to CCA.
  • Embodiments provide well-defined UE measurement behavior for cell selection in this scenario, which is currently not specified by 3GPP.
  • Embodiments also ensure that UEs in this scenario search all possible configured cells that are strong enough before initiating a cell selection procedure. This in turn prevents such UEs from prematurely performing cell selection based on sub-optimal and/or incomplete information about available cells.
  • embodiments improve the performance of networks and UEs operating in shared spectrum.
  • Figure 1 shows exemplary NR user plane (UP) and control plane (CP) protocol stacks.
  • UP NR user plane
  • CP control plane
  • Figure 2 illustrates a high-level views of an exemplary 5G/NR network architecture.
  • Figure 3 shows an exemplary discontinuous reception (DRX) cycle for a UE
  • Figure 4 shows an exemplary scenario in which spectrum coexistence techniques are desirable and/or necessary.
  • Figure 5 shows a timeline of an exemplary CCA procedure performed by a UE or network node wanting to transmit on a channel in unlicensed spectrum.
  • Figure 6 shows a flow diagram of an exemplary method for a UE (e.g, wireless device), according to various embodiments of the present disclosure.
  • Figure 7 shows a flow diagram of an exemplary method for a network node (e.g., base station, eNB, gNB, etc.), according to various embodiments of the present disclosure.
  • a network node e.g., base station, eNB, gNB, etc.
  • Figure 8 shows a communication system according to various embodiments of the present disclosure.
  • Figure 9 shows a UE according to various embodiments of the present disclosure.
  • Figure 10 shows a network node according to various embodiments of the present disclosure.
  • Figure 11 shows host computing system according to various embodiments of the present disclosure.
  • Figure 12 is a block diagram of a virtualization environment in which functions implemented by some embodiments of the present disclosure may be virtualized.
  • Figure 13 illustrates communication between a host computing system, a network node, and a UE via multiple connections, at least one of which is wireless, according to various embodiments of the present disclosure.
  • Radio Access Node As used herein, a “radio access node” (or equivalently “radio network node,” “radio access network node,” or “RAN node”) can be any node in a radio access network (RAN) of a cellular communications network that operates to wirelessly transmit and/or receive signals.
  • RAN radio access network
  • a radio access node examples include, but are not limited to, a base station (e.g., a gNB 5G/NR network or an eNB in an LTE network), base station distributed components (e.g., CU and DU), a high-power or macro base station, a low- power base station (e.g., micro, pico, femto, or home base station, or the like), an integrated access backhaul (IAB) node (or component thereof such as MT or DU), a transmission point, a remote radio unit (RRU or RRH), and a relay node.
  • a base station e.g., a gNB 5G/NR network or an eNB in an LTE network
  • base station distributed components e.g., CU and DU
  • a high-power or macro base station e.g., a low- power base station (e.g., micro, pico, femto, or home base station, or the like)
  • a “core network node” is any type of node in a core network. Some examples of a core network node include, e.g, mobility management entity (MME), serving gateway (SGW), packet data network gateway (P-GW), etc.
  • MME mobility management entity
  • SGW serving gateway
  • P-GW packet data network gateway
  • a core network node can also be a node that implements a particular core network function (NF), such as access and mobility management function (AMF), session management function (SMF), user plane function (UPF), service capability exposure function (SCEF), or the like.
  • NF core network function
  • Communicating wirelessly can involve transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information through air.
  • wireless device is used interchangeably herein with the term “user equipment” (or “UE” for short), with both of these terms having a different meaning than the term “network node”.
  • Radio Node can be either a “radio access node” (or equivalent term) or a “wireless device.”
  • Network Node is any node that is either part of the radio access network (e.g., a radio access node or equivalent term) or of the core network (e.g., a core network node discussed above) of a cellular communications network.
  • a network node is equipment capable, configured, arranged, and/or operable to communicate directly or indirectly with a wireless device and/or with other network nodes or equipment in the cellular communications network, to enable and/or provide wireless access to the wireless device, and/or to perform other functions (e.g, administration) in the cellular communications network.
  • node can be any type of node that is capable of operating in or with a wireless network (including a RAN and/or a core network), including a radio access node (or equivalent term), core network node, or wireless device.
  • a wireless network including a RAN and/or a core network
  • radio access node or equivalent term
  • core network node or wireless device.
  • node may be limited to a particular type of node (e.g., radio access node) based on its particular characteristics in any context.
  • Base station may comprise a physical or a logical node transmitting or controlling the transmission of radio signals, e.g., eNB, gNB, ng-eNB, en- gNB, CU/DU, transmitting radio network node, transmission point (TP), transmission reception point (TRP), remote radio head (RRH), remote radio unit (RRU), Distributed Antenna System (DAS), relay, etc.
  • eNB e.g., eNB, gNB, ng-eNB, en- gNB, CU/DU
  • TP transmission point
  • TRP transmission reception point
  • RRH remote radio head
  • RRU remote radio unit
  • DAS Distributed Antenna System
  • FIG. 2 shows a high-level view of an exemplary 5G network architecture, including a Next Generation Radio Access Network (NG-RAN) 299 and a 5G Core (5GC) 298.
  • NG-RAN Next Generation Radio Access Network
  • 5GC 5G Core
  • NG-RAN 299 can include gNBs (e.g., 210a, b) and ng-eNBs (e.g, 220a, b) that are interconnected with each other via respective Xn interfaces.
  • the gNBs and ng-eNBs are also connected via the NG interfaces to the 5GC, more specifically to Access and Mobility Management Functions (AMFs, e.g, 230a, b) via respective NG-C interfaces and to User Plane Functions (UPFs, e.g., 240a, b) via respective NG-U interfaces.
  • AMFs Access and Mobility Management Functions
  • UPFs User Plane Functions
  • the AMFs can communicate with one or more policy control functions (PCFs, e.g., 250a, b) and network exposure functions (NEFs, e.g., 260a, b).
  • PCFs policy control functions
  • NEFs network exposure functions
  • Each gNB can support the NR radio interface including frequency division duplexing (FDD), time division duplexing (TDD), or a combination thereof.
  • each ng-eNB can support the LTE radio interface but, unlike conventional LTE eNodeBs (eNBs), connects to the 5GC via the NG interface.
  • Each gNB and ng-eNB can serve a geographic coverage area including one more cells, such as cells 211a-b and 221a-b shown as exemplary in Figure 2.
  • the gNBs and ng-eNBs can also use various directional beams to provide coverage in the respective cells.
  • a UE (205) can communicate with the gNB or ng- eNB serving that cell via the NR or LTE radio interface, respectively.
  • the gNBs shown in Figure 2 can include a central (or centralized) unit (CU or gNB-CU) and one or more distributed (or decentralized) units (DU or gNB-DU), which can be viewed as logical nodes.
  • CUs host higher-layer protocols and perform various gNB functions such controlling the operation of DUs, which host lower-layer protocols and can include various subsets of the gNB functions.
  • each of the CUs and DUs can include various circuitry needed to perform their respective functions, including processing circuitry, communication interface circuitry (e.g., for communication viaXn, NG, radio, etc. interfaces), and power supply circuitry.
  • a CU connects to its associated DUs over respective Fl logical interfaces.
  • a CU and its associated DUs are only visible to other gNBs and the 5GC as a gNB, e.g, the Fl interface is not visible beyond a CU.
  • a CU can host higher-layer protocols such as Fl application part protocol (Fl-AP), Stream Control Transmission Protocol (SCTP), GPRS Tunneling Protocol (GTP), Packet Data Convergence Protocol (PDCP), User Datagram Protocol (UDP), Internet Protocol (IP), and Radio Resource Control (RRC) protocol.
  • a DU can host lower-layer protocols such as Radio Link Control (RLC), Medium Access Control (MAC), and physical-layer (PHY) protocols.
  • RLC Radio Link Control
  • MAC Medium Access Control
  • PHY physical-layer
  • NR DL and UL physical resources are organized into equal-sized 1-ms subframes.
  • a subframe is further divided into multiple slots of equal duration, with each slot including multiple OFDM-based symbols.
  • An NR slot can include 14 OFDM symbols for normal cyclic prefix and 12 symbols for extended cyclic prefix.
  • a resource block (RB) consists of a group of 12 contiguous OFDM subcarriers for a duration of a 12- or 14-symbol slot.
  • a resource element (RE) corresponds to one OFDM subcarrier during one OFDM symbol interval.
  • An NR slot can also be arranged with various time-division duplexing (TDD) arrangements of UL and DL symbols. These TDD arrangements include:
  • a UE can be configured with discontinuous reception (DRX) cycle to use in all RRC states.
  • UE DRX operation in RRC CONNECTED is often referred to as connected-DRX (CDRX).
  • Figure 3 shows an exemplary DRX cycle for a UE.
  • the UE is on or active for a portion of each DRX cycle (having cycle length TDRX) and off or inactive for the remainder of each DRX cycle.
  • Example values for TDRX currently used in RRC IDLE and RRC INACTIVE include 320 ms, 640 ms, 1.28 s, 2.56 s, etc.
  • Example values for TDRX currently used in RRC_CONNECTED range from 2 ms to 10.24 s.
  • the on/active time and off/inactive time of each DRX cycle are also called as DRX ON and DRX OFF durations.
  • the off/inactive time may also be called non-DRX state or non-DRX duration.
  • an extended DRX (eDRX) cycle is being specified for UEs in RRC IDLE and RRC INACTIVE states, with the purpose of further reducing UE energy consumption compared to conventional DRX.
  • An eDRX cycle length ranges between few seconds to several minutes or even hours but is generally longer than TDRX.
  • an eDRX cycle may range from 5.12 seconds (shortest eDRX) up to 10485.76 s (largest eDRX).
  • the eDRX configuration parameters can be negotiated between UE and the network via higher layer signaling such as NAS messages.
  • the network transmits eDRX parameters including eDRX cycle length, paging time window (PTW), hyper system frame number (H-SFN), paging H-SFN (PH) etc.
  • eDRX cycle length paging time window
  • H-SFN hyper system frame number
  • PH paging H-SFN
  • a UE performs measurements on DL RS (e.g., beams) of one or more cells in different RRC states.
  • Each cell measured by a UE may operate on the same carrier frequency as the UE’s serving cell (e.g., an intra- frequency carrier) or it may operate on a different carrier frequency than the UE’s current serving cell (e.g., non-serving carrier frequency).
  • the non-serving carrier is often referred to as an inter-frequency carrier if the serving and measured cells belong to the same RAT bit different carrier frequencies, or as an inter-RAT carrier if the serving and measured cells belong to different RATs.
  • Examples of UE cell measurements include cell identification (e.g., PCI acquisition, PSS/SSS detection, cell detection, cell search, etc), RSRP, RSRQ, secondary synchronization RSRP (SS-RSRP), SS- RSRQ, SINR, RS-SINR, SS-SINR, CSI-RSRP, CSI-RSRQ, RSSI, acquisition of SI and/or CGI, RSTD, UE RX-TX time difference measurement, and RLM (including out-of-sync and in-sync detection).
  • cell identification e.g., PCI acquisition, PSS/SSS detection, cell detection, cell search, etc
  • RSRP RSRP
  • RSRQ secondary synchronization RSRP
  • SS-RSRP secondary synchronization RSRP
  • SS-RSRP secondary synchronization RSRP
  • SS-RSRP secondary synchronization RSRP
  • SS-RSRP secondary synchronization RSRP
  • SS-RSRP secondary
  • a UE measures SS-RSRP and SS-RSRQ and evaluates cell selection criterion S for its serving cell at least once every M1*N1 DRX cycles.
  • TSMTC SMTC periodicity
  • DRX cycle ⁇ 0.64 second
  • Ml l.
  • the UE filters the SS-RSRP and SS-RSRQ measurements of the serving cell based on at least two (2) measurements. At least two measurements with the set used for the filtering must be spaced apart by at least one-half of the DRX cycle.
  • the UE If the UE has evaluated in Nserv consecutive DRX cycles that its serving cell belonging to a carrier not subject to CCA does not fulfil the cell selection criterion S, the UE initiates measurements of all neighbor cells indicated by the serving cell broadcast SI, regardless of the measurement rules currently limiting UE measurement activities. Table 1 below gives values for Nserv.
  • the UE If the UE has evaluated in Nserv_ccA consecutive DRX cycles that a serving cell belonging to a carrier subject to CCA does not fulfil the cell selection criterion S, the UE initiates measurements of all neighbor cells indicated by the serving cell broadcast SI, regardless of the measurement rules currently limiting UE measurement activities. Table 1 below gives values for Nserv_CCA.
  • Qoffsettemp offset temporarily applied to a cell, signaled in the cell.
  • the UE in RRC IDLE has not found any suitable cell based on searches and measurements using the intra-frequency, inter-frequency and inter-RAT information indicated in the system information for 10 s, the UE shall initiate cell selection procedures for the selected PLMN as defined in 3 GPP TS 38.304 (v 16.6.0).
  • NR networks Besides conventional use in licensed (i.e., exclusive) spectrum, NR networks also can operate in unlicensed bands in shared spectrum, referred to generally as NR-U. Coexistence techniques are needed in these deployments to enable spectrum sharing between different operators or other systems.
  • FIG. 4 shows an exemplary scenario in which spectrum coexistence techniques are desirable and/or necessary.
  • network A (410) includes access nodes (e.g., base stations) AN1A, AN2A, and AN3A, which serve UEs including UE1A, UE2A, and UE3A.
  • network B (420) includes access nodes (e.g., base stations) AN1B, AN2B, and AN3B, which serve UEs including UE1B, UE2B, and UE3B.
  • Networks “A” and “B” are located in the same geographic area and share the same frequency spectrum, but are controlled by different entities (e.g., operators).
  • any coexistence techniques are preferably distributed so that there is no need to exchange information between different networks or controlling entities, which would create significant complexities.
  • Operation in unlicensed bands involves a unique set of rules intended to promote spectrum sharing with otherwise competing transceivers. These rules promote an etiquette or behavior that facilitates spectrum sharing and/or co-existence.
  • a node e.g., UE or base station
  • LBT listen-before-talk
  • CCA clear channel assessment
  • the MAC layer initiates a transmission and requests the PHY layer to initiate the LBT procedure.
  • the PHY layer indicates the LBT outcome (e.g., success or failure).
  • An LBT procedure can involve sensing the medium as idle for a number of time intervals, which can be done in various ways including energy detection, preamble detection, or virtual carrier sensing.
  • LBT has become well-known and popular due to ubiquitous use by Wireless LANs (also known as “WiFi”), even though most regulatory agencies did not enforce LBT operation.
  • WiFi Wireless LANs
  • LBT functionality was required by all radio transceivers, regardless of whether they were WiFi or LTE LAA.
  • Energy detection (ED) thresholds were defined, simulated, debated, and soon became part of the regulatory specifications to be met by all devices that operate in unlicensed bands.
  • ED energy detection
  • a channel is assessed to be idle when the received energy or power during the sensing time duration is below a certain ED threshold; otherwise, the channel is considered busy.
  • An example ED threshold is -72 dBm. In some cases, the ED threshold may depend on the channel bandwidth, e.g., -72 dBm 20 MHz bandwidth, -75 dBm for 10 MHz bandwidth, etc. If the channel is assessed as “busy” then the prospective transmitter (i.e., UE or network node) is required to defer transmission.
  • Figure 5 shows a timeline of an exemplary CCA procedure performed by a UE or network node wanting to transmit on a channel in unlicensed spectrum.
  • the prospective transmitter initially senses the channel busy for some duration.
  • the transmitter has a transmission opportunity (TXOP) or a channel occupancy time (COT) during which it may transmit a signal, with the COT being less than a maximum COT (MCOT) that depends of regional rules or laws, the sensing period s, etc.
  • a typical COT is 1-10 ms based on a MCOT of 10 ms.
  • the backoff time may be a deterministic value or a probabilistic value (e.g., selected from a random distribution).
  • the network node can only transmit signals to be measured by the UE when the channel is available as determined from the network node’s CCA procedure.
  • This can cause various problems, issues, and/or difficulties for UEs.
  • a network node may be unable to transmit the RS that a UE needs to measure.
  • a UE may need to initiate cell selection before the UE finishes serving cell evaluation and/or neighbor cell detection based on such RS.
  • the UE may not be able to measure/ detect cells that could be better candidates due to CCA-delayed transmission in those cells. This may cause the UE to select a cell that is sub-optimal for camping because the UE’s 10-second search ended before it could find a cell with better radio conditions.
  • embodiments of the present disclosure provide flexible and efficient techniques for cell selection by a UE operating in a non-connected state (e.g., RRC IDLE or RRC IN ACTIVE) and configured with DRX and at least one carrier frequency that is subject to CCA.
  • Embodiments provide well-defined UE measurement behavior for cell selection for UEs in this scenario, which is currently not specified by 3GPP. Additionally, embodiments ensure that UEs in this scenario search all possible configured cells that are strong enough before initiating a cell selection procedure. This in turn prevents such UEs from prematurely performing cell selection based on sub-optimal and/or incomplete information about available cells.
  • a UE in a non-connected state e.g., RRC IDLE, RRC INACTIVE
  • T max(10s, P1CCA*TDRX) and:
  • Pl CCA K1+ PL is the time for the UE to finish at least one time serving cell evaluation and/or neighbor cell detection.
  • KI is a scaling factor related to the DRX cycle length and RS occasion periodicity, e.g., SMTC periodicity, and
  • TDRX DRX cycle length in seconds.
  • Pls is the number of DRX cycles each with at least one RS occasion (e.g., SMTC occasion) not available during a time period, TO.
  • a UE in a non-connected state (e.g., RRC IDLE, RRC INACTIVE) initiates cell selection procedures for a selected PLMN when the UE does not find any new suitable cell based on searches and measurements on cells during the time period T, where T is a function of at least one CCA-related parameter for at least one cell on which the UE performs search and/or measurements and a function of at least one parameter related to the UE Rx beam sweeping.
  • T max(10s, P1CCA*TDRX) and:
  • N1 scaling factor for UE performing Rx beam sweeping in FR2.
  • Pls is the number of DRX cycles each with at least one RS occasion (e.g., SMTC occasion) not available during a time period, TO.
  • the UE obtains information about the cells on which to perform the searches and/or measurements from SI broadcast by its serving cell. For example, the UE can obtain information indicating whether each cell is an intra-frequency carrier, an inter-frequency carrier, or an inter-RAT carrier.
  • the value Pls should not exceed a limit Pls, max.
  • the UE restarts the measurements that could lead to initiating a cell selection procedure upon Pl s exceeding Pls, max.
  • the UE all initiate cell selection procedures upon Pl s exceeding P 1 s,max.
  • the term “clear channel assessment” may correspond to any type of carrier sense multiple access (CSMA) procedure or mechanism that is performed by a device on a carrier as a prerequisite to the device transmitting signals on that carrier (which may alternately be referred to as “carrier frequency”, “frequency layer”, “channel”, “radio channel”, “radio frequency channel”, etc.).
  • CSMA scheme “channel assessment scheme”, “listen-before-talk” (or “LBT” for short), “shared channel access mechanism” (or scheme), “shared spectrum channel access mechanism” (or scheme) may be used interchangeably with CCA.
  • the frequency band of a carrier subject to CCA may also be referred to as “unlicensed band”, “unlicensed spectrum”, “shared spectrum channel access band”, “band for operation with shared spectrum channel access”, or the like.
  • CCA-based operation is a form of contentionbased operation, with the transmission of signals on a carrier subject to CCA also being called “contention-based transmission”. Although contention-based operation is typically used for transmission on carriers of unlicensed frequency band, this mechanism may also be used for operating on carriers belonging to licensed bands, such as to reduce interference.
  • the transmission of signals on a carrier not subject to CCA is also called “contention-free transmission”.
  • LBT or CCA can be performed by a UE as a prerequisite to UL transmission, and as such may be referred to as “UL CCA”.
  • LBT or CCA can be performed by a network node (e.g., gNB) as a prerequisite to DL transmission, and as such may be referred to as “DL CCA”.
  • the term “signal” or “radio signal” refers to any physical signal or physical channel.
  • physical channels include PBCH, NPBCH, PDCCH, PDSCH, sPUCCH, sPDSCH, sPUCCH, sPUSCH, MPDCCH, NPDCCH, NPDSCH, E-PDCCH, PUSCH, PUCCH, NPUSCH, etc.
  • DL physical signals include RS such as PSS, SSS, CSI-RS, DMRS, SS/PBCH block (SSB), discovery reference signal (DRS), cell RS (CRS), positioning RS (PRS), etc.
  • UL physical signals include sounding RS (SRS), DMRS, etc.
  • RS may be periodic meaning that they occur with a certain periodicity such as 20 ms, 40 ms, etc.
  • RS may also be aperiodic.
  • Each SSB carries NR-PSS, NR-SSS and NR-PBCH in four (4) successive symbols.
  • An SSB burst includes one or more SSBs and is repeated with a certain periodicity such as 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, 160 ms, etc.
  • a UE is configured with information about SSB based on an SSB measurement timing configuration (SMTC) received from the network.
  • An SMTC includes parameters such as SMTC periodicity, SMTC occasion length in time or duration, SMTC time offset relative to reference time (e.g., serving cell’s SFN), etc.
  • an SMTC occasion may also occur with a certain periodicity such as 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, 160 ms, etc.
  • the term physical channel refers to any channel carrying higher layer information e.g., data, control etc.
  • Embodiments described herein are related to the scenario of a UE operating in a nonconnected state (e.g., RRC IDLE or RRC INACTIVE) and configured with DRX and with at least one carrier frequency that is subject to CCA.
  • Each cell measured by the UE may operate on the same carrier frequency as the UE’s serving cell (e.g., an intra-frequency carrier) or it may operate on a different carrier frequency than the UE’s current serving cell (e.g., non-serving carrier frequency).
  • the non-serving carrier may be an inter-frequency carrier if the serving and measured cells belong to the same RAT bit different carrier frequencies, or an inter-RAT carrier if the serving and measured cells belong to different RATs.
  • the UE’s serving cell may operate in a particular frequency range such as FR1, FR2, or FR3, which are listed in order of increasing frequencies.
  • FR1 may be 410-7125 MHz while FR2 may be all frequencies above some threshold (e.g., 24 GHz) or all frequencies in a range with the threshold being the lower end of the range (e.g., 24-71 GHz).
  • frequencies in FR3 may be above FR2.
  • the transmitted signals in relatively higher frequencies often need to be beamformed due to their higher signal dispersion and path loss in most transmission environments.
  • a network node will transmit SSB using transmit beamforming and the UE will use corresponding beamforming to receive and measure the SSB.
  • the UE performs receive beam sweeping in a range of directions to determine direction of arrival of signals to be measured.
  • the receive beam sweeping may also be called spatial beam sweeping, beam tracking, or three-dimensional beam sweeping.
  • the UE forms a receive beam in the determined direction and performs measurement on the signals received via the beam.
  • the UE may obtain information about the one or more carriers to be measured for cell reselection while the UE is operating in DRX (optionally also eDRX) in the non-connected state in various ways, including one or more of the following:
  • pre-defined information e.g., stored on the UE’s SIM or USIM card
  • the UE applies UL CCA before transmitting on a cell and/or carrier frequency subject to CCA. Therefore, the UE can determine that UL CCA has failed (or UL CCA failure has occurred) if the UE is unable to transmit a signal due to CCA failure in the uplink.
  • the UE may determine an outcome or result of DL CCA (e.g., DL CCA failure or DL CCA success) on a cell and/or carrier frequency subject to CCA based on one or more of the following techniques.
  • the UE can determine that DL CCA has failed (e.g., at the network node transmitter) when the UE is unable to receive a signal that the UE expects to have been transmitted. In other words, the signal is unavailable, not present, and/or not detected by or at the UE.
  • the UE may attempt to detect the expected signal (e.g., SSB) by correlating some energy captured by the receiver (e.g., in certain time-frequency resources) with some pre-defined sequences (e.g., one or more candidate SSBs).
  • the expected signal e.g., SSB
  • the UE When the output or result of the correlation is below a certain threshold (T').the UE assumes that the expected signal (e.g., SSB) was not transmitted by the network node due to DL CCA failure. Otherwise, when the output or result of the correlation is equal to or above , the UE assumes that the signal (e.g., SSB) was transmitted by the network node due to DL CCA success.
  • T' a certain threshold
  • the network node may transmit the results or outcome of its DL CCA failures to the UE in a message, e.g., broadcast SI.
  • the network node may transmit the outcome or results of the DL CCA in the BS in the last Z1 number of time resources or signals in terms of bitmap to the UE.
  • Each bit may indicate whether the CCA was failure (e.g., “0”) or successful (e.g., “1”).
  • a CCA failure during a configured occasion for a signal (e.g., RS) may also be expressed as unavailability of the signal at the UE during that occasion.
  • the number of CCA failures (N) may be consecutive or non-consecutive during some duration TO. As some examples, N can correspond to any of the following:
  • a RS occasion may be considered “unavailable” at the UE when the RS occasion (e.g., SMTC) contains RS (e.g., SSBs) configured by the network node for a cell (e.g., UE serving cell) on a carrier frequency subject to CCA, but the first two successive candidate RS positions (e.g., SSB positions) for the same RS index (e.g., SSB index) within the discovery burst transmission window are not available at the UE due to DL CCA failures at the network node during the corresponding detection, measurement, or evaluation period; otherwise the RS occasion (e.g., SMTC occasion) is considered as “available” at the UE.
  • RS occasion e.g., SMTC
  • RS e.g., SSBs
  • the UE in a non-connected state configured with DRX first performs serving cell measurements and evaluates cell selection criterion during Nserv_ccA DRX cycles.
  • the UE subsequently performs one or more cell selection procedures for a selected PLMN when the UE does not find any new suitable cell based on searches and/or measurements on cells during a period T, where T is a function of at least one CCA-related parameter for at least one cell (e.g., serving cell) on which the UE performs search and/or measurements.
  • T is also a function of at least one parameter related to UE receive beam sweeping performed on at least one cell (e.g., serving cell).
  • the UE may determine T based on one or more rules and/or functions, which may be pre-defined or configured by a network node or autonomously determined by the UE.
  • the UE performs one or more measurements (e.g., SS-RSRP and SS-RSRQ) on the serving cell at least once every J > 1 DRX cycles.
  • J (l+M n )*Ml DRX cycles
  • Ml 1 and depends on a relation between periodicity (TRS) of RS used for measurements and DRX cycle length (TDRX).
  • TRS periodicity
  • TDRX DRX cycle length
  • Ml DRX cycle length
  • the UE uses the results of the measurements (e.g., SS-RSRP and SS-RSRQ) to evaluate the cell reselection criterion S once every J > 1 DRX cycle in Nserv_ccA consecutive DRX cycles.
  • Nserv_ccA can be defined as shown in Table 3 below for the UE’s serving cell in FR1 :
  • Nserv_ccA can be defined as shown in Table 4 below for the UE’s serving cell in FR2.
  • N1 represents a scaling factor for receive (Rx) beam sweeping.
  • N se rv_ccAin FR2 (example)
  • Nserv_ccA time in FR2 can be defined as shown in Table 5 below, in which
  • Rx beam sweeping scaling factor is also considered for the CCA procedure.
  • the UE restarts the measurements used for serving cell evaluation if Ms exceeds M s ,max.
  • the UE shall initiate the measurements of all neighbor cells indicated by the serving cell, regardless of the measurement rules currently limiting UE measurement activities.
  • the measurements performed by the UE on the neighbor cells may comprise one or more of: cell detection, RSRP and/or RSRQ measurements on one or more identified cells, evaluation of the cell etc.
  • the UE may obtain information about the neighbor cells by receiving a message from the network node e.g., in a broadcast message (e.g., in a SIB) transmitted in the UE’s serving cell.
  • the obtained information may include one or more of the following: cell identifiers (e.g., PCI, CGI), carrier frequency information (e.g., frequency channel number such as ARFCN, EARFCN, NR-ARFNC), type of RAT (e g., NR, LTE, UTRA), etc.
  • the obtained information may also include CCA-related information for one or more cells of carriers that are subject to CCA.
  • Examples of the CCA-related information include of results of CCA operations performed by the network node in some recent duration (Txl) and expected or predicted results of CCA operations to be performed by the network node in some upcoming duration (Tx2).
  • Examples of results of CCA operations are number of CCA failures (Nf) during Txl/Tx2, number of CCA successes (Ns) during Txl/Tx2, relation between Nf and Ns (e.g., Nf/Ns or Ns/Nf), etc.
  • the UE may use the obtained results of the CCA operations by the network node for various operations. For example, the UE may search and measure cells on carriers in increasing order of number and/or probability of CCA failures. This will allow the UE to speed up the cell search process by starting with cells having the lowest number and/or probability of CCA failures.
  • the UE may rank neighbor cells based on both the obtained results of the CCA operations and a UE received signal measurement (e.g., RSRP, RSRQ, etc.).
  • the UE may rank neighbor cells having the same or similar received signal levels based on the respective results of the CCA operations for those cells.
  • the UE may select a new serving cell which has lowest number of CCA failures indicated by obtained information or measured/ estimated by the UE during last TO time period. By camping on a cell with less or least number of CCA failures, the UE can make quicker measurement during Nserv_ccA and will consume less energy doing so. Measuring neighbor cells in an order based on CCA failure information also enables the UE to make quicker measurement of neighbor cell and thus reduce UE energy consumption while doing so.
  • the UE performs one or more cell selection procedures for a selected PLMN when the UE does not find any new suitable cell based on searches and/or measurements on cells during a period T, where T is a function of at least one CCA-related parameter for at least one cell (e.g., serving cell) on which the UE performs search and/or measurements.
  • T is a function of at least one CCA-related parameter for at least one cell (e.g., serving cell) on which the UE performs search and/or measurements.
  • the value T ensures that the UE does not trigger cell selection procedure for the selected PLMN before the serving cell evaluation and neighbor cell detection have been completed.
  • the one or more cell selection procedures triggered by the UE not finding a suitable cell during T can include scanning all channels in NR bands according to UE capabilities to find or detect a suitable cell; and/or selecting a cell using stored frequency information, cell parameters from previously received measurement control information elements, and/or information from previously detected cells.
  • CCA-related parameters include number of CCA failures occurring or detected by the UE during certain time period (TO), number of successful CCA detected by the UE during TO, maximum allowed number of CCA failures during TO etc.
  • TO time period
  • T is also a function of at least one parameter related to UE receive beam sweeping performed on at least one cell (e.g., serving cell).
  • An example of such parameter is the beam sweeping scaling factor etc.
  • the UE may obtain T (or the at least one CCA parameter of which T is a function) T in various ways, including one or more of the following:
  • pre-configured information e.g., stored on the UE’s SIM or USIM card
  • T a function of at least one CCA parameter.
  • T can be expressed as function of a, PICCA, TDRX, eDRX cycle scaling factor (P), and eDRX cycle length (T eDRX ) as follows:
  • T f2(a, , PICCA, TDRX, T eDRX )
  • T can be expressed as function of a, PICCA, eDRX cycle scaling factor (P) and eDRX cycle length (T eDRX ) as follows:
  • T f3(a, p, PICCA, T eDRX )
  • a and p can equal 0 as a special case.
  • functions fl -f3 include maximum, minimum, product, sum, ceiling, floor, ratio, average, xth percentile, and any combination thereof.
  • the eDRX cycle scaling factor (P) is the same for all eDRX cycle lengths.
  • P may be a variable that is a function of one or more of the following:
  • T eDRX • eDRX cycle length (T eDRX ).
  • P > Hb if T eDRX ⁇ threshold He; otherwise P ⁇ Hb.
  • FR the carrier frequency of the serving cell.
  • P is smaller (e.g., 2) for FR1 and larger (e.g., 4) for FR2.
  • PC UE power class
  • P is smaller (e.g., 2) for certain PC (e.g., PC2-4) and larger (e.g., 4) for other PC (e.g., PCI and PC5).
  • Values for scaling factor PICCA can be derived based on various functions of parameters related to serving cell evaluation, neighbor cell detection time, and CCA procedure.
  • Some examples of PICCA when no beam sweeping is used are given below:
  • PICCA f6(Kl, gl(Pl s , Pls, max))
  • PICCA when beam sweeping is used (e.g., in FR2) are given below:
  • PICCA f8(Kl, Nl, Pl s,max)
  • PICCA f9(Kl, Nl, g2(Pl s , Pls, max))
  • the parameter Nl is a scaling factor related to UE Rx beam sweeping in FR2.
  • TO may be pre-defined or configured by the network node (e.g., via broadcast or unicast RRC signaling).
  • Pls, max may further depend on one or more parameters such as DRX cycle length, eDRX cycle length, periodicity of a reference signal (TRS) (e.g., SMTC period, DBT window period, etc.).
  • TRS reference signal
  • Pls, max 8 for TDRX ⁇ 1.28 s
  • Pls, max 4 for TDRX > 1.28 s.
  • the value of KI can be in the formula used for deriving PICCA based on one or more of following:
  • the network node • configured by the network node (e.g., via broadcast SIB or unicast RRC message);
  • pre-configured information e.g., stored on the UE’s SIM or USIM card
  • PC UE power class
  • Pmax UE maximum output power
  • T when eDRX is not configured or not considered by the UE.
  • the first group of examples are for when no beam sweeping is used (e.g., in FR1).
  • PICCA KI + Pls
  • T can be expressed by the following function:
  • T max(10s, (K1+ P1 S )*TDRX)
  • T max(10s, (K1+ P l s,max)*TDRx)
  • the first group of examples are for when beam sweeping is used (e.g., in FR2).
  • TDRX DRX cycle length
  • T can be expressed by the following function:
  • T max(10s, (K1*N1 + P1 s ,max)*T D Rx), where:
  • N1 1 for serving cell in FR1 and N1 is defined as follows for FR2: o
  • Nl 8.
  • the UE when Pl s exceeds P l s, max, the UE will initiate a cell selection procedure for the selected PLMN. Alternatively, when Pl s exceeds P l s, max, the UE will restart the measurements for serving cell and neighbor cell evaluation.
  • the value of a can depend on the number of receive antennas used by the UE for measurements. For example, a > Hl if number of receive antennas in the UE is less than XI; otherwise a ⁇ Hl. In one specific example, Hl is 20 and XI is 2.
  • T can depend on the DRX cycle length (TDRX) and/or the eDRX cycle length (TBDRX) configured for the UE. Examples of these embodiments are given below.
  • T max(a, N1*(K1 + P1 S )*TDRX)
  • 10 seconds
  • PICCA N1*(K1 + P1 s )
  • T max(10s, N1*(K1 + P1 S )*TDRX)
  • T can be expressed as follows:
  • T max(10s, N1*(K1 + P1 s ,ma X )*T DRx )
  • T can be determined based on any of the following functions:
  • T max(a, (KI + P1 S )*TDRX), P*T eDRX )
  • T max(a, (KI + P1 S )*T eDRX )
  • T max( ⁇ , (KI + P1 s ,max)*TDRx), P*T eDRX )
  • T max(a, (KI + P1 s ,max)*T £ DRx)
  • T can be determined by the following function:
  • T max(a, (K1*N1 + P1 s )*TDRX), P*T eDRX )
  • T max(a, (K1*N1 + P1 s ,max)*T D Rx), P*T eDRX )
  • T eDRX cycle length T eDRX
  • no beam sweeping e.g., in FR1
  • is in seconds
  • PICCA KI + P1 s
  • T can be determined by the following function:
  • T max(a, (K1*N1 + P1 s )*T eDRX )
  • T max( ⁇ , (K1*N1 + P l s,max)*T eDRx )
  • T max(a, N1*(K1 + P1 S )*TDRX), P*T eDRX )
  • T can be determined by the following function:
  • T max(a, N1*(K1 + Pl s ,max)*T D Rx), P*T eDRX )
  • T eDRX cycle length T eDRX
  • no beam sweeping e.g., in FR1
  • a is in seconds
  • PICCA KI + Pl s
  • T can be determined by the following function:
  • T max(a, Nl* (KI + P1 S )*T eDRX )
  • a can be a fixed value such as 10 seconds.
  • the eDRX cycle scaling factor (P) can have any of the characteristics and/or values previously discussed above.
  • Figures 6-7 show exemplary methods (e.g., procedures) for a UE and a network node, respectively.
  • various features of the operations described below correspond to various embodiments described above.
  • the exemplary methods shown in Figures 6-7 can be used cooperatively to provide various benefits, advantages, and/or solutions to problems described herein.
  • Figures 6-7 show specific blocks in particular orders, the operations of the exemplary methods can be performed in different orders than shown and can be combined and/or divided into blocks having different functionality than shown. Optional blocks or operations are indicated by dashed lines.
  • Figure 6 shows an exemplary method (e.g., procedure) for a UE configured for operation in a wireless network, according to various embodiments of the present disclosure.
  • the exemplary method can be performed by a UE (e.g, wireless device, loT device, etc.) such as described elsewhere herein.
  • a UE e.g, wireless device, loT device, etc.
  • the exemplary method can include the operations of block 630, where the UE can perform a search for a suitable cell while operating in DRX and in a non-connected state (e.g., RRC IDLE, RRC INACTIVE) with respect to the wireless network.
  • Performing the search includes the operations of sub-block 631, where the UE can perform measurements of at least one cell, of the wireless network, that is subject to a CCA requirement.
  • the exemplary method can also include the operations of block 650, where the UE can initiate one or more cell selection procedures in response to performing the search for at least a minimum period (e.g., T in the various embodiments discussed above) without identifying a suitable cell.
  • the minimum period is a function of one or more CCA-related parameters for the at least one cell.
  • the minimum period is also a function of one or more DRX-related parameters.
  • the at least one cell includes the UE’s serving cell and the DRX includes periodic DRX cycles, each having a cycle length of TDRX.
  • the measurements are performed on the serving cell every Jth DRX cycle.
  • J is a function of the following: the cycle length TDRX, a periodicity of a signal being measured, and a maximum number of DRX cycles between measurements.
  • performing the search in block 630 includes the operations of sub-block 632, where the UE can evaluate results of the measurements every Jth DRX cycle against one or more cell reselection criteria, wherein the minimum period comprises a number of consecutive DRX cycles (e.g., Nserv_ccA in the various embodiments discussed above).
  • the number of consecutive DRX cycles is a function of the cycle length TDRX and the periodicity of the signal being measured.
  • the number of consecutive DRX cycles is also a function of one or more of the following: UE power class (PC), and whether the UE uses receive beam sweeping to measure the signal.
  • PC UE power class
  • the number of consecutive DRX cycles is also a function of a number of DRX cycles during which the signal being measured is not available to be measured by the UE on at least one occasion due to a CCA failure (e.g., Pls in the various embodiments discussed above).
  • the UE can perform different operations when the number of DRX cycles during which the signal is not available to be measured by the UE, within a time period, exceeds a maximum number of unavailable DRX cycles for the time period (e.g., Pls, max in the various embodiments discussed above).
  • the UE can initiate the one or more cell selection procedures in block 650 based on this condition.
  • the exemplary method can include the operations of block 640, where based on this condition the UE can restart the search for a suitable cell in relation to the minimum period (e.g., initiate a search timer with a value corresponding to the minimum period).
  • the minimum period e.g., initiate a search timer with a value corresponding to the minimum period.
  • the exemplary method can also include the operation of block 620, where the UE can obtain, via the serving cell (i.e., one of the at least one cell subject to CCA), information about a plurality of neighbor cells, wherein the information includes CCA-related information.
  • initiating one or more cell selection procedures in block 650 includes the operations of sub-blocks 651-652, where the UE can rank the neighbor cells based on the CCA-related information and initiate the cell selection procedures on the neighbor cells in order of ranking.
  • ranking the neighbor cells in sub-block 651 is further based on measurements of the neighbor cells made by the UE while performing the search (e.g., in block 630).
  • the CCA-related information for each neighbor cell includes one or more of the following:
  • the neighbor cells are ranked (i.e., based on the received CCA-related information) in order of one of the following: decreasing likelihood of CCA success during the subsequent time interval; increasing likelihood of CCA failure during the subsequent time interval; decreasing CCA success rate during the previous time interval; or increasing CCA failure rate during the subsequent time interval.
  • the DRX includes periodic DRX cycles having a cycle length of TDRX and the minimum period is a function of the following: a duration (PICCA) required for the UE to evaluate or detect the at least one cell subject to the CCA requirement; the cycle length TDRX; and a periodicity of a signal (e.g., SSB) being measured in the at least one cell.
  • the minimum period is also a function of one or more of the following: UE power class, number of UE antennas used to perform the measurements, frequency range of the at least one cell subject to CCA requirement, and whether the UE uses receive beam sweeping to perform the measurements.
  • the duration is a function of one or more of the following:
  • frequency range of the at least one cell e.g., FR1, FR2, etc.
  • one or more of the following is also a function of the cycle length TDRX:
  • the DRX includes extended periodic DRX cycles, each having an extended cycle length T eDRX and including one or more DRX cycles.
  • the extended cycle length TCDRX is greater than the cycle length TDRX.
  • the minimum period is a function of the extended cycle length T eDRX instead of or in addition to being a function of the cycle length TDRX.
  • the exemplary method can also include the operations of block 610, where the UE can obtain the minimum period, or the CCA-related parameters of which the minimum period is a function, via one or more of the following:
  • Figure 7 shows an exemplary method (e.g., procedure) for a network node configured to serve at least one cell that is subject to a CCA requirement in a wireless network, according to various embodiments of the present disclosure.
  • the exemplary method can be performed by a network node (e.g., base station, eNB, gNB, ng-eNB, etc., or component thereof) such as described elsewhere herein.
  • a network node e.g., base station, eNB, gNB, ng-eNB, etc., or component thereof
  • the exemplary method can include the operations of block 710, where the network node can transmit one of the following in the at least one cell:
  • a minimum period e.g., T in the various embodiments discussed above
  • UEs to search for a suitable cell during UE DRX operation in a non-connected state with respect to the wireless network, before UE initiation of one or more cell selection procedures;
  • the minimum period is also a function of one or more parameters related to the DRX operation.
  • the DRX includes periodic DRX cycles having a cycle length of TDRX and the minimum period is a function of the following: a duration (PICCA) required for the UE to evaluate or detect the at least one cell subject to the CCA requirement; the cycle length TDRX; and a periodicity of a signal (e.g., SSB) being measured by the UE in the at least one cell subject to a CCA requirement.
  • the minimum period is also a function of one or more of the following: UE power class, number of UE antennas used to perform the measurements, frequency range of the at least one cell subject to CCA requirement, and whether the UE uses receive beam sweeping to perform the measurements.
  • the duration can be a function of any of the parameters that were discussed above in relation to corresponding UE embodiments and variants.
  • various other parameters can also be a function of the cycle length TDRX, including certain parameters (of which the minimum period is a function) that were discussed above in relation to UE embodiments.
  • the DRX includes extended periodic DRX cycles, each having an extended cycle length T eDRX and including one or more DRX cycles.
  • the extended cycle length TCDRX is greater than the cycle length TDRX.
  • the minimum period is a function of the extended cycle length T eDRX instead of or in addition to being a function of the cycle length TDRX.
  • the exemplary method can also include the operations of block 720, where the network node can transmit, via the at least one cell, information about a plurality of neighbor cells, wherein the information includes CCA-related information.
  • the CCA-related information for each neighbor cell can include any of the CCA- related information discussed above in relation to UE embodiments.
  • FIG. 8 shows an example of a communication system 800 in accordance with some embodiments.
  • the communication system 800 includes a telecommunication network 802 that includes an access network 804 (such as a RAN) and a core network 806, which includes one or more core network nodes 808.
  • the access network 804 includes one or more access network nodes, such as network nodes 810a-b (one or more of which may be generally referred to as network nodes 810), or any other similar 3GPP access node or non-3GPP access point.
  • the network nodes 810 facilitate direct or indirect connection of UEs, such as by connecting UEs 812a-d (one or more of which may be generally referred to as UEs 812) to the core network 806 over one or more wireless connections.
  • Example wireless communications over a wireless connection include transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors.
  • the communication system 800 may include any number of wired or wireless networks, network nodes, UEs, and/or any other components or systems that may facilitate or participate in the communication of data and/or signals whether via wired or wireless connections.
  • the communication system 800 may include and/or interface with any type of communication, telecommunication, data, cellular, radio network, and/or other similar type of system.
  • UEs 812 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and/or operable to communicate wirelessly with the network nodes 810 and other communication devices.
  • network nodes 810 are arranged, capable, configured, and/or operable to communicate directly or indirectly with UEs 812 and/or with other network nodes or equipment in telecommunication network 802 to enable and/or provide network access, such as wireless network access, and/or to perform other functions, such as administration in telecommunication network 802.
  • core network 806 connects network nodes 810 to one or more hosts, such as host 816. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts.
  • Core network 806 includes one more core network nodes (e.g., core network node 808) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and/or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 808.
  • Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and/or a User Plane Function (UPF).
  • MSC Mobile Switching Center
  • MME Mobility Management Entity
  • HSS Home Subscriber Server
  • AMF Access and Mobility Management Function
  • SMF Session Management Function
  • AUSF Authentication Server Function
  • SIDF Subscription Identifier De-concealing function
  • UDM Unified Data Management
  • SEPP Security Edge Protection Proxy
  • NEF Network Exposure Function
  • UPF User Plane Function
  • Host 816 may be under the ownership or control of a service provider other than an operator or provider of access network 804 and/or telecommunication network 802, and may be operated by the service provider or on behalf of the service provider.
  • Host 816 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio/video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.
  • Communication system 800 of Figure 8 enables connectivity between the UEs, network nodes, and hosts.
  • the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and/or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and/or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and/or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.
  • GSM Global System for Mobile Communications
  • UMTS Universal Mobile Telecommunications System
  • LTE Long Term Evolution
  • the telecommunication network 802 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 802 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 802. For example, the telecommunications network 802 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and/or Massive Machine Type Communication (mMTC)/Massive loT services to yet further UEs.
  • URLLC Ultra Reliable Low Latency Communication
  • eMBB Enhanced Mobile Broadband
  • mMTC Massive Machine Type Communication
  • UEs 812 are configured to transmit and/or receive information without direct human interaction.
  • a UE may be designed to transmit information to access network 804 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from access network 804.
  • a UE may be configured for operating in single- or multi-RAT or multi-standard mode.
  • a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e., being configured for multi -radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).
  • MR-DC multi -radio dual connectivity
  • hub 814 communicates with the access network 804 to facilitate indirect communication between one or more UEs (e.g., UE 812c and/or 812d) and network nodes (e.g., network node 810b).
  • hub 814 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs.
  • hub 814 may be a broadband router enabling access to core network 806 for the UEs.
  • hub 814 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from UEs, network nodes 810, or by executable code, script, process, or other instructions in hub 814.
  • hub 814 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data.
  • hub 814 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, hub 814 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which hub 814 then provides to the UE either directly, after performing local processing, and/or after adding additional local content.
  • hub 814 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy loT devices.
  • Hub 814 may have a constant/persistent or intermittent connection to the network node 810b. Hub 814 may also allow for a different communication scheme and/or schedule between hub 814 and UEs (e.g., UE 812c and/or 812d), and between hub 814 and core network 806. In other examples, hub 814 is connected to core network 806 and/or one or more UEs via a wired connection. Moreover, hub 814 may be configured to connect to an M2M service provider over access network 804 and/or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with network nodes 810 while still connected via hub 814 via a wired or wireless connection.
  • UEs may establish a wireless connection with network nodes 810 while still connected via hub 814 via a wired or wireless connection.
  • hub 814 may be a dedicated hub - that is, a hub whose primary function is to route communications to/from the UEs from/to network node 810b.
  • hub 814 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 810b, but which is additionally capable of operating as a communication start and/or end point for certain data channels.
  • Figure 9 shows a UE 900 in accordance with some embodiments.
  • Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle-mounted or vehicle embedded/integrated wireless device, etc.
  • Other examples include any UE identified by 3GPP, including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and/or an enhanced MTC (eMTC) UE.
  • NB-IoT narrow band internet of things
  • MTC machine type communication
  • eMTC enhanced MTC
  • a UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X).
  • D2D device-to-device
  • DSRC Dedicated Short-Range Communication
  • V2V vehicle-to-vehicle
  • V2I vehicle-to-infrastructure
  • V2X vehicle-to-everything
  • a UE may not necessarily have a user in the sense of a human user who owns and/or operates the relevant device.
  • a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller).
  • a UE may represent a device that is not intended for sale
  • UE 900 includes processing circuitry 902 that is operatively coupled via bus 904 to input/output interface 906, power source 908, memory 910, communication interface 912, and/or any other component, or any combination thereof.
  • processing circuitry 902 that is operatively coupled via bus 904 to input/output interface 906, power source 908, memory 910, communication interface 912, and/or any other component, or any combination thereof.
  • Certain UEs may utilize all or a subset of the components shown in Figure 9. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.
  • Processing circuitry 902 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in memory 910.
  • Processing circuitry 902 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field- programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above.
  • the processing circuitry 902 may include multiple central processing units (CPUs).
  • the input/output interface 906 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and/or output devices.
  • Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof.
  • An input device may allow a user to capture information into the UE 900.
  • Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like.
  • the presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user.
  • a sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof.
  • An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.
  • USB Universal Serial Bus
  • power source 908 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. Power source 908 may further include power circuitry for delivering power from power source 908 itself, and/or an external power source, to the various parts of UE 900 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of power source 908. Power circuitry may perform any formatting, converting, or other modification to the power from power source 908 to make the power suitable for the respective components of the UE 900 to which power is supplied.
  • an external power source e.g., an electricity outlet
  • Photovoltaic device e.g., or power cell
  • Power source 908 may further include power circuitry for delivering power from power source 908 itself, and/or an external power source, to the various parts of UE 900 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example
  • Memory 910 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth.
  • memory 910 includes one or more application programs 914, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 916.
  • Memory 910 may store, for use by UE 900, any of a variety of various operating systems or combinations of operating systems.
  • Memory 910 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and/or ISIM, other memory, or any combination thereof.
  • RAID redundant array of independent disks
  • HD-DVD high-density digital versatile disc
  • HDDS holographic digital data storage
  • DIMM external mini-dual in-line memory module
  • SDRAM synchronous dynamic random access memory
  • SDRAM synchronous dynamic random access memory
  • the UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’
  • eUICC embedded UICC
  • iUICC integrated UICC
  • SIM card removable UICC commonly known as ‘SIM card.’
  • the memory 910 may allow the UE 900 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data.
  • An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 910, which may be or comprise a device-readable storage medium.
  • Processing circuitry 902 may be configured to communicate with an access network or other network using communication interface 912.
  • Communication interface 912 may comprise one or more communication subsystems and may include or be communicatively coupled to antenna 922.
  • Communication interface 912 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network).
  • Each transceiver may include transmitter 918 and/or receiver 920 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth).
  • transmitter 918 and receiver 920 may be coupled to one or more antennas (e.g., antenna 922) and may share circuit components, software or firmware, or alternatively be implemented separately.
  • communication functions of communication interface 912 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof.
  • Communications may be implemented in according to one or more communication protocols and/or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol/intemet protocol (TCP/IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.
  • a UE may provide an output of data captured by its sensors, through its communication interface 912, via a wireless connection to a network node.
  • Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE.
  • the output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., an alert is sent when moisture is detected), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).
  • a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection.
  • the states of the actuator, the motor, or the switch may change.
  • the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.
  • a UE when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare.
  • loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door/window sensor, a flood/moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-t
  • AR Augmented
  • a UE may represent a machine or other device that performs monitoring and/or measurements and transmits the results of such monitoring and/or measurements to another UE and/or a network node.
  • the UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device.
  • the UE may implement the 3GPP NB-IoT standard.
  • a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation.
  • any number of UEs may be used together with respect to a single use case.
  • a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone.
  • the first UE may adjust the throttle on the drone (e.g., by controlling an actuator) to increase or decrease the drone’s speed.
  • the first and/or the second UE can also include more than one of the functionalities described above.
  • a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.
  • Figure 10 shows a network node 1000 in accordance with some embodiments.
  • network nodes include, but are not limited to, access points (e.g., radio access points) and base stations (e.g., radio base stations, Node Bs, eNBs, and gNBs).
  • access points e.g., radio access points
  • base stations e.g., radio base stations, Node Bs, eNBs, and gNBs.
  • Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations.
  • a base station may be a relay node or a relay donor node controlling a relay.
  • a network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and/or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio.
  • RRUs remote radio units
  • RRHs Remote Radio Heads
  • Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio.
  • Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).
  • DAS distributed antenna system
  • network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell/multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and/or Minimization of Drive Tests (MDTs).
  • MSR multi-standard radio
  • RNCs radio network controllers
  • BSCs base station controllers
  • BTSs base transceiver stations
  • OFDM Operation and Maintenance
  • OSS Operations Support System
  • SON Self-Organizing Network
  • positioning nodes e.g., Evolved Serving Mobile Location Centers (E-SMLCs)
  • Network node 1000 includes processing circuitry 1002a memory 1004, communication interface 1006, and power source 1008.
  • Network node 1000 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components.
  • network node 1000 comprises multiple separate components (e.g., BTS and BSC components)
  • one or more of the separate components may be shared among several network nodes.
  • a single RNC may control multiple NodeBs.
  • each unique NodeB and RNC pair may in some instances be considered a single separate network node.
  • network node 1000 may be configured to support multiple radio access technologies (RATs).
  • RATs radio access technologies
  • Network node 1000 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1000, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 1000.
  • wireless technologies for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 1000.
  • RFID Radio Frequency Identification
  • Processing circuitry 1002 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and/or encoded logic operable to provide, either alone or in conjunction with other network node 1000 components, such as the memory 1004, to provide network node 1000 functionality.
  • processing circuitry 1002 includes a system on a chip (SOC). In some embodiments, the processing circuitry 1002 includes one or more of radio frequency (RF) transceiver circuitry 1012 and baseband processing circuitry 1014. In some embodiments, radio frequency (RF) transceiver circuitry 1012 and baseband processing circuitry 1014 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 1012 and baseband processing circuitry 1014 may be on the same chip or set of chips, boards, or units.
  • SOC system on a chip
  • the processing circuitry 1002 includes one or more of radio frequency (RF) transceiver circuitry 1012 and baseband processing circuitry 1014.
  • radio frequency (RF) transceiver circuitry 1012 and baseband processing circuitry 1014 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver
  • Memory 1004 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or any other volatile or non-volatile, non-transitory device-readable and/or computer-executable memory devices that store information, data, and/or instructions that may be used by the processing circuitry 1002.
  • volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or any other volatile or non-vol
  • the memory 1004 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and/or other instructions (collectively denoted computer program product 1004a) capable of being executed by the processing circuitry 1002 and utilized by the network node 1000.
  • the memory 1004 may be used to store any calculations made by the processing circuitry 1002 and/or any data received via the communication interface 1006.
  • the processing circuitry 1002 and memory 1004 is integrated.
  • Communication interface 1006 is used in wired or wireless communication of signaling and/or data between a network node, access network, and/or UE. As illustrated, communication interface 1006 comprises port(s)/terminal(s) 1016 to send and receive data, for example to and from a network over a wired connection. Communication interface 1006 also includes radio front- end circuitry 1018 that may be coupled to, or in certain embodiments a part of, the antenna 1010. Radio front-end circuitry 1018 comprises filters 1020 and amplifiers 1022. Radio front-end circuitry 1018 may be connected to antenna 1010 and processing circuitry 1002. The radio frontend circuitry may be configured to condition signals communicated between antenna 1010 and processing circuitry 1002.
  • Radio front-end circuitry 1018 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. Radio front-end circuitry 1018 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1020 and/or amplifiers 1022. The radio signal may then be transmitted via antenna 1010. Similarly, when receiving data, the antenna 1010 may collect radio signals which are then converted into digital data by radio front-end circuitry 1018. The digital data may be passed to processing circuitry 1002. In other embodiments, the communication interface may comprise different components and/or different combinations of components.
  • network node 1000 does not include separate radio front-end circuitry 1018, instead, processing circuitry 1002 includes radio front-end circuitry and is connected to antenna 1010. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1012 is part of communication interface 1006. In still other embodiments, communication interface 1006 includes one or more ports or terminals 1016, radio front-end circuitry 1018, and RF transceiver circuitry 1012, as part of a radio unit (not shown), and the communication interface 1006 communicates with baseband processing circuitry 1014, which is part of a digital unit (not shown).
  • Antenna 1010 may include one or more antennas, or antenna arrays, configured to send and/or receive wireless signals.
  • Antenna 1010 may be coupled to radio front-end circuitry 1018 and may be any type of antenna capable of transmitting and receiving data and/or signals wirelessly.
  • antenna 1010 is separate from network node 1000 and connectable to network node 1000 through an interface or port.
  • Antenna 1010, communication interface 1006, and/or processing circuitry 1002 may be configured to perform any receiving operations and/or certain obtaining operations described herein as being performed by the network node. Any information, data and/or signals may be received from a UE, another network node and/or any other network equipment. Similarly, antenna 1010, communication interface 1006, and/or processing circuitry 1002 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and/or signals may be transmitted to a UE, another network node and/or any other network equipment.
  • Power source 1008 provides power to the various components of network node 1000 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). Power source 1008 may further comprise, or be coupled to, power management circuitry to supply the components of network node 1000 with power for performing the functionality described herein.
  • network node 1000 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of power source 1008.
  • power source 1008 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.
  • Embodiments of network node 1000 may include additional components beyond those shown in Figure 10 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and/or any functionality necessary to support the subject matter described herein.
  • network node 1000 may include user interface equipment to allow input of information into network node 1000 and to allow output of information from network node 1000. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for network node 1000.
  • FIG 11 is a block diagram of a host 1100, which may be an embodiment of host 816 of Figure 8, in accordance with various aspects described herein.
  • host 1100 may be or comprise various combinations hardware and/or software, including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, container, or processing resources in a server farm.
  • Host 1100 may provide one or more services to one or more UEs.
  • Host 1100 includes processing circuitry 1102 that is operatively coupled via bus 1104 to input/output interface 1106, network interface 1108, power source 1110, and memory 1112. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Figures 9 and 10, such that the descriptions thereof are generally applicable to the corresponding components of host 1100.
  • Memory 1112 may include one or more computer programs including one or more host application programs 1114 and data 1116, which may include user data, e.g., data generated by a UE for host 1100 or data generated by host 1100 for a UE.
  • host 1100 may utilize only a subset or all of the components shown.
  • Host application programs 1114 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), MPEG, VP9) and audio codecs (e.g., FLAC, Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, or implementations of UEs (e.g., handsets, desktop computers, wearable display systems, heads-up display systems).
  • Host application programs 1114 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network.
  • host 1100 may select and/or indicate a different host for over-the-top services for a UE.
  • Host application programs 1114 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real- Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (MPEG-DASH), etc.
  • HTTP Live Streaming HLS
  • RTMP Real-Time Messaging Protocol
  • RTSP Real- Time Streaming Protocol
  • MPEG-DASH Dynamic Adaptive Streaming over HTTP
  • FIG. 12 is a block diagram illustrating a virtualization environment 1200 in which functions implemented by some embodiments may be virtualized.
  • virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources.
  • virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components.
  • Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 1200 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host.
  • VMs virtual machines
  • the node may be entirely virtualized.
  • Applications 1202 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 1200 to implement some of the features, functions, and/or benefits of some of the embodiments disclosed herein.
  • Hardware 1204 includes processing circuitry, memory that stores software and/or instructions (collectively denoted computer program product 1204a) executable by hardware processing circuitry, and/or other hardware devices as described herein, such as a network interface, input/output interface, and so forth.
  • Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1206 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1208a-b (one or more of which may be generally referred to as VMs 1208), and/or perform any of the functions, features and/or benefits described in relation with some embodiments described herein.
  • Virtualization layer 1206 may present a virtual operating platform that appears like networking hardware to VMs 1208.
  • VMs 1208 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1206.
  • VMs 1208 may be implemented on one or more of VMs 1208, and the implementations may be made in different ways.
  • Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.
  • NFV network function virtualization
  • VM 1208 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine.
  • Each VM 1208, and that part of hardware 1204 that executes that VM be it hardware dedicated to that VM and/or hardware shared by that VM with others of the VMs, forms separate virtual network elements.
  • a virtual network function is responsible for handling specific network functions that run in one or more VMs 1208 on top of hardware 1204 and corresponds to application 1202.
  • Hardware 1204 may be implemented in a standalone network node with generic or specific components. Hardware 1204 may implement some functions via virtualization. Alternatively, hardware 1204 may be part of a larger cluster of hardware (e.g., such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 1210, which, among others, oversees lifecycle management of applications 1202.
  • hardware 1204 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station.
  • some signaling can be provided with the use of a control system 1212 which may alternatively be used for communication between hardware nodes and radio units.
  • Figure 13 shows a communication diagram of a host 1302 communicating via a network node 1304 with a UE 1306 over a partially wireless connection in accordance with some embodiments.
  • host 1302 Like host 1100, embodiments of host 1302 include hardware, such as a communication interface, processing circuitry, and memory. Host 1302 also includes software, which is stored in or accessible by the host 1302 and executable by the processing circuitry.
  • the software includes a host application that may be operable to provide a service to a remote user, such as UE 1306 connecting via an over-the-top (OTT) connection 1350 extending between UE 1306 and host 1302.
  • OTT over-the-top
  • Network node 1304 includes hardware enabling it to communicate with host 1302 and UE 1306.
  • Connection 1360 may be direct or pass through a core network e.g., 806 of Figure 8) and/or one or more other intermediate networks, such as one or more public, private, or hosted networks.
  • an intermediate network may be a backbone network or the Internet.
  • UE 1306 includes hardware and software, which is stored in or accessible by UE 1306 and executable by the UE’s processing circuitry.
  • the software includes a client application, such as a web browser or operator-specific “app” that may be operable to provide a service to a human or non-human user via UE 1306 with the support of host 1302.
  • a client application such as a web browser or operator-specific “app” that may be operable to provide a service to a human or non-human user via UE 1306 with the support of host 1302.
  • an executing host application may communicate with the executing client application via OTT connection 1350 terminating at UE 1306 and host 1302.
  • the UE's client application may receive request data from the host's host application and provide user data in response to the request data.
  • OTT connection 1350 may transfer both the request data and the user data.
  • the UE's client application may interact with the user to generate the user data that it provides to the host application through OTT connection 1350.
  • OTT connection 1350 may extend via a connection 1360 between host 1302 and network node 1304 and via wireless connection 1370 between network node 1304 and UE 1306 to provide the connection between host 1302 and UE 1306.
  • Connection 1360 and wireless connection 1370, over which the OTT connection 1350 may be provided, have been drawn abstractly to illustrate the communication between host 1302 and UE 1306 via network node 1304, without explicit reference to any intermediary devices and the precise routing of messages via these devices.
  • host 1302 provides user data, which may be performed by executing a host application.
  • the user data is associated with a particular human user interacting with UE 1306.
  • the user data is associated with a UE 1306 that shares data with host 1302 without explicit human interaction.
  • host 1302 initiates a transmission carrying the user data towards UE 1306.
  • Host 1302 may initiate the transmission responsive to a request transmitted by UE 1306. The request may be caused by human interaction with UE 1306 or by operation of the client application executing on UE 1306.
  • the transmission may pass via network node 1304, in accordance with the teachings of the embodiments described throughout this disclosure.
  • network node 1304 transmits to UE 1306 the user data that was carried in the transmission that host 1302 initiated, in accordance with the teachings of the embodiments described throughout this disclosure.
  • UE 1306 receives the user data carried in the transmission, which may be performed by a client application executed on UE 1306 associated with the host application executed by host 1302.
  • UE 1306 executes a client application which provides user data to host 1302.
  • the user data may be provided in reaction or response to the data received from host 1302.
  • UE 1306 may provide user data, which may be performed by executing the client application.
  • the client application may further consider user input received from the user via an input/output interface of UE 1306.
  • UE 1306 initiates, in step 1318, transmission of the user data towards host 1302 via the network node 1304.
  • network node 1304 receives user data from UE 1306 and initiates transmission of the received user data towards host 1302.
  • host 1302 receives the user data carried in the transmission initiated by UE 1306.
  • One or more of the various embodiments improve the performance of OTT services provided to UE 1306 using OTT connection 1350, in which wireless connection 1370 forms the last segment. More precisely, embodiments described herein provide flexible and efficient techniques for cell selection by a UE operating in a non-connected state (e.g., RRC IDLE or RRC IN ACTIVE) and configured with DRX and at least one carrier frequency subject to CCA. Embodiments provide well-defined UE measurement behavior for cell selection in this scenario and ensure that UEs in this scenario search all possible configured cells that are strong enough before initiating a cell selection procedure. This in turn prevents such UEs from prematurely performing cell selection based on sub-optimal and/or incomplete information about available cells.
  • a non-connected state e.g., RRC IDLE or RRC IN ACTIVE
  • Embodiments provide well-defined UE measurement behavior for cell selection in this scenario and ensure that UEs in this scenario search all possible configured cells that are strong enough before initiating a cell selection procedure. This in turn
  • embodiments improve the performance of networks and UEs operating in shared spectrum. Accordingly, OTT services can be delivered more reliably to UEs via networks operating in shared spectrum. This increases the value of such OTT services to both end users and service providers.
  • factory status information may be collected and analyzed by host 1302.
  • host 1302 may process audio and video data which may have been retrieved from a UE for use in creating maps.
  • host 1302 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights).
  • host 1302 may store surveillance video uploaded by a UE.
  • host 1302 may store or control access to media content such as video, audio, VR or AR which it can broadcast, multicast or unicast to UEs.
  • host 1302 may be used for energy pricing, remote control of non-time critical electrical load to balance power generation needs, location services, presentation services (such as compiling diagrams etc. from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing and/or transmitting data.
  • a measurement procedure may be provided for the purpose of monitoring data rate, latency, and other factors on which the one or more embodiments improve.
  • the measurement procedure and/or the network functionality for reconfiguring the OTT connection may be implemented in software and hardware of host 1302 and/or UE 1306.
  • sensors (not shown) may be deployed in or in association with other devices through which OTT connection 1350 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above or by supplying values of other physical quantities from which software may compute or estimate the monitored quantities.
  • the reconfiguring of OTT connection 1350 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not directly alter the operation of network node 1304. Such procedures and functionalities may be known and practiced in the art.
  • measurements may involve proprietary UE signaling that facilitates measurements of throughput, propagation times, latency and the like, by host 1302.
  • the measurements may be implemented in that software causes messages to be transmitted, in particular empty or ‘dummy’ messages, using OTT connection 1350 while monitoring propagation times, errors, etc.
  • the term unit can have conventional meaning in the field of electronics, electrical devices and/or electronic devices and can include, for example, electrical and/or electronic circuitry, devices, modules, processors, memories, logic solid state and/or discrete devices, computer programs or instructions for carrying out respective tasks, procedures, computations, outputs, and/or displaying functions, and so on, as such as those described herein.
  • any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses.
  • Each virtual apparatus may comprise a number of these functional units.
  • These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processor (DSPs), special-purpose digital logic, and the like.
  • the processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc.
  • Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein.
  • the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more embodiments of the present disclosure.
  • device and/or apparatus can be represented by a semiconductor chip, a chipset, or a (hardware) module comprising such chip or chipset; this, however, does not exclude the possibility that a functionality of a device or apparatus, instead of being hardware implemented, be implemented as a software module such as a computer program or a computer program product comprising executable software code portions for execution or being run on a processor.
  • functionality of a device or apparatus can be implemented by any combination of hardware and software.
  • a device or apparatus can also be regarded as an assembly of multiple devices and/or apparatuses, whether functionally in cooperation with or independently of each other.
  • devices and apparatuses can be implemented in a distributed fashion throughout a system, so long as the functionality of the device or apparatus is preserved. Such and similar principles are considered as known to a skilled person.
  • Embodiments of the techniques and apparatus described herein also include, but are not limited to, the following enumerated examples: Al .
  • a method for a user equipment (UE) configured for operation in a wireless network comprising: performing a search for a suitable cell while operating in discontinuous reception (DRX) and in a non-connected state with respect to the wireless network, wherein the search includes performing measurements of at least one cell, of the wireless network, that is subject to a clear channel assessment (CCA) requirement; and initiating one or more cell selection procedures in response to performing the search for a period (T) without identifying a suitable cell, wherein T is a function of one or more CCA-related parameters for the at least one cell.
  • DRX discontinuous reception
  • CCA clear channel assessment
  • the at least one cell includes the UE’s serving cell; the DRX includes periodic DRX cycles having a period or cycle length of TDRX; and the measurements are performed on the serving cell every J DRX cycles, where J is a function of the following: TDRX, a periodicity of a signal being measured, and a maximum number of DRX cycles between measurements.
  • performing the search comprises evaluating results of the measurements every J DRX cycles against one or more cell reselection criteria, wherein T is a number of consecutive DRX cycles (Nserv_ccA).
  • Nserv_ccA is a function of TDRX and the periodicity of the signal being measured.
  • Nserv_ccA is also a function of one or more of the following: UE power class (PC), and whether the UE uses receive beam sweeping to measure the signal.
  • PC UE power class
  • A7 The method of any of embodiments A5-A6, wherein Nserv_ccA is also a function of the number of DRX cycles during which the signal being measured is not available to be measured by the UE on at least one occasion due to a CCA failure, subject to a maximum number of DRX cycles.
  • A7a The method of embodiment A7, further comprising performing one of the following when the number of DRX cycles during which the signal is not available to be measured exceeds the maximum number of DRX cycles: restarting the period (T) of the search for a suitable cell, or initiating the one or more cell selection procedures.
  • A8 The method of any of embodiments A3-A7a, wherein: the method further comprises obtaining, via the serving cell, information about a plurality of neighbor cells, wherein the information includes CCA-related information; and initiating one or more cell selection procedures comprises: ranking the neighbor cells based on the CCA-related information; and initiating the cell selection procedures on the neighbor cells in order of ranking.
  • the CCA-related information for each neighbor cell includes one or more of the following: number of downlink (DL) CCA failures (Nf) for the neighbor cell during a previous time interval (Txl); number of DL CCA successes (Ns) for the neighbor cell during the previous time interval (Txl); relation between Nf and Ns during the previous time interval (Txl); predicted number of DL CCA failures (Nf) for the neighbor cell during a subsequent time interval (Tx2); predicted number of DL CCA successes (Ns) for the neighbor cell during the subsequent time interval (Tx2); and predicted relation between Nf and Ns during the subsequent time interval (Tx2).
  • the neighbor cells are ranked in order of one of the following: decreasing likelihood of CCA success during the subsequent time interval; increasing likelihood of CCA failure during the subsequent time interval; decreasing CCA success rate during the previous time interval; or increasing CCA failure rate during the subsequent time interval.
  • Al 1 The method of any of embodiments Al -A3, wherein: the DRX includes periodic DRX cycles having a period or cycle length of TDRX; and
  • T is a function of the following: duration (PICCA) required for the UE to evaluate or detect the at least one cell subject to the CCA requirement;
  • TDRX TDRX
  • a periodicity of a signal being measured in the at least one cell TDRX
  • T is also a function of one or more of the following: UE power class (PC), number of UE antennas used to perform the measurements, frequency range of the at least one cell, and whether the UE uses receive beam sweeping to perform the measurements.
  • PC UE power class
  • Al 3 The method of any of embodiments Al 1 -Al 2, wherein the duration (PICCA) is a function of one or more of the following: a relation (KI) between DRX cycle length and the periodicity of a signal being measured; a number of DRX cycles (Pls) during which the signal being measured is not available to be measured by the UE during the duration (PICCA), due to CCA failure; a maximum number of DRX cycles (Pls, max) during which the signal being measured is not available to be measured; and frequency range of the at least one cell.
  • KI a relation between DRX cycle length and the periodicity of a signal being measured
  • Pls number of DRX cycles
  • Pls, max a maximum number of DRX cycles
  • Al 5 The method of any of embodiments Al 1 -Al 4, wherein: the DRX includes extended periodic DRX cycles, each having a period or cycle length of TCDRX > TDRX and including one or more DRX cycles; and
  • T is a function of T eDRX instead of or in addition to TDRX.
  • A16 The method of any of embodiments A1-A15, further comprising obtaining T, or the CCA-related parameters of which T is a function, via one or more of the following: a message from a network node serving the at least one cell; a storage medium of the UE;
  • a method for a network node configured to serve at least one cell that is subject to a clear channel assessment (CCA) requirement in a wireless network comprising: transmitting one of the following in the at least one cell: a minimum period (T) for UEs to search for a suitable cell during discontinuous reception (DRX) operation in a non-connected with respect to the wireless network, before initiating one or more cell selection procedures; or one or more CCA-related parameters for the at least one cell, of which T is a function.
  • CCA clear channel assessment
  • T is also a function of one or more parameters related to the DRX operation.
  • T is a function of the following: duration (PICCA) required for the UE to evaluate or detect the at least one cell subject to the CCA requirement;
  • T is also a function of one or more of the following: UE power class (PC), number of UE antennas used to perform the measurements, frequency range of the at least one cell, and whether the UE uses receive beam sweeping to perform the measurements.
  • PC UE power class
  • duration is a function of one or more of the following: a relation (KI) between DRX cycle length and the periodicity of a signal being measured; a number of DRX cycles (Pls) during which the signal being measured is not available to be measured by the UE during the duration (PICCA), due to CCA failure; a maximum number of DRX cycles (Pls, max) during which the signal being measured is not available to be measured; and frequency range of the at least one cell.
  • KI a relation between DRX cycle length and the periodicity of a signal being measured
  • Pls number of DRX cycles
  • Pls, max maximum number of DRX cycles
  • the DRX includes extended periodic DRX cycles, each having a period or cycle length of TCDRX > TDRX and including one or more DRX cycles;
  • T is a function of TCDRX instead of or in addition to TDRX.
  • the CCA-related information for each neighbor cell includes one or more of the following: number of downlink (DL) CCA failures (Nf) for the neighbor cell during a previous time interval (Txl); number of DL CCA successes (Ns) for the neighbor cell during the previous time interval (Txl); relation between Nf and Ns during the previous time interval (Txl); predicted number of DL CCA failures (Nf) for the neighbor cell during a subsequent time interval (Tx2); predicted number of DL CCA successes (Ns) for the neighbor cell during the subsequent time interval (Tx2); and predicted relation between Nf and Ns during the subsequent time interval (Tx2).
  • CL A user equipment (UE) configured for operation in a wireless network, the UE comprising: communication interface circuitry configured to communicate with a network node via at least one cell; and processing circuitry operatively coupled to the communication interface circuitry, whereby the processing circuitry and the communication interface circuitry are configured to perform operations corresponding to any of the methods of embodiments Al -Al 6.
  • a user equipment configured for operation in a wireless network, the UE being further configured to perform operations corresponding to any of the methods of embodiments A1-A16.
  • a non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a user equipment (UE) configured for operation in a wireless network, configure the UE to perform operations corresponding to any of the methods of embodiments Al -Al 6.
  • UE user equipment
  • a computer program product comprising computer-executable instructions that, when executed by processing circuitry of a user equipment (UE) configured for operation in a wireless network, configure the UE to perform operations corresponding to any of the methods of embodiments Al -Al 6.
  • UE user equipment
  • a network node configured to serve at least one cell that is subject to a clear channel assessment (CCA) requirement in a wireless network, the network node comprising: communication interface circuitry configured to communicate with user equipment (UEs) via the at least one cell; and processing circuitry operatively coupled to the communication interface circuitry, whereby the processing circuitry and the communication interface circuitry are configured to perform operations corresponding to any of the methods of embodiments B1-B9.
  • CCA clear channel assessment
  • a network node configured to serve at least one cell that is subject to a clear channel assessment (CCA) requirement in a wireless network, the network node being further configured to perform operations corresponding to any of the methods of embodiments B1-B9.
  • CCA clear channel assessment
  • a non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a network node configured to serve at least one cell that is subject to a clear channel assessment (CCA) requirement in a wireless network, configure the network node to perform operations corresponding to any of the methods of embodiments B1-B9.
  • CCA clear channel assessment
  • a computer program product comprising computer-executable instructions that, when executed by processing circuitry of a network node configured to serve at least one cell that is subject to a clear channel assessment (CCA) requirement in a wireless network, configure the network node to perform operations corresponding to any of the methods of embodiments Bl- B9.
  • CCA clear channel assessment

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Abstract

Embodiments include methods for a user equipment (UE) configured for operation in a wireless network. Such methods include performing a search for a suitable cell while operating in discontinuous reception (DRX) and in a non-connected state with respect to the wireless network. More specifically, performing the search includes performing measurements of at least one cell, of the wireless network, that is subject to a clear channel assessment (CCA) requirement. Such methods include initiating one or more cell selection procedures in response to performing the search for at least a minimum period without identifying a suitable cell. The minimum period is a function of one or more CCA-related parameters for the at least one cell. Other embodiments include complementary methods for a network node, as well as UEs and network nodes configured to perform such methods.

Description

CELL SELECTION DURING OPERATION IN UNLICENSED SPECTRUM
TECHNICAL FIELD
Embodiments of the present disclosure relate generally to wireless communication networks, and more specifically to improving operation of such networks based on techniques for user equipment (UEs) to select cells operating in shared or unlicensed spectrum.
BACKGROUND
Currently the fifth generation (“5G”) of cellular systems, also referred to as New Radio (NR), is being standardized within the Third-Generation Partnership Project (3GPP). NR is developed for maximum flexibility to support multiple and substantially different use cases. These include enhanced mobile broadband (eMBB), machine type communications (MTC), ultra-reliable low latency communications (URLLC), side-link device-to-device (D2D), and several other use cases. NR was initially specified in 3GPP Release 15 (Rel-15) and continues to evolve through subsequent releases, such as Rel-16 and Rel-17.
5G/NR technology shares many similarities with fourth-generation Long-Term Evolution (LTE). For example, NR uses CP-OFDM (Cyclic Prefix Orthogonal Frequency Division Multiplexing) in the downlink (DL) from network to user equipment (UE), and both CP-OFDM and DFT-spread OFDM (DFT-S-OFDM) in the uplink (UL) from UE to network. As another example, NR DL and UL time-domain physical resources are organized into equal-sized 1-ms subframes. A subframe is further divided into multiple slots of equal duration, with each slot including multiple OFDM-based symbols. However, time-frequency resources can be configured much more flexibly for an NR cell than for an LTE cell. For example, rather than a fixed 15-kHz OFDM sub-carrier spacing (SCS) as in LTE, NR SCS can range from 15 to 240 kHz, with even greater SCS considered for future NR releases (e.g., in higher frequency bands).
Figure 1 shows an exemplary configuration of NR user plane (UP) and control plane (CP) protocol stacks between a UE (110), a gNodeB (gNB, e.g., base station, 120), and an access and mobility management function (AMF, 130) in the 5G core network (5GC). Physical (PHY), Medium Access Control (MAC), Radio Link Control (RLC), and Packet Data Convergence Protocol (PDCP) layers between the UE and the gNB are common to UP and CP. The PDCP layer provides ciphering/deciphering, integrity protection, sequence numbering, reordering, and duplicate detection for CP and UP.
On CP side, the non-access stratum (NAS) layer is between UE and AMF and handles UE/gNB authentication, mobility management, and security control. The RRC layer sits below NAS in the UE but terminates in the gNB rather than the AMF. RRC controls communications between UE and gNB at the radio interface as well as the mobility of a UE between cells in the NG-RAN. RRC also broadcasts system information (SI) and establishes, configures, maintains, and releases DRBs and Signaling Radio Bearers (SRBs) used by UEs. Additionally, RRC controls addition, modification, and release of carrier aggregation (CA) and dual-connectivity (DC) configurations for UEs. RRC also performs various security functions such as key management.
After a UE is powered ON it will be in the RRC IDLE state until an RRC connection is established with the network, at which time the UE will transition to RRC_CONNECTED state (e.g. , where data transfer can occur). The UE returns to RRC IDLE after the connection with the network is released. In RRC IDLE state, the UE’s radio is active on a discontinuous reception (DRX) schedule configured by upper layers. During DRX active periods (also referred to as “DRX On durations”), an RRC_IDLE UE receives SI broadcast in the cell where the UE is camping, performs measurements of neighbor cells to support cell reselection, and monitors a paging channel on physical DL control channel (PDCCH) for pages from 5GC via gNB. A UE in RRC IDLE state is not known to the gNB serving the cell where the UE is camping. How'ever, NR RRC includes an RRC INACTIVE state in which a UE is known by the serving gNB.
In addition to providing coverage via cells as in LTE, NR networks also provide coverage via “beams.” In general, a downlink (DL, i.e., network to UE) “beam” is a coverage area of a network-transmitted reference signal (RS) that may be measured or monitored by a UE. In NR, for example, RS can include any of the following: synchronization signal/PBCH block (SSB), channel state information RS (CSI-RS), tertiary reference signals (or any other sync signal), positioning RS (PRS), demodulation RS (DMRS), phase-tracking reference signals (PTRS), etc. In general, SSB is available to all UEs regardless of the state of their connection with the network, while other RS (e.g., CSI-RS, DM-RS, PTRS) are associated with specific UEs that have a network connection.
A UE performs measurements on DL RS (e.g., beams) of one or more cells in different RRC states. Each cell measured by a UE may operate on the same carrier frequency as the UE’s serving cell (e.g., an intra-frequency carrier) or it may operate on a different carrier frequency than the UE’s current serving cell (e.g., non-serving carrier frequency). The non-serving carrier is often referred to as an inter-frequency carrier if the serving and measured cells belong to the same RAT bit different carrier frequencies, or as an inter-RAT carrier if the serving and measured cells belong to different RATs.
Examples of UE cell measurements include cell identification (e.g., PCI acquisition, PSS/SSS detection, cell detection, cell search, etc), RS Received Power (RSRP), RS Received Quality (RSRQ), secondary synchronization RSRP (SS-RSRP), SS-RSRQ, SINR, RS-SINR, SS-SINR, CSI-RSRP, CSI-RSRQ, received signal strength indicator (RSSI), acquisition of system information (SI) and/or cell global ID (CGI), RS Time Difference (RSTD), UE RX-TX time difference measurement, and Radio Link Monitoring (RLM, including out-of-sync and insync detection).
The network typically provides the UE (e.g., via RRC) a measurement configuration and a measurement reporting configuration. These configurations can include parameters such as measurement gap pattern (MGP), carrier frequency information, types of measurements (e.g., RSRP), higher-layer filtering coefficient, time-to-trigger report, and reporting mechanism (e.g., periodic, event triggered, etc). Based on these configurations, the UE performs the measurements for various purposes including mobility (e.g., cell change, cell selection, cell reselection, handover, RRC connection re-establishment etc), positioning, self-organizing network (SON) support, minimization of drive tests (MDT), operation and maintenance (O&M), network planning and optimization, etc.
License Assisted Access (LAA) is a feature of LTE that leverages the unlicensed 5 GHz band in combination with licensed spectrum to deliver a performance boost for mobile device users. It uses DL CA to combine LTE in licensed and unlicensed bands to provide better data rates and a better user experience. For example, in LAA, the UE’s PCell is in a licensed band while the UE’s SCells can be in an unlicensed band. Since LAA operates in the 5-GHz band where Wi-Fi operates, it must be able to co-exist with Wi-Fi by avoiding channels that are being used by WiFi users. LAA uses a concept called Listen-before-talk (LBT) that dynamically selects 5-GHz- band channel(s) that is(are) not being used, i.e., a “clear channel.” If no clear channel is available, LAA will share a channel fairly with others. As such, LBT is often referred to as clear channel assessment (CCA). NR Rel-16 includes a feature similar to LTE LAA, referred to as NR- Unlicensed or “NR-U”.
As mentioned above, a UE operating in RRC_IDLE receives SI broadcast in the cell where the UE is camping and performs measurements of serving and neighbor cells to support cell reselection. If the UE in RRC_IDLE has not found any suitable cells after 10 seconds of searches and measurements using the intra-frequency, inter-frequency and inter-RAT information indicated in the broadcast SI, the UE is required to initiate a cell selection procedure.
SUMMARY
In NR-U, however, the network can only transmit signals to be measured by the UE when the channel is available as determined by the transmitting node’s CCA procedure. This can cause various problems, issues, and/or difficulties for UEs. For example, given the 10-second limit discussed above, a UE may need to initiate cell selection even if the UE hasn’t finished serving cell evaluation or neighbor cell detection due to CCA failures. This may cause the UE to select a cell that is sub-optimal for camping because the UE’s search ended before it could find a cell with better radio conditions.
Embodiments of the present disclosure provide specific improvements to operation of UEs in unlicensed or shared spectrum, such as by providing, enabling, and/or facilitating solutions to overcome exemplary problems summarized above and described in more detail below.
Embodiments include methods (e.g., procedures) for a UE (e.g, wireless device, loT device, etc.) configured for operation in a wireless network. These exemplary methods can include performing a search for a suitable cell while operating in DRX and in a non-connected state with respect to the wireless network. The search includes performing measurements of at least one cell, of the wireless network, that is subject to a CCA requirement. These exemplary methods can also include initiating one or more cell selection procedures in response to performing the search for at least a minimum period without identifying a suitable cell. In particular, the minimum period is a function of one or more CCA-related parameters for the at least one cell.
In some embodiments, the minimum period is also a function of one or more DRX-related parameters. In some embodiments, the at least one cell includes the UE’s serving cell and the DRX includes periodic DRX cycles, each having a cycle length of TDRX. Moreover, the measurements are performed on the serving cell every Jth DRX cycle. In particular, J is a function of the following: the cycle length TDRX, a periodicity of a signal being measured, and a maximum number of DRX cycles between measurements.
In some of these embodiments, performing the search includes evaluating results of the measurements every Jth DRX cycle against one or more cell reselection criteria, wherein the minimum period comprises a number of consecutive DRX cycles. In some variants, the number of consecutive DRX cycles is a function of the cycle length TDRX and the periodicity of the signal being measured. In some further variants, the number of consecutive DRX cycles is also a function of one or more of the following: UE power class, and whether the UE uses receive beam sweeping to measure the signal. Various examples of these embodiments were given above in equation form.
In some variants of these embodiments, the number of consecutive DRX cycles is also a function of a number of DRX cycles during which the signal being measured is not available to be measured by the UE on at least one occasion due to a CCA failure. In further variants, the UE can perform different operations when the number of DRX cycles during which the signal is not available to be measured by the UE, within a time period, exceeds a maximum number of unavailable DRX cycles for the time period. In some further variants, the UE can initiate the one or more cell selection procedures based on this condition. In other further variants, these exemplary methods can include, based on this condition, restarting the search for a suitable cell in relation to the minimum period. In some embodiments, these exemplary methods can also include obtaining, via the serving cell, information about a plurality of neighbor cells. The information includes CCA- related information. In such embodiments, initiating one or more cell selection procedures includes ranking the neighbor cells based on the CCA-related information and initiating the cell selection procedures on the neighbor cells in order of ranking. In some of these embodiments, ranking the neighbor cells is further based on measurements of the neighbor cells made by the UE while performing the search.
In some of these embodiments, the CCA-related information for each neighbor cell includes one or more of the following:
• number of downlink CCA failures for the neighbor cell during a previous time interval;
• number of downlink CCA successes for the neighbor cell during the previous time interval;
• relation between number of downlink CCA failures and number of downlink CCA successes during the previous time interval;
• predicted number of downlink CCA failures for the neighbor cell during a subsequent time interval;
• predicted number of downlink CCA successes for the neighbor cell during the subsequent time interval; and
• predicted relation between number of downlink CCA failures and number of downlink CCA successes during the subsequent time interval.
In some variants, the neighbor cells are ranked (i.e., based on the received CCA-related information) in order of one of the following: decreasing likelihood of CCA success during the subsequent time interval; increasing likelihood of CCA failure during the subsequent time interval; decreasing CCA success rate during the previous time interval; or increasing CCA failure rate during the subsequent time interval.
In other embodiments, the DRX includes periodic DRX cycles having a cycle length of TDRX and the minimum period is a function of the following: a duration (PICCA) required for the UE to evaluate or detect the at least one cell subject to the CCA requirement; the cycle length TDRX; and a periodicity of a signal (e.g., SSB) being measured in the at least one cell. In some of these embodiments, the minimum period is also a function of one or more of the following: UE power class, number of UE antennas used to perform the measurements, frequency range of the at least one cell subject to CCA requirement, and whether the UE uses receive beam sweeping to perform the measurements.
In some of these embodiments, the duration (PICCA) is a function of one or more of the following:
• a relation between the cycle length TDRX and the periodicity of a signal being measured; • a number of DRX cycles, within a time period, during which the signal being measured is not available to be measured by the UE due to CCA failure;
• a maximum number of DRX cycles during which the signal being measured is not available to be measured by the UE due to CCA failure; and
• frequency range of the at least one cell.
In some variants, one or more of the following is also a function of the cycle length TDRX:
• the relation between the cycle length TDRX and the periodicity of a signal being measured;
• the maximum number of DRX cycles during which the signal being measured is not available to be measured by the UE due to CCA failure; and
• a scaling factor related to UE beam sweeping and/or frequency range of the at least one cell.
In some of these embodiments, the DRX includes extended periodic DRX cycles, each having an extended cycle length TeDRX and including one or more DRX cycles. The extended cycle length TCDRX is greater than the cycle length TDRX. In such embodiments, the minimum period is a function of the extended cycle length TeDRX instead of or in addition to being a function of the cycle length TDRX. Various examples of these embodiments were given above in equation form.
In some embodiments, these exemplary methods can also include obtaining the minimum period, or the CCA-related parameters of which the minimum period is a function, via one or more of the following:
• a message from a network node serving the at least one cell subject to CCA requirement;
• a storage medium of the UE;
• UE determination based on historical data or statistics for the minimum period or the CCA- related parameters of which the minimum period is a function; and
• UE determination based on non-CCA-related parameters.
Other embodiments include exemplary methods (e.g., procedures) for a network node (e.g, base station, eNB, gNB, ng-eNB, etc., or component thereof) configured to serve at least one cell that is subject to a CCA requirement in a wireless network. In general, these embodiments are complementary to the UE embodiments summarized above.
These exemplary methods can include transmitting one of the following via the at least one cell: a minimum period for UEs to search for a suitable cell during UE DRX operation in a nonconnected state with respect to the wireless network, before UE initiation of one or more cell selection procedures; or • one or more CCA-related parameters for the at least one cell, of which the minimum period is a function.
In some embodiments, the minimum period is also a function of one or more parameters related to the DRX operation. In some of these embodiments, the DRX includes periodic DRX cycles having a cycle length of TDRX and the minimum period is a function of the following: a duration (PICCA) required for the UE to evaluate or detect the at least one cell subject to the CCA requirement; the cycle length TDRX; and a periodicity of a signal (e.g., SSB) being measured by the UE in the at least one cell subject to a CCA requirement. In some variants, the minimum period is also a function of one or more of the following: UE power class, number of UE antennas used to perform the measurements, frequency range of the at least one cell subject to CCA requirement, and whether the UE uses receive beam sweeping to perform the measurements.
In various embodiments, the duration (PICCA) can be a function of any of the parameters that were summarized above in relation to corresponding UE embodiments and variants. In various embodiments, various other parameters can also be a function of the cycle length TDRX, including certain parameters (of which the minimum period is a function) that were summarized above in relation to UE embodiments.
In some embodiments, the DRX includes extended periodic DRX cycles, each having an extended cycle length TeDRX and including one or more DRX cycles. The extended cycle length TCDRX is greater than the cycle length TDRX. In such embodiments, the minimum period is a function of the extended cycle length TeDRX instead of or in addition to being a function of the cycle length TDRX. Various examples of these embodiments were given above in equation form.
In some embodiments, these exemplary methods can also include transmitting, via the at least one cell, information about a plurality of neighbor cells. The information includes CCA- related information, which in various embodiments can include any of the CCA-related information summarized above in relation to UE embodiments.
Other embodiments include UEs (e.g., wireless devices) and network nodes (e.g., base stations, eNBs, gNBs, ng-eNBs, etc., or components thereof) configured to perform operations corresponding to any of the exemplary methods described herein. Other embodiments include non-transitory, computer-readable media storing program instructions that, when executed by processing circuitry, configure such UEs or network nodes to perform operations corresponding to any of the exemplary methods described herein.
These and other embodiments described herein provide flexible and efficient techniques for cell selection by a UE operating in a non-connected state (e.g., RRC IDLE or RRC IN ACTIVE) and configured with DRX and at least one carrier frequency that is subject to CCA. Embodiments provide well-defined UE measurement behavior for cell selection in this scenario, which is currently not specified by 3GPP. Embodiments also ensure that UEs in this scenario search all possible configured cells that are strong enough before initiating a cell selection procedure. This in turn prevents such UEs from prematurely performing cell selection based on sub-optimal and/or incomplete information about available cells. At a high level, embodiments improve the performance of networks and UEs operating in shared spectrum.
These and other objects, features, and advantages of embodiments of the present disclosure will become apparent upon reading the following Detailed Description in view of the Drawings briefly described below.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows exemplary NR user plane (UP) and control plane (CP) protocol stacks.
Figure 2 illustrates a high-level views of an exemplary 5G/NR network architecture.
Figure 3 shows an exemplary discontinuous reception (DRX) cycle for a UE
Figure 4 shows an exemplary scenario in which spectrum coexistence techniques are desirable and/or necessary.
Figure 5 shows a timeline of an exemplary CCA procedure performed by a UE or network node wanting to transmit on a channel in unlicensed spectrum.
Figure 6 shows a flow diagram of an exemplary method for a UE (e.g, wireless device), according to various embodiments of the present disclosure.
Figure 7 shows a flow diagram of an exemplary method for a network node (e.g., base station, eNB, gNB, etc.), according to various embodiments of the present disclosure.
Figure 8 shows a communication system according to various embodiments of the present disclosure.
Figure 9 shows a UE according to various embodiments of the present disclosure.
Figure 10 shows a network node according to various embodiments of the present disclosure.
Figure 11 shows host computing system according to various embodiments of the present disclosure.
Figure 12 is a block diagram of a virtualization environment in which functions implemented by some embodiments of the present disclosure may be virtualized.
Figure 13 illustrates communication between a host computing system, a network node, and a UE via multiple connections, at least one of which is wireless, according to various embodiments of the present disclosure. DETAILED DESCRIPTION
Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.
Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where a step must necessarily follow or precede another step due to some dependency. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features, and advantages of the enclosed embodiments will be apparent from the following description.
Furthermore, the following terms are used throughout the description given below:
• Radio Access Node: As used herein, a “radio access node” (or equivalently “radio network node,” “radio access network node,” or “RAN node”) can be any node in a radio access network (RAN) of a cellular communications network that operates to wirelessly transmit and/or receive signals. Some examples of a radio access node include, but are not limited to, a base station (e.g., a gNB 5G/NR network or an eNB in an LTE network), base station distributed components (e.g., CU and DU), a high-power or macro base station, a low- power base station (e.g., micro, pico, femto, or home base station, or the like), an integrated access backhaul (IAB) node (or component thereof such as MT or DU), a transmission point, a remote radio unit (RRU or RRH), and a relay node.
• Core Network Node: As used herein, a “core network node” is any type of node in a core network. Some examples of a core network node include, e.g, mobility management entity (MME), serving gateway (SGW), packet data network gateway (P-GW), etc. A core network node can also be a node that implements a particular core network function (NF), such as access and mobility management function (AMF), session management function (SMF), user plane function (UPF), service capability exposure function (SCEF), or the like. • Wireless Device: As used herein, a “wireless device” (or “WD” for short) is any type of device that is capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other wireless devices. Communicating wirelessly can involve transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information through air. Unless otherwise noted, the term “wireless device” is used interchangeably herein with the term “user equipment” (or “UE” for short), with both of these terms having a different meaning than the term “network node”.
• Radio Node: As used herein, a “radio node” can be either a “radio access node” (or equivalent term) or a “wireless device.”
• Network Node: As used herein, a “network node” is any node that is either part of the radio access network (e.g., a radio access node or equivalent term) or of the core network (e.g., a core network node discussed above) of a cellular communications network. Functionally, a network node is equipment capable, configured, arranged, and/or operable to communicate directly or indirectly with a wireless device and/or with other network nodes or equipment in the cellular communications network, to enable and/or provide wireless access to the wireless device, and/or to perform other functions (e.g, administration) in the cellular communications network.
• Node: As used herein, the term “node” (without any prefix) can be any type of node that is capable of operating in or with a wireless network (including a RAN and/or a core network), including a radio access node (or equivalent term), core network node, or wireless device. However, the term “node” may be limited to a particular type of node (e.g., radio access node) based on its particular characteristics in any context.
• Base station: As used herein, a “base station” may comprise a physical or a logical node transmitting or controlling the transmission of radio signals, e.g., eNB, gNB, ng-eNB, en- gNB, CU/DU, transmitting radio network node, transmission point (TP), transmission reception point (TRP), remote radio head (RRH), remote radio unit (RRU), Distributed Antenna System (DAS), relay, etc.
Note that the description herein focuses on a 3GPP cellular communications system and, as such, 3GPP terminology or terminology similar to 3GPP terminology is oftentimes used. However, the concepts disclosed herein are not limited to a 3GPP system. Furthermore, although the term “cell” is used herein, it should be understood that (particularly with respect to 5G NR) beams may be used instead of cells and, as such, concepts described herein apply equally to both cells and beams. Figure 2 shows a high-level view of an exemplary 5G network architecture, including a Next Generation Radio Access Network (NG-RAN) 299 and a 5G Core (5GC) 298. As shown in the figure, NG-RAN 299 can include gNBs (e.g., 210a, b) and ng-eNBs (e.g, 220a, b) that are interconnected with each other via respective Xn interfaces. The gNBs and ng-eNBs are also connected via the NG interfaces to the 5GC, more specifically to Access and Mobility Management Functions (AMFs, e.g, 230a, b) via respective NG-C interfaces and to User Plane Functions (UPFs, e.g., 240a, b) via respective NG-U interfaces. Moreover, the AMFs can communicate with one or more policy control functions (PCFs, e.g., 250a, b) and network exposure functions (NEFs, e.g., 260a, b).
Each gNB can support the NR radio interface including frequency division duplexing (FDD), time division duplexing (TDD), or a combination thereof. In contrast, each ng-eNB can support the LTE radio interface but, unlike conventional LTE eNodeBs (eNBs), connects to the 5GC via the NG interface. Each gNB and ng-eNB can serve a geographic coverage area including one more cells, such as cells 211a-b and 221a-b shown as exemplary in Figure 2. The gNBs and ng-eNBs can also use various directional beams to provide coverage in the respective cells. Depending on the cell in which it is located, a UE (205) can communicate with the gNB or ng- eNB serving that cell via the NR or LTE radio interface, respectively.
The gNBs shown in Figure 2 can include a central (or centralized) unit (CU or gNB-CU) and one or more distributed (or decentralized) units (DU or gNB-DU), which can be viewed as logical nodes. CUs host higher-layer protocols and perform various gNB functions such controlling the operation of DUs, which host lower-layer protocols and can include various subsets of the gNB functions. As such, each of the CUs and DUs can include various circuitry needed to perform their respective functions, including processing circuitry, communication interface circuitry (e.g., for communication viaXn, NG, radio, etc. interfaces), and power supply circuitry.
A CU connects to its associated DUs over respective Fl logical interfaces. A CU and its associated DUs are only visible to other gNBs and the 5GC as a gNB, e.g, the Fl interface is not visible beyond a CU. A CU can host higher-layer protocols such as Fl application part protocol (Fl-AP), Stream Control Transmission Protocol (SCTP), GPRS Tunneling Protocol (GTP), Packet Data Convergence Protocol (PDCP), User Datagram Protocol (UDP), Internet Protocol (IP), and Radio Resource Control (RRC) protocol. In contrast, a DU can host lower-layer protocols such as Radio Link Control (RLC), Medium Access Control (MAC), and physical-layer (PHY) protocols.
NR DL and UL physical resources are organized into equal-sized 1-ms subframes. A subframe is further divided into multiple slots of equal duration, with each slot including multiple OFDM-based symbols. An NR slot can include 14 OFDM symbols for normal cyclic prefix and 12 symbols for extended cyclic prefix. A resource block (RB) consists of a group of 12 contiguous OFDM subcarriers for a duration of a 12- or 14-symbol slot. A resource element (RE) corresponds to one OFDM subcarrier during one OFDM symbol interval. An NR slot can also be arranged with various time-division duplexing (TDD) arrangements of UL and DL symbols. These TDD arrangements include:
• DL-only (i.e., no UL transmission) slot with transmission late-start in symbol 1;
• DL-heavy, with one UL symbol and guard periods before and after the UL symbol to facilitate change of transmission direction;
• UL-heavy, with a single UL symbol that can carry DL control information; and
• UL-only with transmission on-time start in symbol 0 and the initial UL symbol usable to carry DL control information.
To reduce energy consumption, a UE can be configured with discontinuous reception (DRX) cycle to use in all RRC states. UE DRX operation in RRC CONNECTED is often referred to as connected-DRX (CDRX). Figure 3 shows an exemplary DRX cycle for a UE. In this exemplary arrangement, the UE is on or active for a portion of each DRX cycle (having cycle length TDRX) and off or inactive for the remainder of each DRX cycle. Example values for TDRX currently used in RRC IDLE and RRC INACTIVE include 320 ms, 640 ms, 1.28 s, 2.56 s, etc. Example values for TDRX currently used in RRC_CONNECTED range from 2 ms to 10.24 s. The on/active time and off/inactive time of each DRX cycle are also called as DRX ON and DRX OFF durations. The off/inactive time may also be called non-DRX state or non-DRX duration.
For NR, an extended DRX (eDRX) cycle is being specified for UEs in RRC IDLE and RRC INACTIVE states, with the purpose of further reducing UE energy consumption compared to conventional DRX. An eDRX cycle length ranges between few seconds to several minutes or even hours but is generally longer than TDRX. For example, an eDRX cycle may range from 5.12 seconds (shortest eDRX) up to 10485.76 s (largest eDRX). The eDRX configuration parameters can be negotiated between UE and the network via higher layer signaling such as NAS messages. During this negotiation the network transmits eDRX parameters including eDRX cycle length, paging time window (PTW), hyper system frame number (H-SFN), paging H-SFN (PH) etc. Within each PTW of the eDRX cycle, the UE is configured with one or more DRX cycles.
As mentioned above, a UE performs measurements on DL RS (e.g., beams) of one or more cells in different RRC states. Each cell measured by a UE may operate on the same carrier frequency as the UE’s serving cell (e.g., an intra- frequency carrier) or it may operate on a different carrier frequency than the UE’s current serving cell (e.g., non-serving carrier frequency). The non-serving carrier is often referred to as an inter-frequency carrier if the serving and measured cells belong to the same RAT bit different carrier frequencies, or as an inter-RAT carrier if the serving and measured cells belong to different RATs. Examples of UE cell measurements include cell identification (e.g., PCI acquisition, PSS/SSS detection, cell detection, cell search, etc), RSRP, RSRQ, secondary synchronization RSRP (SS-RSRP), SS- RSRQ, SINR, RS-SINR, SS-SINR, CSI-RSRP, CSI-RSRQ, RSSI, acquisition of SI and/or CGI, RSTD, UE RX-TX time difference measurement, and RLM (including out-of-sync and in-sync detection).
As specified in 3GPP TS 38.304 (v!6.6.0), a UE measures SS-RSRP and SS-RSRQ and evaluates cell selection criterion S for its serving cell at least once every M1*N1 DRX cycles. In particular, Ml=2 if SMTC periodicity (TSMTC) > 20 ms and DRX cycle < 0.64 second; otherwise Ml=l. The UE filters the SS-RSRP and SS-RSRQ measurements of the serving cell based on at least two (2) measurements. At least two measurements with the set used for the filtering must be spaced apart by at least one-half of the DRX cycle.
If the UE has evaluated in Nserv consecutive DRX cycles that its serving cell belonging to a carrier not subject to CCA does not fulfil the cell selection criterion S, the UE initiates measurements of all neighbor cells indicated by the serving cell broadcast SI, regardless of the measurement rules currently limiting UE measurement activities. Table 1 below gives values for Nserv.
Table 1.
Figure imgf000015_0001
Figure imgf000015_0002
If the UE has evaluated in Nserv_ccA consecutive DRX cycles that a serving cell belonging to a carrier subject to CCA does not fulfil the cell selection criterion S, the UE initiates measurements of all neighbor cells indicated by the serving cell broadcast SI, regardless of the measurement rules currently limiting UE measurement activities. Table 1 below gives values for Nserv_CCA.
Table 2.
Figure imgf000016_0001
An example cell selection criterion S is fulfilled when Srxlev > 0 AND Squal > 0, where these terms are defined as following:
• Srxlev (dB) = Qrxlevmeas (Qrxlevmin + Qrxlevminoffset ) Pcompensation - Qoffsettemp
• Squal = cell selection quality value (dB), derived from RSRQ.
• Qrxlevmeas = measured cell RX level value (RSRP)
• Qrxlevmin = minimum required RX level in the cell (dBm), signaled in the cell.
• Qrxlevminoffset = offset to Qrxlevmin, signaled in the cell.
• Qoffsettemp = offset temporarily applied to a cell, signaled in the cell.
If the UE in RRC IDLE has not found any suitable cell based on searches and measurements using the intra-frequency, inter-frequency and inter-RAT information indicated in the system information for 10 s, the UE shall initiate cell selection procedures for the selected PLMN as defined in 3 GPP TS 38.304 (v 16.6.0).
Besides conventional use in licensed (i.e., exclusive) spectrum, NR networks also can operate in unlicensed bands in shared spectrum, referred to generally as NR-U. Coexistence techniques are needed in these deployments to enable spectrum sharing between different operators or other systems.
Figure 4 shows an exemplary scenario in which spectrum coexistence techniques are desirable and/or necessary. In the scenario shown in Figure 4, network A (410) includes access nodes (e.g., base stations) AN1A, AN2A, and AN3A, which serve UEs including UE1A, UE2A, and UE3A. Similarly, network B (420) includes access nodes (e.g., base stations) AN1B, AN2B, and AN3B, which serve UEs including UE1B, UE2B, and UE3B. Networks “A” and “B” are located in the same geographic area and share the same frequency spectrum, but are controlled by different entities (e.g., operators). In this scenario, any coexistence techniques are preferably distributed so that there is no need to exchange information between different networks or controlling entities, which would create significant complexities.
Operation in unlicensed bands involves a unique set of rules intended to promote spectrum sharing with otherwise competing transceivers. These rules promote an etiquette or behavior that facilitates spectrum sharing and/or co-existence. According to a common coexistence technique, before a node (e.g., UE or base station) is allowed to transmit in unlicensed spectrum, it needs to perform a listen-before-talk (LBT) or clear channel assessment (CCA) procedure. For example, in the 5 GHz band, these sensing procedures are performed over 20-MHz channels. In general, the MAC layer initiates a transmission and requests the PHY layer to initiate the LBT procedure. After completion, the PHY layer indicates the LBT outcome (e.g., success or failure). An LBT procedure can involve sensing the medium as idle for a number of time intervals, which can be done in various ways including energy detection, preamble detection, or virtual carrier sensing.
LBT has become well-known and popular due to ubiquitous use by Wireless LANs (also known as “WiFi”), even though most regulatory agencies did not enforce LBT operation. The introduction of LTE LAA and subsequent definition of LTE LAA regulations ensured LBT functionality was required by all radio transceivers, regardless of whether they were WiFi or LTE LAA. Energy detection (ED) thresholds were defined, simulated, debated, and soon became part of the regulatory specifications to be met by all devices that operate in unlicensed bands.
As an example of energy detection (ED), a channel is assessed to be idle when the received energy or power during the sensing time duration is below a certain ED threshold; otherwise, the channel is considered busy. An example ED threshold is -72 dBm. In some cases, the ED threshold may depend on the channel bandwidth, e.g., -72 dBm 20 MHz bandwidth, -75 dBm for 10 MHz bandwidth, etc. If the channel is assessed as “busy” then the prospective transmitter (i.e., UE or network node) is required to defer transmission.
Figure 5 shows a timeline of an exemplary CCA procedure performed by a UE or network node wanting to transmit on a channel in unlicensed spectrum. In this procedure, the prospective transmitter initially senses the channel busy for some duration. After a deferral period, the transmitter senses the channel to be idle in the period labelled “s” (for sensing). For example, s = 25 ps. After a backoff time following the idle sensing, the transmitter has a transmission opportunity (TXOP) or a channel occupancy time (COT) during which it may transmit a signal, with the COT being less than a maximum COT (MCOT) that depends of regional rules or laws, the sensing period s, etc. For example, a typical COT is 1-10 ms based on a MCOT of 10 ms. The backoff time may be a deterministic value or a probabilistic value (e.g., selected from a random distribution).
When the transmitter in Figure 5 is a network node (e.g., gNB) serving a cell, the network node can only transmit signals to be measured by the UE when the channel is available as determined from the network node’s CCA procedure. This can cause various problems, issues, and/or difficulties for UEs. For example, due to CCA failures, a network node may be unable to transmit the RS that a UE needs to measure. Given the 10-second limit discussed above, a UE may need to initiate cell selection before the UE finishes serving cell evaluation and/or neighbor cell detection based on such RS. In other words, the UE may not be able to measure/ detect cells that could be better candidates due to CCA-delayed transmission in those cells. This may cause the UE to select a cell that is sub-optimal for camping because the UE’s 10-second search ended before it could find a cell with better radio conditions.
Furthermore, currently there are no specified cell selection procedures for reduced capability (Redcap) UEs operating on an NR-U carrier subject to CCA and configured with an eDRX cycle. The combination of these features requires new procedures and requirements for cell selection for a selected PLMN. Not only is the current maximum 10-second measurement time too short, but the fact that it is fixed may be problematic for this combination of features.
Accordingly, embodiments of the present disclosure provide flexible and efficient techniques for cell selection by a UE operating in a non-connected state (e.g., RRC IDLE or RRC IN ACTIVE) and configured with DRX and at least one carrier frequency that is subject to CCA. Embodiments provide well-defined UE measurement behavior for cell selection for UEs in this scenario, which is currently not specified by 3GPP. Additionally, embodiments ensure that UEs in this scenario search all possible configured cells that are strong enough before initiating a cell selection procedure. This in turn prevents such UEs from prematurely performing cell selection based on sub-optimal and/or incomplete information about available cells.
Embodiments will first be summarized, after which a more detailed description is given. In some embodiments, a UE in a non-connected state (e.g., RRC IDLE, RRC INACTIVE) initiates cell selection procedures for a selected PLMN when the UE does not find any new suitable cell based on searches and/or measurements on cells during a period T, where T is a function of at least one CCA-related parameter for at least one cell on which the UE performs search and/or measurements. As a more specific example, T = max(10s, P1CCA*TDRX) and:
• Pl CCA = K1+ PL is the time for the UE to finish at least one time serving cell evaluation and/or neighbor cell detection.
• KI is a scaling factor related to the DRX cycle length and RS occasion periodicity, e.g., SMTC periodicity, and
• TDRX = DRX cycle length in seconds.
• Pls is the number of DRX cycles each with at least one RS occasion (e.g., SMTC occasion) not available during a time period, TO. For example, T0=P1CCA= K1+ Pls.
In some embodiments relevant to cells at higher frequencies (e.g., FR2) in which a UE employs beam sweeping, a UE in a non-connected state (e.g., RRC IDLE, RRC INACTIVE) initiates cell selection procedures for a selected PLMN when the UE does not find any new suitable cell based on searches and measurements on cells during the time period T, where T is a function of at least one CCA-related parameter for at least one cell on which the UE performs search and/or measurements and a function of at least one parameter related to the UE Rx beam sweeping. As a more specific example, T = max(10s, P1CCA*TDRX) and:
• P1CCA = K1 *N1 + P1S,
• N1 = scaling factor for UE performing Rx beam sweeping in FR2.
• Pls is the number of DRX cycles each with at least one RS occasion (e.g., SMTC occasion) not available during a time period, TO. For example, T0=P1CCA= K1 *N1+P1S. In the above embodiments, the UE obtains information about the cells on which to perform the searches and/or measurements from SI broadcast by its serving cell. For example, the UE can obtain information indicating whether each cell is an intra-frequency carrier, an inter-frequency carrier, or an inter-RAT carrier.
In general, the value Pls should not exceed a limit Pls, max. In some embodiments, the UE restarts the measurements that could lead to initiating a cell selection procedure upon Pls exceeding Pls, max. Alternatively, the UE all initiate cell selection procedures upon Pls exceeding P 1 s,max.
As used herein, the term “clear channel assessment” (or “CCA” for short) may correspond to any type of carrier sense multiple access (CSMA) procedure or mechanism that is performed by a device on a carrier as a prerequisite to the device transmitting signals on that carrier (which may alternately be referred to as “carrier frequency”, “frequency layer”, “channel”, “radio channel”, “radio frequency channel”, etc.). The terms “CSMA scheme”, “channel assessment scheme”, “listen-before-talk” (or “LBT” for short), “shared channel access mechanism” (or scheme), “shared spectrum channel access mechanism” (or scheme) may be used interchangeably with CCA.
The frequency band of a carrier subject to CCA may also be referred to as “unlicensed band”, “unlicensed spectrum”, “shared spectrum channel access band”, “band for operation with shared spectrum channel access”, or the like. CCA-based operation is a form of contentionbased operation, with the transmission of signals on a carrier subject to CCA also being called “contention-based transmission”. Although contention-based operation is typically used for transmission on carriers of unlicensed frequency band, this mechanism may also be used for operating on carriers belonging to licensed bands, such as to reduce interference. The transmission of signals on a carrier not subject to CCA is also called “contention-free transmission”. LBT or CCA can be performed by a UE as a prerequisite to UL transmission, and as such may be referred to as “UL CCA”. LBT or CCA can be performed by a network node (e.g., gNB) as a prerequisite to DL transmission, and as such may be referred to as “DL CCA”.
As used herein, the term “signal” or “radio signal” refers to any physical signal or physical channel. Examples of physical channels include PBCH, NPBCH, PDCCH, PDSCH, sPUCCH, sPDSCH, sPUCCH, sPUSCH, MPDCCH, NPDCCH, NPDSCH, E-PDCCH, PUSCH, PUCCH, NPUSCH, etc. Examples of DL physical signals include RS such as PSS, SSS, CSI-RS, DMRS, SS/PBCH block (SSB), discovery reference signal (DRS), cell RS (CRS), positioning RS (PRS), etc. Examples of UL physical signals include sounding RS (SRS), DMRS, etc. RS may be periodic meaning that they occur with a certain periodicity such as 20 ms, 40 ms, etc. RS may also be aperiodic.
Each SSB carries NR-PSS, NR-SSS and NR-PBCH in four (4) successive symbols. An SSB burst includes one or more SSBs and is repeated with a certain periodicity such as 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, 160 ms, etc. A UE is configured with information about SSB based on an SSB measurement timing configuration (SMTC) received from the network. An SMTC includes parameters such as SMTC periodicity, SMTC occasion length in time or duration, SMTC time offset relative to reference time (e.g., serving cell’s SFN), etc. Therefore, an SMTC occasion may also occur with a certain periodicity such as 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, 160 ms, etc. The term physical channel refers to any channel carrying higher layer information e.g., data, control etc.
Embodiments described herein are related to the scenario of a UE operating in a nonconnected state (e.g., RRC IDLE or RRC INACTIVE) and configured with DRX and with at least one carrier frequency that is subject to CCA. Each cell measured by the UE may operate on the same carrier frequency as the UE’s serving cell (e.g., an intra-frequency carrier) or it may operate on a different carrier frequency than the UE’s current serving cell (e.g., non-serving carrier frequency). The non-serving carrier may be an inter-frequency carrier if the serving and measured cells belong to the same RAT bit different carrier frequencies, or an inter-RAT carrier if the serving and measured cells belong to different RATs.
In some embodiments, the UE’s serving cell may operate in a particular frequency range such as FR1, FR2, or FR3, which are listed in order of increasing frequencies. For example, FR1 may be 410-7125 MHz while FR2 may be all frequencies above some threshold (e.g., 24 GHz) or all frequencies in a range with the threshold being the lower end of the range (e.g., 24-71 GHz). For example, frequencies in FR3 may be above FR2.
The transmitted signals in relatively higher frequencies (e.g., above FR1, mm Wave, FR2, etc.) often need to be beamformed due to their higher signal dispersion and path loss in most transmission environments. For example, a network node will transmit SSB using transmit beamforming and the UE will use corresponding beamforming to receive and measure the SSB. As an initial step before measurements, the UE performs receive beam sweeping in a range of directions to determine direction of arrival of signals to be measured. The receive beam sweeping may also be called spatial beam sweeping, beam tracking, or three-dimensional beam sweeping. After determining the direction of arrival, the UE forms a receive beam in the determined direction and performs measurement on the signals received via the beam.
In various embodiments, the UE may obtain information about the one or more carriers to be measured for cell reselection while the UE is operating in DRX (optionally also eDRX) in the non-connected state in various ways, including one or more of the following:
• pre-defined information (e.g., stored on the UE’s SIM or USIM card),
• historical data or statistics (e.g., carriers used for measurements in some most recent duration);
• message received from a network node (e.g., via RRC).
In general, the UE applies UL CCA before transmitting on a cell and/or carrier frequency subject to CCA. Therefore, the UE can determine that UL CCA has failed (or UL CCA failure has occurred) if the UE is unable to transmit a signal due to CCA failure in the uplink. The UE may determine an outcome or result of DL CCA (e.g., DL CCA failure or DL CCA success) on a cell and/or carrier frequency subject to CCA based on one or more of the following techniques.
In a first technique referred to as “autonomous determination by the UE”, the UE can determine that DL CCA has failed (e.g., at the network node transmitter) when the UE is unable to receive a signal that the UE expects to have been transmitted. In other words, the signal is unavailable, not present, and/or not detected by or at the UE. The UE may attempt to detect the expected signal (e.g., SSB) by correlating some energy captured by the receiver (e.g., in certain time-frequency resources) with some pre-defined sequences (e.g., one or more candidate SSBs). When the output or result of the correlation is below a certain threshold (T').the UE assumes that the expected signal (e.g., SSB) was not transmitted by the network node due to DL CCA failure. Otherwise, when the output or result of the correlation is equal to or above , the UE assumes that the signal (e.g., SSB) was transmitted by the network node due to DL CCA success.
In a second technique referred to as “explicit indication from network node”, the network node may transmit the results or outcome of its DL CCA failures to the UE in a message, e.g., broadcast SI. For example, the network node may transmit the outcome or results of the DL CCA in the BS in the last Z1 number of time resources or signals in terms of bitmap to the UE. Each bit may indicate whether the CCA was failure (e.g., “0”) or successful (e.g., “1”). A CCA failure during a configured occasion for a signal (e.g., RS) may also be expressed as unavailability of the signal at the UE during that occasion. The number of CCA failures (N) may be consecutive or non-consecutive during some duration TO. As some examples, N can correspond to any of the following:
• number of RS occasions (e.g., SMTC occasions) not transmitted in the cell during TO due to DL CCA failure.
• number of RS occasions (e.g., SMTC occasions) not available at the UE in the cell during TO.
• number of DRX cycles each with at least one RS occasion (e.g., SMTC occasion) is not transmitted in the cell due to DL CCA failure during TO.
• number of DRX cycles each with at least one RS occasion (e.g., SMTC occasion) not available at the UE during TO.
A RS occasion may be considered “unavailable” at the UE when the RS occasion (e.g., SMTC) contains RS (e.g., SSBs) configured by the network node for a cell (e.g., UE serving cell) on a carrier frequency subject to CCA, but the first two successive candidate RS positions (e.g., SSB positions) for the same RS index (e.g., SSB index) within the discovery burst transmission window are not available at the UE due to DL CCA failures at the network node during the corresponding detection, measurement, or evaluation period; otherwise the RS occasion (e.g., SMTC occasion) is considered as “available” at the UE.
At a high level, the UE in a non-connected state configured with DRX first performs serving cell measurements and evaluates cell selection criterion during Nserv_ccA DRX cycles. The UE subsequently performs one or more cell selection procedures for a selected PLMN when the UE does not find any new suitable cell based on searches and/or measurements on cells during a period T, where T is a function of at least one CCA-related parameter for at least one cell (e.g., serving cell) on which the UE performs search and/or measurements. In some embodiments, T is also a function of at least one parameter related to UE receive beam sweeping performed on at least one cell (e.g., serving cell). In some embodiments, before performing the one or more cell selection procedures, the UE may determine T based on one or more rules and/or functions, which may be pre-defined or configured by a network node or autonomously determined by the UE.
In some embodiments, the UE performs one or more measurements (e.g., SS-RSRP and SS-RSRQ) on the serving cell at least once every J > 1 DRX cycles. In one example, J=(l+Mn)*Ml DRX cycles where:
• Ml > 1 and depends on a relation between periodicity (TRS) of RS used for measurements and DRX cycle length (TDRX). AS a more specific example, TRS =SMTC periodicity (TSMTC) with Ml=2 if TSMTC > 20 ms and DRX cycle < 0.64 s but otherwise Ml=l. • Mn is the maximum separation in terms of number of DRX cycles between two measurements that are used for filtering. In one example Mn= 2.
The UE uses the results of the measurements (e.g., SS-RSRP and SS-RSRQ) to evaluate the cell reselection criterion S once every J > 1 DRX cycle in Nserv_ccA consecutive DRX cycles. For example, Nserv_ccA can be defined as shown in Table 3 below for the UE’s serving cell in FR1 :
Table 3: Nserv_ccAin FR1 (example)
Figure imgf000023_0001
For example, Nserv_ccA can be defined as shown in Table 4 below for the UE’s serving cell in FR2. N1 represents a scaling factor for receive (Rx) beam sweeping.
Table 4: Nserv_ccAin FR2 (example)
Figure imgf000023_0002
Alternatively, Nserv_ccA time in FR2 can be defined as shown in Table 5 below, in which
Rx beam sweeping scaling factor is also considered for the CCA procedure.
Table 5: Nserv_ccAin FR2 (example)
Figure imgf000024_0001
In the examples in Tables 3-5, the UE restarts the measurements used for serving cell evaluation if Ms exceeds Ms,max.
If the UE has evaluated according to Table 3 in FR1 or in Table 4 in FR2 in Nserv_ccA consecutive DRX cycles that the serving cell does not fulfil the cell selection criterion S, then the UE shall initiate the measurements of all neighbor cells indicated by the serving cell, regardless of the measurement rules currently limiting UE measurement activities. The measurements performed by the UE on the neighbor cells may comprise one or more of: cell detection, RSRP and/or RSRQ measurements on one or more identified cells, evaluation of the cell etc.
In one example the UE may obtain information about the neighbor cells by receiving a message from the network node e.g., in a broadcast message (e.g., in a SIB) transmitted in the UE’s serving cell. The obtained information may include one or more of the following: cell identifiers (e.g., PCI, CGI), carrier frequency information (e.g., frequency channel number such as ARFCN, EARFCN, NR-ARFNC), type of RAT (e g., NR, LTE, UTRA), etc. The obtained information may also include CCA-related information for one or more cells of carriers that are subject to CCA. Examples of the CCA-related information include of results of CCA operations performed by the network node in some recent duration (Txl) and expected or predicted results of CCA operations to be performed by the network node in some upcoming duration (Tx2). Examples of results of CCA operations are number of CCA failures (Nf) during Txl/Tx2, number of CCA successes (Ns) during Txl/Tx2, relation between Nf and Ns (e.g., Nf/Ns or Ns/Nf), etc.
The UE may use the obtained results of the CCA operations by the network node for various operations. For example, the UE may search and measure cells on carriers in increasing order of number and/or probability of CCA failures. This will allow the UE to speed up the cell search process by starting with cells having the lowest number and/or probability of CCA failures.
As another example, the UE may rank neighbor cells based on both the obtained results of the CCA operations and a UE received signal measurement (e.g., RSRP, RSRQ, etc.). As a more specific example, the UE may rank neighbor cells having the same or similar received signal levels based on the respective results of the CCA operations for those cells. The UE may select a new serving cell which has lowest number of CCA failures indicated by obtained information or measured/ estimated by the UE during last TO time period. By camping on a cell with less or least number of CCA failures, the UE can make quicker measurement during Nserv_ccA and will consume less energy doing so. Measuring neighbor cells in an order based on CCA failure information also enables the UE to make quicker measurement of neighbor cell and thus reduce UE energy consumption while doing so.
As mentioned above, the UE performs one or more cell selection procedures for a selected PLMN when the UE does not find any new suitable cell based on searches and/or measurements on cells during a period T, where T is a function of at least one CCA-related parameter for at least one cell (e.g., serving cell) on which the UE performs search and/or measurements. In general, the value T ensures that the UE does not trigger cell selection procedure for the selected PLMN before the serving cell evaluation and neighbor cell detection have been completed.
The one or more cell selection procedures triggered by the UE not finding a suitable cell during T can include scanning all channels in NR bands according to UE capabilities to find or detect a suitable cell; and/or selecting a cell using stored frequency information, cell parameters from previously received measurement control information elements, and/or information from previously detected cells.
Examples of CCA-related parameters include number of CCA failures occurring or detected by the UE during certain time period (TO), number of successful CCA detected by the UE during TO, maximum allowed number of CCA failures during TO etc. In another example T is also a function of at least one parameter related to UE receive beam sweeping performed on at least one cell (e.g., serving cell). An example of such parameter is the beam sweeping scaling factor etc.
In various embodiments, the UE may obtain T (or the at least one CCA parameter of which T is a function) T in various ways, including one or more of the following:
• pre-configured information (e.g., stored on the UE’s SIM or USIM card),
• pre-defined information (e.g., by specification),
• historical data or statistics (e.g., in some most recent duration);
• autonomous determination by the UE, without network input; and/or
• message received from a network node (e.g., via RRC).
The following provides various examples of T as a function of at least one CCA parameter. For example, T can be expressed as function of fixed value = a time units or time resources, scaling factor = PICCA and DRX cycle length =TDRX as follows: T = fl (a, Pl CCA, TDRX)
In another example, if an eDRX cycle is configured, then T can be expressed as function of a, PICCA, TDRX, eDRX cycle scaling factor (P), and eDRX cycle length (TeDRX) as follows:
T = f2(a, , PICCA, TDRX, TeDRX)
In another example, if an eDRX cycle is configured, then T can be expressed as function of a, PICCA, eDRX cycle scaling factor (P) and eDRX cycle length (TeDRX) as follows:
T = f3(a, p, PICCA, TeDRX)
In the above examples, a and p can equal 0 as a special case. Examples of functions fl -f3 include maximum, minimum, product, sum, ceiling, floor, ratio, average, xth percentile, and any combination thereof.
In some embodiments, the eDRX cycle scaling factor (P) is the same for all eDRX cycle lengths. For example, P=1 or p=2. In other embodiments, P may be a variable that is a function of one or more of the following:
• eDRX cycle length (TeDRX). For example, P > Hb if TeDRX < threshold He; otherwise P < Hb. For example, p = 2 for TeDRX < 40.96 s and P = 1 for TeDRX > 40.96 s.
• FR of the carrier frequency of the serving cell. For example, P is smaller (e.g., 2) for FR1 and larger (e.g., 4) for FR2.
• UE power class (PC). For example, P is smaller (e.g., 2) for certain PC (e.g., PC2-4) and larger (e.g., 4) for other PC (e.g., PCI and PC5).
Values for scaling factor PICCA can be derived based on various functions of parameters related to serving cell evaluation, neighbor cell detection time, and CCA procedure. Some examples of PICCA when no beam sweeping is used (e.g., in FR1) are given below:
PlccA= f4(Kl, Pls)
Pl CCA = f5(Kl, Pls, max)
PICCA = f6(Kl, gl(Pls , Pls, max))
Some examples of PICCA when beam sweeping is used (e.g., in FR2) are given below:
PICCA = f7 (KI, Nl, Pls)
PICCA = f8(Kl, Nl, Pl s,max)
PICCA = f9(Kl, Nl, g2(Pls, Pls, max))
The parameters KI, Nl, Pls and Pls, max in the above example equations are defined and/or described below based on various examples.
The parameter Nl is a scaling factor related to UE Rx beam sweeping in FR2. The parameter Pls is the number of DRX cycles during a time period TO (e.g., T0=P1CCA) in which at least one RS occasion (e.g., SMTC occasion) is not available. TO may be pre-defined or configured by the network node (e.g., via broadcast or unicast RRC signaling).
The parameter Pls, max is the maximum allowed number of CCA failures in a cell during TO (e.g., TO = PICCA) which may be pre-defined or configured by the network node (e.g., via broadcast or unicast RRC signaling). Pls, max may further depend on one or more parameters such as DRX cycle length, eDRX cycle length, periodicity of a reference signal (TRS) (e.g., SMTC period, DBT window period, etc.). For example, Pls, max =8 for TDRX < 1.28 s and Pls, max =4 for TDRX > 1.28 s.
The parameter KI is a scaling factor related to UE cell evaluation and detection. For example, KI = 6 for DRX cycle length (TDRX) = 0.32 S or 0.64 s, and KI = 3 for DRX cycle length (TDRX) =1.28 s or 2.56 s. KI can be different for FR1 and FR2. The value of KI can be in the formula used for deriving PICCA based on one or more of following:
• configured by the network node (e.g., via broadcast SIB or unicast RRC message);
• pre-configured information (e.g., stored on the UE’s SIM or USIM card),
• pre-defined information (e.g., by specification),
• based on UE power class (PC), which is an indicator of UE maximum output power (Pmax). Examples of UE PCs are PCI with Pmax =31 dBm, PC2 with Pmax= 26 dBm, PC3 with Pmax= 23 dBm, etc.
• based on operating frequency range (e.g., FR1, FR2, FR3, etc.);
• based on type of spectrum access (e.g., licensed carrier or unlicensed carrier, whether carrier is subject to CCA)
Some specific examples of determining T when eDRX is not configured or not considered by the UE are given below. The first group of examples are for when no beam sweeping is used (e.g., in FR1). In one example, when a is in seconds and PICCA = KI + Pls, T can be expressed by the following function:
T = max(a, (K1+ P1S)*TDRX)
In another example, when a = 10 seconds and PICCA = KI + Pls, T can be expressed by the following function:
T = max(10s, (K1+ P1S)*TDRX)
In another example, when a is in seconds and PICCA = KI + Pls, max, T can be expressed by the following function:
T = max(a, (K1+ Pls,max)*TDRx)
In another example, when a = 10 seconds and P1CCA = KI + Pls, max, T can be expressed by the following function: T = max(10s, (K1+ P l s,max)*TDRx)
The first group of examples are for when beam sweeping is used (e.g., in FR2). In one example, when the UE supports PCI with DRX cycle length (TDRX) =2.56S, the UE will initiate the measurements of all neighbor cells after 16*TDRX = 40.96s. In another example, when a is in seconds and P1CCA = K1*N1 + Pls, T can be expressed by the following function:
T = max(a, (K1*N1 + PIS)*TDRX)
In another example, when a = 10 seconds and P1CCA = K1*N1 + Pls, T can be expressed by the following function:
T = max(10s, (K1*N1 + P1S)*TDRX)
In another example, when a is in seconds and PICCA = Kl*Nl + Pls, max, T can be expressed by the following function:
T = max(a, (K1*N1 + Pls, max)* TDRX)
In another example, when a = 10 seconds and PICCA = K1*N1 + Pls, max, T can be expressed by the following function:
T = max(10s, (K1*N1 + P1s,max)*TDRx), where:
• N1 = 1 for serving cell in FR1 and N1 is defined as follows for FR2: o For UEs of PC2-PC4, N1 = 8 for TDRX =0.32S, Nl=5 for TDRX = 0.64s, Nl=4 for TDRX = 1.28s and Nl=3 for TDRX = 2.56s. o For UEs of PCI, Nl= 8.
• KI = 6 for TDRX = 0.32, 0.64s and 3 for TDRX =1.28, 2.56s.
• P l s < P l s, max, which is 16 for TDRX <1.28 s, and 8 otherwise.
In some embodiments, when Pls exceeds P l s, max, the UE will initiate a cell selection procedure for the selected PLMN. Alternatively, when Pls exceeds P l s, max, the UE will restart the measurements for serving cell and neighbor cell evaluation.
In some variants of embodiments in which parameter a is a variable, the value of a can depend on the number of receive antennas used by the UE for measurements. For example, a > Hl if number of receive antennas in the UE is less than XI; otherwise a < Hl. In one specific example, Hl is 20 and XI is 2.
In some embodiments, T can depend on the DRX cycle length (TDRX) and/or the eDRX cycle length (TBDRX) configured for the UE. Examples of these embodiments are given below.
In one example, when a is in seconds and PICCA = N1*(K1 + Pls), T can be expressed by the following function:
T = max(a, N1*(K1 + P1S)*TDRX) In another example, when α = 10 seconds and PICCA = N1*(K1 + P1s), T can be expressed by the following function:
T = max(10s, N1*(K1 + P1S)*TDRX)
In another example, T can be expressed as follows:
T = max(10s, N1*(K1 + P1s,maX)*TDRx)
In another example, when the UE is configured with eDRX cycle length TeDRX, no beam sweeping is used (e.g., in FR1), α is in seconds, and PICCA = KI + Pls, T can be determined based on any of the following functions:
T = max(a, (KI + P1S)*TDRX), P*TeDRX)
T = max(a, (KI + P1S)*TeDRX)
In another example, when the UE is configured with eDRX cycle length TeDRX, no beam sweeping is used (e.g., in FR1), α is in seconds, and PICCA = KI + Pls, max, T can be determined based on any of the following functions:
T = max(α, (KI + P1s,max)*TDRx), P*TeDRX)
T = max(a, (KI + P1s,max)*T£DRx)
In one example, when the UE is configured with eDRX cycle length TeDRX, beam sweeping is used (e.g., in FR2), a is in seconds, and PICCA = K1*N1 + Pls, T can be determined by the following function:
T = max(a, (K1*N1 + P1s)*TDRX), P*TeDRX)
In another example, when the UE is configured with eDRX cycle length TeDRX, beam sweeping is used (e.g., in FR2), α is in seconds, and PICCA = K1*N1 + Pls, max, T can be determined by the following function:
T = max(a, (K1*N1 + P1s,max)*TDRx), P*TeDRX)
In another example, when the UE is configured with eDRX cycle length TeDRX, no beam sweeping is used (e.g., in FR1), α is in seconds, and PICCA = KI + P1s, T can be determined by the following function:
T = max(a, (K1*N1 + P1s)*TeDRX)
In another example, when the UE is configured with eDRX cycle length TeDRX, no beam sweeping is used (e.g., in FR1), α is in seconds, and PICCA = KI + Pls, max, T can be determined by the following function:
T = max(α, (K1*N1 + P l s,max)*TeDRx)
In another example when the UE is configured with eDRX cycle length TeDRX, beam sweeping is used (e.g., in FR2), a is in seconds, and PICCA = N1*(K1 + Pls), T can be determined by the following function: T = max(a, N1*(K1 + P1S)*TDRX), P*TeDRX)
In another example when the UE is configured with eDRX cycle length TeDRX, beam sweeping is used (e.g., in FR2), a is in seconds, and P1CCA= N1*(K1 + Pls, max), T can be determined by the following function:
T = max(a, N1*(K1 + Pl s,max)*TDRx), P*TeDRX)
In another example, when the UE is configured with eDRX cycle length TeDRX, no beam sweeping is used (e.g., in FR1), a is in seconds, and PICCA = KI + Pls, T can be determined by the following function:
T = max(a, Nl* (KI + P1S)*TeDRX)
In another example, when the UE is configured with eDRX cycle length TeDRX, no beam sweeping is used (e.g., in FR1), a is in seconds, and PICCA = KI + Pls, max, T can be determined by the following function:
T = max(a, Nl* (KI + Pl s,max)*T£DRx)
In variants of any of the above examples, a can be a fixed value such as 10 seconds. In any of the above examples, the eDRX cycle scaling factor (P) can have any of the characteristics and/or values previously discussed above.
Various features of the embodiments described above correspond to various operations illustrated in Figures 6-7, which show exemplary methods (e.g., procedures) for a UE and a network node, respectively. In other words, various features of the operations described below correspond to various embodiments described above. Furthermore, the exemplary methods shown in Figures 6-7 can be used cooperatively to provide various benefits, advantages, and/or solutions to problems described herein. Although Figures 6-7 show specific blocks in particular orders, the operations of the exemplary methods can be performed in different orders than shown and can be combined and/or divided into blocks having different functionality than shown. Optional blocks or operations are indicated by dashed lines.
In particular, Figure 6 shows an exemplary method (e.g., procedure) for a UE configured for operation in a wireless network, according to various embodiments of the present disclosure. The exemplary method can be performed by a UE (e.g, wireless device, loT device, etc.) such as described elsewhere herein.
The exemplary method can include the operations of block 630, where the UE can perform a search for a suitable cell while operating in DRX and in a non-connected state (e.g., RRC IDLE, RRC INACTIVE) with respect to the wireless network. Performing the search includes the operations of sub-block 631, where the UE can perform measurements of at least one cell, of the wireless network, that is subject to a CCA requirement. The exemplary method can also include the operations of block 650, where the UE can initiate one or more cell selection procedures in response to performing the search for at least a minimum period (e.g., T in the various embodiments discussed above) without identifying a suitable cell. In particular, the minimum period is a function of one or more CCA-related parameters for the at least one cell.
In some embodiments, the minimum period is also a function of one or more DRX-related parameters. In some embodiments, the at least one cell includes the UE’s serving cell and the DRX includes periodic DRX cycles, each having a cycle length of TDRX. Moreover, the measurements are performed on the serving cell every Jth DRX cycle. In particular, J is a function of the following: the cycle length TDRX, a periodicity of a signal being measured, and a maximum number of DRX cycles between measurements. Some specific examples of J were discussed above in the description of various embodiments.
In some of these embodiments, performing the search in block 630 includes the operations of sub-block 632, where the UE can evaluate results of the measurements every Jth DRX cycle against one or more cell reselection criteria, wherein the minimum period comprises a number of consecutive DRX cycles (e.g., Nserv_ccA in the various embodiments discussed above). In some variants, the number of consecutive DRX cycles is a function of the cycle length TDRX and the periodicity of the signal being measured. In some further variants, the number of consecutive DRX cycles is also a function of one or more of the following: UE power class (PC), and whether the UE uses receive beam sweeping to measure the signal. Various examples of these embodiments were given above in equation form.
In some variants of these embodiments, the number of consecutive DRX cycles is also a function of a number of DRX cycles during which the signal being measured is not available to be measured by the UE on at least one occasion due to a CCA failure (e.g., Pls in the various embodiments discussed above). In further variants, the UE can perform different operations when the number of DRX cycles during which the signal is not available to be measured by the UE, within a time period, exceeds a maximum number of unavailable DRX cycles for the time period (e.g., Pls, max in the various embodiments discussed above). In some further variants, the UE can initiate the one or more cell selection procedures in block 650 based on this condition. In other further variants, the exemplary method can include the operations of block 640, where based on this condition the UE can restart the search for a suitable cell in relation to the minimum period (e.g., initiate a search timer with a value corresponding to the minimum period). Various examples of these variants and further variants were given above in equation form.
In some embodiments, the exemplary method can also include the operation of block 620, where the UE can obtain, via the serving cell (i.e., one of the at least one cell subject to CCA), information about a plurality of neighbor cells, wherein the information includes CCA-related information. In such embodiments, initiating one or more cell selection procedures in block 650 includes the operations of sub-blocks 651-652, where the UE can rank the neighbor cells based on the CCA-related information and initiate the cell selection procedures on the neighbor cells in order of ranking. In some of these embodiments, ranking the neighbor cells in sub-block 651 is further based on measurements of the neighbor cells made by the UE while performing the search (e.g., in block 630).
In some of these embodiments, the CCA-related information for each neighbor cell includes one or more of the following:
• number of downlink CCA failures (e.g., Nf in the various embodiments discussed above) for the neighbor cell during a previous time interval (e.g., Txl in the various embodiments discussed above);
• number of downlink CCA successes (e.g., Ns in the various embodiments discussed above) for the neighbor cell during the previous time interval;
• relation between number of downlink CCA failures and number of downlink CCA successes during the previous time interval;
• predicted number of downlink CCA failures (e.g., Nf in the various embodiments discussed above) for the neighbor cell during a subsequent time interval (e.g., Tx2 in the various embodiments discussed above);
• predicted number of downlink CCA successes (e.g., Ns in the various embodiments discussed above) for the neighbor cell during the subsequent time interval; and
• predicted relation between number of downlink CCA failures and number of downlink CCA successes during the subsequent time interval.
In some variants, the neighbor cells are ranked (i.e., based on the received CCA-related information) in order of one of the following: decreasing likelihood of CCA success during the subsequent time interval; increasing likelihood of CCA failure during the subsequent time interval; decreasing CCA success rate during the previous time interval; or increasing CCA failure rate during the subsequent time interval.
In other embodiments, the DRX includes periodic DRX cycles having a cycle length of TDRX and the minimum period is a function of the following: a duration (PICCA) required for the UE to evaluate or detect the at least one cell subject to the CCA requirement; the cycle length TDRX; and a periodicity of a signal (e.g., SSB) being measured in the at least one cell. In some of these embodiments, the minimum period is also a function of one or more of the following: UE power class, number of UE antennas used to perform the measurements, frequency range of the at least one cell subject to CCA requirement, and whether the UE uses receive beam sweeping to perform the measurements. Various examples of these embodiments and variants were given above in equation form.
In some of these embodiments, the duration (PICCA) is a function of one or more of the following:
• a relation (e.g., KI in the various embodiments discussed above) between the cycle length TDRX and the periodicity of a signal being measured;
• a number of DRX cycles (e.g., Pls in the various embodiments discussed above) within a time period (e.g., TO in the various embodiments discussed above) during which the signal being measured is not available to be measured by the UE due to CCA failure;
• a maximum number of DRX cycles (e.g., Pls, max in the various embodiments discussed above) during which the signal being measured is not available to be measured by the UE due to CCA failure; and
• frequency range of the at least one cell (e.g., FR1, FR2, etc.).
In some variants, one or more of the following is also a function of the cycle length TDRX:
• the relation between the cycle length TDRX and the periodicity of a signal being measured;
• the maximum number of DRX cycles during which the signal being measured is not available to be measured by the UE due to CCA failure; and
• a scaling factor related to UE beam sweeping and/or frequency range of the at least one cell.
In some of these embodiments, the DRX includes extended periodic DRX cycles, each having an extended cycle length TeDRX and including one or more DRX cycles. The extended cycle length TCDRX is greater than the cycle length TDRX. In such embodiments, the minimum period is a function of the extended cycle length TeDRX instead of or in addition to being a function of the cycle length TDRX. Various examples of these embodiments were given above in equation form.
In some embodiments, the exemplary method can also include the operations of block 610, where the UE can obtain the minimum period, or the CCA-related parameters of which the minimum period is a function, via one or more of the following:
• a message from a network node serving the at least one cell subject to CCA requirement;
• a storage medium of the UE;
• UE determination based on historical data or statistics for the minimum period or the CCA- related parameters of which the minimum period is a function; and
• UE determination based on non-CCA-related parameters.
In addition, Figure 7 shows an exemplary method (e.g., procedure) for a network node configured to serve at least one cell that is subject to a CCA requirement in a wireless network, according to various embodiments of the present disclosure. The exemplary method can be performed by a network node (e.g., base station, eNB, gNB, ng-eNB, etc., or component thereof) such as described elsewhere herein.
The exemplary method can include the operations of block 710, where the network node can transmit one of the following in the at least one cell:
• a minimum period (e.g., T in the various embodiments discussed above) for UEs to search for a suitable cell during UE DRX operation in a non-connected state with respect to the wireless network, before UE initiation of one or more cell selection procedures; or
• one or more CCA-related parameters for the at least one cell, of which the minimum period is a function.
In some embodiments, the minimum period is also a function of one or more parameters related to the DRX operation. In some of these embodiments, the DRX includes periodic DRX cycles having a cycle length of TDRX and the minimum period is a function of the following: a duration (PICCA) required for the UE to evaluate or detect the at least one cell subject to the CCA requirement; the cycle length TDRX; and a periodicity of a signal (e.g., SSB) being measured by the UE in the at least one cell subject to a CCA requirement. In some variants, the minimum period is also a function of one or more of the following: UE power class, number of UE antennas used to perform the measurements, frequency range of the at least one cell subject to CCA requirement, and whether the UE uses receive beam sweeping to perform the measurements.
In various embodiments, the duration (PICCA) can be a function of any of the parameters that were discussed above in relation to corresponding UE embodiments and variants. In various embodiments, various other parameters can also be a function of the cycle length TDRX, including certain parameters (of which the minimum period is a function) that were discussed above in relation to UE embodiments.
In some embodiments, the DRX includes extended periodic DRX cycles, each having an extended cycle length TeDRX and including one or more DRX cycles. The extended cycle length TCDRX is greater than the cycle length TDRX. In such embodiments, the minimum period is a function of the extended cycle length TeDRX instead of or in addition to being a function of the cycle length TDRX. Various examples of these embodiments were given above in equation form.
In some embodiments, the exemplary method can also include the operations of block 720, where the network node can transmit, via the at least one cell, information about a plurality of neighbor cells, wherein the information includes CCA-related information. In various embodiments, the CCA-related information for each neighbor cell can include any of the CCA- related information discussed above in relation to UE embodiments.
Although various embodiments are described above in terms of methods, techniques, and/or procedures, the person of ordinary skill will readily comprehend that such methods, techniques, and/or procedures can be embodied by various combinations of hardware and software in various systems, communication devices, computing devices, control devices, apparatuses, non-transitory computer-readable media, computer program products, etc.
Figure 8 shows an example of a communication system 800 in accordance with some embodiments. In this example, the communication system 800 includes a telecommunication network 802 that includes an access network 804 (such as a RAN) and a core network 806, which includes one or more core network nodes 808. The access network 804 includes one or more access network nodes, such as network nodes 810a-b (one or more of which may be generally referred to as network nodes 810), or any other similar 3GPP access node or non-3GPP access point. The network nodes 810 facilitate direct or indirect connection of UEs, such as by connecting UEs 812a-d (one or more of which may be generally referred to as UEs 812) to the core network 806 over one or more wireless connections.
Example wireless communications over a wireless connection include transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 800 may include any number of wired or wireless networks, network nodes, UEs, and/or any other components or systems that may facilitate or participate in the communication of data and/or signals whether via wired or wireless connections. The communication system 800 may include and/or interface with any type of communication, telecommunication, data, cellular, radio network, and/or other similar type of system.
UEs 812 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and/or operable to communicate wirelessly with the network nodes 810 and other communication devices. Similarly, network nodes 810 are arranged, capable, configured, and/or operable to communicate directly or indirectly with UEs 812 and/or with other network nodes or equipment in telecommunication network 802 to enable and/or provide network access, such as wireless network access, and/or to perform other functions, such as administration in telecommunication network 802.
In the depicted example, core network 806 connects network nodes 810 to one or more hosts, such as host 816. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. Core network 806 includes one more core network nodes (e.g., core network node 808) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and/or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 808. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and/or a User Plane Function (UPF).
Host 816 may be under the ownership or control of a service provider other than an operator or provider of access network 804 and/or telecommunication network 802, and may be operated by the service provider or on behalf of the service provider. Host 816 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio/video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.
Communication system 800 of Figure 8 enables connectivity between the UEs, network nodes, and hosts. For example, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and/or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and/or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and/or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.
In some examples, the telecommunication network 802 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 802 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 802. For example, the telecommunications network 802 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and/or Massive Machine Type Communication (mMTC)/Massive loT services to yet further UEs.
In some examples, UEs 812 are configured to transmit and/or receive information without direct human interaction. For instance, a UE may be designed to transmit information to access network 804 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from access network 804. Additionally, a UE may be configured for operating in single- or multi-RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e., being configured for multi -radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).
In the example, hub 814 communicates with the access network 804 to facilitate indirect communication between one or more UEs (e.g., UE 812c and/or 812d) and network nodes (e.g., network node 810b). In some examples, hub 814 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, hub 814 may be a broadband router enabling access to core network 806 for the UEs. As another example, hub 814 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from UEs, network nodes 810, or by executable code, script, process, or other instructions in hub 814. As another example, hub 814 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, hub 814 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, hub 814 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which hub 814 then provides to the UE either directly, after performing local processing, and/or after adding additional local content. In still another example, hub 814 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy loT devices.
Hub 814 may have a constant/persistent or intermittent connection to the network node 810b. Hub 814 may also allow for a different communication scheme and/or schedule between hub 814 and UEs (e.g., UE 812c and/or 812d), and between hub 814 and core network 806. In other examples, hub 814 is connected to core network 806 and/or one or more UEs via a wired connection. Moreover, hub 814 may be configured to connect to an M2M service provider over access network 804 and/or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with network nodes 810 while still connected via hub 814 via a wired or wireless connection. In some embodiments, hub 814 may be a dedicated hub - that is, a hub whose primary function is to route communications to/from the UEs from/to network node 810b. In other embodiments, hub 814 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 810b, but which is additionally capable of operating as a communication start and/or end point for certain data channels. Figure 9 shows a UE 900 in accordance with some embodiments. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle-mounted or vehicle embedded/integrated wireless device, etc. Other examples include any UE identified by 3GPP, including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and/or an enhanced MTC (eMTC) UE.
A UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and/or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).
UE 900 includes processing circuitry 902 that is operatively coupled via bus 904 to input/output interface 906, power source 908, memory 910, communication interface 912, and/or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 9. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.
Processing circuitry 902 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in memory 910. Processing circuitry 902 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field- programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 902 may include multiple central processing units (CPUs).
In the example, the input/output interface 906 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and/or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 900. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.
In some embodiments, power source 908 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. Power source 908 may further include power circuitry for delivering power from power source 908 itself, and/or an external power source, to the various parts of UE 900 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of power source 908. Power circuitry may perform any formatting, converting, or other modification to the power from power source 908 to make the power suitable for the respective components of the UE 900 to which power is supplied.
Memory 910 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, memory 910 includes one or more application programs 914, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 916. Memory 910 may store, for use by UE 900, any of a variety of various operating systems or combinations of operating systems.
Memory 910 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and/or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory 910 may allow the UE 900 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 910, which may be or comprise a device-readable storage medium.
Processing circuitry 902 may be configured to communicate with an access network or other network using communication interface 912. Communication interface 912 may comprise one or more communication subsystems and may include or be communicatively coupled to antenna 922. Communication interface 912 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include transmitter 918 and/or receiver 920 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, transmitter 918 and receiver 920 may be coupled to one or more antennas (e.g., antenna 922) and may share circuit components, software or firmware, or alternatively be implemented separately.
In the illustrated embodiment, communication functions of communication interface 912 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and/or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol/intemet protocol (TCP/IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.
Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 912, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., an alert is sent when moisture is detected), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient). As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.
A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, a motion detector, a thermostat, a smoke detector, a door/window sensor, a flood/moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item-tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and/or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 900 shown in Figure 9.
As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and/or measurements and transmits the results of such monitoring and/or measurements to another UE and/or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation.
In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g., by controlling an actuator) to increase or decrease the drone’s speed. The first and/or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.
Figure 10 shows a network node 1000 in accordance with some embodiments. Examples of network nodes include, but are not limited to, access points (e.g., radio access points) and base stations (e.g., radio base stations, Node Bs, eNBs, and gNBs).
Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and/or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).
Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell/multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and/or Minimization of Drive Tests (MDTs).
Network node 1000 includes processing circuitry 1002a memory 1004, communication interface 1006, and power source 1008. Network node 1000 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which network node 1000 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, network node 1000 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 1004 for different RATs) and some components may be reused (e.g., a same antenna 1010 may be shared by different RATs). Network node 1000 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1000, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 1000.
Processing circuitry 1002 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and/or encoded logic operable to provide, either alone or in conjunction with other network node 1000 components, such as the memory 1004, to provide network node 1000 functionality.
In some embodiments, processing circuitry 1002 includes a system on a chip (SOC). In some embodiments, the processing circuitry 1002 includes one or more of radio frequency (RF) transceiver circuitry 1012 and baseband processing circuitry 1014. In some embodiments, radio frequency (RF) transceiver circuitry 1012 and baseband processing circuitry 1014 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 1012 and baseband processing circuitry 1014 may be on the same chip or set of chips, boards, or units.
Memory 1004 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or any other volatile or non-volatile, non-transitory device-readable and/or computer-executable memory devices that store information, data, and/or instructions that may be used by the processing circuitry 1002. The memory 1004 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and/or other instructions (collectively denoted computer program product 1004a) capable of being executed by the processing circuitry 1002 and utilized by the network node 1000. The memory 1004 may be used to store any calculations made by the processing circuitry 1002 and/or any data received via the communication interface 1006. In some embodiments, the processing circuitry 1002 and memory 1004 is integrated.
Communication interface 1006 is used in wired or wireless communication of signaling and/or data between a network node, access network, and/or UE. As illustrated, communication interface 1006 comprises port(s)/terminal(s) 1016 to send and receive data, for example to and from a network over a wired connection. Communication interface 1006 also includes radio front- end circuitry 1018 that may be coupled to, or in certain embodiments a part of, the antenna 1010. Radio front-end circuitry 1018 comprises filters 1020 and amplifiers 1022. Radio front-end circuitry 1018 may be connected to antenna 1010 and processing circuitry 1002. The radio frontend circuitry may be configured to condition signals communicated between antenna 1010 and processing circuitry 1002. Radio front-end circuitry 1018 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. Radio front-end circuitry 1018 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1020 and/or amplifiers 1022. The radio signal may then be transmitted via antenna 1010. Similarly, when receiving data, the antenna 1010 may collect radio signals which are then converted into digital data by radio front-end circuitry 1018. The digital data may be passed to processing circuitry 1002. In other embodiments, the communication interface may comprise different components and/or different combinations of components.
In certain alternative embodiments, network node 1000 does not include separate radio front-end circuitry 1018, instead, processing circuitry 1002 includes radio front-end circuitry and is connected to antenna 1010. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1012 is part of communication interface 1006. In still other embodiments, communication interface 1006 includes one or more ports or terminals 1016, radio front-end circuitry 1018, and RF transceiver circuitry 1012, as part of a radio unit (not shown), and the communication interface 1006 communicates with baseband processing circuitry 1014, which is part of a digital unit (not shown).
Antenna 1010 may include one or more antennas, or antenna arrays, configured to send and/or receive wireless signals. Antenna 1010 may be coupled to radio front-end circuitry 1018 and may be any type of antenna capable of transmitting and receiving data and/or signals wirelessly. In certain embodiments, antenna 1010 is separate from network node 1000 and connectable to network node 1000 through an interface or port.
Antenna 1010, communication interface 1006, and/or processing circuitry 1002 may be configured to perform any receiving operations and/or certain obtaining operations described herein as being performed by the network node. Any information, data and/or signals may be received from a UE, another network node and/or any other network equipment. Similarly, antenna 1010, communication interface 1006, and/or processing circuitry 1002 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and/or signals may be transmitted to a UE, another network node and/or any other network equipment.
Power source 1008 provides power to the various components of network node 1000 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). Power source 1008 may further comprise, or be coupled to, power management circuitry to supply the components of network node 1000 with power for performing the functionality described herein. For example, network node 1000 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of power source 1008. As a further example, power source 1008 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.
Embodiments of network node 1000 may include additional components beyond those shown in Figure 10 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and/or any functionality necessary to support the subject matter described herein. For example, network node 1000 may include user interface equipment to allow input of information into network node 1000 and to allow output of information from network node 1000. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for network node 1000.
Figure 11 is a block diagram of a host 1100, which may be an embodiment of host 816 of Figure 8, in accordance with various aspects described herein. As used herein, host 1100 may be or comprise various combinations hardware and/or software, including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, container, or processing resources in a server farm. Host 1100 may provide one or more services to one or more UEs.
Host 1100 includes processing circuitry 1102 that is operatively coupled via bus 1104 to input/output interface 1106, network interface 1108, power source 1110, and memory 1112. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Figures 9 and 10, such that the descriptions thereof are generally applicable to the corresponding components of host 1100.
Memory 1112 may include one or more computer programs including one or more host application programs 1114 and data 1116, which may include user data, e.g., data generated by a UE for host 1100 or data generated by host 1100 for a UE. Embodiments of host 1100 may utilize only a subset or all of the components shown. Host application programs 1114 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), MPEG, VP9) and audio codecs (e.g., FLAC, Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, or implementations of UEs (e.g., handsets, desktop computers, wearable display systems, heads-up display systems). Host application programs 1114 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, host 1100 may select and/or indicate a different host for over-the-top services for a UE. Host application programs 1114 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real- Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (MPEG-DASH), etc.
Figure 12 is a block diagram illustrating a virtualization environment 1200 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 1200 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., core network node or host), then the node may be entirely virtualized.
Applications 1202 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment 1200 to implement some of the features, functions, and/or benefits of some of the embodiments disclosed herein.
Hardware 1204 includes processing circuitry, memory that stores software and/or instructions (collectively denoted computer program product 1204a) executable by hardware processing circuitry, and/or other hardware devices as described herein, such as a network interface, input/output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1206 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1208a-b (one or more of which may be generally referred to as VMs 1208), and/or perform any of the functions, features and/or benefits described in relation with some embodiments described herein. Virtualization layer 1206 may present a virtual operating platform that appears like networking hardware to VMs 1208.
VMs 1208 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1206. Different embodiments of the instance of virtual appliance 1202 may be implemented on one or more of VMs 1208, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.
In the context of NFV, VM 1208 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each VM 1208, and that part of hardware 1204 that executes that VM, be it hardware dedicated to that VM and/or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1208 on top of hardware 1204 and corresponds to application 1202.
Hardware 1204 may be implemented in a standalone network node with generic or specific components. Hardware 1204 may implement some functions via virtualization. Alternatively, hardware 1204 may be part of a larger cluster of hardware (e.g., such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 1210, which, among others, oversees lifecycle management of applications 1202. In some embodiments, hardware 1204 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 1212 which may alternatively be used for communication between hardware nodes and radio units.
Figure 13 shows a communication diagram of a host 1302 communicating via a network node 1304 with a UE 1306 over a partially wireless connection in accordance with some embodiments. Example implementations, in accordance with various embodiments, of the UE (such as a UE 812a of Figure 8 and/or UE 900 of Figure 9), network node (such as network node 810a of Figure 8 and/or network node 1000 of Figure 10), and host (such as host 816 of Figure 8 and/or host 1100 of Figure 11) discussed in the preceding paragraphs will now be described with reference to Figure 13.
Like host 1100, embodiments of host 1302 include hardware, such as a communication interface, processing circuitry, and memory. Host 1302 also includes software, which is stored in or accessible by the host 1302 and executable by the processing circuitry. The software includes a host application that may be operable to provide a service to a remote user, such as UE 1306 connecting via an over-the-top (OTT) connection 1350 extending between UE 1306 and host 1302. In providing the service to the remote user, a host application may provide user data which is transmitted using OTT connection 1350.
Network node 1304 includes hardware enabling it to communicate with host 1302 and UE 1306. Connection 1360 may be direct or pass through a core network e.g., 806 of Figure 8) and/or one or more other intermediate networks, such as one or more public, private, or hosted networks. For example, an intermediate network may be a backbone network or the Internet.
UE 1306 includes hardware and software, which is stored in or accessible by UE 1306 and executable by the UE’s processing circuitry. The software includes a client application, such as a web browser or operator-specific “app” that may be operable to provide a service to a human or non-human user via UE 1306 with the support of host 1302. In host 1302, an executing host application may communicate with the executing client application via OTT connection 1350 terminating at UE 1306 and host 1302. In providing the service to the user, the UE's client application may receive request data from the host's host application and provide user data in response to the request data. OTT connection 1350 may transfer both the request data and the user data. The UE's client application may interact with the user to generate the user data that it provides to the host application through OTT connection 1350.
OTT connection 1350 may extend via a connection 1360 between host 1302 and network node 1304 and via wireless connection 1370 between network node 1304 and UE 1306 to provide the connection between host 1302 and UE 1306. Connection 1360 and wireless connection 1370, over which the OTT connection 1350 may be provided, have been drawn abstractly to illustrate the communication between host 1302 and UE 1306 via network node 1304, without explicit reference to any intermediary devices and the precise routing of messages via these devices.
As an example of transmitting data via OTT connection 1350, in step 1308, host 1302 provides user data, which may be performed by executing a host application. In some embodiments, the user data is associated with a particular human user interacting with UE 1306. In other embodiments, the user data is associated with a UE 1306 that shares data with host 1302 without explicit human interaction. In step 1310, host 1302 initiates a transmission carrying the user data towards UE 1306. Host 1302 may initiate the transmission responsive to a request transmitted by UE 1306. The request may be caused by human interaction with UE 1306 or by operation of the client application executing on UE 1306. The transmission may pass via network node 1304, in accordance with the teachings of the embodiments described throughout this disclosure. Accordingly, in step 1312, network node 1304 transmits to UE 1306 the user data that was carried in the transmission that host 1302 initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 1314, UE 1306 receives the user data carried in the transmission, which may be performed by a client application executed on UE 1306 associated with the host application executed by host 1302.
In some examples, UE 1306 executes a client application which provides user data to host 1302. The user data may be provided in reaction or response to the data received from host 1302. Accordingly, in step 1316, UE 1306 may provide user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from the user via an input/output interface of UE 1306. Regardless of the specific manner in which the user data was provided, UE 1306 initiates, in step 1318, transmission of the user data towards host 1302 via the network node 1304. In step 1320, in accordance with the teachings of the embodiments described throughout this disclosure, network node 1304 receives user data from UE 1306 and initiates transmission of the received user data towards host 1302. In step 1322, host 1302 receives the user data carried in the transmission initiated by UE 1306.
One or more of the various embodiments improve the performance of OTT services provided to UE 1306 using OTT connection 1350, in which wireless connection 1370 forms the last segment. More precisely, embodiments described herein provide flexible and efficient techniques for cell selection by a UE operating in a non-connected state (e.g., RRC IDLE or RRC IN ACTIVE) and configured with DRX and at least one carrier frequency subject to CCA. Embodiments provide well-defined UE measurement behavior for cell selection in this scenario and ensure that UEs in this scenario search all possible configured cells that are strong enough before initiating a cell selection procedure. This in turn prevents such UEs from prematurely performing cell selection based on sub-optimal and/or incomplete information about available cells.
At a high level, embodiments improve the performance of networks and UEs operating in shared spectrum. Accordingly, OTT services can be delivered more reliably to UEs via networks operating in shared spectrum. This increases the value of such OTT services to both end users and service providers.
In an example scenario, factory status information may be collected and analyzed by host 1302. As another example, host 1302 may process audio and video data which may have been retrieved from a UE for use in creating maps. As another example, host 1302 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, host 1302 may store surveillance video uploaded by a UE. As another example, host 1302 may store or control access to media content such as video, audio, VR or AR which it can broadcast, multicast or unicast to UEs. As other examples, host 1302 may be used for energy pricing, remote control of non-time critical electrical load to balance power generation needs, location services, presentation services (such as compiling diagrams etc. from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing and/or transmitting data.
In some examples, a measurement procedure may be provided for the purpose of monitoring data rate, latency, and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring OTT connection 1350 between host 1302 and UE 1306, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection may be implemented in software and hardware of host 1302 and/or UE 1306. In some embodiments, sensors (not shown) may be deployed in or in association with other devices through which OTT connection 1350 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above or by supplying values of other physical quantities from which software may compute or estimate the monitored quantities. The reconfiguring of OTT connection 1350 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not directly alter the operation of network node 1304. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling that facilitates measurements of throughput, propagation times, latency and the like, by host 1302. The measurements may be implemented in that software causes messages to be transmitted, in particular empty or ‘dummy’ messages, using OTT connection 1350 while monitoring propagation times, errors, etc.
The foregoing merely illustrates the principles of the disclosure. Various modifications and alterations to the described embodiments will be apparent to those skilled in the art in view of the teachings herein. It will thus be appreciated that those skilled in the art will be able to devise numerous systems, arrangements, and procedures that, although not explicitly shown or described herein, embody the principles of the disclosure and can be thus within the spirit and scope of the disclosure. Various embodiments can be used together with one another, as well as interchangeably therewith, as should be understood by those having ordinary skill in the art.
The term unit, as used herein, can have conventional meaning in the field of electronics, electrical devices and/or electronic devices and can include, for example, electrical and/or electronic circuitry, devices, modules, processors, memories, logic solid state and/or discrete devices, computer programs or instructions for carrying out respective tasks, procedures, computations, outputs, and/or displaying functions, and so on, as such as those described herein.
Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processor (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as Read Only Memory (ROM), Random Access Memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more embodiments of the present disclosure.
As described herein, device and/or apparatus can be represented by a semiconductor chip, a chipset, or a (hardware) module comprising such chip or chipset; this, however, does not exclude the possibility that a functionality of a device or apparatus, instead of being hardware implemented, be implemented as a software module such as a computer program or a computer program product comprising executable software code portions for execution or being run on a processor. Furthermore, functionality of a device or apparatus can be implemented by any combination of hardware and software. A device or apparatus can also be regarded as an assembly of multiple devices and/or apparatuses, whether functionally in cooperation with or independently of each other. Moreover, devices and apparatuses can be implemented in a distributed fashion throughout a system, so long as the functionality of the device or apparatus is preserved. Such and similar principles are considered as known to a skilled person.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
In addition, certain terms used in the present disclosure, including the specification and drawings, can be used synonymously in certain instances (e.g., “data” and “information”). It should be understood, that although these terms (and/or other terms that can be synonymous to one another) can be used synonymously herein, there can be instances when such words can be intended to not be used synonymously.
Embodiments of the techniques and apparatus described herein also include, but are not limited to, the following enumerated examples: Al . A method for a user equipment (UE) configured for operation in a wireless network, the method comprising: performing a search for a suitable cell while operating in discontinuous reception (DRX) and in a non-connected state with respect to the wireless network, wherein the search includes performing measurements of at least one cell, of the wireless network, that is subject to a clear channel assessment (CCA) requirement; and initiating one or more cell selection procedures in response to performing the search for a period (T) without identifying a suitable cell, wherein T is a function of one or more CCA-related parameters for the at least one cell.
A2. The method of embodiment Al, wherein T is also a function of one or more DRX- related parameters.
A3. The method of any of embodiments A1-A2, wherein: the at least one cell includes the UE’s serving cell; the DRX includes periodic DRX cycles having a period or cycle length of TDRX; and the measurements are performed on the serving cell every J DRX cycles, where J is a function of the following: TDRX, a periodicity of a signal being measured, and a maximum number of DRX cycles between measurements.
A4. The method of embodiment A3, wherein performing the search comprises evaluating results of the measurements every J DRX cycles against one or more cell reselection criteria, wherein T is a number of consecutive DRX cycles (Nserv_ccA).
A5. The method of embodiment A4, wherein Nserv_ccA is a function of TDRX and the periodicity of the signal being measured.
A6. The method of embodiment A5, wherein Nserv_ccA is also a function of one or more of the following: UE power class (PC), and whether the UE uses receive beam sweeping to measure the signal.
A7. The method of any of embodiments A5-A6, wherein Nserv_ccA is also a function of the number of DRX cycles during which the signal being measured is not available to be measured by the UE on at least one occasion due to a CCA failure, subject to a maximum number of DRX cycles. A7a. The method of embodiment A7, further comprising performing one of the following when the number of DRX cycles during which the signal is not available to be measured exceeds the maximum number of DRX cycles: restarting the period (T) of the search for a suitable cell, or initiating the one or more cell selection procedures.
A8. The method of any of embodiments A3-A7a, wherein: the method further comprises obtaining, via the serving cell, information about a plurality of neighbor cells, wherein the information includes CCA-related information; and initiating one or more cell selection procedures comprises: ranking the neighbor cells based on the CCA-related information; and initiating the cell selection procedures on the neighbor cells in order of ranking.
A8. The method of embodiment A7, wherein ranking the neighbor cells is further based on measurements of the neighbor cells made by the UE while performing the search.
A9. The method of any of embodiments A7-A8, wherein the CCA-related information for each neighbor cell includes one or more of the following: number of downlink (DL) CCA failures (Nf) for the neighbor cell during a previous time interval (Txl); number of DL CCA successes (Ns) for the neighbor cell during the previous time interval (Txl); relation between Nf and Ns during the previous time interval (Txl); predicted number of DL CCA failures (Nf) for the neighbor cell during a subsequent time interval (Tx2); predicted number of DL CCA successes (Ns) for the neighbor cell during the subsequent time interval (Tx2); and predicted relation between Nf and Ns during the subsequent time interval (Tx2).
A10. The method of embodiment A9, wherein the neighbor cells are ranked in order of one of the following: decreasing likelihood of CCA success during the subsequent time interval; increasing likelihood of CCA failure during the subsequent time interval; decreasing CCA success rate during the previous time interval; or increasing CCA failure rate during the subsequent time interval. Al 1. The method of any of embodiments Al -A3, wherein: the DRX includes periodic DRX cycles having a period or cycle length of TDRX; and
T is a function of the following: duration (PICCA) required for the UE to evaluate or detect the at least one cell subject to the CCA requirement;
TDRX; and a periodicity of a signal being measured in the at least one cell.
A12. The method of embodiment All, wherein T is also a function of one or more of the following: UE power class (PC), number of UE antennas used to perform the measurements, frequency range of the at least one cell, and whether the UE uses receive beam sweeping to perform the measurements.
Al 3. The method of any of embodiments Al 1 -Al 2, wherein the duration (PICCA) is a function of one or more of the following: a relation (KI) between DRX cycle length and the periodicity of a signal being measured; a number of DRX cycles (Pls) during which the signal being measured is not available to be measured by the UE during the duration (PICCA), due to CCA failure; a maximum number of DRX cycles (Pls, max) during which the signal being measured is not available to be measured; and frequency range of the at least one cell.
A14. The method of embodiment A13, wherein one or more of the following is also a function of TDRX: the relation (KI), the maximum number of DRX cycles (Pls, max), and a scaling factor (Nl) related to UE beam sweeping and/or frequency range of the at least one cell.
Al 5. The method of any of embodiments Al 1 -Al 4, wherein: the DRX includes extended periodic DRX cycles, each having a period or cycle length of TCDRX > TDRX and including one or more DRX cycles; and
T is a function of TeDRX instead of or in addition to TDRX.
A16. The method of any of embodiments A1-A15, further comprising obtaining T, or the CCA-related parameters of which T is a function, via one or more of the following: a message from a network node serving the at least one cell; a storage medium of the UE;
UE determination based on historical data or statistics for T or the CCA-related parameters; and
UE determination based on non-CCA-related parameters.
Bl . A method for a network node configured to serve at least one cell that is subject to a clear channel assessment (CCA) requirement in a wireless network, the method comprising: transmitting one of the following in the at least one cell: a minimum period (T) for UEs to search for a suitable cell during discontinuous reception (DRX) operation in a non-connected with respect to the wireless network, before initiating one or more cell selection procedures; or one or more CCA-related parameters for the at least one cell, of which T is a function.
B2. The method of embodiment Bl, wherein T is also a function of one or more parameters related to the DRX operation.
B3. The method of embodiment B2, wherein: the DRX includes periodic DRX cycles having a period or cycle length of TDRX; and
T is a function of the following: duration (PICCA) required for the UE to evaluate or detect the at least one cell subject to the CCA requirement;
TDRX; and a periodicity of a signal being measured by the UE in the at least one cell.
B4. The method of embodiment B3, wherein T is also a function of one or more of the following: UE power class (PC), number of UE antennas used to perform the measurements, frequency range of the at least one cell, and whether the UE uses receive beam sweeping to perform the measurements.
B5. The method of any of embodiments B3-B4, wherein the duration (PICCA) is a function of one or more of the following: a relation (KI) between DRX cycle length and the periodicity of a signal being measured; a number of DRX cycles (Pls) during which the signal being measured is not available to be measured by the UE during the duration (PICCA), due to CCA failure; a maximum number of DRX cycles (Pls, max) during which the signal being measured is not available to be measured; and frequency range of the at least one cell.
B6. The method of embodiment B5, wherein one or more of the following is also a function of TDRX: the relation (KI), the maximum number of DRX cycles (Pls, max), and a scaling factor (Nl) related to UE beam sweeping and/or frequency range of the at least one cell.
B7. The method of any of embodiments B3-B6, wherein: the DRX includes extended periodic DRX cycles, each having a period or cycle length of TCDRX > TDRX and including one or more DRX cycles; and
T is a function of TCDRX instead of or in addition to TDRX.
B8. The method of any of embodiments B1-B7, further comprising transmitting, via the at least one cell, information about a plurality of neighbor cells, wherein the information includes CCA-related information.
B9. The method of embodiment B8, wherein the CCA-related information for each neighbor cell includes one or more of the following: number of downlink (DL) CCA failures (Nf) for the neighbor cell during a previous time interval (Txl); number of DL CCA successes (Ns) for the neighbor cell during the previous time interval (Txl); relation between Nf and Ns during the previous time interval (Txl); predicted number of DL CCA failures (Nf) for the neighbor cell during a subsequent time interval (Tx2); predicted number of DL CCA successes (Ns) for the neighbor cell during the subsequent time interval (Tx2); and predicted relation between Nf and Ns during the subsequent time interval (Tx2).
CL A user equipment (UE) configured for operation in a wireless network, the UE comprising: communication interface circuitry configured to communicate with a network node via at least one cell; and processing circuitry operatively coupled to the communication interface circuitry, whereby the processing circuitry and the communication interface circuitry are configured to perform operations corresponding to any of the methods of embodiments Al -Al 6.
C2. A user equipment (UE) configured for operation in a wireless network, the UE being further configured to perform operations corresponding to any of the methods of embodiments A1-A16.
C3. A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a user equipment (UE) configured for operation in a wireless network, configure the UE to perform operations corresponding to any of the methods of embodiments Al -Al 6.
C4. A computer program product comprising computer-executable instructions that, when executed by processing circuitry of a user equipment (UE) configured for operation in a wireless network, configure the UE to perform operations corresponding to any of the methods of embodiments Al -Al 6.
DI. A network node configured to serve at least one cell that is subject to a clear channel assessment (CCA) requirement in a wireless network, the network node comprising: communication interface circuitry configured to communicate with user equipment (UEs) via the at least one cell; and processing circuitry operatively coupled to the communication interface circuitry, whereby the processing circuitry and the communication interface circuitry are configured to perform operations corresponding to any of the methods of embodiments B1-B9.
D2. A network node configured to serve at least one cell that is subject to a clear channel assessment (CCA) requirement in a wireless network, the network node being further configured to perform operations corresponding to any of the methods of embodiments B1-B9.
D3. A non-transitory, computer-readable medium storing computer-executable instructions that, when executed by processing circuitry of a network node configured to serve at least one cell that is subject to a clear channel assessment (CCA) requirement in a wireless network, configure the network node to perform operations corresponding to any of the methods of embodiments B1-B9.
D4. A computer program product comprising computer-executable instructions that, when executed by processing circuitry of a network node configured to serve at least one cell that is subject to a clear channel assessment (CCA) requirement in a wireless network, configure the network node to perform operations corresponding to any of the methods of embodiments Bl- B9.

Claims

1. A method for a user equipment, UE, configured for operation in a wireless network, the method comprising: performing (630) a search for a suitable cell while operating in discontinuous reception, DRX, and in a non-connected state with respect to the wireless network, wherein performing (630) the search includes performing (631) measurements of at least one cell, of the wireless network, that is subject to a clear channel assessment, CCA, requirement; and initiating (650) one or more cell selection procedures in response to performing (630) the search for at least a minimum period without identifying a suitable cell, wherein the minimum period is a function of one or more CCA-related parameters for the at least one cell.
2. The method of claim 1, wherein the minimum period is also a function of one or more DRX-related parameters.
3. The method of any of claims 1-2, wherein: the at least one cell includes the UE’s serving cell; the DRX includes periodic DRX cycles, each having a cycle length TDRX; and the measurements are performed on the serving cell every Jth DRX cycle, where J is a function of the following: the cycle length TDRX, a periodicity of a signal being measured, and a maximum number of DRX cycles between measurements.
4. The method of claim 3, wherein performing (630) the search comprises evaluating (632) results of the measurements performed every Jth DRX cycle against one or more cell reselection criteria, wherein the minimum period comprises a number of consecutive DRX cycles.
5. The method of claim 4, wherein the number of consecutive DRX cycles is a function of the cycle length TDRX and a periodicity of the signal being measured.
6. The method of claim 5, wherein the number of consecutive DRX cycles is also a function of one or more of the following: UE power class; and whether the UE uses receive beam sweeping to measure the signal.
7. The method of any of claims 5-6, wherein the number of consecutive DRX cycles is also a function of a number of DRX cycles during which the signal being measured is not available to be measured by the UE on at least one occasion due to a CCA failure.
8. The method of claim 7, further comprising performing one of the following when the number of DRX cycles during which the signal is not available to be measured by the UE, within a time period, exceeds a maximum number of unavailable DRX cycles for the time period: restarting (640) the search for a suitable cell in relation to the minimum period, or initiating (650) the one or more cell selection procedures.
9. The method of any of claims 3-8, wherein: the method further comprises obtaining (620), via the serving cell, information about a plurality of neighbor cells, wherein the information includes CCA-related information; and initiating (650) the one or more cell selection procedures comprises: ranking (651) the neighbor cells in an order based on the CCA-related information; and initiating (652) the cell selection procedures on the neighbor cells in the order of ranking.
10. The method of claim 9, wherein ranking (651) the neighbor cells is further based on measurements of the neighbor cells made by the UE while performing the search.
11. The method of any of claims 9-10, wherein the CCA-related information for each neighbor cell includes one or more of the following: number of downlink CCA failures for the neighbor cell during a previous time interval; number of downlink CCA successes for the neighbor cell during the previous time interval; relation between number of downlink CCA failures and number of downlink CCA successes during the previous time interval; predicted number of downlink CCA failures for the neighbor cell during a subsequent time interval; predicted number of downlink CCA successes for the neighbor cell during the subsequent time interval; and predicted relation between number of downlink CCA failures and number of downlink CCA successes during the subsequent time interval.
12. The method of claim 11, wherein the neighbor cells are ranked in order of one of the following: decreasing likelihood of CCA success during the subsequent time interval; increasing likelihood of CCA failure during the subsequent time interval; decreasing CCA success rate during the previous time interval; or increasing CCA failure rate during the subsequent time interval.
13. The method of any of claims 1-3, wherein: the DRX includes periodic DRX cycles, each having a cycle length of TDRX; and the minimum period is a function of the following: a duration PICCA required for the UE to evaluate or detect the at least one cell subject to the CCA requirement; the cycle length TDRX; and a periodicity of a signal being measured in the at least one cell.
14. The method of claim 13, wherein the minimum period is also a function of one or more of the following: UE power class; number of UE antennas used to perform the measurements; frequency range of the at least one cell subject to CCA requirement; and whether the UE uses receive beam sweeping to perform the measurements.
15. The method of any of claims 13-14, wherein the duration PICCA is a function of one or more of the following: a relation between DRX cycle length and the periodicity of a signal being measured; a number of DRX cycles, within a time period, during which the signal being measured is not available to be measured by the UE due to CCA failure; a maximum number of DRX cycles during which the signal being measured is not available to be measured by the UE due to CCA failure; and frequency range of the at least one cell.
16. The method of claim 15, wherein one or more of the following is also a function of the cycle length TDRX: the relation between the cycle length TDRX and the periodicity of a signal being measured; the maximum number of DRX cycles during which the signal being measured is not available to be measured by the UE due to CCA failure; and a scaling factor related to UE beam sweeping and/or frequency range of the at least one cell.
17. The method of any of claims 13-16, wherein: the DRX includes extended periodic DRX cycles, each having an extended cycle length TCDRX and including one or more DRX cycles; the extended cycle length TeDRX is greater than the cycle length TDRX; and the minimum period T is a function of the extended cycle length TeDRX instead of or in addition to being a function of the cycle length TDRX.
18. The method of any of claims 1-17, further comprising obtaining the minimum period, or the CCA-related parameters of which the minimum period is a function, via one or more of the following: a message from a network node serving the at least one cell subject to a CCA requirement; a storage medium of the UE;
UE determination based on historical data or statistics for the minimum period or the CCA-related parameters of which the minimum period is a function; and
UE determination based on non-CCA-related parameters.
19. A method for a network node configured to serve at least one cell, in a wireless network, that is subject to a clear channel assessment, CCA, requirement, the method comprising: transmitting (710) one of the following via the at least one cell: a minimum period for UEs to search for a suitable cell during UE discontinuous reception, DRX, operation in a non-connected state with respect to the wireless network, before UE initiation of one or more cell selection procedures; or one or more CCA-related parameters for the at least one cell, of which the minimum period is a function.
20. The method of claim 19, wherein the minimum period is also a function of one or more parameters related to the DRX operation.
21. The method of claim 20, wherein: the DRX includes periodic DRX cycles, each having a cycle length TDRX; and the minimum period is a function of the following: a duration PICCA required for the UE to evaluate or detect the at least one cell subject to the CCA requirement; the cycle length TDRX; and a periodicity of a signal being measured by the UE in the at least one cell subject to the CCA requirement.
22. The method of claim 21, wherein the minimum period is also a function of one or more of the following: UE power class; number of UE antennas used to perform the measurements; frequency range of the at least one cell subject to CCA requirement; and whether the UE uses receive beam sweeping to perform the measurements.
23. The method of any of claims 21-22, wherein the duration P ICCA is a function of one or more of the following: a relation between DRX cycle length and the periodicity of a signal being measured; a number of DRX cycles, within a time period, during which the signal being measured is not available to be measured by the UE due to CCA failure; a maximum number of DRX cycles during which the signal being measured is not available to be measured by the UE due to CCA failure; and frequency range of the at least one cell.
24. The method of claim 23, wherein one or more of the following is also a function of the cycle length TDRX: the relation between the cycle length TDRX and the periodicity of a signal being measured; the maximum number of DRX cycles during which the signal being measured is not available to be measured, and a scaling factor related to UE beam sweeping and/or frequency range of the at least one cell.
25. The method of any of claims 21-24, wherein: the DRX includes extended periodic DRX cycles, each having an extended cycle length TCDRX and including one or more DRX cycles; the extended cycle length TeDRX is greater than the cycle length TDRX; and the minimum period T is a function of the extended cycle length TeDRX instead of or in addition to being a function of the cycle length TDRX.
26. The method of any of claims 19-25, further comprising transmitting (720), via the at least one cell, information about a plurality of neighbor cells, wherein the information includes CCA-related information.
27. The method of claim 26, wherein the CCA-related information for each neighbor cell includes one or more of the following: number of downlink CCA failures for the neighbor cell during a previous time interval; number of downlink CCA successes for the neighbor cell during the previous time interval; relation between number of DL CCA failures and number of downlink CCA successes during the previous time interval; predicted number of downlink CCA failures for the neighbor cell during a subsequent time interval; predicted number of downlink CCA successes for the neighbor cell during the subsequent time interval; and predicted relation between number of downlink CCA failures and number of downlink CCA successes during the subsequent time interval.
28. A user equipment, UE (110, 205, 812, 900, 1306) configured for operation in a wireless network (299, 410, 420, 804), the UE comprising: communication interface circuitry (912) configured to communicate with a network node (120, 210, 220, 810, 1000, 1202, 1304) via at least one cell; and processing circuitry (902) operatively coupled to the communication interface circuitry, whereby the processing circuitry and the communication interface circuitry are configured to: perform a search for a suitable cell while operating in discontinuous reception, DRX, and in a non-connected state with respect to the wireless network, wherein the search is performed to include measurements of at least one cell, of the wireless network, that is subject to a clear channel assessment, CCA, requirement; and initiate one or more cell selection procedures when the search is performed for at least a minimum period without identifying a suitable cell, wherein the minimum period is a function of one or more CCA-related parameters for the at least one cell.
29. The UE of claim 28, wherein the processing circuitry and the communication interface circuitry are further configured to perform operations corresponding to any of the methods of claims 2-18.
30. A user equipment, UE (110, 205, 812, 900, 1306) configured for operation in a wireless network (299, 410, 420, 804), the UE being further configured to: perform a search for a suitable cell while operating in discontinuous reception, DRX, and in a non-connected state with respect to the wireless network, wherein the search is performed to include measurements of at least one cell, of the wireless network, that is subject to a clear channel assessment, CCA, requirement; and initiate one or more cell selection procedures when the search is performed for at least a minimum period without identifying a suitable cell, wherein the minimum period is a function of one or more CCA-related parameters for the at least one cell.
31. The UE of claim 30, being further configured to perform operations corresponding to any of the methods of claims 2-18.
32. A non-transitory, computer-readable medium (910) storing computer-executable instructions that, when executed by processing circuitry (902) of a user equipment, UE (110, 205, 812, 900, 1306) configured for operation in a wireless network (299, 410, 420, 804), configure the UE to perform operations corresponding to any of the methods of claims 1-18.
33. A computer program product (914) comprising computer-executable instructions that, when executed by processing circuitry (902) of a user equipment, UE (110, 205, 812, 900, 1306) configured for operation in a wireless network (299, 410, 420, 804), configure the UE to perform operations corresponding to any of the methods of claims 1-18.
34. A network node (120, 210, 220, 810, 1000, 1202, 1304) configured to serve at least one cell, in a wireless network (299, 410, 420, 804), that is subject to a clear channel assessment, CCA, requirement, the network node comprising: communication interface circuitry (1006, 1204) configured to communicate with user equipment, UEs (110, 205, 812, 900, 1306) via the at least one cell; and processing circuitry (1002, 1204) operatively coupled to the communication interface circuitry, whereby the processing circuitry and the communication interface circuitry are configured to: transmit one of the following via the at least one cell: a minimum period for UEs to search for a suitable cell during UE discontinuous reception, DRX, operation in a non-connected state with respect to the wireless network, before UE initiation of one or more cell selection procedures; or one or more CCA-related parameters for the at least one cell, of which the minimum period is a function.
35. The network node of claim 34, wherein the processing circuitry and the communication interface circuitry are further configured to perform operations corresponding to any of the methods of claims 20-27.
36. A network node (120, 210, 220, 810, 1000, 1202, 1304) configured to serve at least one cell, in a wireless network (299, 410, 420, 804), that is subject to a clear channel assessment, CCA, requirement, the network node being further configured to: transmit one of the following via the at least one cell: a minimum period for UEs to search for a suitable cell during UE discontinuous reception, DRX, operation in a non-connected state with respect to the wireless network, before UE initiation of one or more cell selection procedures; or one or more CCA-related parameters for the at least one cell, of which the minimum period is a function.
37. The network node of claim 36, being further configured to perform operations corresponding to any of the methods of claims 20-27.
38. A non-transitory, computer-readable medium (1004, 1204) storing computer-executable instructions that, when executed by processing circuitry (1002, 1204) of a network node (120, 210, 220, 810, 1000, 1202, 1304) configured to serve at least one cell, in a wireless network (299, 410, 420, 804), that is subject to a clear channel assessment, CCA, requirement, configure the network node to perform operations corresponding to any of the methods of claims 19-27.
39. A computer program product (1004a, 1204a) comprising computer-executable instructions that, when executed by processing circuitry (1002, 1204) of a network node (120, 210, 220, 810, 1000, 1202, 1304) configured to serve at least one cell, in a wireless network (299, 410, 420, 804), that is subject to a clear channel assessment, CCA, requirement, configure the network node to perform operations corresponding to any of the methods of claims 19-27.
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