WO2021159469A1

WO2021159469A1 - Quantization for port selection codebook with spatial frequency beamforming

Info

Publication number: WO2021159469A1
Application number: PCT/CN2020/075274
Authority: WO
Inventors: Min Huang; Chenxi HAO; Liangming WU
Original assignee: Qualcomm Incorporated
Priority date: 2020-02-14
Filing date: 2020-02-14
Publication date: 2021-08-19

Abstract

A user equipment (UE) reports selected spatial-frequency domain beams in a beamforming system. The UE selects a plurality of sets of ports based on the plurality of reference signals corresponding to spatial layers, determines a common set of ports based on of the plurality of sets of ports, transmits a message identifying the common set of ports, and transmits a message identifying a plurality of layer-specific sets of ports, each layer-specific set of ports corresponding to a spatial layer and being based on the selected set of ports for that spatial layer and the common set of ports.

Description

QUANTIZATION FOR PORT SELECTION CODEBOOK WITH SPATIAL FREQUENCY BEAMFORMING

BACKGROUND Technical Field

The present disclosure relates generally to communication systems, and more particularly, to a wireless communication system.

Introduction

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. An example telecommunication standard is 5G New Radio (NR) . 5G NR is part of a continuous mobile broadband evolution promulgated by Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with Internet of Things (IoT) ) , and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB) , massive machine type communications (mMTC) , and ultra reliable low latency communications (URLLC) . Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There exists a need for further improvements in 5G NR technology. These improvements may also be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a user equipment (UE) . The apparatus may receive, from a base station, a plurality of reference signals corresponding to beam ports; select a plurality of sets of ports based on the plurality of reference signals, wherein each selected set of ports corresponds to a spatial layer; determine a common set of ports based on of the plurality of sets of ports; transmit, to the base station, a message identifying the common set of ports; and transmit, to the base station, a message identifying a plurality of layer-specific sets of ports, each layer-specific set of ports corresponding to a spatial layer and being based on the selected set of ports for that spatial layer and the common set of ports.

In another aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a base station. The apparatus may transmit, to a user equipment (UE) , a plurality of reference signals corresponding to beam ports; receive, from the UE, a message identifying a common set of ports, the common set of ports being based on a plurality of sets of selected ports, the plurality of sets of selected ports being based on the plurality of reference signals, each selected set of ports corresponding to a spatial layer; and receive, from the UE, a message identifying a plurality of layer-specific sets of ports, each layer-specific set of ports corresponding to a spatial layer and being based on the selected set of ports for that spatial layer and the common set of ports.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network.

FIGs. 2A, 2B, 2C, and 2D are diagrams illustrating examples of a first 5G/NR frame, DL channels within a 5G/NR subframe, a second 5G/NR frame, and UL channels within a 5G/NR subframe, respectively.

FIG. 3 is a diagram illustrating an example of a base station and user equipment (UE) in an access network.

FIG. 4 is a diagram 400 illustrating beamforming ports.

FIG. 5 is a communication flow diagram illustrating a UE selecting wideband beam ports of a base station.

FIG. 6 is a diagram illustrating a quantization format for reporting selected ports.

FIG. 7 is a diagram illustrating a quantization format for reporting selected ports.

FIG. 8 is a diagram illustrating a quantization format for reporting selected ports.

FIG. 9 is a flowchart of a method of wireless communication.

FIG. 10 is a flowchart of a method of wireless communication.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs) , central processing units (CPUs) , application processors, digital signal processors (DSPs) , reduced instruction set computing (RISC) processors, systems on a chip (SoC) , baseband processors, field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Accordingly, in one or more example embodiments, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise a random-access memory (RAM) , a read-only memory (ROM) , an electrically erasable programmable ROM (EEPROM) , optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network 100. The wireless communications system (also referred to as a wireless wide area network (WWAN) ) includes base stations 102, UEs 104, an Evolved Packet Core (EPC) 160, and another core network 190 (e.g., a 5G Core (5GC) ) . The base stations 102 may include macrocells (high power cellular base station) and/or small cells (low power cellular base station) . The macrocells include base stations. The small cells include femtocells, picocells, and microcells.

The base stations 102 configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN) ) may interface with the EPC 160 through first backhaul links 132 (e.g., S1 interface) . The base stations 102 configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN) ) may interface with core network 190 through second backhaul links 184. In addition to other functions, the base stations 102 may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity) , inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS) , subscriber and equipment trace, RAN information management (RIM) , paging, positioning, and delivery of warning messages. The base stations 102 may communicate directly or indirectly (e.g., through the EPC 160 or core network 190) with each other over third backhaul links 134 (e.g., X2 interface) . The third backhaul links 134 may be wired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, the small cell 102' may have a coverage area 110' that overlaps the coverage area 110 of one or more macro base stations 102. A network that includes both small cell and macrocells may be known as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs) , which may provide service to a restricted group known as a closed subscriber group (CSG) . The communication links 120 between the base stations 102 and the UEs 104 may include uplink (UL) (also referred to as reverse link) transmissions from a UE 104 to a base station 102 and/or downlink (DL) (also referred to as forward link) transmissions from a base station 102 to a UE 104. The communication links 120 may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The base stations 102/UEs 104 may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL than for UL) . The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (SCell) .

Certain UEs 104 may communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 may use the DL/UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH) , a physical sidelink discovery channel (PSDCH) , a physical sidelink shared channel (PSSCH) , and a physical sidelink control channel (PSCCH) . D2D communication may be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi access point (AP) 150 in communication with Wi-Fi stations (STAs) 152 via communication links 154 in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs 152/AP 150 may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

The small cell 102' may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell 102' may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP 150. The small cell 102', employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network.

A base station 102, whether a small cell 102' or a large cell (e.g., macro base station) , may include and/or be referred to as an eNB, gNodeB (gNB) , or another type of base station. Some base stations, such as gNB 180 may operate in a traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, and/or near mmW frequencies in communication with the UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as an mmW base station. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in the band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW/near mmW radio frequency band (e.g., 3 GHz –300 GHz) has extremely high path loss and a short range. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range. The base station 180 and the UE 104 may each include a plurality of antennas, such as antenna elements, antenna panels, and/or antenna arrays to facilitate the beamforming.

The base station 180 may transmit a beamformed signal to the UE 104 in one or more transmit directions 182'. The UE 104 may receive the beamformed signal from the base station 180 in one or more receive directions 182” . The UE 104 may also transmit a beamformed signal to the base station 180 in one or more transmit directions. The base station 180 may receive the beamformed signal from the UE 104 in one or more receive directions. The base station 180/UE 104 may perform beam training to determine the best receive and transmit directions for each of the base station 180/UE 104. The transmit and receive directions for the base station 180 may or may not be the same. The transmit and receive directions for the UE 104 may or may not be the same.

The EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be in communication with a Home Subscriber Server (HSS) 174. The MME 162 is the control node that processes the signaling between the UEs 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides UE IP address allocation as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to the IP Services 176. The IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services. The BM-SC 170 may provide functions for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN) , and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS traffic to the base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

The core network 190 may include a Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 may be in communication with a Unified Data Management (UDM) 196. The AMF 192 is the control node that processes the signaling between the UEs 104 and the core network 190. Generally, the AMF 192 provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF 195. The UPF 195 provides UE IP address allocation as well as other functions. The UPF 195 is connected to the IP Services 197. The IP Services 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS) , a PS Streaming Service, and/or other IP services.

The base station may include and/or be referred to as a gNB, Node B, eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , a transmit reception point (TRP) , or some other suitable terminology. The base station 102 provides an access point to the EPC 160 or core network 190 for a UE 104. Examples of UEs 104 include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA) , a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player) , a camera, a game console, a tablet, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs 104 may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc. ) . The UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

Referring again to FIG. 1, in certain aspects, the UE 104 may include a quantization component 198, configured to reduce the size of a CSI reporting message transmitted to the base station 180. In certain aspects, the base station 180 may include a quantization component 199 configured to receive and understand the CSI reporting message received from the UE 104. Although the following description may be focused on 5G NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

FIG. 2A is a diagram 200 illustrating an example of a first subframe within a 5G/NR frame structure. FIG. 2B is a diagram 230 illustrating an example of DL channels within a 5G/NR subframe. FIG. 2C is a diagram 250 illustrating an example of a second subframe within a 5G/NR frame structure. FIG. 2D is a diagram 280 illustrating an example of UL channels within a 5G/NR subframe. The 5G/NR frame structure may be FDD in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for either DL or UL, or may be TDD in which for a particular set of subcarriers (carrier system bandwidth) , subframes within the set of subcarriers are dedicated for both DL and UL. In the examples provided by FIGs. 2A, 2C, the 5G/NR frame structure is assumed to be TDD, with subframe 4 being configured with slot format 28 (with mostly DL) , where D is DL, U is UL, and X is flexible for use between DL/UL, and subframe 3 being configured with slot format 34 (with mostly UL) . While

subframes

3, 4 are shown with slot formats 34, 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. Slot formats 0, 1 are all DL, UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. UEs are configured with the slot format (dynamically through DL control information (DCI) , or semi-statically/statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI) . Note that the description infra applies also to a 5G/NR frame structure that is TDD.

Other wireless communication technologies may have a different frame structure and/or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms) . Each subframe may include one or more time slots. Subframes may also include mini-slots, which may include 7, 4, or 2 symbols. Each slot may include 7 or 14 symbols, depending on the slot configuration. For slot configuration 0, each slot may include 14 symbols, and for slot configuration 1, each slot may include 7 symbols. The symbols on DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols. The symbols on UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also referred to as single carrier frequency-division multiple access (SC-FDMA) symbols) (for power limited scenarios; limited to a single stream transmission) . The number of slots within a subframe is based on the slot configuration and the numerology. For slot configuration 0, different numerologies μ 0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots, respectively, per subframe. For slot configuration 1, different numerologies 0 to 2 allow for 2, 4, and 8 slots, respectively, per subframe. Accordingly, for slot configuration 0 and numerology μ, there are 14 symbols/slot and 2 ^μ slots/subframe. The subcarrier spacing and symbol length/duration are a function of the numerology. The subcarrier spacing may be equal to 2 ^μ*15 kHz, where μ is the numerology 0 to 5. As such, the numerology μ=0 has a subcarrier spacing of 15 kHz and the numerology μ=5 has a subcarrier spacing of 480 kHz. The symbol length/duration is inversely related to the subcarrier spacing. FIGs. 2A-2D provide an example of slot configuration 0 with 14 symbols per slot and numerology μ=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs.

A resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs) ) that extends 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs) . The number of bits carried by each RE depends on the modulation scheme.

As illustrated in FIG. 2A, some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include demodulation RS (DM-RS) (indicated as R _x for one particular configuration, where 100x is the port number, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RS) for channel estimation at the UE. The RS may also include beam measurement RS (BRS) , beam refinement RS (BRRS) , and phase tracking RS (PT-RS) .

FIG. 2B illustrates an example of various DL channels within a subframe of a frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) , each CCE including nine RE groups (REGs) , each REG including four consecutive REs in an OFDM symbol. A primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE 104 to determine subframe/symbol timing and a physical layer identity. A secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI) . Based on the PCI, the UE can determine the locations of the aforementioned DM-RS. The physical broadcast channel (PBCH) , which carries a master information block (MIB) , may be logically grouped with the PSS and SSS to form a synchronization signal (SS) /PBCH block. The MIB provides a number of RBs in the system bandwidth and a system frame number (SFN) . The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs) , and paging messages.

As illustrated in FIG. 2C, some of the REs carry DM-RS (indicated as R for one particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE may transmit DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH) . The PUSCH DM-RS may be transmitted in the first one or two symbols of the PUSCH. The PUCCH DM-RS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used. The UE may transmit sounding reference signals (SRS) . The SRS may be transmitted in the last symbol of a subframe. The SRS may have a comb structure, and a UE may transmit SRS on one of the combs. The SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

FIG. 2D illustrates an example of various UL channels within a subframe of a frame. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI) , such as scheduling requests, a channel quality indicator (CQI) , a precoding matrix indicator (PMI) , a rank indicator (RI) , and HARQ ACK/NACK feedback. The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , and/or UCI.

FIG. 3 is a block diagram of a base station 310 in communication with a UE 350 in an access network. In the DL, IP packets from the EPC 160 may be provided to a controller/processor 375. The controller/processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller/processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIBs) , RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release) , inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression/decompression, security (ciphering, deciphering, integrity protection, integrity verification) , and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs) , error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs) , re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs) , demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The TX processor 316 handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK) , quadrature phase-shift keying (QPSK) , M-phase-shift keying (M-PSK) , M-quadrature amplitude modulation (M-QAM) ) . The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a respective spatial stream for transmission.

At the UE 350, each receiver 354RX receives a signal through its respective antenna 352. Each receiver 354RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT) . The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions may be based on channel estimates computed by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to the controller/processor 359, which implements layer 3 and layer 2 functionality.

The controller/processor 359 can be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller/processor 359 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller/processor 359 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with the DL transmission by the base station 310, the controller/processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression/decompression, and security (ciphering, deciphering, integrity protection, integrity verification) ; RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 310 may be used by the TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antenna 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the base station 310 in a manner similar to that described in connection with the receiver function at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

The controller/processor 375 can be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller/processor 375 provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE 350. IP packets from the controller/processor 375 may be provided to the EPC 160. The controller/processor 375 is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

At least one of the TX processor 368, the RX processor 356, and the controller/processor 359 may be configured to perform aspects in connection with 198 of FIG. 1.

At least one of the TX processor 316, the RX processor 370, and the controller/processor 375 may be configured to perform aspects in connection with 198 of FIG. 1.

FIG. 4 is a diagram 400 illustrating beamforming ports. A base station 404 may include N transmission antennas. The base station 404 may utilize a plurality of beamforming vectors to generate multiple ports (e.g., beams) with the same N antennas. A beamforming vector may include a weight for each antenna of the N antennas. Signals are allocated to a port by applying the weights of the beamforming vector for that port to the signal before it is transmitted on the N antennas.

To determine which ports to utilize for downlink to a UE 402, the base station 404 may apply a channel state information reference signal (CSI-RS) sequence to a beamforming vector for a port. The UE 402 may receive the CSI-RS for the port, modified by the downlink channel between the base station 404 and the UE 402 for that port. The process may be repeated for multiple ports (e.g., P ports as illustrated in FIG. 4) . The UE 402 may determine the downlink channel for each port.

FIG. 5 is a communication flow diagram 500 illustrating a UE 502 selecting wideband beam ports of a base station 504.

The UE 502 may transmit a reference signal 512, such as a sounding reference signal (SRS) , to the base station 504. The base station 504 may receive the reference signal 512.

As illustrated at 522, the base station 504 may generate wideband beamforming ports. The base station 504 may utilize the reference signal 512 to determine the uplink channel between the UE 502 and the base station 504 for each sub band. The base station 504 may estimate the downlink channel for each sub band based on the uplink channel (based on downlink-uplink reciprocity) . The base station 504 may, for each sub band, determine a number of downlink spatial-domain beamforming weight vectors based on the estimated downlink channel for that sub band. The base station 504 may also determine a number of downlink frequency-domain beamforming weight vectors for each spatial-domain beamforming weight vector, based on the corresponding weight values of all sub bands. To generate a wideband beamforming port, the base station 504 may linearly combine a spatial-domain beamforming weight vector with a frequency-domain beamforming weight vector. The resulting wideband beamforming port may be a two-dimensional spatial-frequency port.

Once the base station 504 has generated a wideband beamforming port, the base station 504 may transmit a CSI-RS 526 to the UE 502 on the wideband beamforming port. The base station 504 may do this for multiple wideband beamforming ports.

In some aspects, the base station 504 may also transmit a CSI-RS configuration message 524 to the UE 502. The CSI-RS configuration message 524 may include information on how the UE 502 should report the channel state information (CSI) and/or selected ports, which will be discussed in more detail below.

As illustrated at 532, upon receiving the CSI-RS for the respective wideband beamforming ports, the UE 502 may select a subset of the wideband beamforming ports for each spatial layer. For example, the UE 502 may determine the downlink channel between the UE 502 and the base station 504 for each wideband beamforming port, and may select the wideband beamforming ports with the highest channel quality. The UE 502 may also determine a coefficient for each selected wideband beamforming port. The coefficients may be used by the base station 504 to determine the spatial-frequency beam generation in the data channel transfer.

The base station 504 may utilize antennas with multiple polarizations (e.g., two polarizations) . In some aspects, the UE 502 may utilize polarization common port selection, in which the UE 502 utilizes the same ports for both polarizations. When utilizing polarization common port selection, the UE may select ports for one polarization. In some aspects, the UE 502 may utilize polarization specific port selection, in which the UE 502 may utilize port independent of their polarization. When utilizing polarization specific port selection, the UE 502 may select all port which it will use.

In some aspects, the UE 502 may be configured to select a set number of ports. For example, the UE 502 may be preconfigured to select the set number of ports, or the base station 504 may instruct the UE 502 to select the set number of ports (e.g., in the CSI-RS configuration message 524) . In some aspects, where the UE 502 utilizes polarization common port selection, the UE 502 may select ports corresponding to half the set number of ports, and the ports of the other polarization may make up the other half of the set number of ports. In some aspects, where the UE 502 utilizes polarization specific port selection, the UE 502 may select a number of ports corresponding to the set number of ports.

The UE 502 may transmit a CSI report message 534 to the base station 504. The CSI report message 534 may identify the selected wideband beamforming ports and their corresponding coefficient. The format of the CSI report message 534 may be based on the CSI-RS configuration message 524.

The UE 502 must quantize its wideband beam port selection in order to include its selection in the CSI report message 534. For example, the UE 502 may include an indicator for each wideband beam port to indicate if that wideband beam port was selected. The indicator may be a bit, set to 1 if the port is selected and set to 0 if the port is not selected. The indicator may be a value, and the value may be set to 0 if the port is not selected and may be set to the selected coefficient for that port if the port is selected.

Because the UE 502 may select wideband beam ports for each spatial layer, the UE 502 may quantize its selection for each spatial layer and include the result for each spatial layer in the CSI report message 534. If the UE 502 includes an indicator for each wideband beam port for each spatial layer, the payload of the CSI report message 534 can become large.

FIG. 6 is a diagram 600 illustrating a quantization format for reporting selected ports. The UE 502 may have received CSI-RS for a set of ports 610 transmitted by the base station 504. From the set of ports 610, the UE 502 may select a subset of ports for each spatial layer. For example, the UE 502 may select ports 630 for spatial layer 1 and may select ports 640 for spatial layer 2.

The UE 502 may determine a common set of selected ports 620. The common set of selected ports 620 may include all of the ports selected for all spatial layers. For example, as illustrated in FIG. 6, the common set of selected ports 620 may include all of the selected ports 630 for spatial layer 1 and all of the selected ports 640 for spatial layer 2.

In the CSI report message 534, the UE 502 may include a message identifying the common set of selected ports. For example, the UE 502 may include an indication for each port of the received set of ports 610, indicating whether that port is included in the common set of ports 620.

In the CSI report message 534, the UE 502 may also include a layer-specific message indicating which ports of the common set of ports are indicated for each spatial layer. For example, the UE 502 may include an indicator for each port of the common set of ports 620, indicating whether that port is selected for the corresponding spatial layer. As illustrated in FIG. 6, the UE may include an indicator for each port of the common set of ports 620 corresponding to spatial layer 1, and may include an indicator for each port of the common set of ports 620 corresponding to spatial layer 2. The indicators corresponding to spatial layer 1 may indicate that the selected ports 630 are selected for spatial layer 1, and the indicators corresponding to spatial layer 2 may indicate that the selected ports 640 are selected for spatial layer 2.

By including indicators corresponding to the ports of the common set of ports 620 for each spatial layer, rather than including indicators corresponding to the ports of the received set of ports 610, the size of the CSI report message 534 may be reduced. The reduction in size may increase with the number of spatial layers being reported, and decrease with the amount of ports in the common set.

Upon receiving the CSI report message 534, the base station 504 may utilize the common set of selected ports 620 to determine which ports are indicated as selected in the layer-specific messages (e.g., may determine which indicators correspond to which ports) .

FIG. 7 is a diagram 700 illustrating a quantization format for reporting selected ports. The UE 502 may have received CSI-RS for a set of ports 710 transmitted by the base station 504. From the set of ports 710, the UE 502 may select a subset of ports for each spatial layer. For example, the UE 502 may select ports 730 for spatial layer 1 and may select ports 740 for spatial layer 2.

The UE 502 may determine a common set of selected ports 720. The common set of selected ports 720 may be ports which are selected for each spatial layer. For example, as illustrated in FIG. 7, a first portion 732 of the selected ports 730 for spatial layer 1 may be unique to spatial layer 1, and a first portion 742 of the selected ports 740 for spatial layer 2 may be unique to spatial layer 2. A second portion 734 of the selected ports 730 for spatial layer 1 and a second portion 744 of the selected ports 740 for spatial layer 2 may have been selected for both spatial layer 1 and for spatial layer 2. The common set of selected ports 720 may correspond to the second portion 734 of the selected ports 730 for spatial layer 1 and the second portion 744 of the selected ports 740 for spatial layer 2.

In the CSI report message 534, the UE 502 may include a message identifying the common set of selected ports 720. The UE 502 may include an indication for each port of the received set of ports 710, indicating whether that port is included in the common set of selected ports 720.

In the CSI report message 534, the UE 502 may also include a layer-specific message for each spatial layer identifying the ports uniquely selected for that spatial layer. For example, the UE 502 may include an indicator for each port of the received ports 710, other than the ports included in the common set of ports, indicating whether that port is selected for the corresponding spatial layer. As illustrated in FIG. 7, the UE 502 may include an indicator for each port of the received set of ports 710 other than the ports of the common set of ports 720 for spatial layer 1 and may include an indicator for each port of the received set of ports 710 other than the ports of the common set of ports 720 for spatial layer 2. The indicators corresponding to spatial layer 1 may indicate that the first portion 732 of the selected ports 730 are selected for spatial layer 1, and the indicators corresponding to spatial layer 2 may indicate that the first portion 742 of the selected ports 730 are selected for spatial layer 2.

By omitting indicators for the common set of ports 720 in the layer-specific messages for each spatial layer, the size of the CSI report message 534 may be reduced.

Upon receiving the CSI report message 534, the base station 504 may utilize the common set of selected ports 720 to determine which ports are indicated as selected in the layer-specific messages. For example, as the layer-specific messages will include fewer indicators than the number of ports transmitted by the base station 504, the base station 504 may utilize the common set of ports 720 to determine which ports were omitted, and therefore which indicators correspond to which ports. The base station 504 may also determine that the ports included in the common set of ports 720 are selected for each spatial layer.

FIG. 8 is a diagram 800 illustrating a quantization format for reporting selected ports. The UE 502 may have received CSI-RS for a set of ports 810 transmitted by the base station 504. From the set of ports 810, the UE 502 may select a subset of ports for each spatial layer. For example, the UE 502 may select ports 830 for spatial layer 1 and may select ports 840 for spatial layer 2.

The UE 502 may determine a first common set of selected ports 822. The first common set of selected ports 822 may include all of the ports selected for all spatial layers. For example, as illustrated in FIG. 8, the first common set of selected ports 822 may include all of the selected ports 830 for spatial layer 1 and all of the selected ports 840 for spatial layer 2.

The UE 502 may also determine a second common set of selected ports 824. The second common set of selected ports 824 may be ports which are selected for each spatial layer. For example, as illustrated in FIG. 8, a first portion 832 of the selected ports 830 for spatial layer 1 may be unique to spatial layer 1, and a first portion 842 of the selected ports 840 for spatial layer 2 may be unique to spatial layer 2. A second portion 834 of the selected ports 830 for spatial layer 1 and a second portion 844 of the selected ports 840 for spatial layer 2 may have been selected for both spatial layer 1 and for spatial layer 2. The second common set of selected ports 824 may correspond to the second portion 834 of the selected ports 830 for spatial layer 1 and the second portion 844 of the selected ports 840 for spatial layer 2.

In the CSI report message 534, the UE 502 may include a message identifying the first common set of selected ports 822 and the second common set of selected ports 824. The UE 502 may include an indication for each port of the received set of ports 810, indicating whether that port is included in the first common set of selected ports 822. The UE 502 may also include an indication for each port of the first common set of selected ports 822 indicating whether that port is included in the second common set of selected ports 824.

In the CSI report message 534, the UE 502 may also include a layer-specific message for each spatial layer identifying the ports uniquely selected for that spatial layer. For example, the UE 502 may include an indicator for each port of the first common set of selected ports 822, other than the ports of the second common set of ports 824, indicating whether that port is selected for the corresponding spatial layer. As illustrated in FIG. 8, the UE 502 may include an indicator for each port of the first common set of selected ports 822, other than the ports of the second common set of ports 824, for spatial layer 1. The indicators corresponding to spatial layer 1 may indicate that the first portion 832 of the selected ports 830 are selected for spatial layer 1. The UE 502 may also include an indicator for each port of the first common set of selected ports 822, other than the ports of the second common set of ports 824, for spatial layer 2. The indicators corresponding to spatial layer 2 may indicate that the first portion 842 of the selected ports 840 are selected for spatial layer 2.

By including indicators corresponding to the ports of the first common set of ports 822 for each spatial layer, rather than including indicators corresponding to the ports of the received set of ports 810, and by omitting indicators for the second common set of ports 824 in the layer-specific messages for each spatial layer, the size of the CSI report message 534 may be reduced.

Upon receiving the CSI report message 534, the base station 504 may utilize the first common set of selected ports 822 and the second common set of selected ports 824 to determine which ports are indicated as selected in the layer-specific messages. For example, as the layer-specific messages will include fewer indicators than the number of ports in the first common set of ports 822, the base station 504 may utilize the second common set of ports 824 to determine which ports were omitted, and therefore which indicators correspond to which ports. The base station 504 may also determine that the ports included in the second common set of ports 824 are selected for each spatial layer.

Referring again to FIG. 5, in some aspects, the UE 502 may be configured to utilize some or all of the quantization formats described above with respect to FIGS. 6, 7, and 8. In some aspects, the UE 502 may include an indication in the CSI report message 534 identifying which quantization format is used. The base station 504 may receive the indication, and may process the common set or common sets of ports and the layer-specific messages according to the indicated quantization format.

In some aspects, the base station may include, in the CSI-RS configuration message 524, an indication identifying which quantization format the UE 502 should use. The UE 502 may receive the indication and may utilize the identified quantization format.

In some aspects, the base station may include, in the CSI-RS configuration message 524, an indication identifying multiple quantization formats the UE 502 may use. The UE 502 may determine which of the identified quantization formats to use. For example, the UE 502 may determine which of the identified quantization formats results in the smallest payload for the CSI report message 534, and may use that quantization format. The UE 502 may include an indication in the CSI report message 534 identifying which quantization format was selected. The base station 504 may receive the indication, and may process the common set or common sets of ports and the layer-specific messages according to the indicated quantization method.

FIG. 9 is a flowchart 900 of a method of wireless communication. The method may be performed by a UE (e.g., the

UE

350, 502, which may include the memory 360 and which may be the

entire UE

350, 502 or a component of the

UE

350, 502, such as the TX processor 368, the RX processor 356, and/or the controller/processor 359) .

At 902, the UE may receive, from a base station, a plurality of reference signals corresponding to beam ports. The beam ports may be spatial-frequency domain beam ports.

At 904, the UE may select a plurality of sets of ports based on the plurality of reference signals, wherein each selected set of ports corresponds to a spatial layer.

At 906, the UE may determine a common set of ports based on of the plurality of sets of ports.

At 908, the UE may transmit, to the base station, a message identifying the common set of ports.

At 910, the UE may transmit, to the base station, a message identifying a plurality of layer-specific sets of ports. Each layer-specific set of ports may correspond to a spatial layer and may be based on the selected set of ports for that spatial layer and the common set of ports. The common set of ports may include all ports included in any of the plurality of selected sets of ports, and each layer-specific set of ports may include the selected set of ports for that layer. The message identifying the plurality of layer-specific sets of ports may identify which ports of the common set of ports belong to the selected set of ports for the corresponding spatial layer. The message identifying the plurality of layer-specific sets of ports may not include information about ports other than the ports of the common set of ports.

The common set of ports may include the ports that are in each selected set of ports of the plurality of selected sets of ports, and each layer-specific set of ports may include the ports of the selected set of ports for the corresponding spatial layer other than the ports in the common set of ports. The message identifying the plurality of layer-specific sets of ports may identify which ports of the beam ports received from the base station, other than the ports included in the common set of ports, belong to the selected set of ports for the corresponding spatial layer. The message identifying the plurality of layer-specific sets of ports may not include information about ports of the common set of ports.

In some aspects, the UE may determine a second common set of ports based on of the plurality of sets of ports, and may transmit, to the base station, a message identifying the second common set of ports. The common set of ports may include all ports included in any of the plurality of selected sets of ports. The second common set of ports may include the ports that are in each selected set of ports of the plurality of selected sets of ports. Each layer-specific set of ports may include the ports of the selected set of ports for the corresponding spatial layer other than the ports in the second common set of ports. The message identifying the second common set of ports may identify which ports of the common set of ports belong to each selected set of ports of the plurality of selected sets of ports. The message identifying the plurality of layer-specific sets of ports may identify which ports of the common set of ports, other than the ports belonging to the second common set of ports, belong to the selected set of ports for the corresponding spatial layer. The message identifying the plurality of layer-specific sets of ports may not include information about ports other than the ports of the common set of ports and may not include information about ports of the second common set of ports.

FIG. 10 is a flowchart 1000 of a method of wireless communication. The method may be performed by a base station 310, 504 (e.g., the

base station

310, 504, which may include the memory 376 and which may be the

entire base station

310, 504 or a component of the

base station

310, 504, such as the TX processor 316, the RX processor 370, and/or the controller/processor 375) .

At 1002, the base station may transmit, to a UE, a plurality of reference signals corresponding to beam ports. The beam ports may be spatial-frequency domain beam ports.

At 1004, the base station may receive, from the UE, a message identifying a common set of ports. The common set of ports may be based on a plurality of sets of selected ports. The plurality of sets of selected ports may be based on the plurality of reference signals, each selected set of ports corresponding to a spatial layer.

At 1006, the base station may receive, from the UE, a message identifying a plurality of layer-specific sets of ports, each layer-specific set of ports corresponding to a spatial layer and being based on the selected set of ports for that spatial layer and the common set of ports. The common set of ports may include all ports included in any of the plurality of selected sets of ports, and each layer-specific set of ports may include the selected set of ports for that layer. The message identifying the plurality of layer-specific sets of ports may identify which ports of the common set of ports belong to the selected set of ports for the corresponding spatial layer. The message identifying the plurality of layer-specific sets of ports may not include information about ports other than the ports of the common set of ports.

In some aspects, the base station may receive a message identifying a second common set of ports based on of the plurality of sets of ports. The common set of ports may include all ports included in any of the plurality of selected sets of ports. The second common set of ports may include the ports that are in each selected set of ports of the plurality of selected sets of ports. Each layer-specific set of ports may include the ports of the selected set of ports for the corresponding spatial layer other than the ports in the second common set of ports. The message identifying the second common set of ports may identify which ports of the common set of ports belong to each selected set of ports of the plurality of selected sets of ports. The message identifying the plurality of layer-specific sets of ports may identify which ports of the common set of ports, other than the ports belonging to the second common set of ports, belong to the selected set of ports for the corresponding spatial layer. The message identifying the plurality of layer-specific sets of ports may not include information about ports other than the ports of the common set of ports and may not include information about ports of the second common set of ports.

It is understood that the specific order or hierarchy of blocks in the processes/flowcharts disclosed is an illustration of example approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes/flowcharts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. The words “module, ” “mechanism, ” “element, ” “device, ” and the like may not be a substitute for the word “means. ” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for. ”

Claims

A method of wireless communication at a user equipment (UE) , comprising:

receiving, from a base station, a plurality of reference signals corresponding to beam ports;

selecting a plurality of sets of ports based on the plurality of reference signals, wherein each selected set of ports corresponds to a spatial layer;

determining a common set of ports based on of the plurality of sets of ports;

transmitting, to the base station, a message identifying the common set of ports; and

transmitting, to the base station, a message identifying a plurality of layer-specific sets of ports, each layer-specific set of ports corresponding to a spatial layer and being based on the selected set of ports for that spatial layer and the common set of ports.
The method of claim 1, wherein the common set of ports comprises all ports included in any of the plurality of selected sets of ports, and each layer-specific set of ports comprises the selected set of ports for that layer.
The method of claim 2, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the common set of ports belong to the selected set of ports for the corresponding spatial layer.
The method of claim 3, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports other than the ports of the common set of ports.
The method of claim 1, wherein the common set of ports comprises the ports that are in each selected set of ports of the plurality of selected sets of ports, and each layer-specific set of ports comprises the ports of the selected set of ports for the corresponding spatial layer other than the ports in the common set of ports.
The method of claim 5, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the beam ports received from the base station, other than the ports included in the common set of ports, belong to the selected set of ports for the corresponding spatial layer.
The method of claim 5, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports of the common set of ports.
The method of claim 1, further comprising:

determining a second common set of ports based on of the plurality of sets of ports; and

transmitting, to the base station, a message identifying the second common set of ports,

wherein the common set of ports comprises all ports included in any of the plurality of selected sets of ports,

wherein the second common set of ports comprises the ports that are in each selected set of ports of the plurality of selected sets of ports, and

wherein each layer-specific set of ports comprises the ports of the selected set of ports for the corresponding spatial layer other than the ports in the second common set of ports.
The method of claim 8, wherein the message identifying the second common set of ports identifies which ports of the common set of ports belong to each selected set of ports of the plurality of selected sets of ports.
The method of claim 8, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the common set of ports, other than the ports belonging to the second common set of ports, belong to the selected set of ports for the corresponding spatial layer.
The method of claim 8, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports other than the ports of the common set of ports and does not include information about ports of the second common set of ports.
The method of claim 1, wherein the beam ports are spatial-frequency domain beam ports.
An apparatus for wireless communication at a user equipment (UE) , comprising:

means for receiving, from a base station, a plurality of reference signals corresponding to beam ports;

selecting a plurality of sets of ports based on the plurality of reference signals, wherein each selected set of ports corresponds to a spatial layer;

determining a common set of ports based on of the plurality of sets of ports; transmitting, to the base station, a message identifying the common set of ports; and

transmitting, to the base station, a message identifying a plurality of layer-specific sets of ports, each layer-specific set of ports corresponding to a spatial layer and being based on the selected set of ports for that spatial layer and the common set of ports.
The apparatus of claim 13, wherein the common set of ports comprises all ports included in any of the plurality of selected sets of ports, and each layer-specific set of ports comprises the selected set of ports for that layer.
The apparatus of claim 14, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the common set of ports belong to the selected set of ports for the corresponding spatial layer.
The apparatus of claim 15, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports other than the ports of the common set of ports.
The apparatus of claim 13, wherein the common set of ports comprises the ports that are in each selected set of ports of the plurality of selected sets of ports, and each layer-specific set of ports comprises the ports of the selected set of ports for the corresponding spatial layer other than the ports in the common set of ports.
The apparatus of claim 17, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the beam ports received from the base station, other than the ports included in the common set of ports, belong to the selected set of ports for the corresponding spatial layer.
The apparatus of claim 17, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports of the common set of ports.
The apparatus of claim 13, further comprising:

means for determining a second common set of ports based on of the plurality of sets of ports; and

means for transmitting, to the base station, a message identifying the second common set of ports,

wherein the common set of ports comprises all ports included in any of the plurality of selected sets of ports,

wherein the second common set of ports comprises the ports that are in each selected set of ports of the plurality of selected sets of ports, and

wherein each layer-specific set of ports comprises the ports of the selected set of ports for the corresponding spatial layer other than the ports in the second common set of ports.
The apparatus of claim 20, wherein the message identifying the second common set of ports identifies which ports of the common set of ports belong to each selected set of ports of the plurality of selected sets of ports.
The apparatus of claim 20, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the common set of ports, other than the ports belonging to the second common set of ports, belong to the selected set of ports for the corresponding spatial layer.
The apparatus of claim 20, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports other than the ports of the common set of ports and does not include information about ports of the second common set of ports.
The apparatus of claim 13, wherein the beam ports are spatial-frequency domain beam ports.
An apparatus for wireless communication at a user equipment (UE) , comprising:

a memory; and

at least one processor coupled to the memory and configured to:

receive, from a base station, a plurality of reference signals corresponding to beam ports;

select a plurality of sets of ports based on the plurality of reference signals, wherein each selected set of ports corresponds to a spatial layer;

determine a common set of ports based on of the plurality of sets of ports;

transmit, to the base station, a message identifying the common set of ports; and

transmit, to the base station, a message identifying a plurality of layer-specific sets of ports, each layer-specific set of ports corresponding to a spatial layer and being based on the selected set of ports for that spatial layer and the common set of ports.
The apparatus of claim 25, wherein the common set of ports comprises all ports included in any of the plurality of selected sets of ports, and each layer-specific set of ports comprises the selected set of ports for that layer.
The apparatus of claim 26, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the common set of ports belong to the selected set of ports for the corresponding spatial layer.
The apparatus of claim 27, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports other than the ports of the common set of ports.
The apparatus of claim 25, wherein the common set of ports comprises the ports that are in each selected set of ports of the plurality of selected sets of ports, and each layer-specific set of ports comprises the ports of the selected set of ports for the corresponding spatial layer other than the ports in the common set of ports.
The apparatus of claim 29, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the beam ports received from the base station, other than the ports included in the common set of ports, belong to the selected set of ports for the corresponding spatial layer.
The apparatus of claim 29, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports of the common set of ports.
The apparatus of claim 25, wherein the processor is further configured to:

determine a second common set of ports based on of the plurality of sets of ports; and

transmit, to the base station, a message identifying the second common set of ports,

wherein the common set of ports comprises all ports included in any of the plurality of selected sets of ports,

wherein the second common set of ports comprises the ports that are in each selected set of ports of the plurality of selected sets of ports, and

wherein each layer-specific set of ports comprises the ports of the selected set of ports for the corresponding spatial layer other than the ports in the second common set of ports.
The apparatus of claim 32, wherein the message identifying the second common set of ports identifies which ports of the common set of ports belong to each selected set of ports of the plurality of selected sets of ports.
The apparatus of claim 32, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the common set of ports, other than the ports belonging to the second common set of ports, belong to the selected set of ports for the corresponding spatial layer.
The apparatus of claim 32, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports other than the ports of the common set of ports and does not include information about ports of the second common set of ports.
The apparatus of claim 25, wherein the beam ports are spatial-frequency domain beam ports.
A non-transitory computer-readable medium storing computer executable code for wireless communication at a user equipment, the code when executed by a processor cause the processor to perform the method of any of claims 1-12.
A method of wireless communication at a base station, comprising:

transmitting, to a user equipment (UE) , a plurality of reference signals corresponding to beam ports;

receiving, from the UE, a message identifying a common set of ports, the common set of ports being based on a plurality of sets of selected ports, the plurality of sets of selected ports being based on the plurality of reference signals, each selected set of ports corresponding to a spatial layer; and

receiving, from the UE, a message identifying a plurality of layer-specific sets of ports, each layer-specific set of ports corresponding to a spatial layer and being based on the selected set of ports for that spatial layer and the common set of ports.
The method of claim 38, wherein the common set of ports comprises all ports included in any of the plurality of selected sets of ports, and each layer-specific set of ports comprises the selected set of ports for that layer.
The method of claim 39, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the common set of ports belong to the selected set of ports for the corresponding spatial layer.
The method of claim 40, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports other than the ports of the common set of ports.
The method of claim 38, wherein the common set of ports comprises the ports that are in each selected set of ports of the plurality of selected sets of ports, and each layer-specific set of ports comprises the ports of the selected set of ports for the corresponding spatial layer other than the ports in the common set of ports.
The method of claim 42, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the beam ports received from the base station, other than the ports included in the common set of ports, belong to the selected set of ports for the corresponding spatial layer.
The method of claim 42, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports of the common set of ports.
The method of claim 38, further comprising:

receiving a message identifying a second common set of ports based on of the plurality of sets of ports,

wherein the common set of ports comprises all ports included in any of the plurality of selected sets of ports,

wherein the second common set of ports comprises the ports that are in each selected set of ports of the plurality of selected sets of ports, and

wherein each layer-specific set of ports comprises the ports of the selected set of ports for the corresponding spatial layer other than the ports in the second common set of ports.
The method of claim 45, wherein the message identifying the second common set of ports identifies which ports of the common set of ports belong to each selected set of ports of the plurality of selected sets of ports.
The method of claim 45, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the common set of ports, other than the ports belonging to the second common set of ports, belong to the selected set of ports for the corresponding spatial layer.
The method of claim 45, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports other than the ports of the common set of ports and does not include information about ports of the second common set of ports.
The method of claim 38, wherein the beam ports are spatial-frequency domain beam ports.
An apparatus for wireless communication at a user equipment (UE) , comprising:

means for transmitting, to a user equipment (UE) , a plurality of reference signals corresponding to beam ports;

means for receiving, from the UE, a message identifying a common set of ports, the common set of ports being based on a plurality of sets of selected ports, the plurality of sets of selected ports being based on the plurality of reference signals, each selected set of ports corresponding to a spatial layer; and

means for receiving, from the UE, a message identifying a plurality of layer-specific sets of ports, each layer-specific set of ports corresponding to a spatial layer and being based on the selected set of ports for that spatial layer and the common set of ports.
The apparatus of claim 50, wherein the common set of ports comprises all ports included in any of the plurality of selected sets of ports, and each layer-specific set of ports comprises the selected set of ports for that layer.
The apparatus of claim 51, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the common set of ports belong to the selected set of ports for the corresponding spatial layer.
The apparatus of claim 52, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports other than the ports of the common set of ports.
The apparatus of claim 50, wherein the common set of ports comprises the ports that are in each selected set of ports of the plurality of selected sets of ports, and each layer-specific set of ports comprises the ports of the selected set of ports for the corresponding spatial layer other than the ports in the common set of ports.
The apparatus of claim 54, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the beam ports received from the base station, other than the ports included in the common set of ports, belong to the selected set of ports for the corresponding spatial layer.
The apparatus of claim 54, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports of the common set of ports.
The apparatus of claim 50, further comprising:

means for receiving a message identifying a second common set of ports based on of the plurality of sets of ports,

wherein the common set of ports comprises all ports included in any of the plurality of selected sets of ports,

wherein the second common set of ports comprises the ports that are in each selected set of ports of the plurality of selected sets of ports, and

wherein each layer-specific set of ports comprises the ports of the selected set of ports for the corresponding spatial layer other than the ports in the second common set of ports.
The apparatus of claim 57, wherein the message identifying the second common set of ports identifies which ports of the common set of ports belong to each selected set of ports of the plurality of selected sets of ports.
The apparatus of claim 57, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the common set of ports, other than the ports belonging to the second common set of ports, belong to the selected set of ports for the corresponding spatial layer.
The apparatus of claim 57, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports other than the ports of the common set of ports and does not include information about ports of the second common set of ports.
The apparatus of claim 50, wherein the beam ports are spatial-frequency domain beam ports.
An apparatus for wireless communication at a user equipment (UE) , comprising:

a memory; and

at least one processor coupled to the memory and configured to:

transmit, to a user equipment (UE) , a plurality of reference signals corresponding to beam ports;

receive, from the UE, a message identifying a common set of ports, the common set of ports being based on a plurality of sets of selected ports, the plurality of sets of selected ports being based on the plurality of reference signals, each selected set of ports corresponding to a spatial layer; and

receive, from the UE, a message identifying a plurality of layer-specific sets of ports, each layer-specific set of ports corresponding to a spatial layer and being based on the selected set of ports for that spatial layer and the common set of ports.
The apparatus of claim 62, wherein the common set of ports comprises all ports included in any of the plurality of selected sets of ports, and each layer-specific set of ports comprises the selected set of ports for that layer.
The apparatus of claim 63, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the common set of ports belong to the selected set of ports for the corresponding spatial layer.
The apparatus of claim 64, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports other than the ports of the common set of ports.
The apparatus of claim 62, wherein the common set of ports comprises the ports that are in each selected set of ports of the plurality of selected sets of ports, and each layer-specific set of ports comprises the ports of the selected set of ports for the corresponding spatial layer other than the ports in the common set of ports.
The apparatus of claim 66, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the beam ports received from the base station, other than the ports included in the common set of ports, belong to the selected set of ports for the corresponding spatial layer.
The apparatus of claim 66, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports of the common set of ports.
The apparatus of claim 62, wherein the processor is further configured to:

receive a message identifying a second common set of ports based on of the plurality of sets of ports,

wherein the common set of ports comprises all ports included in any of the plurality of selected sets of ports,

wherein the second common set of ports comprises the ports that are in each selected set of ports of the plurality of selected sets of ports, and

wherein each layer-specific set of ports comprises the ports of the selected set of ports for the corresponding spatial layer other than the ports in the second common set of ports.
The apparatus of claim 69, wherein the message identifying the second common set of ports identifies which ports of the common set of ports belong to each selected set of ports of the plurality of selected sets of ports.
The apparatus of claim 69, wherein the message identifying the plurality of layer-specific sets of ports identifies which ports of the common set of ports, other than the ports belonging to the second common set of ports, belong to the selected set of ports for the corresponding spatial layer.
The apparatus of claim 69, wherein the message identifying the plurality of layer-specific sets of ports does not include information about ports other than the ports of the common set of ports and does not include information about ports of the second common set of ports.
The apparatus of claim 62, wherein the beam ports are spatial-frequency domain beam ports.
A non-transitory computer-readable medium storing computer executable code for wireless communication at a user equipment, the code when executed by a processor cause the processor to perform the method of any of claims 38-49.