User equipment and channel access adjustment method for sidelink communication

Abstract

A channel access adjustment method for sidelink (SL) communication by a user equipment (UE) in a shared / unlicensed spectrum, the method comprising: the UE transmitting at least one physical sidelink shared channel (PSSCH) transmission within a reference duration occupied by a latest channel initiated using a type 1 channel access procedure; the UE performs a contention window adjustment operation based on at least one hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback corresponding to the at least one PSSCH transmission.

Description

Background Art 1. Technical Field

[0001] The present disclosure relates to the field of communication systems, and more specifically, to a user equipment (UE) and a channel access adjustment method for sidelink (SL) communication in a shared / unlicensed spectrum, which can provide good communication performance and / or high reliability. 2. Related technical description

[0002] In the development of radio wireless transmission and reception directly between two devices (which is generally referred to as device-to-device (D2D) communication), it was first developed by the 3rd generation partnership project (3GPP) and introduced in Release 12 (officially designated as sidelink communication), and was improved in Release 13 for public safety emergency uses (such as mission-critical communications) to mainly support low data rates and voice-type connections. In 3GPP Releases 14, 15 and 16, sidelink technology was further developed to additionally support vehicle-to-everything (V2X) communications to improve road safety and advanced / autonomous driving use cases, among which V2X communications are part of the global intelligent transportation system (ITS) development. In order to further expand support for sidelink technology to a wider range of applications and devices that utilize limited power / batteries, in Release 17, the technology has been further enhanced in the areas of power conservation and transceiver link reliability. In Release 18, 3GPP further developed the wireless technology and extended its operation to unlicensed spectrum. This is for greater available bandwidth, faster data rates and easier market adoption of D2D communications using sidelinks without requiring any mobile cellular operator to configure and allocate a portion of its extended mobile radio spectrum for data services that do not go through its mobile network.

[0003] There is no base station control and assistance for SL UEs when accessing unlicensed channels, and even in resource allocation (RA) mode 1 under gNB scheduling, UEs can try to access the channel at different times using different LBT channel access procedures with different channel idle period requirements. In this operation scenario, UEs transmitting in the same time slot cannot be coordinated in advance to avoid blocking / rejection of access to unlicensed channels.

[0004] Therefore, a UE and a channel access adjustment method for SL communication in a shared / unlicensed spectrum are needed to solve the problems in the prior art and other problems. Summary of the invention

[0005] In the first aspect of the present disclosure, a channel access adjustment method for a UE to perform SL communication in a shared / unlicensed spectrum includes: the UE sends at least one physical sidelink shared channel (PSSCH) transmission within a reference duration of the latest channel occupancy initiated using a type 1 channel access procedure; and the UE performs a contention window adjustment operation based on at least one hybrid automatic repeat request-acknowledgement (HARQ-ACK) feedback corresponding to the at least one PSSCH transmission.

[0006] In a second aspect of the present disclosure, a UE includes: a transmitter configured to send at least one PSSCH transmission within a reference duration of the latest channel occupancy initiated using a type 1 channel access process; and an executor configured to perform a contention window adjustment operation based on at least one HARQ-ACK feedback corresponding to the at least one PSSCH transmission.

[0007] In a third aspect of the present disclosure, a UE includes: a memory, a transceiver, and a processor, wherein the processor is coupled to the memory and the transceiver. The UE is configured to execute the above method.

[0008] In a fourth aspect of the present disclosure, a non-transitory machine-readable storage medium stores instructions, which, when executed by a computer, cause the computer to execute the above method.

[0009] In a fifth aspect of the present disclosure, a chip includes a processor, and the processor is configured to call and run a computer program stored in a memory so that a device on which the chip is installed executes the above method.

[0010] 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.

[0011] In a seventh aspect of the present disclosure, a computer program product comprises a computer program, and the computer program enables a computer to execute the above method.

[0012] In an eighth aspect of the present disclosure, a computer program causes a computer to execute the above method. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments or related technologies of the present disclosure, the drawings in the embodiments are briefly introduced below. Obviously, the drawings are only some embodiments of the present disclosure, and ordinary technicians in this field can obtain other drawings based on these drawings without creative work.

[0014] Figure 1 is a block diagram of a UE communicating in a communication network system provided by an embodiment of the present disclosure;

[0015] Figure 2 is a schematic diagram of a user plane protocol stack provided by an embodiment of the present disclosure;

[0016] Figure 3 is a schematic diagram of a control plane protocol stack provided by an embodiment of the present disclosure;

[0017] Figure 4 is a flow chart of a channel access adjustment method for SL communication in a shared / unlicensed spectrum provided by an embodiment of the present disclosure;

[0018] Figure 5 It is a schematic diagram of using feedback-based HARQ-ACK count for contention window adjustment in a type 1 channel access process provided by an embodiment of the present disclosure;

[0019] Figure 6 is a block diagram of a UE for wireless communication provided by an embodiment of the present disclosure;

[0020] Figure 7 is an example block diagram of a computing device provided by an embodiment of the present disclosure;

[0021] Figure 8 It is a block diagram of a wireless communication system provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

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

[0023] Shared / Unlicensed Spectrum

[0024] The shared (also called unlicensed or license-exempt) radio spectrum in the 2.4 GHz and 5 GHz bands is commonly used by Wi-Fi and Bluetooth wireless technologies for short-range communications (from a few meters to tens of meters). It is often claimed that the unlicensed spectrum bands carry more traffic than any other radio band because anyone can use the spectrum for free as long as the communication equipment complies with certain local technical regulations. In addition to Wi-Fi and Bluetooth, other radio access technologies (RATs) such as licensed-assisted access (LAA) based on 4G-LTE and 3GPP new radio unlicensed (NR-U) based on 5G-NR mobile systems also operate in the same unlicensed bands. In order to enable devices of different RATs (Wi-Fi, Bluetooth, LAA, NR-U and other possible RATs) to operate simultaneously and coexist fairly in the same geographical area without causing significant interference and interruption to each other's transmissions, clear channel access (CCA) protocols such as listen-before-talk (LBT) used in LAA and NR-U, and carrier sense multiple access / collision avoidance (CSMA / CA) used in Wi-Fi and Bluetooth are used before any wireless transmission to ensure that a wireless communication device does not transmit when another wireless communication device is already transmitting on the same channel.

[0025] For sidelink wireless technology, in order to coexist with existing RATs already operating in unlicensed frequency bands, an LBT-based scheme can be adopted to ensure that there is no ongoing radio channel activity before attempting to access the channel for transmission. For example, when a sidelink UE successfully performs type 1 LBT, the UE is entitled to access and occupy the unlicensed channel for the duration of the channel occupancy time (COT). During the acquired COT, if the COT initiating sidelink UE or the COT responding sidelink UE does not perform wireless transmission and the idle time exceeds 25 microseconds, devices of other RATs may still obtain channel access rights. Therefore, access to the channel may be lost until LBT is successfully performed again. One possible solution to this problem is back-to-back (B2B) transmission.

[0026] B2B transmission / multi-consecutive slots transmission (MCSt)

[0027] The main purpose of B2B transmission (which may also be called "burst transmission" or "multiple consecutive time slot transmission") is to enable SL communication UE to continuously occupy the unlicensed channel for a longer period of time (i.e., more than one time slot) without the risk of losing the channel access right, and to avoid the wireless transmission (Tx) devices of other radio access technologies (RATs) occupying the channel. This is particularly important and useful for SL Tx-UE operating in the unlicensed radio spectrum, especially when there are a large number of data transmission blocks (TBs) or media access control (MAC) packet data units (PDUs) that need to be retransmitted multiple times, sidelink hybrid automatic repeat request (SL-HARQ) feedback is disabled, and / or has a short delay requirement (packet delay budget (PDB)). When the unlicensed wireless channel is busy / congested (for example, many devices try to access the channel for transmission at the same time), it may be difficult and take a long time to obtain channel access rights due to the random backoff timer and priority category in the LBT process. Therefore, when the UE finally has the opportunity to obtain access to the wireless channel, the COT length may last for several milliseconds (e.g., 4 milliseconds, 8 milliseconds, or 10 milliseconds) with the goal of retaining the channel access right for as long as possible (e.g., the entire or most of the COT length) so as to transmit as much data as possible by continuously transmitting in the unlicensed channel, thereby preventing wireless devices of other RATs from having the opportunity to access the channel.

[0028] Unauthorized channel access and occupation

[0029] As mentioned earlier, the UE may perform a Type 1 LBT procedure prior to any SL transmission to first obtain access rights to the unlicensed channel and start the COT. In addition, B2B transmissions may be used to avoid large transmission gaps in order to preserve the COT and channel access rights. In addition to Type 1 LBT, the UE may also use Type 2 LBT during the COT or shared COT, which is required by unlicensed spectrum regulations and applies to gaps of 25 microseconds or less. For example, in Type 2A LBT, if the unlicensed channel is sensed as idle for 25 microseconds or longer, the COT initiating UE is allowed to resume its transmission and / or the COT sharing UE is allowed to start its transmission within the COT. In Type 2B LBT, the allowed transmission gap is 16 microseconds, and Type 2C LBT (where the UE does not need to perform channel sensing) applies to gaps less than 16 microseconds.

[0030] In NR-U and LAA systems, transmission gaps before the UE occupies the unlicensed channel are inevitable due to the propagation delay caused by the scheduling control information between gNBs / gNB to UE, the UE switching from receiving mode (RX) to transmitting mode (TX), and the actual uplink (UL) transmission data information coding and modulation. Sometimes, these gaps may be greater than 25 microseconds, and the cyclic prefix extension may be transmitted first in the UL to avoid the unlicensed channel being occupied by other devices operating in the same frequency band due to excessive channel idle time. The base station (gNB / eNB) determines the duration of the cyclic prefix extension (CPE) transmission in the UL to avoid access blocking / rejection issues between different UEs and indicates it to each scheduled UE, and the UE only needs to follow the indication and perform UL transmission accordingly.

[0031] In SL communications, especially in resource allocation (RA) mode 2, all transmission resources are determined and selected by the UE itself, without any base station intervention, assistance and coordination to avoid transmission conflicts. In addition, the SL system supports frequency domain multiplexing (FDM) transmission from multiple UEs in the same time slot, thereby maximizing radio resource utilization efficiency and reducing communication delays at the same time. However, since there is no base station control and assistance when accessing unlicensed channels, even in RA mode 1 under gNB scheduling, UEs may attempt to access the channel at different times using different LBT channel access procedures with different channel idle period requirements. In this operating scenario, UEs transmitting in the same time slot cannot be coordinated in advance to avoid access blocking / rejection to unlicensed channels.

[0032] Competition Window Adjustment

[0033] As part of the Type 1 LBT channel access procedure, the UE needs to perform different ranges of LBT listening time lengths before obtaining access to shared / unlicensed channels, depending on the channel access priority class (CAPC) level (p) of the data packet, physical channel and / or signal to be transmitted. In order to determine the length of the LBT listening time for a given CAPC level (p) and a specific transmission, the maximum allowed value of the channel listening time is further adjusted based on the "channel contention state" measured by the hybrid automatic repeat and request acknowledgement (HARQ-ACK) feedback from the data receiving device. In NR-U, the time window of the channel contention process is mainly based on the number of "ACK" feedbacks associated with unicast transmissions. However, in NR sidelink communications, the transmission type and HARQ-ACK feedback mechanism of the physical sidelink shared channel (PSSCH) transmission carrying information data packets may be very different from NR-U (for example, code block group transmission is not supported, and HARQ-ACK feedback is not always enabled / available in SL). Therefore, the adjustment process of the SL-U contention window is necessary.

[0034] In some embodiments, for the unlicensed channel access method proposed in the present disclosure, the transmission types of various SL-specific transmissions and their related HARQ-ACK feedback reports that reflect the channel contention status are taken into consideration to determine the appropriate channel listening time length. Other benefits of using the channel access method for SL communication in an unlicensed spectrum proposed in the present disclosure include: the channel access method proposed in the present disclosure provides a fair coexistence mechanism with wireless communication devices of other wireless access technologies operating in the same unlicensed spectrum when adjusting the listening contention window. By adjusting the contention window in the LBT channel listening that reflects the actual congestion status of the channel, more time domain access opportunities can be obtained when the channel is congested, and the channel can be accessed faster when the traffic is low.

[0035] Figure 1It is shown that, in some embodiments, the embodiments of the present disclosure provide one or more UEs 10 (e.g., a first UE) and one or more UEs 20 (e.g., a second UE) communicating in a communication network system 30. 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, and the processor 11 is coupled to the memory 12 and the transceiver 13. The UE 20 may include a memory 22, a transceiver 23, and a processor 21, and the processor 21 is coupled to the memory 22 and the transceiver 23. The processor 11 or the processor 21 may be configured to implement the functions, processes, and / or methods described in this specification. The layers of the radio interface protocol may be implemented in the processor 11 or the processor 21. The memory 12 or the memory 22 is operatively coupled to the processor 11 or the processor 21, and stores various information to operate the processor 11 or the processor 21. The transceiver 13 or the transceiver 23 is operatively coupled to the processor 11 or the processor 21, and sends and / or receives radio signals.

[0036] The processor 11 or the processor 21 may include an application-specific integrated circuit (ASIC), other chipsets, logic circuits and / or data processing devices. The memory 12 or the memory 22 may include a read-only memory (ROM), a random access memory (RAM), a flash memory, a memory card, a storage medium and / or other storage devices. The transceiver 13 or the transceiver 23 may include a baseband circuit for processing radio frequency signals. When the embodiment is implemented in software, the techniques described herein may be implemented by modules (e.g., processes, functions, etc.) that perform the functions described herein. The modules may be stored in the memory 12 or the memory 22 and executed by the processor 11 or the processor 21. The memory 12 or the memory 22 may be implemented inside the processor 11 or the processor 21, or may be implemented outside the processor 11 or the processor 21, in which case it may be communicatively coupled to the processor 11 or the processor 21 in various ways known in the art.

[0037] 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) communications, which are based on sidelink technologies developed in 3GPP long-term evolution (LTE) and new radio (NR) versions 17, 18 and later. UEs communicate directly with each other via a sidelink interface (e.g., a PC5 interface). Some embodiments of the present disclosure relate to sidelink communication technologies in 3GPP NR version 19 and later, such as providing cellular–vehicle to everything (C-V2X) communications.

[0038] In some embodiments, UE 10 may be a sidelink data packet TB transmission UE (Tx-UE). UE 20 may be a sidelink data packet TB reception UE (Rx-UE) or a peer UE. Sidelink data packet TB Rx-UE may be configured to send ACK / NACK feedback to data packet TB Tx-UE. Peer UE 20 is another UE communicating with Tx-UE 10 in the same SL unicast or multicast session.

[0039] Figure 2 An example of a user plane protocol stack provided by an embodiment of the present disclosure is shown. Figure 2It is shown that in some embodiments, in the user plane protocol stack, the service data adaptation protocol (SDAP), the packet data convergence protocol (PDCP), the radio link control (RLC) and the media access control (MAC) sublayers and the physical (PHY) layer (also referred to as the first layer or L1 layer) can be terminated in the UE 10 and the base station 40 (e.g., gNB) on the network side. In one example, the PHY layer provides transmission services for higher layers (e.g., MAC, RRC (radio resource control), etc.). In one example, the services and functions of the MAC sublayer may include mapping between logical channels and transport channels, multiplexing / demultiplexing MAC service data units (SDUs) belonging to one or more different logical channels to / from TBs delivered by the PHY layer, scheduling information reporting, error correction through hybrid automatic repeat request (HARQ) (e.g., one HARQ entity per carrier in the case of carrier aggregation (CA)), handling priorities between UEs through dynamic scheduling, handling priorities between logical channels of a UE through logical channel priorities, and / or padding. The MAC entity may support one or more values ​​and / or transmission timings. In one example, mapping restrictions in logical channel priorities may control which values ​​and / or transmission timings may be used by the logical channel. In one example, the RLC sublayer may support transparent mode (TM), unacknowledged mode (UM), and acknowledged mode (AM) transmission modes. The RLC configuration may be per logical channel, independent of the value and / or transmission time interval (TTI) duration. In one example, automatic repeat request (ARQ) can operate on any value and / or TTI duration of a logical channel configuration.In one example, the services and functions of the PDCP layer of the user plane may include sequence numbering, header compression and decompression, user data transmission, reordering and duplicate detection, PDCP PDU routing (e.g., in the case of separate bearers), PDCP SDU retransmission, encryption, decryption and integrity protection, PDCP SDU discard, PDCP re-establishment and data recovery of RLC AM, and / or replication of PDCP PDU. In one example, the services and functions of SDAP may include mapping between QoS (Quality of Service) flows and data radio bearers. In one example, the services and functions of SDAP may include mapping quality of service indicators (QFI) in downlink (DL) and uplink (UL) data packets. In one example, the protocol entity of SDAP may be configured for a single PDU session.

[0040] Figure 3 An example of a control plane protocol stack provided by an embodiment of the present disclosure is shown. Figure 3It is shown that in some embodiments, in the control plane protocol stack, the PDCP, RLC and MAC layers and the PHY layer may be terminated in the UE 10 and the base station 40 (e.g., gNB) on the network side and perform the above services and functions. In one example, RRC is used to control radio resources between the UE and the base station (e.g., gNB). In one example, RRC may be terminated in the UE and the gNB on the network side. In one example, the services and functions of RRC may include broadcast of system information related to the access stratum (AS) and non-access stratum (NAS), paging initiated by the 5G core network (5GC) or the radio access network (RAN), establishment, maintenance and release of the RRC connection between the UE and the RAN, security functions including key management, establishment, configuration, maintenance and release of signaling radio bearers (SRB) and data radio bearers (DRB), mobility functions, QoS management functions, UE measurement reporting and reporting control, detection and recovery of radio link failures, and / or transmission of NAS messages between the UE and the NAS. In one example, the NAS control protocol may be terminated in the UE and the access and mobility management function (AMF) on the network side, and may perform functions such as authentication and mobility management for 3GPP access and non-3GPP access between the UE and the AMF, and session management for 3GPP access and non-3GPP access between the UE and the session management function (SMF).

[0041] When a specific application is executed in the UE and requires a data communication service, the application layer responsible for executing the specific application provides the application-related information (i.e., application group / category / priority information / ID) to the NAS layer. In this case, the application-related information may be pre-configured / defined in the UE. Alternatively, the application-related information may be received from the network and provided to the application layer by the AS (RRC) layer, and when the application layer starts the data communication service, the application layer requests the AS (RRC) layer to provide the information to receive the information.

[0042] In some embodiments, the transceiver 13 is configured to send at least one PSSCH transmission within a reference duration of the most recent channel occupancy initiated using a type 1 channel access procedure, and the processor is configured to perform a contention window adjustment operation based on at least one HARQ-ACK feedback corresponding to the at least one PSSCH transmission. This can solve the problems in the prior art and other problems, and / or improve SL communication performance and reliability.

[0043] Figure 4 A channel access adjustment method 410 for a UE performing SL communication in a shared / unlicensed spectrum provided by an embodiment of the present disclosure is shown. In some embodiments, the method 410 includes: operation 412, the UE sends at least one PSSCH transmission within a reference duration of the latest channel occupancy initiated using a type 1 channel access process; and operation 414, the UE performs a contention window adjustment operation based on at least one HARQ-ACK feedback corresponding to the at least one PSSCH transmission. This can solve the problems in the prior art and other problems, and / or improve SL communication performance and reliability.

[0044] In some embodiments, at least one HARQ-ACK feedback for contention window adjustment corresponds to at least one PSSCH transmission within a reference duration for the most recent channel occupancy, and at least one HARQ-ACK feedback is based on at least one of an ACK counter, a negative acknowledgement (NACK) counter, or a no HARQ-ACK counter. In some embodiments, if the ACK counter value is equal to or greater than 1, the contention window value for each CAPC level is set to a minimum value. In some embodiments, if the ratio of the ACK counter value to the total number of HARQ-ACK feedbacks is equal to or greater than a first value, the contention window value for each CAPC level is set to a minimum value, and the first value is predefined or configured. In some embodiments, the total number of HARQ-ACK feedbacks is the sum of the ACK counter value, the NACK counter value, and the no HARQ-ACK counter value.

[0045] In some embodiments, if at least one of the ACK counter value is greater than the NACK counter value, the ACK counter value is greater than the no HARQ-ACK counter value, or the ACK counter value is equal to or greater than the second value, the contention window value of each CAPC level is set to a minimum value, and the second value is predefined or configured. In some embodiments, if the ACK counter value and the NACK counter value are the same, the contention window value of each CAPC level remains unchanged. In some embodiments, the ACK counter value and the NACK counter value are both equal to 0. In some embodiments, if the ACK counter value, the NACK counter value, and the no HARQ-ACK counter value are the same, the contention window value of each CAPC level remains unchanged.

[0046] In some embodiments, if the no HARQ-ACK counter value is greater than the ACK counter value and the NACK counter value, the contention window value of each CAPC level remains unchanged. In some embodiments, if the ratio of the no HARQ-ACK counter value to the total number of HARQ-ACK feedbacks is equal to or greater than a third value, the contention window value of each CAPC level remains unchanged, and the third value is predefined or configured. In some embodiments, if the NACK counter value is equal to or greater than 1, the contention window value of each CAPC level is increased to an allowed value. In some embodiments, if the ratio of the NACK counter value to the total number of HARQ-ACK feedbacks is greater than a fourth value, the contention window value of each CAPC level is increased to an allowed value, and the fourth value is predefined or configured.

[0047] In some embodiments, if at least one of the NACK counter value is greater than the ACK counter value, the NACK counter value is greater than the no HARQ-ACK counter value, the NACK counter value is equal to or greater than the fifth value, or the ratio of the NACK counter value to the total HARQ-ACK feedback number is equal to or greater than the sixth value, the contention window value of each CAPC level is increased to the allowed value, and the fifth value and the sixth value are predefined or configured. In some embodiments, the allowed value is the next higher value of the maintenance value of each CAPC level, and the maintenance value is the value of each CAPC level where the contention window value remains unchanged. In some embodiments, at least one of the ACK counter, the NACK counter, or the no HARQ-ACK counter is based on a per-feedback count and / or a per-PSSCH / per-time slot count.

[0048] In some embodiments, when at least one of the following situations occurs in at least one PSSCH transmission and / or at least one physical sidelink control channel (PSCCH) transmission within a reference duration, the no HARQ-ACK counter increases by 1 in both the per feedback count and the per PSSCH / per time slot count: the SL resource pool used for at least one PSSCH transmission and / or at least one PSCCH transmission is not configured with physical sidelink feedback channel (PSFCH) resources; the HARQ feedback enable / disable indication field is disabled in the second stage sidelink control information (SCI) carried on at least one PSSCH transmission; the UE fails to perform a channel access procedure when transmitting at least one HARQ-ACK feedback in at least one PSFCH transmission.

[0049] In some embodiments, for the per PSSCH / per timeslot count, if the ACK counter value and the NACK counter value are the same for at least one PSSCH transmission and / or at least one PSCCH transmission within the reference duration, no HARQ-ACK counter value is incremented. In some embodiments, the ACK counter is incremented by 1 when at least one of the following occurs for at least one PSSCH transmission within the reference duration: in the per feedback count and per PSSCH / per timeslot count, if at least one HARQ-ACK feedback includes an ACK for a unicast transmission; in the per feedback count for multicast transmission, if at least one HARQ-ACK feedback includes an ACK; and in the per PSSCH / per timeslot count for multicast transmission, if at least one HARQ-ACK feedback includes more ACK responses than NACK responses.

[0050] In some embodiments, the NACK counter is increased by 1 when at least one of the following situations occurs in at least one PSSCH transmission within the reference duration: in the per-feedback count and per-PSSCH / per-timeslot count for unicast transmission and multicast transmission with NACK feedback only, if at least one HARQ-ACK feedback includes a NACK; in the per-feedback count for multicast transmission, if at least one HARQ-ACK feedback includes a NACK; in the per-PSSCH / per-timeslot count for multicast transmission, if at least one HARQ-ACK feedback includes a NACK.

[0051] In some embodiments, the term " / " may be interpreted as meaning "and / or". The term "configuration" may refer to "preconfiguration" and "network configuration". The term "predefined" or "predefined rules" in the present disclosure may be implemented by pre-storing corresponding codes, tables or other methods indicating relevant information in a device (e.g., including UE and network equipment). The specific implementation method is not limited in the present disclosure. For example, "predefined" may refer to the content defined in the protocol. It should also be understood that in the present disclosure, "protocol" may refer to a standard protocol in the communication field, such as an LTE protocol, an NR protocol, and related protocols used in future communication systems, and the present disclosure is not limited to this.

[0052] Example:

[0053] In some embodiments, in an innovative method for accessing unlicensed / shared channels in SL communication, a contention window adjustment scheme specifically designed for sidelink is proposed, taking into account all possible HARQ-ACK feedback scenarios in SL communication. In some embodiments, the proposed method provides a simple and effective channel access mechanism and coexists fairly with devices of other RATs in the unlicensed spectrum.

[0054] As mentioned earlier, the code block group (CBG) transmission and HARQ-ACK feedback scheme used in the fifth generation (5G) NR are not adopted in NR SL communications. In addition, for NR system operating in an unlicensed carrier (NR-U), most of the traffic (e.g., more than 95%) in DL and UL transmissions are unicast in nature. Occasionally, broadcast transmissions such as synchronization signal blocks (SSBs) and system information blocks (SIBs) are provided in DL and random access channels (RACHs) are provided in UL. As a special case, SSBs can be transmitted using only type 2A channel access procedures. Therefore, type 1 channel access procedures are used for unicast transmissions in almost all cases, which always require receiving "ACK" or "NACK" feedback from the UE / gNB.

[0055] In some embodiments, in sidelink communications, various transmission types and HARQ-ACK feedback schemes are supported, such as broadcast transmissions that never require HARQ-ACK feedback, multicast transmissions that have full HARQ-ACK feedback ("ACK" and "NACK") and "only NACK" feedback, and unicast transmissions that have full HARQ-ACK feedback ("ACK" and "NACK"). In addition, the SL transmission resource pool can be configured without physical sidelink feedback channel (PSFCH) resources, in which case all transmissions in the resource pool do not require / receive any HARQ-ACK feedback. To make SL operation more complex, sidelink HARQ-ACK feedback can be enabled / disabled in the second stage SCI of scheduling PSSCH to apply to both multicast and unicast transmissions. It can be seen that multiple HARQ-ACK feedback scenarios are supported in SL communications, and therefore, the contention window adjustment of the type 1 channel access process used in NR-U is not applicable to SL communications to access unlicensed / shared channels.

[0056] Proposed CW adjustment scheme based on HARQ-ACK counting

[0057] In order to take into account all SL HARQ-ACK feedback operations, it is recommended to adjust the contention window size / length based on the HARQ-ACK counting method, where all three possible HARQ-ACK results are counted on a per-feedback basis or per-PSSCH / per-time slot basis before performing the adjustment of the contention window size / length for the type 1 channel access process.

[0058] No HARQ-ACK feedback: In SL communication, in several operating scenarios, the receiving UE will not report HARQ-ACK feedback to the transmitting UE. One of the scenarios involves the case where the SL resource pool for PSSCH / PSCCH transmission is not (pre-)configured with PSFCH resources. Therefore, no HARQ-ACK feedback can be transmitted. Another scenario involves SL broadcast transmission, where no HARQ-ACK report is required due to the large and unknown number of UEs that may receive the broadcast message. There is also a case where the "HARQ Feedback Enable / Disable Indication" field is disabled in the second stage SCI carried on the PSSCH. When SL operates in unlicensed spectrum, HARQ-ACK feedback reports are also not transmitted due to the failure of the UE to perform the LBT channel access procedure before transmitting the PSFCH. In the per-feedback count and per-PSSCH / per-timeslot count, when any of the above situations occurs for SLPSSCH / PSCCH transmission within the SL reference duration, the counter related to "no HARQ-ACK feedback" (e.g., no HARQ-ACK counter value) is increased by 1.

[0059] For the case of multicast transmission: As a special case of "no HARQ-ACK feedback", in the per PSSCH / per time slot count, if the number of "ACK" responses and the number of "NACK" responses of SL PSSCH / PSCCH transmissions within the SL reference duration are the same, the counter related to "no HARQ-ACK feedback" (e.g., no HARQ-ACK counter value) is increased by 1.

[0060] The HARQ-ACK result is "ACK": When the UE performs SL transmission related to unicast or multicast, the "Transmission Type Indication" field in the second-stage SCI is set to "10" and "01" respectively, and the "HARQ Feedback Enable / Disable Indication" field carried in the second-stage SCI is enabled, the receiving UE needs to feedback an "ACK" response when successfully decoding the PSSCH / PSCCH; otherwise, a "NACK" response is fed back.

[0061] For the case of unicast transmission: In the per-feedback count and per-PSSCH / per-timeslot count, if the HARQ-ACK feedback of the SL PSSCH / PSCCH transmission within the SL reference duration is an "ACK" response, the counter related to "ACK feedback" (e.g., ACK counter value) is increased by 1. For the case of multicast transmission with ACK or NACK feedback: In the per-feedback count, when one HARQ-ACK feedback of the SL PSSCH / PSCCH transmission within the SL reference duration is an "ACK" response, the counter related to "ACK feedback" (e.g., ACK counter value) is increased by 1. In the per-PSSCH / per-timeslot count, if the number of "ACK" responses of the SL PSSCH / PSCCH transmission within the SL reference duration is more than the number of "NACK" responses, the counter related to "ACK feedback" (e.g., ACK counter value) is increased by 1.

[0062] HARQ-ACK result is "NACK": Contrary to the above "ACK" result, the receiving UE needs to feedback a "NACK" response when decoding of PSSCH / PSCCH fails. In addition, when the UE performs SL transmission related to multicast, the "Transmission Type Indication" field in the second-stage SCI is set to "11" to include only HARQ-ACK information of NACK, and the "HARQ Feedback Enable / Disable Indication" field carried in the second-stage SCI is enabled, the receiving UE only feedbacks a "NACK" response when decoding of PSSCH / PSCCH fails; no feedback response is transmitted when decoding is successful.

[0063] For the case of unicast transmission and multicast transmission with only NACK feedback: in the per-feedback count and per-PSSCH / per-time slot count, if a "NACK" response to HARQ-ACK feedback is received for the SL PSSCH / PSCCH transmission within the SL reference duration, the counter related to the "NACK feedback" (e.g., the NACK counter value) is increased by 1.

[0064] For the case of multicast transmission with ACK or NACK feedback: In the per-feedback count, when one HARQ-ACK feedback of the SL PSSCH / PSCCH transmission within the SL reference duration is a "NACK" response, the counter related to "NACK feedback" (e.g., NACK counter value) is increased by 1. In the per-PSSCH / per-time slot count, if the number of "NACK" responses of the SLPSSCH / PSCCH transmission within the SL reference duration is more than the number of "ACK" responses, the counter related to "NACK feedback" (e.g., NACK counter value) is increased by 1.

[0065] In some embodiments, for adjustment of the contention window size / length, HARQ-ACK feedback corresponding to at least PSSCH transmission within a SL reference duration is used, where the reference duration is used for the latest SL channel occupancy in which HARQ-ACK feedback is available, and the contention window size / length is adjusted according to one or more of the following situations.

[0066] The contention window size / length is set to the minimum value of each CAPC(p) when one or more of the following occurs: for PSSCH transmitted on the channel, if the counter value associated with "ACK feedback" (e.g., ACK counter value) is equal to or greater than 1 (i.e., at least one sidelink HARQ-ACK feedback is "ACK"); if the counter value associated with "ACK feedback" (e.g., ACK counter value) is greater than the counter value associated with "NACK feedback" (e.g., NACK counter value); if the counter value associated with "ACK feedback" (e.g., ACK counter value) is greater than the counter value associated with "no HARQ-ACK feedback" (e.g., no HARQ-ACK counter value); if the counter value associated with "ACK feedback" (e.g., ACK counter value) is equal to or greater than a value X, where X is predefined or (pre) configured; if at least Y% of the total number of HARQ-ACK feedbacks are "ACK", where Y is predefined or (pre) configured. The total number of HARQ-ACK feedbacks is the sum of the ACK counter value, the NACK counter value, and the no HARQ-ACK counter value.

[0067] The contention window size / length remains unchanged when one or more of the following situations occurs: if the counter value associated with "ACK feedback" (e.g., ACK counter value) and the counter value associated with "NACK feedback" (e.g., NACK counter value) are the same; if the counter value associated with "ACK feedback" (e.g., ACK counter value), the counter value associated with "NACK feedback" (e.g., NACK counter value) and the counter value associated with "no HARQ-ACK feedback" (e.g., no HARQ-ACK counter value) are the same; if the counter value associated with "ACK feedback" (e.g., ACK counter value) and the counter value associated with "NACK feedback" (e.g., NACK counter value) are both zero; if the counter value associated with "no HARQ-ACK feedback" (e.g., no HARQ-ACK counter value) is greater than the counter value associated with "ACK feedback" (e.g., ACK counter value) and the counter value associated with "NACK feedback" (e.g., NACK counter value); if at least Z% of the total HARQ-ACK feedback number is "no HARQ-ACK feedback", where Z is predefined or (pre) configured. The total HARQ-ACK feedback number is the sum of the ACK counter value, the NACK counter value, and the no HARQ-ACK counter value.

[0068] The contention window size / length is increased to the next higher allowed value when one or more of the following occurs: for PSSCH transmitted on the channel, if the counter value associated with "NACK feedback" (e.g., NACK counter value) is equal to or greater than 1 (i.e., at least one sidelink HARQ-ACK feedback is "NACK"); if the counter value associated with "NACK feedback" (e.g., NACK counter value) is greater than the counter value associated with "ACK feedback" (e.g., ACK counter value); if the counter value associated with "NACK feedback" (e.g., NACK counter value) is greater than the counter value associated with "no HARQ-ACK feedback" (e.g., no HARQ-ACK counter value); if the counter value associated with "NACK feedback" (e.g., NACK counter value) is equal to or greater than a value M, where M is predefined or (pre) configured; if at least N% of the total HARQ-ACK feedback number is "NACK", where N is predefined or (pre) configured. The total HARQ-ACK feedback number is the sum of the ACK counter value, the NACK counter value, and the no HARQ-ACK counter value.

[0069] refer to Figure 5FIG. 100 provides an example illustration of per-feedback HARQ-ACK count for contention window adjustment during type 1 channel access. In the illustration, it is assumed that the UE first performs a transmission burst of SL channels / signals in 4 consecutive time slots (time slots n, n+1, n+2, and n+3) 101, 102, 103, 104. In each transmission time slot within the burst, a different SL traffic transmission type is transmitted and is associated with a different HARQ-ACK feedback scheme.

[0070] In some embodiments, in time slot n 101, broadcast traffic is transmitted and the HARQ feedback indication in the second stage SCI is disabled. In time slot n+1 102, multicast traffic is transmitted, the HARQ feedback indication in the second stage SCI is enabled, and the transmission type indicates requesting ACK or NACK feedback. In connection-oriented multicast communication, the total number of member UEs in the group is known to all members. In this case, assuming that there are 6 member UEs in the multicast, 4 of the 5 receiving UEs provide "ACK" in the HARQ-ACK feedback, and 1 receiving UE reports "NACK".

[0071] In time slot n+2 103, unicast traffic was transmitted, the HARQ feedback indication in the second stage SCI was enabled, and the receiving UE reported "NACK" in the HARQ-ACK feedback. In time slot n+3 104, multicast traffic was transmitted, the HARQ feedback indication in the second stage SCI was enabled and the transmission type indicated that only NACK feedback was requested. In connectionless multicast transmission, the total number of member UEs in the group within the communication range may be unknown. Therefore, only one PSFCH resource is (pre-)configured for HARQ-ACK feedback, and all UEs that failed to decode the transmitted PSSCH report a "NACK" result using this PSFCH resource. From the perspective of the PSSCH sending UE, only detecting the "NACK" result in the (pre-)configured PSFCH resource is not sufficient to determine the number of UEs that actually failed to decode the PSSCH and reported "NACK".

[0072] In some embodiments, according to the HARQ-ACK counting method proposed in the present disclosure, when the reported HARQ-ACK result is counted per feedback, the contention window adjustment result is as follows: in time slot n 101, the "no HARQ-ACK counter value" may increase by 1; in time slot n+1 102, the "ACK counter value" may increase by 4, and the "NACK counter value" may increase by 1; in time slot n+2 103, the "NACK counter value" may increase by 1; in time slot n+3 104, the "NACK counter value" may increase by 1. In total, the "no HARQ-ACK counter value" is 1, the "ACK counter value" is 4, and the "NACK counter value" is 3. Therefore, since the "ACK counter value" is greater than the "no HARQ-ACK counter value" and the "NACK counter value", the contention window adjustment will be to set the contention window size / length of each CAPC(p) to the minimum value.

[0073] In some embodiments, according to the HARQ-ACK counting method proposed in the present disclosure, when the reported HARQ-ACK result is counted per PSSCH / per time slot, the contention window adjustment result is as follows: in time slot n101, the "no HARQ-ACK counter value" may increase by 1; in time slot n+1 102, since the number of "ACK" responses is greater than the number of "NACK" responses (4 to 1), the "ACK counter value" may increase by 1; in time slot n+2 103, the "NACK counter value" may increase by 1; in time slot n+3 104, the "NACK counter value" may increase by 1. In total, the "no HARQ-ACK counter value" is 1, the "ACK counter value" is 1, and the "NACK counter value" is 2. Therefore, since the "NACK counter value" is greater than the "no HARQ-ACK counter value" and the "ACK counter value", the contention window adjustment will be to increase the contention window size / length of each CAPC(p) to the next higher allowed value.

[0074] It should be noted that the term "predefined" or "predefined rules" in the present disclosure can be implemented by pre-storing corresponding codes, tables or other methods of indicating relevant information in a device (for example, including UE and network equipment). The specific implementation method is not limited in the present disclosure. For example, "predefined" may refer to the content defined in the protocol. It should also be understood that in the present disclosure, "protocol" may refer to a standard protocol in the field of communications, such as an LTE protocol, an NR protocol, and related protocols used in future communication systems, and the present disclosure is not limited to this.

[0075] Figure 6A UE 600 for wireless communication provided by an embodiment of the present disclosure is shown. The UE 600 includes: a transmitter 601, configured to send at least one PSSCH transmission within a reference duration of the latest channel occupancy initiated using a type 1 channel access procedure; and an executor 602, configured to perform a contention window adjustment operation based on at least one HARQ-ACK feedback corresponding to the at least one PSSCH transmission. This can solve the problems in the prior art and other problems, and / or improve SL communication performance and reliability.

[0076] In some embodiments, at least one HARQ-ACK feedback for contention window adjustment corresponds to at least one PSSCH transmission within a reference duration for the most recent channel occupancy, and the at least one HARQ-ACK feedback is based on at least one of an ACK counter, a NACK counter, or a no HARQ-ACK counter. In some embodiments, if the ACK counter value is equal to or greater than 1, the contention window value for each CAPC level is set to a minimum value. In some embodiments, if the ratio of the ACK counter value to the total number of HARQ-ACK feedbacks is equal to or greater than a first value, the contention window value for each CAPC level is set to a minimum value, and the first value is predefined or configured. In some embodiments, the total number of HARQ-ACK feedbacks is the sum of the ACK counter value, the NACK counter value, and the no HARQ-ACK counter value.

[0077] In some embodiments, if at least one of the ACK counter value is greater than the NACK counter value, the ACK counter value is greater than the no HARQ-ACK counter value, or the ACK counter value is equal to or greater than the second value, the contention window value of each CAPC level is set to a minimum value, and the second value is predefined or configured. In some embodiments, if the ACK counter value and the NACK counter value are the same, the contention window value of each CAPC level remains unchanged. In some embodiments, the ACK counter value and the NACK counter value are equal to 0. In some embodiments, if the ACK counter value, the NACK counter value, and the no HARQ-ACK counter value are the same, the contention window value of each CAPC level remains unchanged.

[0078] In some embodiments, if the no HARQ-ACK counter value is greater than the ACK counter value and the NACK counter value, the contention window value of each CAPC level remains unchanged. In some embodiments, if the ratio of the no HARQ-ACK counter value to the total number of HARQ-ACK feedbacks is equal to or greater than a third value, the contention window value of each CAPC level remains unchanged, and the third value is predefined or configured. In some embodiments, if the NACK counter value is equal to or greater than 1, the contention window value of each CAPC level is increased to an allowed value. In some embodiments, if the ratio of the NACK counter value to the total number of HARQ-ACK feedbacks is greater than a fourth value, the contention window value of each CAPC level is increased to an allowed value, and the fourth value is predefined or configured.

[0079] In some embodiments, if at least one of the NACK counter value is greater than the ACK counter value, the NACK counter value is greater than the no HARQ-ACK counter value, the NACK counter value is equal to or greater than the fifth value, or the ratio of the NACK counter value to the total HARQ-ACK feedback number is equal to or greater than the sixth value, the contention window value of each CAPC level is increased to the allowed value, and the fifth value and the sixth value are predefined or configured. In some embodiments, the allowed value is the next higher value of the maintenance value of each CAPC level, and the maintenance value is the value of the level of each CAPC where the contention window value remains unchanged. In some embodiments, at least one of the ACK counter, the NACK counter, or the no HARQ-ACK counter is based on a per-feedback count and / or a per-PSSCH / per-time slot count.

[0080] In some embodiments, the no HARQ-ACK counter increases by 1 in both the per-feedback count and the per-PSSCH / per-timeslot count when at least one of the following conditions occurs in at least one PSSCH transmission and / or at least one PSCCH transmission within a reference duration: the SL resource pool used for at least one PSSCH transmission and / or at least one PSCCH transmission is not configured with PSFCH resources; the HARQ feedback enable / disable indication field is disabled in the second stage SCI carried on at least one PSSCH transmission; and the UE fails to perform a channel access procedure when transmitting at least one HARQ-ACK feedback in at least one PSFCH transmission.

[0081] In some embodiments, for the per PSSCH / per timeslot count, if the ACK counter value and the NACK counter value are the same for at least one PSSCH transmission and / or at least one PSCCH transmission within the reference duration, no HARQ-ACK counter value is incremented. In some embodiments, the ACK counter is incremented by 1 when at least one of the following occurs for at least one PSSCH transmission within the reference duration: in the per feedback count and per PSSCH / per timeslot count, if at least one HARQ-ACK feedback includes an ACK for a unicast transmission; in the per feedback count for multicast transmission, if at least one HARQ-ACK feedback includes an ACK; and in the per PSSCH / per timeslot count for multicast transmission, if at least one HARQ-ACK feedback includes more ACK responses than NACK responses.

[0082] In some embodiments, the NACK counter is increased by 1 when at least one of the following situations occurs in at least one PSSCH transmission within the reference duration: in the per-feedback count and per-PSSCH / per-timeslot count for unicast transmission and multicast transmission with NACK feedback only, if at least one HARQ-ACK feedback includes a NACK; in the per-feedback count for multicast transmission, if at least one HARQ-ACK feedback includes a NACK; in the per-PSSCH / per-timeslot count for multicast transmission, if at least one HARQ-ACK feedback includes a NACK.

[0083] In some embodiments, the term " / " may be interpreted as meaning "and / or". The term "configuration" may refer to "preconfiguration" and "network configuration". The term "predefined" or "predefined rules" in the present disclosure may be implemented by pre-storing corresponding codes, tables or other methods indicating relevant information in a device (e.g., including UE and network equipment). The specific implementation method is not limited in the present disclosure. For example, "predefined" may refer to the content defined in the protocol. It should also be understood that in the present disclosure, "protocol" may refer to a standard protocol in the communication field, such as an LTE protocol, an NR protocol, and related protocols used in future communication systems, and the present disclosure is not limited to this.

[0084] In summary, for the unlicensed channel access method proposed in the present disclosure, the transmission types of various SL-specific transmissions and their related HARQ-ACK feedback reports are taken into consideration to reflect the channel contention status, thereby determining the appropriate channel listening time length. Other benefits of using the channel access method for SL communication in the unlicensed spectrum proposed in the present disclosure include: the channel access method proposed in the present disclosure provides a fair coexistence mechanism with wireless communication devices of other wireless access technologies operating in the same unlicensed spectrum when adjusting the listening contention window. By adjusting the contention window in the LBT channel listening to reflect the actual congestion status of the channel, more time domain access opportunities can be obtained when the channel is congested, and the channel can be accessed faster when the traffic is low.

[0085] The commercial benefits of some embodiments are as follows: 1. Solve the problems in the prior art and other problems; 2. Improve SL communication performance; 3. Provide a fair coexistence mechanism with wireless communication devices of other wireless access technologies operating in the same unlicensed spectrum; 4. By adjusting the contention window in LBT channel listening that reflects the actual congestion state of the channel, more time domain access opportunities can be obtained when the channel is congested, and the channel can be accessed faster when the traffic is low; 5. Some embodiments of the present disclosure are used by 5G-NR chipset suppliers, V2X communication system development suppliers, automobile manufacturers (including cars, trains, trucks, buses, bicycles, motorcycles, helmets, etc.), drones (unmanned aerial vehicles), smartphone manufacturers, smart watches, wireless headphones, wireless headsets, communication devices, remote-controlled vehicles, robots for public safety purposes, augmented reality / virtual reality (AR / VR) device manufacturers (such as games, conferences / seminars, educational purposes), smart home devices (including TVs, audio, speakers, lights, doorbells, locks, cameras, conference headsets, etc.), smart factory and warehouse equipment (including Industrial Internet of Things (IIoT) In some embodiments, the commercial benefits and business importance of the present disclosure include reducing the power consumption of wireless communications, thereby extending the operating time of the device and / or improving user experience and product satisfaction through longer battery charging intervals. Some embodiments of the present disclosure are combinations of "technology / processes" that can be adopted in 3GPP specifications to create a final product. Some embodiments of the present disclosure involve mobile cellular communication technologies in 3GPP NR Release 17, 18, 19 and later versions for providing direct D2D wireless communication services.

[0086] Figure 7 is an example block diagram of a computing device provided by an embodiment of the present disclosure. Any suitable computing device can be used to perform the operations described herein. For example, Figure 7 An example of a computing device 1100 is shown, which may be implemented using any suitably configured hardware and / or software. Figures 1 to 6 In some embodiments of the present invention, the computing device 1100 includes a processor 1112 that is communicatively coupled to a memory 1114 and executes computer executable program code and / or accesses information stored in the memory 1114. The processor 1112 may include a microprocessor, an ASIC, a state machine, or other processing device. The processor 1112 may include any number of processing devices, including one. Such a processor may include or communicate with a computer readable medium storing instructions that, when executed by the processor 1112, cause the processor to perform the operations described herein.

[0087] Memory 1114 may include any suitable non-transitory computer-readable medium. Computer-readable media may include any electronic, optical, magnetic, or other storage device capable of providing computer-readable instructions or other program code to a processor. Non-limiting examples of computer-readable media include disks, memory chips, ROM, RAM, ASICs, configured processors, optical storage, tapes or other magnetic storage, or any other medium from which a computer processor can read instructions. Instructions may include processor-specific instructions generated by a compiler and / or interpreter from any suitable computer programming language, including C, C++, C#, Visual Basic, Java, Python, Perl, JavaScript, and ActionScript.

[0088] The computing device 1100 may also include a bus 1116. The bus 1116 may communicatively couple one or more components of the computing device 1100. The computing device 1100 may also include multiple external or internal devices, such as input or output devices. For example, the computing device 1100 is illustrated as having an input / output (I / O) interface 1118, which is capable of receiving input from one or more input devices 1120 or providing output to one or more output devices 1122. One or more input devices 1120 and one or more output devices 1122 are communicatively coupled to the I / O interface 1118. The communicatively coupling may be implemented in any suitable manner (e.g., connected by a printed circuit board, connected by a cable, communicated by wireless transmission, etc.). Non-limiting examples of the input device 1120 include a touch screen (e.g., one or more cameras for imaging a touch area or a pressure sensor for detecting pressure changes caused by a touch), a mouse, a keyboard, or any other device capable of generating input events in response to a user's physical manipulation of the computing device. Non-limiting examples of output device 1122 include a liquid crystal display (LCD) screen, an external monitor, speakers, or any other device that can be used to display or otherwise present output generated by the computing device.

[0089] The computing device 1100 can execute program code that configures the processor 1112 to perform Figures 1 to 6 The program code may reside in memory 1114 or any suitable computer-readable medium and may be executed by processor 1112 or any other suitable processor.

[0090] The computing device 1100 can also include at least one network interface device 1124. The network interface device 1124 can include any device or group of devices suitable for establishing a wired or wireless data connection with one or more data networks 1128. Non-limiting examples of the network interface device 1124 include an Ethernet network adapter, a modem, etc. The computing device 1100 can transmit messages through the network interface device 1124 in the form of electronic or optical signals.

[0091] Figure 8 700 is an example block diagram of a wireless communication system 700 provided by an embodiment of the present disclosure. The embodiments described herein may be implemented in a system using any appropriately configured hardware and / or software. Figure 8System 700 is shown including at least radio frequency (RF) circuitry 710, baseband circuitry 720, application circuitry 730, memory / storage 740, display 750, camera 760, sensor 770, and I / O interface 780 coupled to one another as shown.

[0092] Application circuitry 730 includes, but is not limited to, one or more single-core or multi-core processors. The processor may include any combination of general-purpose processors and special-purpose processors (e.g., graphics processors, application processors). The processor may be coupled to a memory / storage device and configured to execute instructions stored in the memory / storage device to enable various applications and / or operating systems running on the system.

[0093] The baseband circuit 720 includes, but is not limited to, one or more single-core or multi-core processors. The processor may include a baseband processor. The baseband circuit may implement various radio control functions, enabling communication with one or more radio networks through an RF circuit. The radio control functions include, but are not limited to, signal modulation, encoding, decoding, radio 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 an evolved universal terrestrial radio access network (EUTRAN) and / or other wireless metropolitan area networks (WMAN), wireless local area networks (WLAN), and wireless personal area networks (WPAN). An embodiment in which the baseband circuit is configured to support radio communications of multiple wireless protocols may be referred to as a multi-mode baseband circuit.

[0094] In various embodiments, baseband circuitry 720 may include circuitry for operating on signals that are not strictly considered to be baseband frequencies. For example, in some embodiments, baseband circuitry may include circuitry for operating on signals having intermediate frequencies that are between baseband frequencies and radio frequencies.

[0095] RF circuitry 710 may be used to communicate 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.

[0096] In various embodiments, RF circuitry 710 may include circuitry for operating on signals that are not strictly considered radio frequencies. For example, in some embodiments, RF circuitry may include circuitry for operating on signals having intermediate frequencies that are between baseband frequencies and radio frequencies.

[0097] In various embodiments, the transmitter circuit, control circuit, or receiver circuit described above with respect to the user equipment, eNB, or gNB may be embodied in whole or in part in one or more of the RF circuit, baseband circuit, and / or application circuit. As used herein, "circuit" may refer to, may be part of, or may include an ASIC, electronic circuit, processor (shared, dedicated, or group) and / or memory (shared, dedicated, or group) that executes one or more software or firmware programs, combinational logic circuits, and / or other suitable hardware components that provide the above functionality. In some embodiments, electronic device circuits may be implemented in one or more software or firmware modules, or functions associated with the circuits may be implemented by one or more software or firmware modules.

[0098] In some embodiments, some or all of the constituent components of the baseband circuit, application circuit, and / or memory / storage device may be implemented together on a system on a chip (SOC).

[0099] The memory / storage device 740 may be used to load and store data and / or instructions, for example, for the system. The memory / storage device may include any suitable combination of volatile memory (such as dynamic random access memory (DRAM)) and / or non-volatile memory (such as flash memory) in one embodiment.

[0100] In various embodiments, the I / O interface 780 may include one or more user interfaces designed to enable a user to interact with the system and / or peripheral component interfaces designed to enable peripheral components to interact with the system. User interfaces include, but are not limited to, a physical keyboard or keypad, a touchpad, a speaker, a microphone, etc. Peripheral component interfaces include, but are not limited to, a non-volatile memory port, a universal serial bus (USB) port, an audio jack, and a power interface.

[0101] In various embodiments, the sensor 770 may include one or more sensing devices to determine environmental conditions and / or location information related to the system. In some embodiments, the sensor includes, but is not limited to, a gyroscope sensor, an accelerometer, a proximity sensor, an ambient light sensor, and a positioning unit. The positioning unit may be part of, or interact with, a baseband circuit and / or an RF circuit to communicate with components of a positioning network (e.g., a global positioning system (GPS) satellite).

[0102] In various embodiments, the display 750 may include a display, such as a liquid crystal display and a touch screen display. In various embodiments, the system 700 may be a mobile computing device, such as, but not limited to, a laptop device, a tablet device, a netbook, an ultrabook, a smart phone, AR / VR glasses, etc. In various embodiments, the system may have more or fewer components, and / or different architectures. Where appropriate, the methods described herein may be implemented as a computer program. The computer program may be stored on a storage medium, such as a non-transitory storage medium.

[0103] Those skilled in the art will appreciate that each unit, algorithm, and step described and disclosed in the embodiments of the present disclosure may be implemented using electronic hardware or a combination of computer software and electronic hardware. Whether a function is run in hardware or software depends on the application conditions and design requirements of the technical solution.

[0104] A person skilled in the art may use different methods to implement the functions of each specific application, and these implementations are within the scope of the present disclosure. A person skilled in the art may understand that he / she may refer to the working processes of the systems, devices, and units in the above embodiments, because the working processes of the above systems, devices, and units are substantially the same. For ease of description and brevity, these working processes will not be described in detail.

[0105] It should be 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 exemplary only. The division of units is based only on logical functions, and other divisions exist in the implementation. Multiple units or components can be combined or integrated into another system. Some features can also be omitted or skipped. On the other hand, the mutual coupling, direct coupling or communication coupling shown or discussed is operated indirectly or communicatively in electrical, mechanical or other forms through some ports, devices or units.

[0106] The units explained as separate components may or may not be physically separate. The units shown may or may not be physical units, i.e. located in one place or distributed over multiple network units. Depending on the purpose of the embodiment, some or all units may be used. In addition, each functional unit in each embodiment may be integrated in one processing unit, or physically independent, or integrated in one processing unit containing two or more units.

[0107] If the software functional unit is implemented and used and sold as a product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution proposed in the present disclosure can be basically or partially implemented 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 and includes multiple instructions for causing a computing device (such as a personal computer, a server, or a network device) to perform all or part of the steps disclosed in the embodiments of the present disclosure. The storage medium includes a USB flash drive, a mobile hard disk, a ROM, a RAM, a floppy disk, or other media capable of storing program code.

[0108] While the present disclosure has been described in connection with what are considered to be the most practical and preferred embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments but is intended to cover various arrangements embodied without departing from the broadest interpretation of the appended claims.

Claims

1. A channel access adjustment method, characterized in that: The method is used for a user equipment UE to perform sidelink SL communication in a shared / unlicensed spectrum, and the method includes: The UE sends at least one physical sidelink shared channel (PSSCH) transmission within a reference duration of the most recent channel occupancy initiated using a type 1 channel access procedure; The UE performs a contention window adjustment operation based on at least one hybrid automatic repeat request acknowledgement HARQ-ACK feedback corresponding to the at least one PSSCH transmission.

2. The method according to claim 1, characterized in that At least one HARQ-ACK feedback for the contention window adjustment corresponds to at least one PSSCH transmission within the reference duration for the latest channel occupancy, and the at least one HARQ-ACK feedback is based on at least one of an ACK counter, a negative acknowledgment NACK counter, or a no HARQ-ACK counter.

3. The method according to claim 1 or 2, characterized in that: If the ACK counter value is equal to or greater than 1, the contention window value of each channel access priority CAPC level is set to the minimum value.

4. The method according to any one of claims 1 to 3, characterized in that If the ratio of the ACK counter value to the total number of HARQ-ACK feedbacks is equal to or greater than a first value, the contention window value of each access priority CAPC level is set to a minimum value, wherein the first value is predefined or configured.

5. The method according to claim 4, characterized in that The total HARQ-ACK feedback number is the sum of the ACK counter value, the negative acknowledgement NACK counter value and the no HARQ-ACK counter value.

6. The method according to any one of claims 1 to 5, characterized in that If at least one of the following conditions is satisfied: the ACK counter value is greater than the negative acknowledgment NACK counter value, the ACK counter value is greater than the no HARQ-ACK counter value, or the ACK counter value is equal to or greater than a second value, the contention window value of each access priority CAPC level is set to a minimum value, wherein the second value is predefined or configured.

7. The method according to any one of claims 1 to 6, characterized in that If the ACK counter value and the negative acknowledgement NACK counter value are the same, the contention window value of each access priority CAPC level remains unchanged.

8. The method according to claim 7, characterized in that The ACK counter value and the NACK counter value are both equal to 0.

9. The method according to claim 7 or 8, characterized in that: If the ACK counter value, the NACK counter value and the no HARQ-ACK counter value are the same, the contention window value of each access priority CAPC level remains unchanged.

10. The method according to any one of claims 1 to 8, characterized in that If the No HARQ-ACK counter value is greater than the ACK counter value and the Negative Acknowledgement NACK counter value, the contention window value for each access priority CAPC level remains unchanged.

11. The method according to any one of claims 1 to 10, characterized in that If the ratio of the no HARQ-ACK counter value to the total HARQ-ACK feedback number is equal to or greater than a third value, the contention window value of each access priority CAPC level remains unchanged, wherein the third value is predefined or configured.

12. The method according to any one of claims 1 to 11, characterized in that If the negative acknowledgement NACK counter value is equal to or greater than 1, the contention window value of each access priority CAPC level is increased to the allowed value.

13. The method according to any one of claims 1 to 12, characterized in that If the ratio of the negative acknowledgement NACK counter value to the total HARQ-ACK feedback number is greater than a fourth value, the contention window value of each access priority CAPC level is increased to an allowed value, wherein the fourth value is predefined or configured.

14. The method according to any one of claims 1 to 13, characterized in that If at least one of the following conditions is met: the negative acknowledgment NACK counter value is greater than the ACK counter value, the NACK counter value is greater than the no HARQ-ACK counter value, the NACK counter value is equal to or greater than the fifth value, or the ratio of the NACK counter value to the total HARQ-ACK feedback number is equal to or greater than the sixth value, the contention window value of each access priority CAPC level is increased to the allowed value, wherein the fifth value and the sixth value are predefined or configured.

15. The method according to any one of claims 12 to 14, characterized in that The allowed value is the next higher value of the maintained value for each CAPC level, and the maintained value is the value for each CAPC level at which the contention window value remains unchanged.

16. The method according to any one of claims 2 to 15, characterized in that At least one of the ACK counter, the NACK counter, or the no HARQ-ACK counter is based on a per-feedback count and / or a per-PSSCH / per-timeslot count.

17. The method according to claim 16, characterized in that The no HARQ-ACK counter is incremented by 1 in both the per-feedback count and the per-PSSCH / per-timeslot count when at least one of the following occurs in at least one PSSCH transmission and / or at least one physical sidelink control channel PSCCH transmission within the reference duration: The SL resource pool used for the at least one PSSCH transmission and / or the at least one PSCCH transmission is not configured with a physical sidelink feedback channel PSFCH resource; disabling a HARQ feedback enable / disable indication field in second stage sidelink control information SCI carried on the at least one PSSCH transmission; The UE fails to perform a channel access procedure when transmitting the at least one HARQ-ACK feedback in at least one PSFCH transmission.

18. The method according to claim 16 or 17, characterized in that For the per PSSCH / per timeslot count, if the ACK counter value and the NACK counter value of the at least one PSSCH transmission and / or the at least one PSCCH transmission within the reference duration are the same, then no HARQ-ACK counter value is increased.

19. The method according to any one of claims 16 to 18, characterized in that The ACK counter is incremented by 1 when at least one of the following conditions occurs in at least one PSSCH transmission within the reference duration: In the per-feedback count and the per-PSSCH / per-slot count, if the at least one HARQ-ACK feedback includes an ACK for a unicast transmission; In a per-feedback count for a multicast transmission, if the at least one HARQ-ACK feedback includes an ACK; In the per PSSCH / per timeslot count for multicast transmission, if the at least one HARQ-ACK feedback includes more ACK responses than NACK responses.

20. The method according to any one of claims 16 to 19, characterized in that The NACK counter is incremented by 1 when at least one of the following conditions occurs in at least one PSSCH transmission within the reference duration: In the per-feedback count and per-PSSCH / per-slot count for unicast transmission and multicast transmission with NACK feedback only, if the at least one HARQ-ACK feedback includes a NACK; In a per-feedback count for a multicast transmission, if the at least one HARQ-ACK feedback includes a NACK; In the per PSSCH / per timeslot count for multicast transmission, if the at least one HARQ-ACK feedback includes more NACK responses than ACK responses.

21. A user equipment UE, characterized in that: The UE includes: a transmitter configured to send at least one physical sidelink shared channel, PSSCH, transmission within a reference duration of a most recent channel occupancy initiated using a type 1 channel access procedure; An executor is configured to perform a contention window adjustment operation based on at least one hybrid automatic repeat request acknowledgement HARQ-ACK feedback corresponding to the at least one PSSCH transmission.

22. A user equipment UE, characterized in that: The UE includes: Memory; Transceiver; a processor coupled to the memory and the transceiver; The UE is configured to perform the method as described in any one of claims 1 to 20.

23. A non-transitory machine-readable storage medium, characterized in that The non-transitory machine-readable storage medium stores instructions, and when the instructions are executed by a computer, the computer is caused to perform the method according to any one of claims 1 to 20.

24. A chip, characterized in that: The chip comprises: The processor is configured to call and run a computer program stored in the memory so as to enable a device on which the chip is mounted to perform a method as claimed in any one of claims 1 to 20.

25. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and the computer program enables a computer to execute the method according to any one of claims 1 to 20.

26. A computer program product, characterized in that The computer program product comprises a computer program, which causes a computer to execute the method according to any one of claims 1 to 20.

27. A computer program, characterized in that The computer program causes a computer to execute the method according to any one of claims 1 to 20.

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