DE102022210364A1 - Method and wireless communication system for improving energy efficient coverage - Google Patents

Abstract

A method for energy efficient coverage improvement (CE), comprising the steps of: when the user equipment (UE) is in idle mode, the user equipment (UE) decides whether or not to switch to an alternative network based on the overall network congestion, this information being indicated by the network by reaching the maximum of a failure of a random access (RA) procedure for a level (k) of coverage improvement (CE), and a cell selection in alternative networks is performed, the coverage of the cell is verified and in case the coverage of the cell is sufficient, then the user equipment (UE) switches to an alternative network and performs a random access (RA) procedure, in case the coverage of the cell is insufficient, the user equipment (UE) stays in the same network and increases its previous level (k) of coverage improvement (CE) to the level (k+1) for a subsequent random access (RA) procedure.

Description

AREA OF EXPERTISE

The present disclosure relates to improving energy efficient coverage in wireless communication systems.

BACKGROUND

The Third Generation Partnership Project (3GPP) presents a standardized coverage enhancement (CE) for the Internet-of-Things (IoT) to connect devices to cellular networks under challenging radio conditions. CE is based on the principle of extended transmission time, which takes advantage of the fact that many IoT applications have relaxed data rate and latency requirements and that coverage for such applications can be significantly increased by repeated transmissions. However, CE consumes a lot of radio resources and should be implemented carefully for different applications.

The evolution of wireless communication technologies towards 5G (fifth generation) enables everything to be connected via the Internet. For example, a huge amount of information related to human activities has been recorded, monitored by various types of IoT applications (e.g. health monitoring, smart home, smart transportation, industrial automation) and exchanged over cellular networks. Unfortunately, conventional cellular networks are not designed to accommodate such diverse IoT applications. Accordingly, tremendous efforts have been made to support the emerging IoT scenario in cellular networks, referred to as massive machine-type communications (mMTC) or massive IoT (mloT), as one of the main use cases of 5G.

An extremely large number of IoT devices are expected to be deployed in cellular networks, with the number of connected devices reaching 500 billion by 2030. Each IoT device sporadically generates small-volume packets to report sensor information to the IoT server via a base station (BS/gNB). In particular, an IoT device stays disconnected from the BS to reduce the energy consumption due to sporadic packet generation. This implies that each of the IoT devices should perform a RA (random access) procedure to establish a connection with the BS whenever it transmits data packets to the IoT server. The RA procedure adopted in the existing cellular systems, such as LTE/LTE-A/5G, consists of a four-stage handover procedure. Due to the densely deployed IoT devices in IoT cellular networks, simultaneous RA attempts on a given RA timeslot (or equivalently, a physical RA channel (PRACH)) may cause a collision problem. A collision problem is most likely to cause the poor access performance (i.e., RA failure) at the device side. Specifically, IoT devices may spend a considerable amount of time accessing the networks, and thus the networks cannot guarantee an acceptable end-to-end delay according to their access priority.

• • Schritt1. Übertragungen der Präambel: Jede IoT-Vorrichtung wählt zufällig eine einzige RA-Präambel unter einer Menge verfügbarer RA-Präambeln aus und überträgt sie auf dem PRACH.
• • Schritt2. Direktzugriffsantworten: Die BS detektiert, welche Präambeln aktiv sind. In Reaktion auf die detektierten Präambeln überträgt die BS RAR(random access response - Direktzugriffsantwort)-Nachrichten, von denen jede aus einer RA-Präambel-Kennung (RA preamble identifier - RAPID), einem Zeitabgleich (timing alignment - TA), einer Uplink-Genehmigung (uplinkgrant-UG) und einer temporären Kennung besteht. Jede IoT-Vorrichtung, die im ersten Schritt eine Präambel übertragen hat, wartet auf die RAR-Nachricht, die dieselbe RAPID enthält. Falls die entsprechende RAR-Nachricht vorhanden ist, nutzt jede Vorrichtung Informationen innerhalb der Nachricht für den anschließenden Schritt (d. h. Schritt3).
• • Schritt3. Eingeplante Übertragungen: Jede IoT-Vorrichtung überträgt ihre geplante Nachricht (z. B. eine Verbindungsanforderungsnachricht) auf der zugewiesenen Uplink-Ressource auf dem gemeinsam genutzten physikalischen Uplink-Kanal (physical uplink shared channel - PUSCH), die durch den UG-Wert angegeben ist, der in der im zweiten Schritt empfangenen RAR-Nachricht enthalten ist. Um zu bestimmen, ob die Ressourcenkollision auf der verwendeten Uplink-Ressource auftritt oder nicht, startet jede IoT-Vorrichtung einen CR(contention resolution - Konfliktlösungs)-Zeitgeber, sobald die Schritt-3-Nachricht übertragen wird.
• • Schritt4. Bestätigung: Die BS reflektiert echoartig die Kennungen der IoT-Vorrichtungen, deren übertragene geplante Nachrichten ohne jegliche Ressourcenkollisionen erfolgreich decodiert wurden. Wenn jede IoT-Vorrichtung die richtige ACK(acknowledgement - Bestätigung)-Nachricht empfängt, bevor der CR-Zeitgeber abläuft, dann betrachtet sie den RA-Versuch als einen Erfolg. Anderenfalls betrachtet sie den RA-Versuch als ein Versagen und versucht das RA-Verfahren erneut am nächsten verfügbaren RA-Zeitschlitz nach dem Durchführen eines Rückziehers (back-off).

In cellular systems, data communication requires a prior connection between each IoT device and the BS. To establish a connection, a device should go through the 4 steps of the RA process. In summary, the general description of the traditional RA method in cellular networks (e.g. LTE/LTE-A/5G) is as follows:

• • Step 1. Preamble Transmissions: Each IoT device randomly selects a single RA preamble from a set of available RA preambles and transmits it on the PRACH.
• • Step 2. Random access responses: The BS detects which preambles are active. In response to the detected preambles, the BS transmits RAR (random access response) messages, each of which consists of an RA preamble identifier (RAPID), a timing alignment (TA), an uplink Approval (uplinkgrant-UG) and a temporary identifier exists. Each IoT device that transmitted a preamble in the first step waits for the RAR message containing the same RAPID. If the corresponding RAR message is present, each device uses information within the message for the subsequent step (ie, step3).
• • Step 3. Scheduled Transmissions: Each IoT device transmits its scheduled message (e.g., a connection request message) on the assigned uplink resource on the shared used physical uplink shared channel (PUSCH), which is indicated by the UG value contained in the RAR message received in the second step. To determine whether the resource collision occurs on the used uplink resource or not, each IoT device starts a contention resolution (CR) timer once the step 3 message is transmitted.
• • Step4. Acknowledgment: The BS echoes the identifiers of the IoT devices whose transmitted scheduled messages were successfully decoded without any resource collisions. If each IoT device receives the correct ACK (acknowledgment) message before the CR timer expires, then it considers the RA attempt a success. Otherwise, it considers the RA attempt a failure and retries the RA procedure at the next available RA timeslot after performing a back-off.

US2022131602 A1 discloses a method, network node, and wireless device for reliable link performance for cellular Internet of Things (IoT) and New Radio (NR) in non-terrestrial networks. In some embodiments, a network node configured to operate in a non-terrestrial cellular network is provided. The network node includes processing circuitry configured to provide an indication of transmission property information associated with reconfiguration of precoding weights, wherein the indication of transmission property information provides information associated with decoding a shared physical downlink channel or a physical downlink control channel.

WO 2021204079 A1 describes methods, systems and devices for wireless communications in which a block error rate (BLER) in communications in a non-terrestrial network (NTN) can be reduced by coverage improvement techniques. Coverage improvement techniques may include time slot bundling for communications on a physical downlink control channel (PDCCH), where repetitions of a PDCCH may occupy multiple time frequency locations spanning multiple time slots. Such time slots may be consecutive or non-consecutive and in some cases multiple repetitions of the PDCCH may be provided in the same time slot. The pattern of time frequency locations of the repetitions may be periodic or non-periodic. Further, the repeats may be exact copies or different redundancy versions of the same encoded DCI. Additionally, repeat communications on the uplink or downlink shared control channel, broadcast channel communications, or any combination thereof may be provided.

CN 113644950 discloses a communication method in a non-terrestrial network (NTN) and a communication device for a non-terrestrial network used to solve the problem that a radio cell covered by a terrestrial base station and a radio cell covered by a satellite is covered cannot be distinguished when the UE (User Equipment) is performing a communication service that is sensitive to time delay, and the cell covered by the satellite may be selectable. The method includes the following steps: A first network device determines radio cell type information of a radio cell covered by a second network device, the radio cell type information being used to indicate that the radio cell is a radio cell for ground network communication or a radio cell of a non-terrestrial communication network acts. And the first power supply sends the radio cell type information to the third power supply. In the embodiment according to the invention, when the interface connection between the first network device and the third network device is established under the NTN scenario, the relevant NTN information (namely the radio cell information of the second network device) is transported, so that the third network device also has the performance and can recognize the properties of the first power supply.

US 2021194572 A1 provides a method and apparatus for determining UE parameters, a mass storage medium and a base station. The method includes: determining a minimum round trip time between each UE in a cell and a satellite; determining frame information of a network-side uplink radio frame based on the minimum round-trip time and frame information of a network-side downlink radio frame, the minimum round-trip time being a time difference by which the network-side uplink radio frame lags behind the network-side downlink radio frame; and determining a UE parameter of each UE based on the network-side uplink radio frame and the network-side downlink radio frame, the UE parameter comprising TA and/or K2. Through the ver An NTN network can be supported under the condition that modification of software and hardware of a UE of a terrestrial network is minimized, thereby effectively avoiding additional maintenance effort for software and hardware.

WO 2022082771 A1 describes beam management for non-terrestrial networks (NTN). An exemplary aspect is a baseband processor comprising: a memory interface; and processing communicatively coupled to the memory and transceiver interfaces and connected to a base station (BS) in a radio cell of a non-terrestrial network (NTN), and wherein the radio cell comprises a plurality of bandwidth parts (BWPs), associated with a plurality of beams configured to perform operations including: receiving signaling from the base station (BS) comprising a channel state indicator reference signal (CSI-RS) configuration, associated with a first BWP of the plurality of BWPs, the CSI-RS configuration comprising a beam management configuration for the plurality of beams, changing from a second BWP of the plurality of BWPs to the first BWP according to the CSI-RS configuration and measuring one or more of the plurality of beams according to the beam measurement configuration; and generating a measurement report that includes a Layer 1 reference signal received power (L1-RSRP) measurement from the measured one or more of the plurality of beams.

US2021306927 A1 describes a method for operating an infrastructure device that forms part of a wireless communication network. The wireless communication network comprises a base station and part of a non-terrestrial network, wherein the part of the non-terrestrial network transmits one or more spot beams to provide a wireless access interface for transmitting signals to a communication device and for receiving signals representing data from a communication device in a coverage area of a radio cell or one of the spot beams, wherein the spot beam forms a radio cell. The method comprises transmitting, to the communication device, an indication of a first condition that should be met before the communication device should transmit auxiliary information to the infrastructure device, receiving the auxiliary information from the communication device once the first condition is met, determining, based on the auxiliary information, that a radio cell change of the communication device should be initiated, and initiating the radio cell change of the communication device.

In the WO 2022082662 A1 can better ensure proper timing and synchronization of transmissions within a wireless communication network comprising a terrestrial network and a non-terrestrial network (NTN). A user equipment (UE) can maintain (e.g., determine and update on an ongoing basis) a timing advance (TA) value that the UE can apply to uplink (UL) transmissions to account for propagation delays, including changes in propagation delays, between the UE, the NTN, and the terrestrial network. TA maintenance can be based on network transmissions, random access channel (RACH) procedures, control messages, timing drift rates (e.g., of the UE or NTN satellite), beam changes, and more.

WO 2022082744 A1 discloses a user equipment (UE) associated with a non-terrestrial network (NTN). The UE includes a processor configured to determine a first time offset based on processing a time offset indication signal comprising the first time offset or an associated parameter received from a base station. In some embodiments, the first time offset indicates a time offset on the downlink (DL) to uplink (UL) interaction between the UE and the base station. The processor is further configured to determine a second time offset based on processing a subsequent time offset indication signal comprising the second time offset or an associated parameter received from the base station at a subsequent time instance. In some embodiments, the processor is further configured to update the first time offset with the second time offset.

WO 2021156749 A1 describes a method performed by a wireless device comprising obtaining a remaining service time (Tservice) associated with a first satellite or a first spot beam. Based on the remaining service time, the wireless device determines whether to initiate a connection with the first satellite or the first spot beam.

Massive IoT is a technology that supports a massive number of devices, long battery life of the devices and low complexity of the devices to achieve low costs as well as coverage improvements to reach devices in challenging locations (forest, basement, etc.).

LPWAN is a wireless technology designed for long-range, low-bitrate battery-powered IoT devices (particularly massive IoT devices). NB-IoT is an IoT wireless technology introduced by 3GPP to meet the LPWAN requirement.

Power saving mechanisms are designed to improve the energy efficiency of a UE. The UE battery life decides the UE useful life (NB-loT) and the expected useful life of an IoT device is more than 10 years. 3GPP introduced a power saving mechanism (UE) (DRx, eDRx, RAI, WuS) to improve the energy efficiency of UEs.

Massive IoT devices that remain under poor coverage conditions for extended periods suffer from higher energy consumption, as higher levels of coverage improvement (CE) result in lower battery runtime.

The main objective of this application is to provide a solution to all of these possibilities to maintain communication at a lower level of coverage improvement (CE) for a massive IoT device (UE).

The task described is solved by the embodiments of this application.

According to a particular embodiment, the energy efficient coverage enhancement (CE) method is characterized by a user equipment (UE) device connected to a wireless communications network, wherein the user equipment (UE) in the event of a maximum random access (RA) failure procedure, decides to obtain a higher level of coverage improvement (CE) or to switch networks.

A specific embodiment is characterized by an energy efficient coverage improvement (CE) method comprising the following steps: the user equipment (UE) is in sleep mode, the user equipment (UE) decides whether to switch to an alternative network based on the overall network congestion or not, this information being indicated by the network by reaching the maximum of a failure of a random access (RA) method for a level (k) of a coverage improvement (CE), a cell selection in alternative networks is carried out, the coverage of the cell is verified and in the event that the coverage of the radio cell is sufficient, then the user equipment (UE) switches to an alternative network and carries out a direct access (RA) procedure, in the event that the coverage of the radio cell is not sufficient, then the user equipment ( UE) in the same network and increases the level (k) of a coverage improvement (CE) to the level (k+1) for a random access (RA) method.

According to a particular embodiment, the energy efficient coverage improvement (CE) method includes the following steps: the user equipment (UE) is in connected mode, the user equipment (UE) decides whether or not to switch to an alternative network based on the overall network congestion, where this decision information is determined by reaching the maximum of a failure of a random access (RA) method for a level (k) of a coverage improvement (CE), in the case that the maximum of a failure of a random access (RA) method for a level (k ) a coverage improvement (CE) is achieved, a test is carried out as to whether the handover to an alternative network triggered by the user equipment (UE) should be carried out, if the result of the test is positive, then the handover to an alternative network is carried out , if the result of the test is negative, then the user equipment (UE) remains in the same network and increases the level (k) of a coverage improvement (CE) to the level (k+1) for a random access (RA) method.

A specific embodiment is characterized by the method for energy efficient coverage improvement (CE) according to claims 1 to 3, wherein the network switches from a terrestrial network to a non-terrestrial network (TN to NTN) or from a non-terrestrial network to a terrestrial network (NTN to TN) in case of reaching a maximum failure of the random access (RA) method.

A particular embodiment is characterized by the following: wherein the user equipment (UE) is a Narrowband Internet of Things (NB-IoT) user equipment which provides for the use of the non-terrestrial network to the terrestrial network (NTN) before obtaining the coverage improvement at a higher level (CE, CE 1, CE 2) when initially connected to the terrestrial network (TN).

A specific embodiment is characterized by: wherein the user equipment (UE) is a Narrowband Internet of Things (NB-IoT) user equipment UE that provides for utilization of the terrestrial network (TN) before acquiring the coverage enhancement at a higher level (CE, CE 1, CE 2) when initially connected to the non-terrestrial network to the terrestrial network (NTN).

A particular embodiment is characterized in that when the user equipment (UE) reaches the maximum failure of the random access (RA) procedure, the user equipment (UE) may choose to switch to an alternative network rather than increasing the level (k) of coverage improvement (CE), thereby reducing the signaling overhead and/or power consumption of the user equipment (UE).

A specific embodiment of the method for energy efficient coverage improvement (CE) by a base station (gNB) in a wireless communication network is characterized by the following steps: upon receiving a random access (RA) request of a coverage improvement (CE), a notification is sent to a user equipment (UE ) sent in idle state and
the user device (UE) decides whether or not to switch to an alternative network based on the overall network congestion,
wherein this decision information is determined by reaching the maximum failure of a random access (RA) method for a level (k) of coverage improvement (CE),
in the event that the maximum failure of a random access (RA) method is reached for a level (k) of coverage improvement (CE),
a test is carried out as to whether the handover triggered by the user device (UE) should be carried out to an alternative network,
if the result of the test is positive, the handover to an alternative network is carried out,
if the result of the test is negative, then the user equipment (UE) remains in the same network and increases the level (k) of a coverage improvement (CE) to the level (k+1) for a random access (RA) method, where the base station (gNB) configures whether the user equipment (UE) should switch to an alternative network.

A particular embodiment of the method for energy efficient coverage improvement (CE) by a base station (gNB) in a wireless communication network is characterized by the following steps: upon receiving a random access (RA) request for coverage improvement (CE), a notification is sent to a user equipment (UE) in the connected state, the user equipment (UE) decides whether or not to switch to an alternative network based on the overall network congestion, this decision information being determined by reaching the maximum of a failure of a random access (RA) method for a level (k) of coverage improvement (CE), in case the maximum of a failure of a random access (RA) method for a level (k) of coverage improvement (CE) is reached, a test is made whether the handover to an alternative network initiated by the user equipment (UE) should be performed, if the result of the test is positive, then the handover to an alternative network is performed, if the result of the test is negative, then the user equipment (UE) stays in the same network and increases the level (k) a coverage improvement (CE) to level (k+1) for a random access (RA) procedure, wherein the base station (gNB) configures whether the user equipment (UE) should switch to an alternative network.

• bei Empfangen einer Direktzugriffs(RA)-Anforderung einer Abdeckungsverbesserung (CE) wird eine Benachrichtigung an ein Benutzergerät (UE) im verbundenen Zustand gesendet,
• das Benutzergerät (UE) entscheidet basierend auf der Gesamtnetzüberlastung, ob es zu einem alternativen Netz wechseln soll oder nicht, wobei diese Entscheidungsinformationen durch das Erreichen des Maximums eines Versagens eines Direktzugriffs(RA)-Verfahrens für ein Niveau (k) einer Abdeckungsverbesserung (CE) bestimmt werden, im Falle, dass das Maximum eines Versagens eines Direktzugriffs(RA)-Verfahrens für ein Niveau (k) einer Abdeckungsverbesserung (CE) erreicht wird, wird ein Test, ob die durch das Benutzergerät (UE) ausgelöste Übergabe zu einem alternativen Netz durchgeführt werden soll, vorgenommen, wenn das Ergebnis des Tests positiv ist, dann wird die Übergabe zu einem alternativen Netz durchgeführt, wenn das Ergebnis des Tests negativ ist, dann bleibt das Benutzergerät (UE) in demselben Netz und erhöht das Niveau (k) einer Abdeckungsverbesserung (CE) auf das Niveau (k+1) für ein Direktzugriffs(RA)-Verfahren, wobei die Basisstation (gNB) konfiguriert, ob das Benutzergerät (UE) zu einem alternativen Netz wechseln soll.

A particular embodiment of the method for energy efficient coverage improvement (CE) by a base station (gNB) in a wireless communication network is characterized by the following steps:

• upon receiving a Coverage Improvement (CE) Random Access (RA) request, a notification is sent to a User Equipment (UE) in the connected state,
• the user equipment (UE) decides whether or not to switch to an alternative network based on the overall network congestion, this decision information being determined by reaching the maximum of a failure of a random access (RA) method for a level (k) of coverage improvement (CE), in case the maximum of a failure of a random access (RA) method for a level (k) of coverage improvement (CE) is reached, a test is performed as to whether the handover to an alternative network initiated by the user equipment (UE) is to be performed, if the result of the test is positive, then the handover to an alternative network is performed, if the result of the test is negative, then the user equipment (UE) remains in the same network and increases the level (k) of a coverage improvement (CE) to the level (k+1) for a random access (RA) procedure, wherein the base station (gNB) configures whether the user equipment (UE) should switch to an alternative network.

A specific embodiment is characterized by a device for receiving a transmission for energy efficient coverage enhancement (CE) from a user equipment (UE) in a wireless communication network, the device comprising a wireless transceiver and a processor coupled to a memory in which computer program instructions are stored, the instructions configured to implement the steps of claims 1 to 7.

A specific embodiment is characterized by a device for receiving an energy efficient coverage enhancement (CE) transmission from a base station (gNB) in a wireless communications network, the device comprising a wireless transceiver and a processor coupled to a memory (602). the computer program instructions are stored, wherein the instructions are configured to implement the steps of claims 8 to 9.

A specific embodiment is characterized by a user device (UE) comprising a device according to claim 10.

A specific embodiment is characterized by a base station comprising a device according to claim 11.

• wobei das Benutzergerät (UE) einen Prozessor, der mit einem Speicher gekoppelt ist, in dem Computerprogrammanweisungen gespeichert sind, umfasst, wobei die Anweisungen dazu konfiguriert sind, die Schritte nach den Ansprüchen 1 bis 7 zu implementieren.

A specific embodiment is characterized by a wireless communications system for performing energy efficient coverage enhancement from a base station to a user device, the base station comprising a processor coupled to a memory in which computer program instructions are stored, the instructions being configured to To implement steps according to claims 8 to 9:

• wherein the user device (UE) comprises a processor coupled to a memory in which computer program instructions are stored, the instructions being configured to implement the steps according to claims 1 to 7.

• das Benutzergerät (UE) sendet eine Direktzugriffs(RA)-Anforderung eines Niveaus (k) einer Abdeckungsverbesserung (CE) an eine Funkzelle A,
• die Funkzelle A sendet ein Niveau (k) einer Abdeckungsverbesserung (CE) wegen Direktzugriffs(RA)-Versagens zurück an das Benutzergerät (UE) und wartet, dass das Benutzergerät (UE) mit einem höheren Niveau (k) einer Abdeckungsverbesserung (CE) verbunden wird,
• das Benutzergerät (UE) sendet eine Direktzugriffs(RA)-Anforderung eines Niveaus (k) einer Abdeckungsverbesserung (CE) an eine Funkzelle B, und wenn für das Benutzergerät (UE) kein Direktzugriff (RA) möglich ist, puffert die Funkzelle A die Daten des Benutzergeräts (UE),
• die Funkzelle B sendet eine Direktzugriffs(RA)-Nachricht zu einem Niveau (k) einer Abdeckungsverbesserung (CE) zurück an das Benutzergerät (UE), das Benutzergerät (UE) und die Funkzelle B werden verbunden,
• die Funkzelle B aktualisiert Angaben des Benutzergeräts (UE), wenn die Funkzelle A eine Aktualisierung von der Funkzelle B betreffend das Benutzergerät (UE) erhält, überträgt die Funkzelle A die Daten des Benutzergeräts (UE) an die Funkzelle, wenn
• die Funkzelle A keine Aktualisierungen von anderen Funkzellen über das Benutzergerät (UE) erhält, erklärt die Funkzelle A ein Funkverbindungsversagen (radio link failure - RLF).

A particular embodiment is characterized by a wireless communication system for performing an energy efficient coverage improvement according to claim 14, wherein a user equipment (UE) initiated handover is performed after the user equipment (UE) has made a handover decision information based on defined criteria from at least one radio cell A to at least one other radio cell B after the following steps are performed:

• the user equipment (UE) sends a random access (RA) request of a coverage improvement (CE) level (k) to a radio cell A,
• the radio cell A sends a level (k) of coverage improvement (CE) due to random access (RA) failure back to the user equipment (UE) and waits for the user equipment (UE) to be connected to a higher level (k) of coverage improvement (CE),
• the user equipment (UE) sends a random access (RA) request of a coverage improvement (CE) level (k) to a radio cell B, and if no random access (RA) is possible for the user equipment (UE), the radio cell A buffers the data of the user equipment (UE),
• the radio cell B sends a random access (RA) message to a level (k) of coverage improvement (CE) back to the user equipment (UE), the user equipment (UE) and the radio cell B are connected,
• Cell B updates user equipment (UE) information, if cell A receives an update from cell B concerning the user equipment (UE), cell A transmits the user equipment (UE) data to cell B, if
• If cell A does not receive updates from other cells via the user equipment (UE), cell A declares a radio link failure (RLF).

The information medium can be any entity or device capable of storing the program. For example, the medium may comprise a storage medium such as a ROM, for example a CD-ROM or a ROM in the form of a microelectronic circuit, a FLASH memory or any magnetic recording medium, for example a hard disk drive.

Additionally, the information medium may be a transmittable medium, such as an electrical or optical signal, transmittable via an electrical or optical cable, radio, or other means.

Alternatively, the information medium may be an integrated circuit in which the program is embedded, the circuit being adapted to carry out the methods in question or to be used in carrying them out. The advantages of the device, the user equipment, the wireless system, the computer program and the information medium are consistent with those set out in connection with the corresponding method according to any of the above-mentioned embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

• - 1 die Abdeckungsverbesserung (CE) zeigt
• - 2 a einen erfolgreichen RA zeigt
• - 2 b ein Versagen des Direktzugriffs (RA) und eine Neuübertragung zeigt
• - 3 die Wiederholung der Präambel (CE) zeigt
• - 4 das Flussdiagramm eines Verfahrens zur Abdeckungsverbesserung (CE) nach dem Stand der Technik zeigt
• - 5 das Flussdiagramm der ersten Ausführungsform an der UE-Seite zeigt
• - 6 das Flussdiagramm der ersten Ausführungsform an der gNB-Seite zeigt
• - 7 das Flussdiagramm der zweiten Ausführungsform an der UE-Seite zeigt
• - 8 das Flussdiagramm der zweiten Ausführungsform an der gNB-Seite zeigt
• - 9 die durch das UE ausgelöste Übergabe zeigt.

Further advantages and characteristics of the invention will become clearer upon reading the following description, given as a simple illustrative and non-restrictive example, and from the accompanying drawings, among which:

• - 1 the coverage improvement (CE) shows
• - 2 a shows a successful RA
• - 2 B shows a random access (RA) failure and retransmission
• - 3 the repetition of the preamble (CE) shows
• - 4 shows the flowchart of a prior art coverage improvement (CE) method
• - 5 shows the flowchart of the first embodiment at the UE side
• - 6 shows the flowchart of the first embodiment on the gNB side
• - 7 shows the flowchart of the second embodiment at the UE side
• - 8th shows the flowchart of the second embodiment on the gNB side
• - 9 shows the handover triggered by the UE.

DETAILED DESCRIPTION

The following detailed description, which refers to the accompanying 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 implemented. The detailed description includes specific details to provide a comprehensive understanding of the various concepts. However, professionals will recognize that these concepts can be implemented without these specific details. In particular, while this disclosure may use 3GPP 5G NR terminology to exemplify embodiments herein, this should not be construed as limiting the scope of the invention.

Some of the embodiments provided herein will now be described more fully with reference to the accompanying drawings. However, other embodiments are included within the scope of the subject matter disclosed herein, and the disclosed subject matter should not be construed as limited only to the embodiments set forth herein; these embodiments are provided rather by way of example to convey the scope of the subject matter to those skilled in the art.

In general, all terms used herein should be construed in accordance with their usual meaning in the relevant technical field, unless a different meaning is clearly stated and/or follows from the context in which they are used. All references to an element, device, component, means, step, etc. are to be openly construed as referring to at least one instance of the item, device, component, means, step, etc., unless expressly stated otherwise. The steps of any of the methods disclosed herein need not be performed in the exact order disclosed unless a step is expressly described as following or preceding another step and/or where it is implied that a step follows another step follows or precedes this. Any feature of any embodiment disclosed herein may be applied to any other embodiment wherever appropriate. Likewise, any advantage of any of the embodiments may be applied to any other embodiments and vice versa. Additional objects, features, and advantages of the disclosed embodiments will become apparent from the following description.

In some embodiments, a more general term “network node” may be used and may correspond to any type of radio network node or any network node that communicates with a UE (directly or through another node) and/or with another network node. Examples of network nodes are NodeB, MeNB, ENB, a network node belonging to MCG or SCG, a base station (BS), a multi-standard radio (MSR) radio node such as MSR BS, eNodeB, gNodeB, a network controller, a radio network controller (RNC), a base station controller (BSC), a relay, a transmitter node control relay, a base transceiver station (BTS). Access point (AP), transmission points, transmission nodes, RRU, RRH, nodes in a distributed antenna system (DAS), a core network node (e.g. a Mobile Switching Center - MSC, a Mobility Management Entity - MME) etc.), Operations & Maintenance (O&M), an Operations Support System (OSS), a Self Optimized Network (SON), a positioning node (e.g. (approximately:) an advanced service center for the supply of mobile devices - Evolved-Serving Mobile Location Center - E-SMLC)), a minimization of the check of the reception quality during rapid changes of location - (Minimization of Drive Tests - MDT), test equipment (physical node or software), etc.

In some embodiments, the non-limiting term user equipment (UE) or wireless device may be used for and refer to any type of wireless device that communicates with a network node and/or with another UE in a cellular or mobile communication system. Examples of a UE include a target device, a device to device (D2D) UE, a machine UE or a UE capable of machine to machine (M2M) communication, a PDA, a PAD, a tablet, mobile terminals, a smartphone, laptop embedded equipment (LEE), laptop mounted equipment (LME), USB dongles, a UE category M1, a UE category M2, a ProSe UE, a V2V UE, a V2X UE, etc.

Furthermore, terms such as base station/gNodeB and UE should be considered non-limiting and in particular do not imply any particular hierarchical relationship between the two; In general, “gNodeB” could be considered as device 1 and “UE” could be considered as device 2, and these two devices communicate with each other over a radio channel. And in the following, the sender or the receiver could be either a gNodeB (gNB) or a UE.

Narrowband Internet of Things (NB-IoT) is a low-power wide-area network (LPWAN) radio technology standard developed by 3GPP for cellular devices and services. The specification was frozen in 3GPP Release 12 (LTE Advanced Pro) in June 2016. Other 3GPP IoT technologies include eMTC (enhanced machine-type communication) and EC-GSM-IoT. NB-IoT specifically focuses on indoor coverage, low cost, long battery life, and high link density. NB-IoT uses a subset of the LTE standard, but limits the bandwidth to a single narrowband of 200 kHz. It uses OFDM modulation for downlink communications and SC-FDMA for uplink communications. IoT applications that require more frequent communications are better served by NB-IoT, which has no duty cycle limitations operating on the licensed spectrum.

1 shows the coverage improvement. Coverage enhancement is intended to provide reliable connections with extended coverage and a retransmission, retry and power boost scheme as well as CE groups are introduced into the NB-loT during both the RACH procedure and the data transfer procedure. Retransmission means repeating the RA request in the event of no RA response. One repetition means one Repetition of the preambles to increase the probability of detection at the gNB. Power boosting means increasing the transmit power level to compensate for higher path loss.

1 represents a coverage improvement for NTNs in accordance with aspects of the present disclosure. The wireless communication system may include one or more base stations, one or more UEs, and a core network. In some examples, the wireless communication system may be a Long Term Evolution (LTE) network, an LTE-A (LTE-Advanced) network, an LTE-A-Pro network, or a New Radio (NR) network. In some examples, the wireless communications system may support: extended broadband communications, ultra-reliable (e.g., mission-critical) communications, low-latency communications, communications with low-cost, low-complexity devices, or any combination thereof.

The base stations may be distributed over a geographical area to form the wireless communication system and may be devices of different shapes or with different capabilities. The base stations and the UEs may communicate wirelessly via one or more communication links. Each base station can provide a coverage area over which the UEs and the base station can establish one or more communication links. The coverage area may be an example of a geographic area over which a base station and a UE may support communication of signals according to one or more radio access technologies.

The UEs may be distributed throughout a coverage area of the wireless communication system, and each UE may be stationary or mobile or both at different times. The UEs may be devices in different forms or with different capabilities. The UEs described here may be capable of communicating with different types of devices, such as other UEs, the base stations, or network equipment (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network equipment).

The base stations can communicate with the core network or with each other or with both. For example, the base stations may interface with the core network via one or more backhaul connections (e.g. via an S1, N2, N3 or another interface). The base stations can communicate with each other over the backhaul links (e.g. via an X2, Xn or other interface) either directly (e.g. directly between base stations) or indirectly (e.g. via a core network) or both. In some examples, the backhaul connections may be or include one or more wireless connections.

One or more of the base stations described herein may include, or be referred to by one of ordinary skill in the art, a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB), a next generation NodeB, or a giga-NodeB (both of which may be referred to as a gNB), a home-NodeB, a home-eNodeB, or other appropriate terminology.

A UE may include or be referred to as: a mobile device, a wireless device, a remote device, a handheld device or a subscriber device or other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal or a client, among other examples. A UE may include or be referred to as: a personal electronic device such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, a UE may include or be referred to as: a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE ) device or a machine type communications (MTC) device, among other examples, which may be implemented in various objects such as devices or vehicles, measuring devices, among other examples.

The UEs described herein may be capable of communicating with various types of devices, such as other UEs, which may sometimes act as relays, as well as the base stations and network equipment, including macro eNBs or gNBs, small cell eNBs or gNBs or relay base stations, among other examples, as in 1 shown.

The UEs and the base stations may wirelessly communicate with each other over one or more communication links over one or more carriers. The term “carrier” may refer to a set of radio frequency spectrum resources having a defined physical layer structure for supporting the communication links. For example, a carrier used for a communication link may comprise a portion of a radio frequency spectrum band (e.g., a bandwidth part (BWP)) operating according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling coordinating operation for the carrier, user data, or other signaling. The wireless communication system may support communication with a UE using carrier aggregation or multi-carrier operation. A UE may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers.

Signal waveforms transmitted over a carrier may be formed from multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or OFDM with discrete Fourier transform (discrete Fourier transform spread OFDM)). In a system using MCM techniques, a resource element may consist of a symbol duration (e.g., a modulation symbol duration) and a subcarrier, where the symbol duration and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both). The more resource elements a UE receives and the higher the order of the modulation scheme, the higher the data rate for the UE can be. A wireless communications resource may reference a combination of a radio frequency spectrum resource, a temporal resource, and a spatial resource (e.g., spatial layers or beams), and the use of multiple spatial layers may further increase the data rate or data integrity for communications with a UE.

The time intervals for the base stations or the UEs may be expressed in multiples of a basic time unit, which may, for example, refer to a sampling period Ts = 1/ (Δfmax · Nf) seconds, where Δfmax may represent the maximum supported subcarrier spacing and Nf may represent the maximum supported discrete Fourier transform (DFT) size. Time intervals of a communication resource may be organized according to radio frames, each having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0-1023).

Each frame may include multiple sequentially numbered subframes or time slots, and each subframe or time slot may have the same duration. In some examples, a frame may be divided into subframes (e.g., in the time domain) and each subframe may be further divided into a number of time slots.

Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include a number of symbol durations (e.g., depending on the length of the cyclic prefix preceding each symbol duration). In some wireless communication systems 100, a time slot may be further divided into multiple mini-time slots containing one or more symbols. Excluding the cyclic prefix, each symbol duration may include one or more (e.g., Nf) sampling periods. The duration of a symbol duration may depend on the subcarrier spacing or frequency band of operation.

A subframe, a time slot, a mini-time slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol durations in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs).

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example using one or more time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A control region (e.g., a control resource set (CORESET)) for a physical control channel may be defined by a number of symbol durations and may extend across the system bandwidth or a subset of the system bandwidth of the carrier. One or more control regions (e.g., CORESETs) may be configured for a set of the UEs. For example, one or more of the UEs may monitor or search control regions for control information according to one or more search space groups, and each search space group may include one or more control channel candidates in one or more aggregation levels arranged in a cascaded manner. An aggregation level for a control channel candidate may refer to a number of control channel resources (e.g., control channel elements, CCEs) associated with encoded information for a control information format with a given payload size. Search space groups may include common search space groups configured to send control information to multiple UEs, as well as UE-specific search space groups for sending control information to a specific UE.

In some examples, a base station may be mobile and therefore provide communication coverage for a moving geographic coverage area. In some examples, different geographic coverage areas associated with different technologies may overlap, but the different geographic coverage areas may be supported by the same base station. In other examples, the overlapping geographic coverage areas associated with different technologies may be supported by different base stations. For example, the wireless communication system may include a heterogeneous network in which different types of base stations provide coverage for different geographic coverage areas using the same or different radio access technologies.

The wireless communication system may be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communication system may be configured to support ultra-reliable low-latency communications (URLC) or mission-critical communications. The UEs may be designed to support ultra-reliable functions, low-latency functions, or critical functions (e.g., mission-critical functions). Ultra-reliable communications may include private communications or group communications and may be supported by one or more mission-critical services, such as mission-critical push-to-talk (MCPTT), mission-critical video (MCVideo), or mission-critical data (MCData). Support for mission-critical functions may include prioritization of services, and mission-critical services may be used for public safety applications or general commercial applications. The terms ultra-reliable, low latency, mission critical, and ultra-reliable low latency can be used interchangeably here.

In some examples, a UE may also be able to communicate directly with other UEs over a device-to-device (D2D) communication link (e.g., using a peer-to-peer (P2P) protocol or a D2D protocol). One or more UEs using D2D communications may be located within the geographic coverage area of a base station. Other UEs in such a group may be located outside the geographic coverage area of a base station or may otherwise be unable to receive transmissions from a base station. In some examples, groups of UEs communicating via D2D communications may utilize a one-to-many (1:M - one-to-many) system in which each UE transmits to every other UE in the group. In some examples, a base station facilitates resource planning for D2D communications. In other cases, D2D communications between UEs are performed without the involvement of a base station.

The core network may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network may be an evolved packet core (EPC) or 5G core (5GC), which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF) and at least one user plane entity that routes packets or interfaces with external networks (e.g. a serving gateway (S-GW), a Packet Data Network (PDN) gateway (P-GW) or a user plane function (UPF)). The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication and bearer management for the UEs served by the base stations associated with the core network. User IP packets may be conveyed by the user plane entity, which may provide IP address allocation and other functions. The user plane entity may be associated with the IP services of the network operators. Operators' IP services may include access to the Internet, one or more intranets, an IP Multimedia Subsystem (IMS) or a packet-switched streaming service.

Some of the network devices, such as a base station, may include subcomponents, such as an access network entity, which is an example of an access note controller (ANC). Each access network entity may communicate with the UEs through one or more other access network transmission entities, which may be referred to as radio heads, smart radio heads, or transmission/reception points (TRPs). Each access network transmission entity may include one or more antenna panels. In some configurations, various functions of each access network entity or base station may be distributed across different network devices (e.g., radio headends and ANCs) or consolidated into a single network device (e.g., a base station).

The wireless communication system may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally, the range from 300 MHz to 3 GHz is known as the ultra high frequency (UHF) range or the decimeter band because the wavelengths range in length from approximately one decimeter to one meter. The UHF waves may be blocked or redirected by buildings and environmental features, but the waves can penetrate structures sufficiently to allow a macrocell to provide service to the UEs located inside. Transmission of UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) compared to transmission using the smaller frequencies and longer waves of the radio frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

The wireless communication system may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system may employ a License Assisted Access (LAA) radio access technology, an LTE-Unlicensed (LTE-U) radio access technology, or an NR technology in an unlicensed band, such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in unlicensed radio frequency spectrum bands, devices such as the base stations and the UEs may employ carrier sensing for collision detection and avoidance. In some examples, operation in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA). Operation in unlicensed spectrum may include, among other examples, downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions.

A base station or UE may be equipped with multiple antennas that may be used to implement techniques such as transmit diversity, receive diversity, communications using multiple transmit and receive antennas (multiple-input multiple-output - MIMO), or beamforming. The antennas of a base station or UE may be located in one or more antenna arrays or antenna panels that may support MIMO operation or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be arranged together in an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with a base station may be located in different geographic locations. A base station may include an antenna array having a number of rows and columns of antenna ports that the base station may use to support beamforming of communications with a UE. Similarly, a UE may include one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, an antenna panel may support radio frequency beamforming for a signal transmitted over an antenna port.

Beamforming, which may also be referred to as spatial filtering, directional transmission or directional reception, is a signal processing technique that can be used at a transmitting device or a receiving device (e.g. a base station, a UE) to produce an antenna beam (e.g. B. to shape or direct a transmitting beam, a receiving beam) along a spatial path between the transmitting device and the receiving device. Beamforming can be achieved by combining the signals communicated across antenna elements of an antenna array such that some signals propagating in specific orientations with respect to an antenna array are subject to constructive interference while others are subject to destructive interference.

Adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying amplitude offsets, phase offsets, or both to signals carried via the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a specific orientation (e.g., with respect to the antenna arrangement of the transmitting device or the receiving device, or with respect to another orientation).

The wireless communication system includes base stations, UEs, satellites and a core network. In some examples, the wireless communication system may be an LTE network, an LTE-A network, an LTE-A Pro network, or an NR network. In some cases, a wireless communications system may support: extended broadband communications, ultra-reliable (e.g., mission-critical) communications, low-latency communications, or communications with low-cost, low-complexity devices.

The wireless communication system may also include one or more satellites. A satellite may communicate with base stations (also referred to as gateways in NTNs) and UEs (or other high altitude or terrestrial communication devices). A satellite may be any suitable type of communication satellite configured to mediate communications between different end nodes in a wireless communication system. A satellite may be an example of a space satellite, a balloon, a steerable aircraft, an airplane, a drone, an unmanned airship, and/or the like. In some examples, the satellite may be in geosynchronous or geostationary Earth orbit, low Earth orbit, or medium Earth orbit. A satellite may be a multi-beam satellite configured to provide services to multiple service beam coverage areas in a predetermined geographic service area. The satellite may be located at any distance from the surface of the Earth.

In some cases, a cell may be provided or established by a satellite as part of a non-terrestrial network. A satellite may, in some cases, perform the functions of a base station, act as a bent-pipe satellite, or act as a regenerative satellite, or a combination thereof. In other cases, a satellite may be an example of a smart satellite or a satellite with intelligence. For example, a smart satellite may be configured to perform more functions than a regenerative satellite (e.g., it may be configured to perform specific algorithms beyond those used in regenerative satellites, to be reprogrammed, etc.). A bent-pipe transponder or satellite may be configured to receive signals from ground stations and transmit those signals to other ground stations. In some cases, a bent-pipe transponder or satellite may amplify signals or switch from uplink frequencies to downlink frequencies. A regenerative transponder or satellite may be configured to relay signals like the bent pipe transponder or satellite, but may also use on-board processing to perform other functions. Examples of these other functions may include demodulating a received signal, decoding a received signal, re-encoding a signal to be transmitted, or modulating the signal to be transmitted, or a combination thereof. For example, a bent pipe satellite (e.g., a satellite) may receive a signal from a base station and may relay the signal to a UE or base station, or vice versa. In accordance with various aspects of the present disclosure, coverage improvement for communications with satellites 120 may be provided by repetitions of communications, which may reduce BLER and increase the reliability of communications.

A UE may include a UE communication management unit. The UE communications management unit may receive an indication of replay activation from a base station or satellite for communications. The UE communications management unit may designate resources for communications containing replays in response to the retry indication. When receiving communications, the UE communications management unit may buffer signals from resources containing multiple transmissions and attempt to decode the associated communications. In some cases, when transmitting an uplink message to the base station or satellite, the UE communication management unit may create multiple retries of the communication based on the configured retries. Further, in some cases, uplink messages may be transmitted using a lower frequency bandwidth than a full channel bandwidth to provide higher power density and increase the probability of receiving the uplink message.

A base station may include a base station communications management unit. The base station communications management unit may configure a coverage enhancement scheme at one or more UEs in which a number of repetitions of communications are provided to help reduce BLER. Replays can be provided by time slot bundling for PDCCH in consecutive or non-consecutive time slots or by multiple replays in the same time slot.

Coverage enhancement: CE is achieved through temporal repetition, retransmission and power enhancement in in-band and guard band operation modes. The coverage enhancement feature of NB-IoT is useful when the sensors are located in remote or challenging areas. Reliable coverage enhancement is achieved through repeated transmission of data and control signaling. Each transmission can be configured to be repeated for a designated number of times to achieve higher chances of success at the desired coverage level.

The number of repeat values is directly proportional to the Maximum Coupling Loss (MCL).

The number of repetitions increases the SNR at the receiver. An increase in the number of repetitions leads to an increase in energy consumption. A high repetition count leads to higher latency. CE results in a waste of radio resources (a UE occupies a channel for a longer duration in the case of a higher level CE). CE is suitable for latency-insensitive applications (applications that can tolerate a transmission delay of 10 seconds). Avoiding CE upgrade by any alternative can improve energy efficiency and reduce radio resource waste.
2 shows the production of a successful RA.
2 B shows RA failure and retransmission.
3 shows the repetition of the preamble (CE).

In these 2a , 2 B and 3 The UE behavior is as follows: If all RA attempts have failed, then the UE performs a cell reselection in sleep mode or reports an RLF in connected mode.

4 shows the flowchart of a state-of-the-art CE procedure. A user equipment (UE) attempts to perform the random access (RA). In case a failure is generated, an acquisition of a higher level of CE is performed. When there is no longer a failure of a regular radio access (RA) procedure, the process stops.

The key aspect of this new method is to create a mechanism in which a UE makes a decision whether to obtain a higher level of CE or switch networks (TN to) in the event that it reaches a maximum failure of the RA method NTN or NTN to TN). A UE (NB-loT) may consider using the NTN before obtaining a higher level of a CE (CE 1, CE 2) when initially connected to a TN. A UE (NB-loT) may consider using the TN before obtaining a higher level of a CE (CE 1, CE 2) if it is initially connected to an NTN.

5 shows the flow chart of the first embodiment at the UE side. Method for energy efficient coverage improvement (CE) by a user equipment (UE) device connected to a wireless communication network, wherein the user equipment (UE), in case it reaches a maximum failure of the random access (RA) method, decides to use a higher level of to obtain a coverage improvement (CE) or to change networks. The user equipment (UE) is in idle mode, the user equipment (UE) decides whether to change to an alternative network or not based on the overall network congestion, this information being indicated by the network by reaching the maximum of a failure of a random access (RA) procedure for a level (k) of coverage improvement (CE), a cell selection is performed in alternative networks, the coverage of the cell is verified and in case the coverage of the cell is sufficient then the user equipment (UE) changes to an alternative network and performs a random access (RA) procedure, in case the coverage of the cell is not sufficient then the user equipment (UE) stays in the same network and increases the level (k) of coverage improvement (CE) to the level (k+1) for a random access (RA) procedure.

The UE only switches to an alternative network if there is good coverage in the alternative network. If not, the UE stays in the same network and increases the level of a CE.

6 shows the flowchart of the first embodiment at the base station (gNB) side.

The method includes receiving a random access (RA) request for coverage enhancement (CE), sending a notification to a user equipment (UE) in the sleep mode state, and the user equipment (UE) deciding whether to switch to an alternative network based on the overall network congestion or not, this decision information being determined by reaching the maximum of a random access (RA) method failure for a level (k) of coverage improvement (CE), in the case that the maximum of a random access (RA) method failure for a level (k) of coverage improvement (CE) is reached, a test is made as to whether the handover triggered by the user equipment (UE) should be carried out to an alternative network, if the result of the test is positive, then the handover becomes performed on an alternative network, if the result of the test is negative, then the user equipment (UE) remains in the same network and increases the level (k) of a coverage improvement (CE) to the level (k+1) for a random access (RA) Method, wherein the base station (gNB) configures whether the user equipment (UE) should switch to an alternative network.

7 shows the flowchart of the second embodiment on the UE side. This embodiment includes the following steps: the user equipment (UE) is in connected mode, the user equipment (UE) decides whether or not to switch to an alternative network based on the overall network congestion, this decision information being determined by reaching the maximum of a failure Random access (RA) method for a level (k) of coverage improvement (CE) is determined in the event that the maximum failure of a random access (RA) method for a level (k) of coverage improvement (CE) is reached a test as to whether the handover to an alternative network triggered by the user equipment (UE) should be carried out, if the result of the test is positive, then the handover to an alternative network is carried out, if the result of the test is negative, then the user equipment (UE) remains in the same network and increases the level (k) of a coverage improvement (CE) to the level (k+1) for a random access (RA) method.

8th shows the flowchart of the second embodiment on the gNB side.

The method comprises the following steps: receiving a radio access (RA) request of a coverage improvement (CE), a notification to a user equipment (UE) in the connected state, the user equipment (UE) decides based on the overall network congestion whether to switch to an alternative network or not, this decision information being determined by reaching the maximum of a failure of a random access (RA) procedure for a level (k) of coverage improvement (CE), in case the maximum of the failure of a random access (RA) procedure for a level (k) of coverage improvement (CE) is reached, a test is made whether the handover to an alternative network initiated by the user equipment (UE) should be performed. If the result of the test is positive, then the handover to an alternative network is performed, if the result of the test is negative, then the user equipment (UE) remains in the same network and increases the level (k) of coverage improvement (CE) to the level (k+1) for a random access (RA) procedure, whereby the base station (gNB) configures whether the user equipment (UE) should switch to an alternative network.

• Das Benutzergerät (UE) sendet eine Direktzugriffs(RA)-Anforderung eines Niveaus (k) einer Abdeckungsverbesserung (CE) an eine Funkzelle A.

9 shows the handover triggered by the UE. A wireless communication system for performing energy efficient coverage improvement, wherein a user equipment (UE) triggered handover is performed after the user equipment (UE) receives handover decision information tion based on defined criteria from at least one radio cell A to at least one other radio cell B after the following steps are carried out:

• The user equipment (UE) sends a random access (RA) request of a level (k) of coverage improvement (CE) to a cell A.

Cell A sends a level (k) of coverage improvement (CE) upon random access (RA) failure back to the user equipment (UE) and waits for the user equipment (UE) to connect to a higher level (k) of coverage improvement (CE).

The user equipment (UE) sends a random access (RA) request of a coverage improvement (CE) level (k) to a cell B, and if random access (RA) is not possible for the user equipment (UE), cell A buffers the user equipment (UE) data.

The cell B sends a random access (RA) response at a level (k) of coverage improvement (CE) back to the user equipment (UE). The user device (UE) and the radio cell B are connected.

Cell B updates user equipment (UE) information, if cell A receives an update from cell B regarding the user equipment (UE), cell A transmits the user equipment (UE) data to the cell, if cell A does not receive updates from other cells about the user equipment (UE), cell A declares a radio link failure (RLF).

The advantages of these new approaches are low power consumption. NB-IoT & LTE-M chipsets focus on the wireless properties that applications require and have power-saving features such as sleep mode, long-period location updates and extended discontinuous reception, which ensures optimal energy efficiency.

In addition, deep building penetration is possible. NB-IoT and LTE-M have a power density of up to 20 decibels (NB-loT) and 15 decibels (LTE-M) higher than GSM with narrowband modulation and multiple transmission repetitions. This ensures better network coverage inside buildings.

A very important aspect of this new approach is the low cost. Both LTE-M and NB-IoT score with low module costs as well as low operating and service prices. This is ensured by the simple chipset design that eliminates unnecessary LTE features and increasing production volumes.

All solutions described are LTE-based. NB-IoT and LTE-M are based on LTE and can be integrated into existing LTE infrastructures via a software update. Since both NB-IoT and LTE-M can be deployed on GSM and LTE spectrum, no additional spectrum licenses are required.

Unlike sensors that cannot transmit over long distances, both NB-IoT and LTE-M work via plug & play. The sensors are directly connected to the NB-IoT and/or LTE-M network without the need to install local networks or gateways.

Another very relevant aspect of the solutions described is that they are extremely secure. NB-IoT and LTE-M are globally standardized technologies and use LTE security mechanisms in accordance with 3GPP. Abbreviations: Discontinuous reception DRX Extended discontinuous reception gNB: gNodeB eDRX Internet of Things IoT Low Power Wide Area Network LPWAN Narrow Band Internet of Things NB-IoT Release Assistance Indicator RAI Direct access (random access) R.A Random Access Channel RACH User Equipment U.E Wake Up Signal WuS

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2022131602 A1 [0006]
• CN 113644950 [0008]
• US 2021194572 A1 [0009]
• WO 2022082771 A1 [0010]
• US 2021306927 A1 [0011]
• WO 2022082662 A1 [0012]
• WO 2022082744 A1 [0013]
• WO 2021156749 A1 [0014]

Claims (15)

A method for energy efficient coverage enhancement (CE) by a user equipment (UE) device connected to a wireless communications network, wherein the user equipment (UE) decides whether to obtain a higher level of coverage enhancement (CE) or switch networks, in Case that it reaches a maximum failure of the random access method. Methods for energy-efficient coverage improvement (CE). Claim 1 , comprising the following steps that the user equipment (UE) follows when it is in sleep mode: The user equipment (UE) decides whether or not to switch to an alternative network based on the overall network congestion, which information is transmitted through the network by reaching of the maximum failure of a random access (RA) method for a level (k) of coverage improvement (CE), then the user equipment (UE) proceeds with cell selection in alternative networks, verifying the coverage of the cell, and in In the event that the coverage of the radio cell is sufficient, the user equipment (UE) switches to an alternative network and carries out a direct access (RA) procedure. In the event that the coverage of the radio cell is not sufficient, the user equipment (UE) remains in the same network and increases the level (k) of a coverage improvement (CE) to the level (k+1) for a random access (RA) method. Procedure for energy efficient coverage improvement (CE) according to Claim 1 , comprising the following steps that the user equipment (UE) follows when in connected mode: the user equipment (UE) decides whether or not to switch to an alternative network based on the overall network congestion, this decision information being determined by reaching the maximum of a failure of a random access (RA) procedure for a level (k) of coverage improvement (CE), in case the maximum of a failure of a random access (RA) procedure for a level (k) of coverage improvement (CE) is reached, a test is made whether the handover to an alternative network initiated by the user equipment (UE) should be performed, if the result of the test is positive, then the handover to an alternative network is performed, if the result of the test is negative, then the user equipment (UE) stays in the same network and increases the level (k) of coverage improvement (CE) to the level (k+1) for a random access (RA) procedure. Methods for energy-efficient coverage improvement (CE). Claim 1 until 3 , wherein in the event of reaching a maximum failure of the random access (RA) method, the network switches from a terrestrial network to a non-terrestrial network (TN to NTN) or from a non-terrestrial network to a terrestrial network (NTN to TN). Procedure according to the Claims 1 until 4 , wherein the user device (UE) is a user device for the narrowband Internet of things UE (Narrowband Internet of Things - NB-IoT), which provides a use of the non-terrestrial network (NTN) to the terrestrial network (TN) before it Coverage improvement obtained at a higher level (CE, CE 1, CE 2) when initially connected to the terrestrial network (TN). Procedure according to the Claims 1 until 5 , wherein the user equipment (UE) is a narrowband Internet of Things UE (NB-loT) user equipment that provides utilization of the terrestrial network (TN) before obtaining the coverage improvement at a higher level (CE, CE 1, CE 2) if it is originally connected to the non-terrestrial network to the terrestrial network (NTN). Procedure according to Claim 1 or 6 the method being characterized in that when the user equipment (UE) reaches the maximum failure of the random access (RA) procedure, the user equipment (UE) has the option of changing the network rather than increasing the level of coverage improvement (CE), thereby reducing the signaling overhead and/or power consumption of the user equipment, UE. A method for energy efficient coverage enhancement (CE) by a base station (gNB) in a wireless communications network, the method comprising: upon receiving a random access (RA) request for coverage enhancement (CE), a notification is sent to an idle user equipment (UE). and the user equipment (UE) decides whether or not to switch to an alternative network based on the overall network congestion, this decision information being provided by reaching the maximum of a direct access failure Access (RA) method for a level (k) of coverage improvement (CE) is determined in the event that the maximum failure of a random access (RA) method for a level (k) of coverage improvement (CE) is reached a test as to whether the user equipment (UE) triggered handover to an alternative network should be carried out, if the result of the test is positive, then the handover to an alternative network is carried out, if the result of the test is negative, then the user equipment (UE) remains in the same network and increases the current level (k) of the coverage improvement (CE) to the level (k+1) for a random access (RA) method, where the base station (gNB) configures whether the user equipment (UE) should switch to an alternative network. A method for energy efficient coverage improvement (CE) by a base station (gNB) in a wireless communication network, the method comprising: upon receiving a random access (RA) request for coverage improvement (CE), a notification is sent to a user equipment (UE) in the connected state, the user equipment (UE) decides whether or not to switch to an alternative network based on the overall network congestion, this decision information being determined by reaching the maximum of a failure of a random access (RA) method for a level (k) of coverage improvement (CE), in case the maximum of a failure of a random access (RA) method for a level (k) of coverage improvement (CE) is reached, a test is made whether the handover to an alternative network initiated by the user equipment (UE) should be performed, if the result of the test is positive, then the handover to an alternative network is performed, if the result of the test is negative, then the user equipment (UE) stays in the same network and increases the current level (k) a coverage improvement to level (k+1) for a random access (RA) scheme, wherein the base station (gNB) configures whether the user equipment (UE) should switch to an alternative network. Apparatus for receiving a transmission for energy efficient coverage enhancement (CE) from a user equipment (UE) in a wireless communication network, the apparatus comprising a wireless transceiver and a processor coupled to a memory having computer program instructions stored therein, the instructions configured to perform the steps of Claims 1 until 7 to implement. Apparatus for receiving a transmission for energy efficient coverage enhancement (CE) from a base station (gNB) in a wireless communication network, the apparatus comprising a wireless transceiver and a processor coupled to a memory (602) having computer program instructions stored therein, the instructions configured to perform the steps of Claims 8 until 9 to implement. User device, comprising a device according to Claim 10 . Base station, comprising a device according to Claim 11 . A wireless communications system for performing energy efficient coverage enhancement from a base station to a user device, the base station comprising a processor coupled to a memory in which computer program instructions are stored, the instructions being configured to perform the steps of Claims 8 until 9 to implement: wherein the user device (UE) comprises a processor coupled to a memory in which computer program instructions are stored, the instructions being configured to perform the steps according to the Claims 1 until 7 to implement. Wireless communication system for performing energy efficient coverage improvement according to Claim 14 , wherein a user equipment (UE)-triggered handover is performed after the user equipment (UE) has made a handover decision information based on defined criteria from at least one radio cell A to at least one other radio cell B, after the following steps are performed: a.) the user equipment (UE) sends a random access (RA) request of a level (k) of coverage improvement (CE) to a radio cell A, b.) in case of a failure of a random access (RA) at a level (k) of coverage improvement (CE) the radio cell A waits for the user equipment (UE) to be connected to a higher level (k) of coverage improvement (CE), c.) the user equipment (UE) sends a random access (RA) request of a level (k) of coverage improvement (CE) to a radio cell B, and if direct access (RA) is not possible for the user equipment (UE), the radio cell A buffers the user equipment (UE) data, d.) the radio cell B sends a random access (RA) response at a level (k) of coverage improvement (CE) back to the user equipment (UE), e.) the user equipment (UE) and the radio cell B are connected, f.) the radio cell B updates user equipment (UE) information via an X2 interface, if the radio cell A receives an update from the radio cell B concerning the user equipment (UE), the radio cell A transmits the user equipment (UE) data to the radio cell B, g.) if the radio cell A does not receive updates from other radio cells via the user equipment (UE), cell A declares a radio link failure (RLF).

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