User equipment and beam management method in sidewalk communication

Abstract

A beam management method of user equipment (UE) in sideward communication includes performing sideward transmissions to another UE or a group of other UEs using a transmit beam set during a beam management procedure, receiving a sideward hybrid automatic repeat request (SL-HARQ) report from another UE or a group of other UEs, and selecting and / or determining a subset of the one or more transmit beams based on the SL-HARQ report.

Description

Technical Field

[0001] The present disclosure relates to the field of communication systems, and more particularly, to a beam management method in user equipment (UE) and sideline communications, which can provide good communication performance and / or high reliability. Background Art

[0002] In Release 16 of the 3rd Generation Partnership Project (3GPP), sidelink technology has been developed based on the latest fifth-generation (5G) New Radio (NR) access system. The 5G NR access system supports frequency range 1 (FR1) (410 MHz to 7125 MHz) and frequency range 2 (FR2) (24250 MHz to 71000 MHz), as well as various OFDM transmission parameter sets / subcarrier spacings (SCS) (15 kHz, 30 kHz, 60 kHz, and 120 kHz). One of the main motivations for supporting additional spectrum bands compared to the 4G Long Term Evolution (LTE) system (i.e., frequency range 2, FR2) is to enable the use of larger spectrum bandwidths to support high data rate applications and various SCSs, thereby providing extremely low-latency wireless transmission for delay-sensitive services. However, the main disadvantages of using high-frequency bands (i.e., FR2) for wireless transmission are that the signal strength attenuates significantly with distance from the transmitter (high path loss), and due to the short wavelength, the system is prone to frequency / phase errors. For the NR sidelink system, it is said that the FR2 spectrum band will be supported by introducing the phase tracking reference signal (PT-RS) in Release 16. However, no specific enhancements or features are supported in the NR sidelink to combat / mitigate the high path loss problem in FR2.

[0003] Therefore, a beam management method for user equipment (UE) and sidelink communication is needed, which can solve the problems in the prior art, provide beam management for sidelink communication, improve sidelink (SL) communication performance, minimize / reduce sidelink (SL) resource usage, and / or provide high reliability. Summary of the Invention

[0004] In a first aspect of the present disclosure, a user equipment (UE) includes an executor, a receiver, and a selector, wherein the executor performs sidelink transmission to another UE or a group of other UEs using a set of transmit beams during a beam management process, the receiver is used to receive a sidelink hybrid automatic repeat request (SL-HARQ) report from the other UE or the group of other UEs, and the selector is used to select and / or determine a subset of one or more transmit beams based on the SL-HARQ report.

[0005] In a second aspect of the present disclosure, a beam management method for a user equipment (UE) in sidelink communication includes: performing sidelink transmission to another UE or a group of other UEs using a set of transmit beams during a beam management process, receiving a sidelink hybrid automatic repeat request (SL-HARQ) report from the other UE or a group of other UEs, and selecting and / or determining a subset of one or more transmit beams based on the SL-HARQ report.

[0006] In a third aspect of the present disclosure, a user equipment (UE) includes a memory, a transceiver, and a processor coupled to the memory and the transceiver. The UE is configured to execute the above method.

[0007] In a fourth aspect of the present disclosure, a non-transitory machine-readable storage medium stores instructions thereon, which, when executed by a computer, causes the computer to perform the above method.

[0008] In a fifth aspect of the present disclosure, a chip includes a processor, and the processor is used to call and run a computer program stored in a memory so that a device equipped with the chip executes the above method.

[0009] In a sixth aspect of the present disclosure, a computer-readable storage medium stores a computer program for causing a computer to execute the above method.

[0010] In a seventh aspect of the present disclosure, a computer program product includes a computer program, and the computer program enables a computer to execute the above method.

[0011] In an eighth aspect of the present disclosure, a computer program enables a computer to execute the above method. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present disclosure or related technologies, the following figures will be briefly introduced in the embodiments. It is obvious that the figures are only some embodiments of the present disclosure, and ordinary technicians in this field can obtain other figures based on these figures without any prior knowledge.

[0013] Figure 1is a block diagram of a user equipment (UE) communicating in a communication network system according to an embodiment of the present disclosure.

[0014] Figure 2 FIG. 4 is a schematic diagram illustrating a user plane protocol stack according to an embodiment of the present disclosure.

[0015] Figure 3 is a schematic diagram illustrating a control plane protocol stack according to an embodiment of the present disclosure.

[0016] Figure 4 3 is a flowchart illustrating a beam management method of a UE in sideline communication according to an embodiment of the present disclosure.

[0017] Figure 5 is a schematic diagram illustrating proposed UE-centric beamforming and beam management for SL GC and UC communication based on SL-HARQ feedback reporting according to an embodiment of the present disclosure.

[0018] Figure 6 2 is a schematic diagram illustrating a method of SL-HARQ feedback in PSFCH proposed for transmit beamforming and beam management of SL communication according to an embodiment of the present disclosure.

[0019] Figure 7 is a diagram illustrating proposed TB-centric beamforming and beam management for SL GC communication based on NACK-only SL-HARQ reporting according to an embodiment of the present disclosure.

[0020] Figure 8 is a block diagram of a UE for wireless communication according to an embodiment of the present disclosure.

[0021] Figure 9 is a block diagram of a wireless communication system according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0022] The following will describe in detail the technical matters, structural features, objectives and effects of the embodiments of the present disclosure in conjunction with the accompanying drawings. Specifically, the terms used in the embodiments of the present disclosure are only for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure.

[0023] In the evolution of radio wireless transmission and reception directly between two devices, commonly referred to as device-to-device (D2D) communication, it was first developed by the 3rd Generation Partnership Project (3GPP), introduced in Release 12 (formally designated as sidewalk communication), and improved in Release 13 for public safety emergency uses such as mission-critical communications to primarily support low data rates and voice-type connections. In 3GPP Releases 14, 15, and 16, sidewalk technology was improved to additionally support vehicle-to-everything (V2X) communications as part of the global development of intelligent transportation systems (ITS), thereby improving road safety and facilitating advanced / autonomous driving use cases. To further expand support for sidewalk technology to a wider range of applications and devices with limited power / battery, the technology was further enhanced in Release 17 in terms of power saving and transceiver link reliability. For Release 18, 3GPP is currently looking to evolve wireless technologies and extend their operation into unlicensed spectrum to enable greater available bandwidth, faster data rates, and easier market adoption of D2D communications using sidelinks without requiring any mobile cellular operator to be involved in allocating and configuring a portion of its expensive and valuable radio spectrum for data services that do not pass through its mobile network.

[0024] Since 3GPP Release 16, sidelink technology has been developed based on the latest fifth-generation (5G) New Radio (NR) access system, which supports Frequency Range 1 (FR1) bands (410 MHz to 7125 MHz) and Frequency Range 2 (FR2) bands (24250 MHz to 71000 MHz), as well as various OFDM transmission parameter sets / subcarrier spacing (SCS) (15 kHz, 30 kHz, 60 kHz, and 120 kHz). One of the main motivations for supporting additional spectrum bands compared to 4G Long Term Evolution (LTE) systems (i.e., FR2) is the ability to use larger spectrum bandwidths to support high data rate applications and various SCSs, thereby providing extremely low-latency wireless transmission for delay-sensitive services. However, the main disadvantages of using high-frequency bands (i.e., FR2) for wireless transmission are significant signal strength attenuation with distance from the transmitter (high path loss) and susceptibility to frequency / phase errors due to the shorter wavelength. For the NR sidelink system, support for the FR2 spectrum band is purportedly achieved through the introduction of a phase tracking reference signal (PT-RS) in Release 16. However, no specific enhancements or features are supported in the NR sidelink to combat / mitigate the high path loss issue in FR2.

[0025] Transmit beamforming and scanning in the downlink

[0026] Since the introduction of 5G-NR systems in Release 15, transmit beamforming and beam management concepts and functionality have been developed and introduced on the downlink (DL) and uplink (UL) of the Uu interface to improve received signal strength, enhance cellular DL and UL coverage, and minimize / reduce radio interference to neighboring cells. To implement this transmit beamforming / beam management functionality on the Uu interface (particularly in the DL), the concept of beam scanning has been introduced: forming a transmit beam and sweeping it across all directions in the space (horizontal and vertical spatial domains) supported by the base station (gNB). Once the user equipment (UE) receives all transmit beams, or as many as possible (according to a predefined pattern and time interval), it selects the best beam and sends a physical random-access channel (PRACH) to the gNB on the RACH opportunity corresponding to the selected best beam. At the gNB, the gNB determines the selected best beam from the UE based on the received RACH opportunity and completes the random access procedure using the selected best beam, allowing the UE to connect to the base station. The same optimal beam can also be used for subsequent data communications between the gNB and UE until further update / handover.

[0027] The need for transmit beamforming and beam management in the sidelink

[0028] As mentioned earlier, radio communications in the high-frequency spectrum (i.e., FR2 band) may suffer from significant attenuation of the transmitted signal and spatial propagation losses compared to the lower frequency bands where cellular systems traditionally operate. There is currently no other way to improve the communication range / signal coverage while also supporting transmit beamforming and beam management for NR sideline technology, except that sideline communication devices can use PT-RS to correct the phase error in the received carrier frequency in FR2 and the maximum device transmit power is limited by the power class definition of the device. By improving the sideline signal coverage / communication range, it enables some new use cases and applications for users, such as enhancing the network coverage of SL relays on FR2 carriers and offloading network traffic to the sideline FR2 carriers of two UEs within the same cell.

[0029] Back-to-back (B2B) / multi-consecutive slots transmission (MCSt)

[0030] The original purpose of B2B transmission (also known as "burst transmission" or "multi-continuous time slot transmission") is to enable a sidelink (SL) communicating UE to continuously occupy the initial channel occupancy time (COT) of an unlicensed spectrum channel or a longer time (i.e., multiple time slots) within a COT shared with another UE, thereby reducing the risk of wireless transmission (Tx) devices of another radio access technology (RAT) being unable to access the unlicensed spectrum channel. This B2B transmission is particularly important and useful for SL Tx-UEs operating in the unlicensed radio frequency spectrum with large data transmission blocks (TBs) or medium access control (MAC) packet data units (PDUs), requiring multiple retransmissions, with sidelink hybrid automatic repeat request (SL-HARQ) feedback disabled, and / or with short latency requirements (small packet delay budgets (PDBs)). When the unlicensed spectrum channel is busy / congested (e.g., many devices are trying to access the channel for transmission at the same time), accessing the channel may be difficult and take a long time due to the random backoff timer and priority class in the Type 1 listen-before-talk (LBT) process. Therefore, when the UE finally has the opportunity to access the wireless channel within the Channel Occupancy Time (COT) length (which may last for several milliseconds (e.g., 2, 4, 6, or 10 milliseconds)), the goal is to retain channel access for as long as possible (e.g., the entire or most of the COT length) to transmit as much data as possible by continuously transmitting in the unlicensed spectrum channel so that wireless devices of other RATs do not have the opportunity to access the channel.

[0031] Sidelink HARQ feedback for multicast and unicast communications

[0032] To support more advanced applications and use cases using NR SL technology, such as vehicle platooning in V2X, autonomous driving, and high data rate augmented reality (AR) / virtual reality (VR) in commercial applications, 3GPP Release 16 introduced the sidelink HARQ feedback function for sidelink groupcast (GC) and unicast (UC) communications. The sidelink HARQ feedback function is used to report the acknowledgment (ACK) or negative acknowledgment (NACK) from the receiving UE (Rx-UE) to determine the subsequent retransmission of the same data TB from the Tx-UE.

[0033] In sidelink GC communication, two SL-HARQ feedback reporting mechanisms are supported, namely "Multicast Option 1" and "Multicast Option 2". For "Multicast Option 1", when the received physical sidelink control channel (PSCCH) and physical sidelink shared channel (PSSCH) are not successfully decoded, the Rx-UE only feeds back a NACK report in the PSFCH. That is, no ACK is reported at all. This SL-HARQ feedback operation is applicable to connectionless multicast communications based on the communication distance range where the number of target Rx-UEs within the distance range is unknown to the Tx-UE. For "Multicast Option 2", ACK and NACK feedback reports of the Rx-UE are supported for connection-oriented multicast communications where the total number of UE members in the same group is known to all UEs.

[0034] In sidelink UC communication, similar to multicast option 2, ACK and NACK feedback reporting of Rx-UE is supported.

[0035] In some embodiments, for the currently proposed transmit beamforming and beam management scheme for sideline communications (e.g., in FR2 spectrum), a subset of one or more candidate transmit beams used by the sideline Tx-UE to improve SL communication performance can be selected and determined based on the sideline HARQ acknowledgement (ACK) and / or negative acknowledgement (NACK) feedback from the sideline Rx-UE in the same GC and UC communications, thereby minimizing / reducing SL resource usage by avoiding always performing beam scanning in all directions to transmit data information. Other benefits of using the proposed HARQ-based beamforming and beam management method for SL communication include:

[0036] By eliminating the use of PSCCH and PSSCH for beam management and reporting, sidelink (SL) resources are further saved, thereby reducing the overall sidelink traffic load and minimizing / reducing half-duplex issues by performing fewer transmissions, while supporting beamforming and beam management functions to enhance sidelink communications.

[0037] By reusing the existing real-time SL-HARQ feedback signaling mechanism, candidate / optimal transmit beams are quickly indicated and determined for all Rx-UEs. Therefore, there is no need to rely on PC5 radio resource control (RRC) between SL communicating UEs to support transmit beamforming and beam management.

[0038] The same beamforming and beam management process as for initial candidate / best beam selection can also be applied for beam failure recovery.

[0039] Figure 1 In some embodiments, one or more user equipment (UE) 10 (e.g., a first UE) and one or more user equipment (UE) 20 (e.g., a second UE) communicating in a communication network system 30 according to an embodiment of the present disclosure are shown. The communication network system 30 includes one or more UEs 10 and one or more UEs 20. The UE 10 may include a memory 12, a transceiver 13, and a processor 11 coupled to the memory 12 and the transceiver 13. The UE 20 may include a memory 22, a transceiver 23, and a processor 21 coupled to the memory 22 and the transceiver 23. The processor 11 or 21 may be used to implement the functions, processes, and / or methods described in this specification. The radio interface protocol layer may be implemented in the processor 11 or 21. The memory 12 or 22 may be operably coupled to the processor 11 or 21 and store various information to operate the processor 11 or 21. The transceiver 13 or 23 may be operably coupled to the processor 11 or 21 and transmit and / or receive radio signals.

[0040] The processor 11 or 21 may include an application-specific integrated circuit (ASIC), other chipsets, logic circuits, and / or data processing devices. The memory 12 or 22 may include a read-only memory (ROM), a random access memory (RAM), flash memory, a memory card, a storage medium, and / or other storage devices. The transceiver 13 or 23 may include a baseband circuit for processing radio frequency signals. When the embodiment is implemented in software, the technology described herein may be implemented using modules (e.g., procedures, functions, etc.) that perform the functions described herein. These modules may be stored in the memory 12 or 22 and executed by the processor 11 or 21. The memory 12 or 22 may be implemented within the processor 11 or 21, or implemented outside the processor 11 or 21, in which case the memory 12 or 22 may be communicatively coupled to the processor 11 or 21 in various ways known in the art.

[0041] Communications between UEs involve vehicle-to-everything (V2X) communications, including vehicle-to-vehicle (V2V), vehicle-to-pedestrian (V2P), and vehicle-to-infrastructure / network (V2I / N) based on sidewalk technologies developed under 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) and New Radio (NR) Release 17, Release 18, and higher. UEs communicate directly with each other via sidewalk interfaces such as PC5 interfaces. Some embodiments of the present disclosure relate to sidewalk communication technologies in 3GPP NR Release 17 and higher, for example, providing cellular-vehicle-to-everything (C-V2X) communications.

[0042] In some embodiments, UE 10 may be a sidelink packet transport block (TB) transmitting UE (Tx-UE). UE 20 may be a sidelink packet TB receiving UE (Rx-UE) or a peer UE. A sidelink packet TB Rx-UE may be configured to send ACK / NACK feedback to a packet TB Tx-UE. Peer UE 20 is another UE communicating with Tx-UE 10 in the same SL unicast or multicast session.

[0043] Figure 2 An example user plane protocol stack according to an embodiment of the present disclosure is shown. Figure 2In some embodiments, the user plane protocol stack includes the service data adaptation protocol (SDAP), the packet data convergence protocol (PDCP), the radio link control layer (RLC), the media access control (MAC) sublayer, and the physical (PHY) layer (also known as the first layer or layer 1 (L1) layer) that can terminate at the UE 10 and the base station 40 (e.g., gNB) on the network side. In the example, the PHY layer provides transport services to higher layers (e.g., MAC, RRC, etc.). In an example, the services and functions of the MAC sublayer may include: mapping between logical channels and transport channels, multiplexing MAC service data units (SDUs) belonging to one or different logical channels into transport blocks (TBs) transmitted to the PHY layer or demultiplexing MAC SDUs belonging to one or different logical channels from TBs transmitted from the PHY layer, scheduling information reporting, error correction through hybrid automatic repeat request (HARQ) (e.g., in the case of carrier aggregation (CA), there is one HARQ entity per carrier), priority handling between UEs through dynamic scheduling, priority handling between logical channels of a UE through logical channel priorities, and / or padding. The MAC entity may support one or more parameter sets (numerologies) and / or transmission timings. In an example, mapping restrictions in logical channel priorities may control which parameter set and / or transmission timing a logical channel can use. In an example, the RLC sublayer may support transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM) transmission modes. RLC configuration can be per logical channel, independent of parameter set and / or transmission time interval (TTI) duration. In an example, automatic repeat request (ARQ) can operate on any parameter set and / or TTI duration configured for a logical channel.In an example, the services and functions of the PDCP layer for the user plane may include sequence numbering, header compression and decompression, transmission of user data, reordering and duplicate detection, PDCP PDU routing (e.g., in the case of separate bearers), retransmission of PDCP SDUs, encryption, decryption and integrity protection, PDCP SDU discard, PDCP re-establishment and data recovery for RLC AM, and / or duplication of PDCP PDUs. In an example, the services and functions of SDAP may include mapping between QoS flows and data radio bearers. In an example, the services and functions of SDAP may include mapping quality of service indicators (QFIs) in downlink (DL) and uplink (UL) packets. In an example, the protocol entities of SDAP may be used for separate PDU sessions.

[0044] Figure 3 An example control plane protocol stack according to an embodiment of the present disclosure is shown. Figure 2 In some embodiments, the control plane protocol stack, wherein the PDCP, RLC, MAC sublayer, and PHY layer may terminate at the UE 10 and the network-side base station 40 (e.g., gNB), performs the aforementioned services and functions. In this example, RRC is used to control radio resources between the UE and the base station (e.g., gNB). In this example, RRC may terminate at the UE and the network-side gNB. In this example, RRC services and functions may include broadcasting system information related to the AS and NAS, paging initiated by the 5GC or RAN, establishing, maintaining, and releasing an RRC connection between the UE and the RAN, security functions including key management, establishment, configuration, maintenance, and release of signaling radio bearers (SRBs) and data radio bearers (DRBs), mobility functions, QoS management functions, UE measurement reporting and reporting control, radio link failure detection and recovery, and / or non-access stratum (NAS) message transmission from the UE to the NAS or from the NAS to the UE. In the example, the NAS control protocol can be terminated at the AMF on the UE and network side, and can perform, for example, authentication, mobility management between UEs with 3GPP access and non-3GPP access and the AMF, and session management between UEs with 3GPP access and non-3GPP access and the SMF.

[0045] When a specific application is executed in the UE and requires data communication services, the application layer responsible for executing the specific application provides application-related information, namely, application group / category / priority information / ID, to the NAS layer. In this case, the application-related information can be pre-configured / defined in the UE. (Alternatively, the application-related information is received from the network and provided to the application layer from the AS (RRC) layer. When the application layer starts the data communication service, the application layer requests the AS (RRC) layer to provide the information.)

[0046] In some embodiments, the processor 11 is configured to perform sidelink transmissions to another UE 20 or a group of other UEs 20 using a set of transmit beams during a beam management process, the transceiver 13 is configured to receive a sidelink hybrid automatic repeat request (SL-HARQ) report from the other UE 20 or the group of other UEs 20, and the processor 11 is configured to select and / or determine a subset of one or more transmit beams based on the SL-HARQ report. This can address issues in the prior art, provide beam management for sidelink communications, improve sidelink (SL) communication performance, minimize / reduce sidelink (SL) resource usage, and / or provide high reliability.

[0047] Figure 4 A method 410 for beam management of a UE in sidelink communication according to an embodiment of the present disclosure is shown. In some embodiments, the method 410 includes: block 412, performing sidelink transmission to another UE or a group of other UEs using a set of transmit beams during a beam management process; block 414, receiving a sidelink hybrid automatic repeat request (SL-HARQ) report from the other UE or the group of other UEs; and block 416, selecting and / or determining a subset of one or more transmit beams based on the SL-HARQ report. This can solve problems in the prior art, provide beam management for sidelink communication, improve sidelink (SL) communication performance, minimize / reduce sidelink (SL) resource usage, and / or provide high reliability.

[0048] In some embodiments, the term " / " may be interpreted as meaning "and / or". The term "configured" may refer to "preconfigured" and "network configured". The term "predefined" or "predefined rules" in the present disclosure may be implemented by pre-storing corresponding codes, tables, or other methods of indicating relevant information in a device (e.g., including UE and network equipment). In the present disclosure, the specific implementation is not limited. For example, "predefined" may refer to a definition in a protocol. It should also be understood that the "protocol" in the present disclosure may refer to a standard protocol in the field of communications, which may include, for example, an LTE protocol, an NR protocol, and related protocols used in future communication systems, and the present disclosure is not limited thereto.

[0049] Example:

[0050] In some embodiments, for the new innovative beamforming and management method disclosed in the present invention for identifying and updating a set of one or more candidate / optimal transmit beams for (re)transmission of sidelink (SL) data transmission blocks (TB) (mainly for SL unicast and SL multicast communications), the existing supported SL hybrid automatic repeat and request (HARQ) feedback mechanism can be utilized to avoid additional resource usage and minimize the time delay in performing beam management.

[0051] For the existing SL-HARQ feedback mechanism, as mentioned above, the SL communication receiving UE uses the physical sidelink feedback channel (PSFCH) to send / provide acknowledgment (ACK) and negative acknowledgment (NACK) reports. In the existing SL time slot structure, two orthogonal frequency division multiplexing (OFDM) symbols at the end of the SL time slot can be allocated / (pre-)configured for PSFCH transmission. These two symbols carry exactly the same feedback information (i.e., repeated), where the first symbol is intended to be used as a training symbol for the receiver's automatic gain control (AGC) rather than for information decoding. PSFCH resources / symbols can be (pre-)configured in each SL time slot, every other SL time slot, or every four SL time slots. This is called a PSFCH resource cycle / period (N=1, 2, or 4).

[0052] In order to enable the SL data receiving UE (Rx-UE) to provide the SL-HARQ feedback report to the original data sending UE (Tx-UE) after attempting to decode the received PSCCH and PSSCH, it is always assumed / required that the Rx-UE can complete the data decoding attempt and prepare the SL-HARQ report to be sent (a sequence signal of ACK or NACK, depending on whether the decoding is successful or failed) within two time slots (K=2). That is, if the Rx-UE receives PSCCH and PSSCH in time slot k, the corresponding SL-HARQ report (ACK, NACK or only NACK) can be provided to the Tx-UE at the earliest using the PSFCH resources allocated / (pre)configured in time slot k+2. If PSFCH resources are not allocated / (pre)configured in time slot k+2 (for example, when N=2 or 4), the SL-HARQ report will be fed back in the next time slot in which PSFCH resources are allocated / (pre)configured. Therefore, depending on the PSFCH resource cycle / period length (N=1, 2 or 4), the PSFCH time slot (i.e., PSFCH symbol) may need to carry / multiplex SL-HARQ feedback reports for 1, 2 or 4 SL time slots containing PSCCH and PSSCH.

[0053] In addition, the amount of PSFCH resources allocated / (pre)configured in a time slot can also support connection-oriented multicast communications, in which multiple Rx-UEs need to provide separate SL-HARQ feedback reports for the same transmitted PSCCH and PSSCH in a time slot. That is, if there are 10 Rx-UEs in a connection-oriented multicast session, and SL-HARQ feedback is indicated as "Multicast Option 2" in the sidelink control information (SCI), in which ACK and NACK resources can be provided to each Rx-UE (to consider two possible decoding results), the total number of PSFCH resources required in this case is 20. In the case of "Multicast Option 1", since the SL-HARQ feedback of the Rx-UE may only contain NACK reports when the data transmission block (TB) decoding fails, and the total number of Rx-UEs is unknown, common PSFCH resources for only NACK feedback are sufficient for PSCCH and PSSCH transmissions. For SL unicast communication, since there is always only one Rx-UE, two PSFCH resources are required (one for ACK and the other for NACK).

[0054] In order to multiplex all SL-HARQ feedback reports in the PSFCH resource cycle / period, while taking into account different SL-HARQ feedback options and different SL propagation types in a single PSFCH symbol, separate resource blocks (RBs) are allocated / (pre)configured for SL-HARQ feedback transmitted by PSSCH in different SL time slots, and ACK / NACK reports from different Rx-UEs are code-division multiplexed using separate cyclic prefixes within the RB. Therefore, in addition to the "multicast option 1" in which all Rx-UEs use common PSFCH resources, the data TB sending Tx-UE can obtain the SL-HARQ feedback report (including ACK, NACK, and / or discontinuous transmission (DTX)) of the transmitted PSCCH and PSSCH from each target Rx-UE two time slots later. DTX means that no SL-HARQ feedback report is provided because the Rx-UE did not detect the transmitted PSCCH and PSSCH. When this happens, it indicates that the received power of the PSCCH is too low to be decoded, so that the Rx-UE cannot even determine whether the PSCCH is received and can provide an SL-HARQ feedback report. Therefore, due to not obtaining the expected SL-HARQ feedback report from the Rx-UE, the Tx-UE can determine that the received power of the PSCCH is too low to be decoded / detected. In summary, based on these feedback principles and characteristics in the existing SL-HARQ report design, the present invention proposes to enhance the reporting process in the following way: SL-HARQ reports can also be used for transmit beamforming and beam management in sideline communications.

[0055] In addition to saving resources and minimizing the time delay in performing beam management for SL communications, another issue associated with reusing conventional beamforming / beam scanning techniques in 5G-NR Uu links, especially in connectionless GC communications, is the excessive repetition of SL retransmissions of the same TB in all spatial directions (scanning all supported transmit beams) when only one NACK report is received.

[0056] Other challenges in beamforming and management for GC communications include:

[0057] The existing SL structure design does not support the transmission of the channel state information reference signal (CSI-RS) for wireless channel condition measurement to support multiple-input and multiple-output (MIMO) in multi-layer transmission and the channel quality indicator (CQI) adaptation in the GC.

[0058] In sidelink GC communication, neither connection-oriented nor connectionless communication supports PC5 RRC signaling. Therefore, no pre-set signaling is possible between member UEs in GC communication to exchange details about beamforming and beam management configurations.

[0059] In wireless communications, the radio propagation environment and channel conditions can change rapidly due to the movement of radio transmitters, receivers, or even surrounding objects or vehicles. It is often observed that rapidly changing channel environments can cause dramatic variations in received signal strength / amplitude, phase rotation, and frequency shifts due to the Doppler effect. Therefore, if the transmitting UE is unable to transmit the SL signal quickly enough, which is measured by the receiving UE to select the optimal beam, the receiving UE will be unable to accurately determine which of the transmitting UE's transmit beams will provide the best performance.

[0060] Proposed transmit beamforming and beam management methods

[0061] To minimize the need and amount of transmit beam scanning and management by the Tx-UE in sidelink GC and UC communications, thereby reducing the amount of SL resources and the processing time and decoding workload of the Rx-UE, as previously mentioned, it is proposed to use transmit beam determination based on SL-HARQ feedback, at least when performing SL retransmissions of the same data packet (TB). For certain SL-HARQ feedback schemes (i.e., when both ACK and NACK are reported), the same transmit beam set used for retransmissions is also used to send other data packets (TB).

[0062] For SL multicast and unicast communications, two different transmit beamforming and management approaches are possible. The key difference lies in whether the transmit beam selection is UE-centric or TB-centric. The UE-centric approach aims to find the optimal set of beams with the fewest number of beams for all Rx-UEs, while the TB-centric approach focuses on delivering each data TB with the fewest number of retransmissions for all Rx-UEs.

[0063] Exemplary Method 1 (UE-based transmit beam selection / determination):

[0064] In a UE-centric approach for selecting / determining a subset of one or more transmit beams as part of beamforming and beam management in SL multicast and unicast communications, where the SL-HARQ feedback reporting scheme for multicast communications is indicated to be based on "Multicast Option 2" (for ACK and NACK feedback), the key steps in the beam management process are as follows:

[0065] Step 1. Data packet TB The Tx-UE first uses a transmit beam set (eg, the full set of transmit beams supported by the Tx-UE) in the transmit beam initial selection process, transmit beam tracking / update process, and beam failure recovery process.

[0066] Step 2. Each Rx-UE decodes and measures each received SL transmission and feeds back an ACK or NACK SL-HARQ report for the best candidate beam in the PSFCH resource cycle / period.

[0067] Step 3. Based on all received SL-HARQ reports, at the Tx-UE, a subset of one or more transmit beams is selected / determined on a per Rx-UE or a group of Rx-UEs basis.

[0068] Step 4. If necessary (e.g., not every Rx-UE reports ACK and / or the number of subsets of transmit beams is high), subsequent retransmissions of the same data packet TB are performed using the selected / determined subset of one or more transmit beams, and steps 2), 3), and 4) are repeated.

[0069] For the proposed exemplary method 1, the Tx-UE uses a subset of the one or more transmit beams that it ultimately selects / determines for subsequent SL transmissions of data packets (TB) within the same GC or UC communication until a transmit beam tracking / update procedure or a beam failure recovery procedure is performed. More specifically, the behavior of the Tx-UE and Rx-UE is described in detail below.

[0070] Tx-UE behavior

[0071] In order to initiate / trigger the initial beam selection process, the beam update process, or the beam failure recovery process in the sidelink GC communication, and then have the member UE provide the SL-HARQ feedback report so that the Tx-UE selects / determines a subset of one or more transmit beams, since PC5 RRC signaling is not supported in the sidelink GC communication, the sidelink control information (SCI) and / or the medium access control (MAC) control element (CE) are used to indicate the initiation / trigger to the Rx-UE.

[0072] In sideline UC communication, the initiation / triggering of the above-mentioned initial beam selection process, beam update process, or beam failure recovery process can be performed by configuring the SCI, MAC CE, and / or PC5 RRC signaling of the SL resource set that can appear periodically.

[0073] For the initial transmission of data packet TB using the transmit beam set in step 1) above (e.g., the full set of transmit beams supported by the Tx-UE), the Tx-UE may use multi-continuous slot transmission (MCSt) to select and reserve SL resources in multiple consecutive time slots to mitigate / minimize the impact of potentially rapidly changing propagation channel environments and obtain fair / comparable measurement results when determining the optimal beam.

[0074] MCSt can also be used for subsequent retransmissions of the same data packet TB using a subset of one or more transmit beams in step 4). Note that the initial transmission and retransmission of the data packet TB using a set of one or more transmit beams in steps 1) and 4) may span multiple PSFCH resource cycles / periods.

[0075] Based on the SL-HARQ feedback reports received from the Rx-UE and their corresponding candidate beam indices / IDs, the Tx-UE can perform one or more rounds of retransmissions of the same data packet TB using the reported candidate beams until the Tx-UE is able to determine the final subset of one or more transmit beams of the Rx-UE (e.g., at least one ACK is received from each Rx-UE).

[0076] Based on each received SL-HARQ feedback from the Rx-UE during the PSFCH resource cycle / period, the Tx-UE determines the suitability of the transmit beam used during the previous SL transmission. For example, a reported ACK indicates "applicable," NACK indicates "not applicable" or "needs further evaluation," and DTX indicates "not applicable" because the Rx-UE cannot even decode the PSCCH corresponding to the previous SL transmission. This means that transmit beams corresponding to the DTX state may not be considered and therefore may be excluded from the Rx-UE's candidate beams.

[0077] If one or more ACKs are received from the Rx-UE, the corresponding transmit beam used in the previous round of SL transmission is regarded / considered as a candidate beam for the Rx-UE.

[0078] When receiving multiple ACKs in sidelink UC communication, the Tx-UE should send subsequent data packets (TBs) using the corresponding transmit beams to further screen the final optimal transmit beam for the Rx-UE. For sidelink GC communication, the Tx-UE should associate each Rx-UE with multiple candidate beams. This allows the Tx-UE to flexibly group multiple Rx-UEs into the same transmit beam when they share a common candidate beam.

[0079] If no ACK is received and one or more NACKs are received, the transmit beam corresponding to the NACK feedback report is considered a candidate beam for subsequent retransmissions of the same data packet TB. If one or more ACKs are received from the Rx-UE for subsequent retransmissions of the same data packet TB, the corresponding transmit beam is considered an updated candidate beam for the Rx-UE.

[0080] During retransmissions of the same data packet TB, the transmit beam index / ID used for each retransmission can be indicated so that the Rx-UE can combine the soft bits from the retransmitted data packets TB using the same transmit beam index / ID and accurately determine which transmit beam provides the best performance for SL GC or UC communication.

[0081] Rx-UE behavior

[0082] In sidelink GC or UC communication, after receiving SL transmission indicated in the SCI, MACE CE, and / or PC5 RRC from the Tx-UE for initial transmit beam selection, transmit beam update, or recovery from beam failure detection, the target / member Rx-UE of the same GC or UC communication performs at least one of the following:

[0083] Each received SL transmission (PSCCH and PSSCH) of the same data packet TB in the allocated SL time slot and frequency resources (eg, resource allocation of MCSt) is decoded and measured.

[0084] When decoding different PSSCH transmissions of the same data packet TB across multiple SL slots, the Rx-UE may not combine the soft bits of different PSSCH transmissions using different transmit beams to improve PSSCH decoding performance / reliability. In order to fairly and accurately compare the SL communication performance using different transmit beams (based on the decoding results of the PSSCH of the same data packet TB), the Rx-UE can only combine the soft bits using the same transmit beam (i.e., from different rounds of (re)transmissions of the same data packet TB) to improve the decoding results.

[0085] The measurement of each received SL transmission in UC communication may be based on the sidelink CSI-RS reference signal received power (eg, SL CSI-RSRP).

[0086] As mentioned above, since CSI-RS transmission is not supported in sidelink GC communication, the corresponding measurement can be based on other SL signals, such as PSCCH or PSSCH demodulation reference signal (DM-RS) for sidelink RSRP measurement.

[0087] The SL-HARQ ACK or NACK feedback report is sent in the PSFCH based on the decoding result corresponding to the best / highest measurement in each PSFCH resource cycle / period.

[0088] When the PSFCH resource cycle / period is 1 (N=1), the Rx-UE feeds back a SL-HARQ report for each received SL transmission. For DTX, no SL-HARQ feedback report is transmitted in the PSFCH. If at least one ACK is determined in the PSFCH resource cycle / period, only the ACK is reported. If multiple ACKs are determined for each PSFCH resource cycle / period, only the ACK corresponding to the highest measured RSRP is reported.

[0089] References Figure 4 and Figure 5 Schematic diagrams 100 and 200 in the figures show exemplary illustrations of the transmit beamforming and beam management scheme based on SL-HARQ feedback according to the proposed exemplary method 1 for the case of side-by-side multicast communication. Assume that the indicated SL-HARQ feedback scheme is based on "multicast option 2", in which ACK or NACK is reported based on the SL data packet TB decoding result. According to the exemplary schematic diagram 100, the side-by-side Tx-UE 111 communicating with multiple other member UEs in a connection-oriented multicast session is capable of generating / producing a set of 8 transmit beams, and the indexes of the 8 transmit beams are #1 to #8 (101 to 108), respectively. As shown in FIG. Figure 1 and Figure 2 As shown in some embodiments, the locations of the other member UEs are not dispersed in all directions, but are grouped into three different clusters. Therefore, rather than performing beam scanning in all directions every time to transmit data packets TB from sideline Tx-UE 111, SL transmission of data packets TB can be concentrated only in the directions of the other member UEs (i.e., using only transmit beam #2 102, transmit beam #4 104, and transmit beam #7 107). This is more efficient, saves resources, saves power, and has higher reliability.

[0090] According to the proposed example method 1 for transmit beamforming and beam management based on SL-HARQ feedback for connected GC communication, for the initial selection of a transmit beam, the Tx-UE 111 may first repeatedly use the MCSt to perform multiple initial transmissions of the same data packet TB over eight consecutive SL time slots 201 to 208, each transmission using a different transmit beam supported by the Tx-UE (from beam index #1 to #8). As shown in some embodiments of schematic diagram 200, the transmit beam indices used for the repeated initial transmissions of the data packet TB over the SL time slots 201 to 208 are not sequential. In practice, the transmit beam indices used on the SL time slots may be randomized to avoid using adjacent or nearby transmit beams in the same PSFCH resource cycle / period. If adjacent or nearby transmit beams are used in the same PSFCH resource cycle / period, the Rx-UE is forced to report the SL-HARQ of the transmit beam with the higher SL measurement. In some cases, this is not ideal because multiple transmit beams may be considered as candidate beams in the same PSFCH resource cycle / period. Therefore, transmit beams that are farther apart from each other can be used in the same PSFCH resource cycle / period to avoid this undesirable consequence.

[0091] For the sake of these simple examples, it is further assumed that PSFCH resources are (pre)configured every two time slots in the SL resource pool (i.e., PSFCH resource cycle / period N=2). According to the existing SL-HARQ feedback timing design, the received SL PSSCH is separated from the corresponding PSFCH transmission opportunity by at least K=2 time slots. For the SL PSSCH received in time slot n (201) and time slot n+1 (202), the corresponding SL-HARQ feedback PSFCH transmission opportunity is located in the same PSFCH symbol 209 in time slot n+3. Similarly, the PSFCH symbol 210 in time slot n+5 is the SL-HARQ feedback opportunity corresponding to the PSSCH received in time slot n+2 (203) and time slot n+3 (204). The PSFCH symbol 211 in time slot n+7 is used for the PSSCH received in time slot n+4 (205) and time slot n+5 (206). The PSFCH symbol 212 in slot n+9 is used for the PSSCH received in slot n+6 (207) and slot n+7 (208). Since no other member UEs in the same GC communication are within the coverage of transmit beam indices #1 and #5, it is assumed that no SL-HARQ feedback is reported in PSFCH resource opportunity 209.

[0092] Furthermore, since some other member UEs are within the coverage of transmit beam index #2, it is assumed that they all report ACK in PSFCH resource opportunity 210. Similarly, for transmit beam index #7, some Rx-UEs report ACK in PSFCH resource opportunity 211. For transmit beam index #4, the remaining Rx-UEs report ACK in PSFCH resource opportunity 212. Therefore, Tx-UE 111 selects / determines transmit beams with indices #2, #7, and #4 as the final transmit beam subset for future SL transmission of other data packets TB.

[0093] Exemplary Method 2 (TB-based transmit beam selection / determination):

[0094] In a TB-centric approach for selecting / determining a subset of one or more transmit beams as part of beamforming and beam management in SL multicast communications, where the SL-HARQ feedback reporting scheme for multicast communications is indicated to be based on "Multicast Option 1" (for NACK feedback only), the key steps in the beam management process are as follows:

[0095] Step A. For each data packet TB, whenever the initial transmission of the data packet TB is performed in all directions, the Tx-UE uses a transmit beam set (e.g., the full set of transmit beams supported by the Tx-UE), because the goal / intention of this type of GC communication is to deliver the data packet TB to all surrounding Rx-UEs within the communication range (there is no fixed direction).

[0096] Step B. Each target Rx-UE in the same GC communication decodes and measures all initial transmissions of the same data packet TB received from the Tx-UE, and feeds back a NACK report of the best candidate beam in the PSFCH resource cycle / period only when decoding fails.

[0097] Step C. When at least one NACK SL-HARQ report is received and the maximum number of transmissions for a data packet TB is not reached, at the Tx-UE, a subset of one or more transmit beams is selected / determined (e.g., filtered from a previously used set of transmit beams) based on each data packet TB.

[0098] Step D. A subset of the one or more transmit beams selected / determined is used for subsequent retransmissions of the same data packet TB, and each target Rx-UE that failed to successfully decode the same data packet TB may attempt to decode the TB again, and repeat the above steps B), C), and D) until no more NACK reports are received or the maximum number of transmissions of the data packet TB is reached.

[0099] For the proposed exemplary method 2, since the main goal / intention of such GC communication is to successfully transmit the data packet TB to the surrounding Rx-UEs in all directions (as described above), there is no need to identify or perform the initial selection of one or more subsets of the best transmit beams for each target Rx-UE as in the exemplary method 1 proposed in the present disclosure. Therefore, there is no need to maintain, track and update the subset of one or more best transmit beams, nor is there a need to perform beam failure recovery. The basic / principle mechanism behind the proposed exemplary method 2 of beamforming and beam management for sidelink GC communication in the SL-HARQ feedback scheme with multicast option 1 is to provide SL retransmission of the same data packet TB in the direction in which the NACK report is received and in the direction that will provide the best decoding success chance for the Rx-UE.

[0100] Tx-UE behavior

[0101] For the initial transmission of a data packet TB using the transmit beam set in step 1) above (e.g., the full set of transmit beams supported by the Tx-UE), the Tx-UE may use multi-contiguous slot transmission (MCSt) that selects and reserves SL resources in multiple consecutive time slots to mitigate / minimize the impact of a potentially rapidly changing propagation channel environment and obtain fair / comparable measurement results when determining the best beam for potential retransmissions of the same data packet TB.

[0102] MCSt can also be used for subsequent retransmissions of the same data packet TB using a subset of one or more transmit beams in step D) above. Note that the initial transmission and retransmission of the data packet TB using a set of one or more transmit beams in steps A) and D) above may span multiple PSFCH resource cycles / periods.

[0103] Based on the reported NACKs and their corresponding candidate beam indices / IDs fed back by the SL-HARQ, the Tx-UE performs one or more retransmissions of the same data packet TB using the reported candidate beams until no more NACK reports are received or the maximum number of transmissions for the data packet TB is reached. Upon receiving one or more NACK reports fed back by the SL-HARQ, the Tx-UE selects / determines a subset of one or more transmit beams corresponding to the NACK feedback reports and uses them for subsequent retransmissions of the same data packet TB.

[0104] Rx-UE behavior

[0105] Upon receiving one or more SL transmissions of the same data packet TB of a GC communication indicating "Multicast Option 1" as the SL-HARQ feedback reporting scheme in the SCI, the target Rx-UE of the same GC communication performs at least one of the following:

[0106] Each received SL transmission (PSCCH and PSSCH) of a data packet TB in the allocated SL time slot and frequency resources (e.g., resource allocation of MCSt) is decoded and measured until decoding is successful. In some examples, when decoding different PSSCH transmissions of the same data packet TB on the allocated SL time slot, the Rx-UE can combine soft bits from different PSSCH transmissions using different transmit beams to improve PSSCH decoding performance / reliability. As mentioned earlier, since CSI-RS transmission is not supported in sidelink GC communication, the corresponding measurement can be based on other SL signals, such as PSCCH or PSSCH demodulation reference signal (DM-RS) for sidelink RSRP measurement.

[0107] When at least one decoding attempt fails and decoding of a data packet TB has not yet been successful, a NACK report of the SL-HARQ feedback corresponding to the best / highest measurement in the PSFCH resource cycle / period is sent. In some examples, for DTX, no SL-HARQ feedback report is transmitted in the PSFCH. If decoding of a data packet TB is successful in the PSFCH resource cycle / period, the Rx-UE stops further decoding attempts for the same data packet TB and does not provide SL-HARQ feedback for the PSFCH resource cycle / period.

[0108] refer to Figure 6Schematic diagram 300 in the figure shows an exemplary illustration of a transmit beamforming and beam management scheme based on SL-HARQ feedback according to the proposed exemplary method 2 for a side-by-side multicast communication case. Assume that the indicated SL-HARQ feedback scheme is based on "multicast option 1", in which only NACK is reported when the SL data packet TB decoding attempt is unsuccessful. According to the exemplary schematic diagram 300, a side-by-side Tx-UE (311) transmitting a SL data packet TB to its surrounding UEs in a connectionless multicast session is capable of generating / producing a set of 8 transmit beams, with the 8 transmit beams being indexed #1 to #8 (301 to 308) respectively. As shown in some embodiments, the locations of the surrounding UEs are scattered in all directions. Since the main purpose of such a connectionless SL multicast communication is to successfully transmit the data packet TB to the surrounding UEs within the communication range, and the target receiving UEs are not fixed to a certain group of UEs, it is meaningless to determine the minimum subset of transmit beams specific to a certain group of UEs. The exact surrounding UEs and the number of surrounding UEs may vary from one data packet TB transmission to the next data packet TB transmission. Therefore, for the initial transmission of each data packet TB, as the first SL transmission attempt, the Tx-UE needs to perform beam scanning in all directions to deliver the data packet TB to all its surrounding UEs. Then, based on the SL-HARQ feedback of only NACK reports, the Tx-UE can select / determine a subset of one or more transmit beams for retransmission of the same data packet TB until no NACKs are received / reported.

[0109] According to the proposed example method 2 of transmit beamforming and beam management based on SL-HARQ feedback for connectionless GC communication, for the initial transmission of the SL data packet TB, the Tx-UE 311 repeatedly performs SL transmission in all directions using different transmit beams of beam indices #1 to #8 (301 to 308) supported by the Tx-UE. Figure 2 Unlike the previous example diagram in schematic diagram 200 of , in example method 2, the transmit beam indices used to send repeated initial transmissions of a data packet TB can be sequential (i.e., adjacent / nearby transmit beams can be used sequentially). This is intended to quickly and successfully decode the data packet TB, as the primary goal is to combine soft bits from repeated initial transmissions using different transmit beams to improve PSSCH decoding performance / reliability.

[0110] For the sake of these simple examples, assume that in repeated initial transmissions of the same data packet TB, the Tx-UE detects that at least one NACK is reported in the corresponding transmit beam indices #2 (302), #5 (305), and #7 (307). Therefore, according to the proposed example method 2, the Tx-UE 311 selects / determines at least transmit beams #2 (302), #5 (305), and #7 (307) as a subset of transmit beams for subsequent SL retransmissions of the data packet TB.

[0111] In summary, in order to minimize / reduce resource usage, reduce traffic load and save transmission and processing power, while improving the side-by-side multicast and unicast communication performance of side-by-side devices, two innovative transmit beamforming and beam management methods based on SL-HARQ feedback reports are proposed in some embodiments of the present disclosure. In some examples, for the proposed exemplary method 1, the Tx-UE will use the subset of one or more transmit beams finally selected / determined for subsequent SL transmission of data packets TB in the same GC or UC communication until a transmit beam tracking / update process or a beam fault recovery process is performed. In some examples, since the main goal / intention of such GC communication is to successfully transmit data packets TB to surrounding Rx-UEs in all directions (as described above), there is no need to identify or perform the initial selection of a subset of one or more optimal transmit beams for each target Rx-UE as in the exemplary method 1 proposed in the present disclosure. Therefore, there is no need to maintain, track and update a subset of one or more optimal transmit beams, nor is there a need to perform beam fault recovery. The basic / principle mechanism behind the proposed exemplary method 2 for beamforming and beam management for sidelink GC communication in the SL-HARQ feedback scheme with multicast option 1 is to provide SL retransmission of the same data packet TB in the direction where the NACK report is received and in the direction that will provide the best decoding success chance for the Rx-UE.

[0112] Figure 8 A UE 800 for wireless communication according to an embodiment of the present disclosure is shown. UE 800 includes an executor 801, a receiver 802, and a selector 803. The executor 801 is configured to perform sidelink transmission to another UE or a group of other UEs using a set of transmit beams during a beam management process. The receiver 802 is configured to receive a sidelink hybrid automatic repeat request (SL-HARQ) report from the other UE or the group of other UEs. The selector 803 is configured to select and / or determine a subset of one or more transmit beams based on the SL-HARQ report. This can solve problems in the prior art, provide beam management for sidelink communications, improve sidelink (SL) communication performance, minimize / reduce sidelink (SL) resource usage, and / or provide high reliability.

[0113] In some embodiments, the beam management process includes a transmit beam initial selection process, a transmit beam tracking / update process, and / or a beam failure recovery process. In some embodiments, in sideway multicast communication (GC), the initiation / triggering of the beam management process is performed by the UE using sideway control information (SCI) signaling and / or medium access control (MAC) control element (CE) signaling. In some embodiments, in sideway unicast communication (UC), the initiation / triggering of the beam management process is performed by the UE using SCI signaling, MAC CE signaling, and / or PC5 radio resource control (RRC) signaling. In some embodiments, during the beam management process, the UE uses multiple consecutive time slot transmission (MCSt) in the initial transmission and one or more subsequent retransmissions of a data transmission block (TB). In some embodiments, the SL-HARQ report includes an acknowledgment (ACK) and / or a negative acknowledgment (NACK) of the best candidate beam in the physical sideway feedback channel (PSFCH) resource cycle / period.

[0114] In some embodiments, for the same data TB, soft bits transmitted by different physical sidelink shared channels (PSSCHs) using the same transmit beam are combined. In some embodiments, the measurement of each sidelink transmission in UC communication is based on the reference signal received power (RSRP) of the sidelink channel state information reference signal (CSI-RS) (SL CSI-RSRP). In some embodiments, the measurement of each sidelink transmission in GC communication is based on the PSCCH or PSSCH demodulation reference signal (DM-RS) used for sidelink RSRP measurement. In some embodiments, the SL-HARQ report is transmitted in the PSFCH based on the decoding result corresponding to the best / highest measurement in each PSFCH resource cycle / period. In some embodiments, at least one of the following is met: if the PSFCH resource cycle / period is 1, the UE receives the SL-HARQ report for each sidelink transmission; for discontinuous transmission (DTX), the SL-HARQ report is not transmitted in the PSFCH; if at least one ACK is determined in the PSFCH resource cycle / period, only the ACK is reported; and if multiple ACKs are determined for each PSFCH resource cycle / period, only the ACK corresponding to the highest measured RSRP is reported.

[0115] In some embodiments, based on the SL-HARQ report, the UE is configured to select and / or determine a subset of one or more transmit beams based on another UE or based on a group of other UEs. In some embodiments, at least one of the following is satisfied: based on the SL-HARQ report in the PSFCH resource cycle / period, the UE is used to determine the suitability of the transmit beam used during the previous round of SL transmission; if the UE receives one or more ACKs from another UE or a group of other UEs, the one or more corresponding transmit beams are regarded as one or more candidate beams for the other UE or a group of other UEs; when the UE receives multiple ACKs in the sideline UC communication, the UE uses the corresponding transmit beam to send subsequent data TBs to further screen the final optimal transmit beam for the other UE or a group of other UEs; when the UE receives multiple ACKs in the sideline GC communication, the UE associates multiple candidate beams with each other UE or a group of other UEs; if the UE does not receive an ACK and receives one or more NACKs, the transmit beam corresponding to the NACK feedback report is regarded as a candidate beam for subsequent retransmission of the same data TB; and when the UE receives one or more ACKs for subsequent retransmissions of the same data TB, the one or more corresponding transmit beams are regarded as one or more updated candidate beams for the other UE or a group of other UEs.

[0116] In some embodiments, if not every other UE reports an ACK and / or the number of the subset of transmit beams is higher, the UE uses the selected and / or determined subset of one or more transmit beams for subsequent retransmissions of the same data TB, and repeatedly receives SL-HARQ reports, selects and / or determines the subset of one or more transmit beams based on the SL-HARQ reports, and uses the selected and / or determined subset of one or more transmit beams for subsequent retransmissions of the same data TB. In some embodiments, the UE uses the selected / determined subset of one or more transmit beams for subsequent sidelink transmissions of the data TB in the same GC communication or UC communication until a transmit beam tracking / update process and / or a beam failure recovery process is performed. In some embodiments, during the beam management process, the transmit beam index / ID of each of the initial transmission and one or more subsequent retransmissions of the same data TB is indicated to another UE or a group of other UEs. In some embodiments, for each data TB, the UE performs an initial transmission of the data TB in the GC communication using a set of transmit beams.

[0117] In some embodiments, during the beam management process, the UE uses MCSt in the initial transmission and one or more subsequent retransmissions of the data TB. In some embodiments, the SL-HARQ report includes a NACK for the best candidate beam in the PSFCH resource period / time period only when decoding fails. In some embodiments, for the same data TB, the soft bits of the received PSSCH transmissions using different transmit beams are combined. In some embodiments, the measurement of each sideline transmission in the GC communication is based on the PSCCH or PSSCH demodulation reference signal (DM-RS) used for sideline RSRP measurement. In some embodiments, when at least one decoding attempt fails and the decoding of the data TB is unsuccessful, a NACK for the SL-HARQ report is transmitted in the PSFCH corresponding to the best / highest measurement in each PSFCH resource period / time period. In some embodiments, at least one of the following is met: for DTX, the SL-HARQ report is not transmitted in the PSFCH; and if the decoding of the data TB in the PSFCH resource period / time period is successful, the decoding attempt for the same data TB is stopped and the SL-HARQ report is not transmitted for the PSFCH resource period / time period.

[0118] In some embodiments, when the UE receives at least one NACK reported by the SL-HARQ and the maximum number of transmissions for a data TB is not reached, the UE selects and / or determines a subset of one or more transmit beams based on each data TB. In some embodiments, when the UE receives one or more NACKs reported by the SL-HARQ, the UE selects and / or determines a subset of one or more transmit beams corresponding to the one or more NACKs reported by the SL-HARQ, and uses the subset of one or more transmit beams corresponding to the one or more NACKs reported by the SL-HARQ for one or more subsequent retransmissions of the same data TB. In some embodiments, the subset of one or more transmit beams selected and / or determined is used for one or more subsequent retransmissions of the same data TB, and the beam management process is repeated until the UE no longer receives NACKs reported by the SL-HARQ or the maximum number of transmissions for the data TB is reached.

[0119] The commercial benefits of some embodiments are as follows: 1. Solve problems in the prior art. 2. Provide beam management for sidewalk communications. 3. Improve sidewalk (SL) communication performance. 4. Minimize / reduce sidewalk (SL) resource usage. 5. Provide high reliability. 6. Some embodiments of the present disclosure are used by 5G-NR chipset suppliers, V2X communication system development suppliers, including automobile manufacturers such as cars, trains, trucks, buses, bicycles, motorcycles, helmets, drones (unmanned aerial vehicles), smartphone manufacturers, smart watches, wireless earbuds, wireless headphones, communication devices for public safety, remote control vehicles, and robots, AR / VR device manufacturers (for example, games, conferences / seminars, education), smart home appliances (including TVs, audio, speakers, lights, doorbells, locks, cameras, conference headsets, etc.), smart factory and warehouse equipment (including IIoT devices, robots, robotic arms, and simple production machines). In some embodiments, the commercial benefits and commercial importance of the disclosed invention include reducing wireless communication power consumption, which means longer device runtime and / or longer runtime between battery charges, resulting in better user experience and product satisfaction. Some embodiments of the present disclosure are combinations of technologies and procedures that can be adopted in 3GPP specifications to create a final product. Some embodiments of the present disclosure relate to mobile cellular communication technologies for providing direct device-to-device (D2D) wireless communication services in 3GPP NR Release 17, Release 18, and higher.

[0120] Figure 9 7 is a block diagram of an example wireless communication system 700 according to an embodiment of the present disclosure. The embodiments described herein may be implemented into a system using any suitably configured hardware and / or software. Figure 9 A system 700 is shown, which includes at least a radio frequency (RF) circuit 710, a baseband circuit 720, an application circuit 730, a memory / storage 740, a display 750, a camera 760, a sensor 770, and an input / output (I / O) interface 780 coupled to each other as shown.

[0121] Application circuitry 730 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processors may include any combination of general-purpose processors and specialized processors (e.g., graphics processors, application processors). The processors may be coupled to memory / storage and configured to execute instructions stored in the memory / storage to enable various applications and / or operating systems to run on the system.

[0122] The baseband circuit 720 may include, for example, but not limited to, circuits of one or more single-core or multi-core processors. The processor may include a baseband processor. The baseband circuit may handle various wireless control functions that can communicate with one or more wireless networks via RF circuits. The wireless control functions may include, but are not limited to, signal modulation, encoding, decoding, wireless frequency shifting, etc. In some embodiments, the baseband circuit may provide communications compatible with one or more radio technologies. For example, in some embodiments, the baseband circuit may support communications with the Evolved Universal Terrestrial Radio Access Network (EUTRAN) and / or other wireless metropolitan area networks (WMANs), wireless local area networks (WLANs), and wireless personal area networks (WPANs). An embodiment in which the baseband circuit is used to support wireless communications of multiple wireless protocols may be referred to as a multimode baseband circuit.

[0123] In various embodiments, baseband circuitry 720 may include circuitry that operates with signals that are not strictly considered to be at baseband frequencies. For example, in some embodiments, baseband circuitry may include circuitry that operates with signals having an intermediate frequency that is between the baseband frequency and the radio frequency.

[0124] RF circuitry 710 may enable communication with a wireless network using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry may include switches, filters, amplifiers, etc. to facilitate communication with a wireless network.

[0125] In various embodiments, RF circuitry 710 may include circuitry that operates with signals that are not strictly considered to be at radio frequencies. For example, in some embodiments, RF circuitry may include circuitry that operates with signals having an intermediate frequency that is between baseband frequency and radio frequency.

[0126] In various embodiments, the transmitter circuitry, control circuitry, or receiver circuitry discussed above with respect to user equipment, eNBs, or gNBs may be embodied in whole or in part in one or more of the radio frequency circuitry, baseband circuitry, and / or application circuitry. As used herein, "circuitry" may refer to an application-specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and / or memory (shared, dedicated, or group) executing one or more software or firmware programs, combinatorial logic circuitry, and / or other suitable hardware components that provide the described functionality. In some embodiments, electronic device circuitry may be implemented in one or more software or firmware modules, or the functionality associated with the circuitry may be implemented by one or more software or firmware modules.

[0127] In some embodiments, some or all components of the baseband circuit, application circuit, or memory / storage may be implemented together on a system on a chip (SOC).

[0128] Memory / storage 740 may be used to load and store data and / or instructions, such as for the system. The memory / storage of one embodiment may include any combination of suitable volatile memory (e.g., dynamic random access memory (DRAM)) and / or non-volatile memory (e.g., flash memory).

[0129] In various embodiments, the I / O interface 780 may include one or more user interfaces designed to allow a user to interact with the system and / or peripheral component interfaces designed to allow peripheral components to interact with the system. The user interface may include, but is not limited to, a physical keyboard or keypad, a touchpad, a speaker, a microphone, etc. The peripheral component interface may include, but is not limited to, a non-volatile memory port, a universal serial bus (USB) port, an audio jack, and a power interface.

[0130] In various embodiments, the sensors 770 may include one or more sensing devices to determine environmental conditions and / or location information relevant to the system. In some embodiments, the sensors may include, but are not limited to, gyroscopes, accelerometers, proximity sensors, ambient light sensors, and positioning units. The positioning unit may also be part of or interact with baseband circuitry and / or RF circuitry to communicate with components of a positioning network such as global positioning system (GPS) satellites.

[0131] In various embodiments, display 750 may include displays such as liquid crystal displays and touch screen displays. In various embodiments, system 700 may be a mobile computing device, such as, but not limited to, a laptop, a tablet, a netbook, an ultrabook, a smartphone, AR / VR glasses, etc. In various embodiments, the system may have more or fewer components or a different architecture. Where appropriate, the methods described herein may be implemented as computer programs. The computer programs may be stored on a storage medium, such as a non-transitory storage medium.

[0132] Those skilled in the art will appreciate that the various units, algorithms, and steps described and disclosed in the embodiments of the present disclosure may be implemented through electronic hardware or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the application conditions and design requirements of the technical solution.

[0133] Those skilled in the art may implement the functions in different ways for each specific application, and such implementations are within the scope of this disclosure. Those skilled in the art will appreciate that since the operating processes of the above-mentioned systems, devices, and units are substantially the same, those skilled in the art may refer to the operating processes of the systems, devices, and units in the above-mentioned embodiments. For ease of description and simplicity, these operating processes will not be described in detail.

[0134] It is understood that the systems, devices, and methods disclosed in the embodiments of the present disclosure can be implemented in other ways. The above embodiments are merely exemplary. The division of units is based solely on logical functions, and other divisions may exist in the implementation. Multiple units or components can be combined or integrated into another system. It is also possible to omit or skip certain features. On the other hand, the mutual coupling, direct coupling, or communicative coupling shown or discussed operates indirectly or communicatively through some ports, devices, or units in electrical, mechanical, or various other forms.

[0135] Units shown as separate components for purposes of explanation may be physically separate or non-separated. The units shown may or may not be physical units, i.e., located in one location or distributed across multiple network units. Some or all of the units may be used depending on the purpose of the embodiment. Furthermore, the functional units in various embodiments may be integrated into a single processing unit, physically separate, or integrated into a single processing unit with two or more units.

[0136] When the software functional unit is implemented, used and sold as a product, it can be stored in a readable storage medium in a computer. Based on this understanding, the technical solution proposed in the present disclosure can be implemented essentially or partially in the form of a software product. Alternatively, a part of the technical solution that is beneficial to the prior art can be implemented in the form of a software product. The software product in the computer is stored in a storage medium, including multiple commands for a computing device (such as a personal computer, server or network device) to run all or part of the steps disclosed in the embodiment of the present disclosure. The storage medium includes a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a floppy disk or other various media capable of storing program code.

[0137] While the present disclosure has been described in connection with what is considered to be the most practical and preferred embodiment, it is to be understood that the disclosure is not limited to the disclosed embodiment, but is intended to cover various arrangements embodied within the broadest interpretation of the appended claims.

Claims

1. A beam management method for a user equipment (UE) in sideline communication, comprising: performing sidelink transmission to another UE or a group of other UEs using the set of transmit beams during a beam management procedure; receiving a sidelink hybrid automatic repeat request (SL-HARQ) report from the other UE or the group of other UEs; and A subset of one or more transmit beams is selected and / or determined based on the SL-HARQ report.

2. The method according to claim 1, wherein The beam management process includes a transmit beam initial selection process, a transmit beam tracking / update process, and / or a beam failure recovery process.

3. The method according to claim 1 or 2, wherein: In sidelink multicast communication (GC), the initiation / triggering of the beam management process is performed by the UE using sidelink control information (SCI) signaling and / or medium access control (MAC) element (CE) signaling.

4. The method according to claim 1 or 2, wherein: In sidelink unicast communication (UC), the initiation / triggering of the beam management process is performed by the UE using SCI signaling, MAC CE signaling, and / or PC5 radio resource control (RRC) signaling.

5. The method according to any one of claims 1 to 4, wherein During the beam management procedure, the UE uses multiple consecutive slots transmission (MCSt) in an initial transmission and one or more subsequent retransmissions of a data transmission block (TB).

6. The method according to any one of claims 1 to 5, wherein The SL-HARQ report includes an acknowledgement (ACK) and / or a negative acknowledgement (NACK) of the best candidate beam in a physical sidelink feedback channel (PSFCH) resource period / time period.

7. The method according to any one of claims 1 to 6, wherein For the same data TB, soft bits transmitted using different physical sidelink shared channels (PSSCHs) of the same transmit beam are combined.

8. The method according to any one of claims 1 to 7, wherein The measurement of each sidelink transmission in UC communication is based on the reference signal received power (RSRP) of the sidelink channel state information reference signal (CSI-RS) (SL CSI-RSRP).

9. The method according to any one of claims 1 to 8, wherein The measurement of each sidelink transmission in GC communication is based on the PSCCH or PSSCH Demodulation Reference Signal (DM-RS) used for sidelink RSRP measurement.

10. The method according to any one of claims 1 to 9, wherein The SL-HARQ report is transmitted in the PSFCH based on the decoding result corresponding to the best / highest measurement in each PSFCH resource cycle / period.

11. The method according to claim 10, wherein: Meet at least one of the following: If the PSFCH resource cycle / period is 1, the UE receives the SL-HARQ report for each sidelink transmission; For discontinuous transmission (DTX), no SL-HARQ report is transmitted in the PSFCH; If at least one ACK is determined in the PSFCH resource period / time period, only reporting the ACK; as well as If multiple ACKs are determined per PSFCH resource cycle / period, only the ACK corresponding to the highest measured RSRP is reported.

12. The method according to any one of claims 1 to 11, wherein Based on the SL-HARQ report, the UE is configured to select and / or determine a subset of the one or more transmit beams based on the other UE or based on the group of other UEs.

13. The method according to claim 12, wherein: Meet at least one of the following: Based on the SL-HARQ report in the PSFCH resource cycle / period, the UE is configured to determine the suitability of the transmit beam used during the previous round of SL transmission; If the UE receives one or more ACKs from the other UE or the group of other UEs, considering one or more corresponding transmit beams as one or more candidate beams for the other UE or the group of other UEs; When the UE receives multiple ACKs in the sidelink UC communication, the UE sends subsequent data TB using the corresponding transmit beam to further screen a final optimal transmit beam for the other UE or the group of other UEs; When the UE receives multiple ACKs in the sidelink GC communication, the UE associates each other UE or the group of other UEs with multiple candidate beams; If the UE does not receive an ACK and receives one or more NACKs, consider the transmit beam corresponding to the NACK feedback report as a candidate beam for subsequent retransmission of the same data TB; as well as When the UE receives one or more ACKs for the subsequent retransmissions of the same data TB, the one or more corresponding transmit beams are considered as one or more updated candidate beams for the other UE or the group of other UEs.

14. The method according to any one of claims 1 to 13, wherein If not every other UE reports an ACK and / or the number of subsets of transmit beams is higher, the UE uses the selected and / or determined subset of one or more transmit beams for subsequent retransmissions of the same data TB, and repeatedly receives the SL-HARQ report, selects and / or determines the subset of one or more transmit beams based on the SL-HARQ report, and uses the selected and / or determined subset of the one or more transmit beams for the subsequent retransmissions of the same data TB.

15. The method according to any one of claims 1 to 14, wherein The UE uses the selected / determined subset of one or more transmit beams for subsequent sidelink transmission of data TBs in the same GC communication or UC communication until the transmit beam tracking / update process and / or the beam failure recovery process is performed.

16. The method according to any one of claims 1 to 15, wherein During the beam management procedure, the transmit beam index / ID of each of the initial transmission and one or more subsequent retransmissions of the same data TB is indicated to the other UE or the group of other UEs.

17. The method according to claim 1, wherein For each data TB, the UE performs an initial transmission of the data TB in GC communication using the transmit beam set.

18. The method according to claim 17, wherein During the beam management procedure, the UE uses MCSt in the initial transmission and one or more subsequent retransmissions of a data TB.

19. The method according to claim 17 or 18, wherein Only when decoding fails, the SL-HARQ report includes a NACK for the best candidate beam in the PSFCH resource period / time.

20. The method according to any one of claims 17 to 19, wherein For the same data TB, the soft bits of received PSSCH transmissions using different transmit beams are combined.

21. The method according to any one of claims 17 to 20, wherein The measurement of each sidelink transmission in GC communication is based on the PSCCH or PSSCH Demodulation Reference Signal (DM-RS) used for sidelink RSRP measurement.

22. The method according to any one of claims 17 to 21, wherein When at least one decoding attempt fails and the decoding of the data TB is unsuccessful, a NACK of the SL-HARQ report is transmitted in the PSFCH corresponding to the best / highest measurement in each PSFCH resource cycle / period.

23. The method according to claim 22, wherein Meet at least one of the following: For DTX, no SL-HARQ report is transmitted in the PSFCH; and If the decoding of the data TB is successful in the PSFCH resource period / time period, the decoding attempt of the same data TB is stopped and no SL-HARQ report is transmitted for the PSFCH resource period / time period.

24. The method according to any one of claims 17 to 23, wherein When the UE receives at least one NACK of the SL-HARQ report and the maximum number of transmissions of the data TBs is not reached, the UE selects and / or determines a subset of the one or more transmit beams based on each data TB.

25. The method according to claim 24, wherein When the UE receives one or more NACKs reported by the SL-HARQ, the UE selects and / or determines a subset of the one or more transmit beams corresponding to the one or more NACKs reported by the SL-HARQ, and uses the subset of the one or more transmit beams corresponding to the one or more NACKs reported by the SL-HARQ for the one or more subsequent retransmissions of the same data TB.

26. The method according to any one of claims 17 to 25, wherein A subset of one or more transmit beams is selected and / or determined for one or more subsequent retransmissions of the same data TB, and the beam management process is repeated until the UE no longer receives a NACK for the SL-HARQ report or the maximum number of transmissions of the data TB is reached.

27. A user equipment (UE), comprising: an executor for performing sidelink transmission to another UE or a group of other UEs using the set of transmit beams during a beam management procedure; a receiver for receiving a sidelink hybrid automatic repeat request (SL-HARQ) report from the other UE or the group of other UEs; and A selector is configured to select and / or determine a subset of one or more transmit beams based on the SL-HARQ report.

28. A user equipment (UE), comprising: Memory; transceiver; as well as a processor coupled to the memory and the transceiver; The UE is used to execute the method according to any one of claims 1 to 26.

29. A non-transitory machine-readable storage medium having stored thereon instructions, which, when executed by a computer, cause the computer to perform the method according to any one of claims 1 to 26.

30. A chip, comprising: A processor, configured to call and run a computer program stored in a memory, so as to enable a device equipped with the chip to perform a method according to any one of claims 1 to 26.

31. A computer-readable storage medium having a computer program stored therein, wherein: The computer program causes a computer to execute the method according to any one of claims 1 to 26.

32. A computer program product comprising a computer program, wherein The computer program causes a computer to execute the method according to any one of claims 1 to 26.

33. A computer program, wherein The computer program causes a computer to execute the method according to any one of claims 1 to 26.

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