Method for adjusting the contention window and terminal

Abstract

This application discloses a method for adjusting a contention window and a terminal, belonging to the field of communication technologies. The method for adjusting a contention window according to an embodiment of this application includes, when a terminal accesses a channel by means of Type1 channel access, adjusting a contention window size CWS based on feedback of a transmission within a first transmission or a first reference period, wherein the first transmission and / or a second transmission are included within the first reference period, and the first transmission or the second transmission includes at least one of a sidelink SL transmission based on a blind retransmission mechanism, a transmission of a channel state information CSI request or a user equipment - to - user equipment cooperation request, a physical sidelink feedback channel PSFCH or a sidelink synchronization signal block S - SSB transmission, a NACK - only groupcast transmission, an ACK / NACK based groupcast transmission, and a physical sidelink shared channel PSSCH unicast transmission.

Description

Technical Field

[0001] This application claims the priority of a Chinese patent application with an application number of 202210864261.2 and an invention title of "Method for Adjusting Contention Window and Terminal", which was filed on July 20, 2022. All the contents of this application are incorporated herein by reference.

[0002] This application belongs to the field of communication technologies, and specifically relates to a method for adjusting a contention window and a terminal.

Background Art

[0003] In future communication systems, an unlicensed band can assist in expanding the services of communication operators as a supplement to a licensed band. To maintain consistency with the deployment in a New Radio (NR) system and maximize unlicensed access based on the NR system as much as possible, the unlicensed band can operate in bands of 5 GHz, 37 GHz, and 60 GHz. Although the wide bandwidth (80 MHz or 100 MHz) of the unlicensed band can reduce the implementation complexity of a gNB (base station) and a UE (User Equipment), the unlicensed band is shared by various radio access technologies (RATs) such as Wireless Fidelity (WiFi), radar, and Long Term Evolution License Assisted Access (LTE-LAA). Therefore, to ensure that all devices can use the resources fairly, the unlicensed band must comply with regulations such as Listen Before Talk (LBT) and Maximum Channel Occupancy Time (MCOT) when in use.

[0004] In unlicensed band transmissions, when performing Contention Window Size (CWS) adjustments on sidelink (SL) transmission channels, it is necessary to determine the corresponding reference duration. However, for characteristics of SLs such as blind retransmissions, PSFCH transmissions, and groupcast transmissions in SLs, which may or may not have feedback, there are currently no regulations or methods in the relevant technologies related to CWS adjustments. [Overview of the project] [Problems that the invention aims to solve]

[0005] The embodiments of this application provide a method and terminal for adjusting the contention window that can solve the problem of CWS adjustment for SL transmission on an unlicensed band. [Means for solving the problem]

[0006] In the first aspect, a method for adjusting the contention window applied to a terminal, When a terminal accesses a channel via Type 1 channel access, the process includes the step of adjusting the contention window size CWS based on feedback from a first transmission or a transmission within a first reference period. The first reference period includes the first transmission and / or the second transmission, The first transmission or the second transmission is blood Channel status information CSI request or user device inter-device cooperation request Inter-UE coordination request transmission, Physical sidelink feedback channel PSFCH or sidelink synchronous signal block S-SSB transmission, Negative responses only NACK-only Provide feedbackGroupcast transmission and ACK / NACK based groupcast transmission to We will provide a method that includes at least one of ours.

[0008] The 2 In this aspect, the system includes a processor and memory, the memory storing a program or command that can be executed by the processor, and when the program or command is executed by the processor, the first aspect is described below. Adjusting the contention window Provide a terminal that implements the steps of the method. [Effects of the Invention]

[0013] In the embodiments of this application, when a terminal accesses a channel via Type 1 channel access, a new reference duration is defined for transmissions on the unlicensed band that have no feedback or have special feedback, such as blind retransmissions, unicast, and groupcast transmissions of SLs, and by adjusting the CWS based on the feedback of the first transmission or transmissions within the first reference duration, the SL UE can reasonably adjust the CWS when accessing channels on the unlicensed band, thereby avoiding transmission collisions and improving transmission efficiency. [Brief explanation of the drawing]

[0014] [Figure 1] This is a block diagram of a wireless communication system to which the embodiments of this application can be applied. [Figure 2] This is a schematic flowchart of a method for adjusting a contention window provided by an embodiment of this application. [Figure 3] This is one schematic diagram of the transmission provided by the embodiment of this application. [Figure 4] This is a schematic diagram of the transmission provided by the embodiment of this application, part two. [Figure 5] This is the third schematic diagram of the transmission provided by the embodiment of this application. [Figure 6] This is the fourth schematic diagram of the transmission provided by the embodiment of this application. [Figure 7] This is the fifth schematic diagram of the transmission provided by the embodiment of this application. [Figure 8] This is the sixth schematic diagram of the transmission provided by the embodiment of this application. [Figure 9] This is a schematic diagram of the structure of a contention window adjustment device provided by an embodiment of this application. [Figure 10] This is a schematic diagram of the structure of a communication device provided by the embodiment of this application. [Figure 11] This is a schematic diagram of the hardware structure of a terminal that implements the embodiment of this application. [Modes for carrying out the invention]

[0015] In the following, the technical solutions in the embodiments of this application will be clearly described with reference to the accompanying drawings of the embodiments of this application. Naturally, the embodiments described are only a part of the embodiments of this application, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application shall all fall within the scope of protection of this application.

[0016] In the specification and claims of this application, terms such as “first,” “second,” etc., are used to distinguish similar subjects and not to indicate a specific order or sequence. It should be understood that, in order to allow the embodiments of this application to be carried out in any order other than that illustrated or described herein, the terms used in this manner are, in some cases, interchangeable, and that subjects distinguished by “first,” “second,” etc., are generally of the same kind and do not limit the number of subjects; for example, the first subject may be one or more. Furthermore, “and” in the specification and claims indicates at least one of the connected subjects, and the symbol “ / ” generally indicates that the preceding and following related subjects are in an “or” relationship.

[0017] It should be noted that the technology described in the embodiments of this application is not limited to the Long Term Evolution (LTE) / LTE-Advanced (LTE-A) system, and may also be used in other wireless communication systems, such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single-Carrier Frequency-Division Multiple Access (SC-FDMA), and other systems. The terms "system" and "network" in the embodiments of this application are always used interchangeably. The described technology may be used in the systems and wireless technologies mentioned above, and may also be used in other systems and wireless technologies. In the following description, for illustrative purposes, the New Radio (NR) system is described and the NR terms are used in most of the following descriptions, but these technologies are also applicable beyond the NR system, for example, to the 6th Generation (6 th Generation, 6G) communication system.

[0018] Figure 1 shows a block diagram of a wireless communication system to which the embodiments of this application can be applied. The wireless communication system includes a terminal 11 and a network-side device 12. Terminal 11 may be a mobile phone, tablet personal computer, laptop computer (also called notebook computer), personal digital assistant (PDA), palmtop computer, netbook, ultra-mobile personal computer (UMPC), mobile internet device (MID), augmented reality (AR) / virtual reality (VR) equipment, robot, wearable device, in-vehicle equipment (VUE), pedestrian equipment (PUE), smart home (home appliances with wireless communication capabilities, such as refrigerators, televisions, washing machines or furniture), game console, personal computer (PC), ATM or kiosk terminal, and other terminal-side equipment. Wearable devices include smartwatches, smart bracelets, smart earphones, smart glasses, smart accessories (smart bracelets, smart hand chains, smart rings, smart necklaces, smart ankle bracelets, smart anklets, etc.), smart bands, smart clothing, etc. The embodiments of this application do not limit the specific type of terminal 11. The network-side equipment 12 may include access network equipment or core network equipment, and the access network equipment 12 may also be called wireless access network equipment, radio access network (RAN), wireless access network function, or wireless access network unit.The access network equipment 12 may include a base station, a WLAN access point, or a WiFi node, and the base station may also be called a node B, an evolved node B (eNB), an access point, a base transceiver station (BTS), a radio base station, a radio transceiver, a basic service set (BSS), an extended service set (ESS), a home B node, a home evolved B node, a transmitting and receiving point (TRP), or any other appropriate term in the art, and the base station is not limited to any particular technical term as long as similar technical effects are achieved. In the embodiments of this application, only a base station in an NR system is described as an example, but the specific type of base station is not limited.The core network device may include at least one of the following, but is not limited thereto: core network node, core network function, Mobility Management Entity (MME), Access and Mobility Management Function (AMF), Session Management Function (SMF), User Plane Function (UPF), Policy Control Function (PCF), Policy and Charging Rules Function (PCRF) unit, Edge Application Server Discovery Function (EASDF), Unified Data Management (UDM), Unified Data Repository (UDR), Home Subscriber Server (HSS), Centralized network configuration (CNC), Network Repository Function (NRF), Network Exposure Function (NEF), Local NEF (or L-NEF), Binding Support Function (BSF), Application Function (AF). In the embodiments of this application, only the core network device in the NR system is taken as an example for description, but the specific type of the core network device is not limited.

[0019] First, the related content according to this application will be described below.

[0020] I. Unlicensed Band When a transmission node needs to perform LBT before transmitting information, it performs energy detection (ED) on surrounding nodes. If the detected power is below a certain threshold, the channel is considered idle and the transmission node can transmit. Otherwise, the channel is considered busy and the transmission node cannot transmit. A transmission node may be a base station, UE, WiFi AP, etc. The transmission node's channel occupancy time (COT) after the start of transmission must not exceed the maximum channel occupancy time (MCOT). Furthermore, according to the occupied channel bandwidth (OCB) regulation, in the unlicensed band, a transmission node must occupy at least 70% (60GHz) or 80% (5GHz) of the total bandwidth for each transmission. In NR-based unlicensed band access (NRU) technology, commonly used LBT types are classified into Type 1, Type 2A, Type 2B, and Type 2C. Type 1 LBT is a back-off based channel listening mechanism, where the transmission node performs a back-off when it hears that the channel is busy and continues listening until it hears that the channel is idle. Type 2C is a type where the transmission node does not perform LBT, i.e., no LBT or immediate transmission. Type 2A and Type 2B LBT are one-shot LBTs, meaning the node performs an LBT once before transmission, transmitting if the channel is idle and not transmitting if the channel is busy. The difference between Type 2A LBT and Type 2B LBT is that Type 2A is suitable when LBT is performed within 25us and the gap between two transmissions is 25us or more when COT is shared, while Type 2B is suitable when LBT is performed within 16us and the gap between two transmissions is 16us when COT is shared. Furthermore, Type 2 LBT is suitable for LAA / eLAA / FeLAA, and eNB and UE may use Type 2 LBT when the gap between two transmissions is 25us or more when COT is shared. In addition, in frequency range 2-2, there are three types of LBT: Type 1, Type 2, and Type 3. Type 1 is a backoff-based channel listening mechanism, Type 2 is a one-shot LBT that performs LBT for 5us within 8us, and Type 3 does not perform LBT. A downlink (DL) or uplink (UL) transmission burst is a set of transmissions transmitted from a base station or UE with a gap of 16us or less. Within the same DL / UL transmission burst, the base station or UE may transmit directly without LBT after the gap. If the gap between transmissions exceeds 16us, they may be considered separate DL / UL transmission bursts.

[0021] 2. CWS adjustment When a UE accesses a channel via Type 1 channel access, it can adjust the CWS based on Hybrid Automatic Repeat Request (HARQ) / acknowledgement (ACK) of data transmitted within the reference duration. If there is new HARQ feedback, the CWS is adjusted using the feedback from the most recent COT. If the HARQ feedback is ACK, CW is set to CWmin. If the HARQ feedback is Non-ACKnowledgement (NACK), CW is set to min(CW×2+1, CWmax). Otherwise, CW is maintained unchanged. The Reference Duration is the channel occupancy time from the start of the COT to the first slot containing at least one Physical Uplink Shared Channel (PUSCH) that has completed transmission on all allocated resources, or the channel occupancy time from the start of the COT to the first transmission burst containing a PUSCH that has completed transmission on all allocated resources.

[0022] Three, SL Sidelink (SL) transmission is data transmission between user equipment (UEs) directly at the physical layer. LTE sidelink is broadcast-based and can support basic vehicle-to-everything (V2X) secure communication, but it cannot be applied to other higher-level V2X services. 5G NR systems can support a more comprehensive range of service types by supporting more advanced sidelink transmission designs such as unicast, multicast, or groupcast. An Automatic Gain Control (AGC) symbol is required before each SL transmission, and a gap symbol is required after each SL transmission. The AGC symbol is typically a repeating transmission of the following symbol, such as a Physical Sidelink Control Channel (PSCCH), Physical Sidelink Shared Channel (PSSCH), or Physical Sidelink Feedback Channel (PSFCH). The SL UE can only initiate PSCCH / PSSCH or PSFCH transmission at a fixed position within the slot.

[0023] The following describes in detail, with reference to the attached drawings, the method for adjusting the contention window and the terminals provided by the embodiments of this application, through several embodiments and their application scenarios.

[0024] Figure 2 is a schematic flowchart of the contention window adjustment method provided by the embodiment of the present application, and as shown in Figure 2, the contention window adjustment method provided by the embodiment of the present application is When a terminal accesses a channel via Type 1 channel access, the process includes step 200 of adjusting the contention window size CWS based on feedback from a first transmission or a transmission within a first reference period. The first reference period includes the first transmission and / or the second transmission, The first transmission or the second transmission is Sidelink SL transmission based on a blind retransmission mechanism, Sending a Channel State Information (CSI) request or an Inter-UE coordination request, Physical Sidelink Feedback Channel (PSFCH) or Sidelink Synchronization Signal and PBCH block (S-SSB) transmission, Groupcast transmission that only provides NACK-only feedback for negative responses, Affirmative / negative response-based ACK / NACK-based group cast transmission, It includes at least one of the following: unicast, physical sidelink shared channel (PSSCH) transmission.

[0025] This application provides a method for adjusting the CWS when there are transmissions in the unlicensed band that have no feedback or have special feedback, such as blind retransmissions of SLs or groupcasts, and when PSSCH unicast transmissions are present in the unlicensed band, so that SL terminals can rationally adjust the CWS when accessing channels in the unlicensed band, thereby avoiding transmission collisions and improving transmission efficiency.

[0026] It should be understood that the groupcast transmissions in this application refer to groupcast PSSCH transmissions, i.e., NACK-only groupcast PSSCH transmissions and ACK / NACK-based groupcast PSSCH transmissions.

[0027] Optionally, if the first transmission is a sidelink SL transmission based on a blind retransmission mechanism, the CWS is adjusted based on feedback from the first transmission or transmissions within the first reference period.

[0028] Optionally, if the first transmission is a channel status information CSI request or an Inter-UE coordination request, the CWS is adjusted based on the first transmission.

[0029] Optionally, if the first transmission is a physical sidelink feedback channel (PSFCH) or a sidelink synchronization signal block (S-SSB) transmission, the CWS is adjusted based on the first transmission.

[0030] Optionally, if the first transmission is a NACK-only groupcast transmission, the CWS is adjusted based on feedback from the first transmission or transmissions within the first reference period.

[0031] Optionally, if the first transmission is an ACK / NACK based groupcast transmission, adjust the CWS based on feedback from transmissions within the first reference period.

[0032] Optionally, if the first transmission is a unicast PSSCH transmission, adjust the CWS based on feedback from transmissions within the first reference period.

[0033] The optional step of adjusting the CWS based on feedback from a transmission within a first reference period includes the step of adjusting the CWS based on feedback from a second transmission, wherein the second transmission is later than the first transmission and the first transmission is of a different type than the second transmission.

[0034] Optionally, the first reference period is: The period from the starting position of the first COT to the first position, The period from the starting position of the first COT to the second position, The period from the starting position of the first COT to the position where the first position and the second position end earliest, The period of the first transmission burst within the first COT, which includes the first transmission or the second transmission, Including at least one of the first COTs, The first position is the end position of the first slot in which at least one of the first or second transmissions has been completed on all allocated resources, and the second position is the end position of the first transmission burst in which the first or second transmission has been completed on all allocated resources. The first COT is the COT before accessing the channel via Type 1 channel access; that is, the first COT may be understood as a past COT. Furthermore, based on the definition of the first reference period, it can be determined that the first transmission and the second transmission are within the first COT.

[0035] In some selective embodiments, the second transmission occurs after the first transmission, and the first transmission is of a different type than the second transmission. For example, sidelink SL transmission based on a blind retransmission mechanism, channel state information request or user-device collaboration request transmission, physical sidelink feedback channel or sidelink synchronization signal block transmission, NACK-only groupcast transmission, ACK / NACK based groupcast transmission, and unicast physical sidelink shared channel transmission each correspond to one transmission type.

[0036] In some selective embodiments, the first transmission is performed from the starting position of the first COT.

[0037] If the first transmission is a sidelink SL transmission based on a blind retransmission mechanism, the step of adjusting the contention window size CWS based on feedback of the first transmission or transmissions within the first reference period includes at least one of the following a), b), and c):

[0038] a) Maintain the CWS without making any changes. In one embodiment, for COTs whose starting position includes SL transmission based on a blind retransmission mechanism, the reference duration is not defined, i.e., the CWS is maintained without changing it.

[0039] In one embodiment, a reference duration including SL transmission based on a blind retransmission mechanism is treated as an invalid reference duration, and the CWS is not adjusted based on feedback from this reference duration.

[0040] b) Each retransmission is treated as a NACK, and the completion of all retransmissions is treated as an ACK. The CWS is then sequentially adjusted according to the adjustment rules corresponding to the ACK and NACK, respectively. The step of sequentially adjusting the CWS according to the adjustment regulations corresponding to ACK and NACK, respectively, is optional. In each retransmission, there is a step to adjust CWS to min(CW×2+1,CWmax), After all retransmissions are complete, the step includes at least one of the following: adjusting CWS to CWmin, CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0041] If HARQ-ACK feedback is received after the last CWS update and there is at least one ACK in the HARQ-ACK corresponding to PSSCH within the reference duration of the most recent COT, adjust CWS to CWmin; otherwise, adjust CWS to min(CW×2+1,CWmax).

[0042] Furthermore, for the Nth retransmission, the CWS is adjusted based on the CWS from the N-1th retransmission.

[0043] c) If the second transmission includes an ACK / NACK based groupcast transmission or a physical sidelink shared channel PSSCH unicast transmission, the CWS is adjusted based on feedback from the transmission within the first reference period.

[0044] If the first transmission is an SL transmission based on a blind retransmission mechanism, it should be understood that the Reference duration is defined as the period encompassing both the first and second transmissions, or the period encompassing only the second transmission. In other words, Defined as the period from the start position of the first COT to the end position of the first SL transmission or transmission burst based on the HARQ retransmission mechanism that has completed transmission on all allocated resources, i.e., the first reference period includes the first transmission and the second transmission, or Defined as the length of the first SL transmission or SL transmission burst based on the first HARQ retransmission mechanism that has completed transmission on all allocated resources, i.e., the first reference period includes the second transmission.

[0045] By defining the above Reference duration, the defined Reference duration will include at least one SL transmission based on a HARQ retransmission mechanism.

[0046] The SL transmission based on the HARQ retransmission mechanism may be unicast and / or groupcast transmission.

[0047] Optionally, unicast transmission is unicast PSSCH transmission.

[0048] Optionally, groupcast transmission is ACK / NACK based groupcast transmission.

[0049] If the first reference period includes a second transmission, and the second transmission is an ACK / NACK based groupcast transmission or a unicast PSSCH transmission, it should be understood that the CWS will be adjusted based on the feedback from the transmissions within the first reference period.

[0050] If the second transmission is an ACK / NACK based groupcast transmission, the step of adjusting the CWS based on feedback from the transmission within the first reference period is: Steps include adjusting the CWS based on the received ACK and / or NACK, The process includes at least one of the following steps: adjusting the CWS based on feedback of all ACKs and / or NACKs from one transmission block TB.

[0051] The optional step of adjusting the CWS based on the received ACK and / or NACK is: If the number of received ACKs exceeds X, the CWS is adjusted to CWmin. If the received NACK exceeds Y, the CWS is adjusted to min(CW×2+1,CWmax), The process includes at least one of the following steps: if the received ACK or NACK is Z1 to Z2, maintain the CWS without changing it. X, Y, Z1, and Z2 are all numbers between 0 and 1 (exclusive of 0), or X, Y, Z1, and Z2 are all integers greater than or equal to 0. CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0052] The optional step of adjusting the CWS based on feedback of all ACKs and / or NACKs of one transmission block TB is: If all of the TB feedback is ACK, the step is to adjust CWS to CWmin, If at least one of the TB feedbacks is NACK, the step is to adjust CWS to min(CW×2+1,CWmax), The process includes at least one of the following steps: if the total number of received ACKs is less than the number of receiving terminals, adjust CWS to min(CW×2+1,CWmax); CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0053] If the second transmission is a unicast PSSCH transmission, the step of adjusting the CWS based on feedback from the transmission within the first reference period is: If HARQ-ACK feedback is received after the last update of CWS, and at least one ACK exists in the HARQ-ACK within the most recent COT reference period, the step is to adjust CWS to CWmin. If HARQ-ACK feedback is received after the last CWS update, and no ACKs exist in the HARQ-ACK within the most recent COT reference period, the CWS is adjusted to min(CW×2+1,CWmax). If no HARQ-ACK feedback has been received since the last update of the CWS, and the terminal transmission does not include a retransmission, or the terminal transmission is within Tw hours after the earliest COT reference period since the last update of the CWS, the step is to maintain the CWS unchanged. The procedure includes at least one of the following steps: if no HARQ-ACK feedback is received after the last update of the CWS, and the terminal transmission includes a retransmission, and the terminal transmission is not within Tw hours after the earliest COT reference period after the last update of the CWS, then adjust the CWS to min(CW×2+1,CWmax); Tw = max(Xms, length of transmission burst starting from the reference period of the earliest COT + 1ms), where X = 5 or 10, CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window. Transmission at the terminal is unicast PSSCH transmission.

[0054] The previous CWS update refers to the CWS adjustment immediately preceding the current Type 1 channel access.

[0055] The following describes, with specific examples, how to adjust the CWS when the first transmission is a sidelink SL transmission based on a blind retransmission mechanism.

[0056] Figure 3 is a schematic diagram of a transmission provided by an embodiment of the present application. As shown in Figure 3, the Tx UE performs a blind retransmission within COT1, which includes one initial transmission and three retransmissions, and then performs a PSSCH transmission based on HARQ feedback retransmission. When the Tx UE obtains a new COT by performing a Type 1 LBT in slot 7, it needs to adjust the CWS based on the feedback of the transmission within COT1. The Reference duration can be determined according to the prior art and may be, for example, slot 0. In the blind retransmission mechanism, there is no HARQ feedback, so there is no feedback regarding SL transmissions within the reference duration, and this reference duration may be an invalid reference duration. Alternatively, in this case, the reference duration is not defined. That is, if the previous COT includes SL transmissions based on blind retransmissions, the CWS is maintained unchanged.

[0057] Furthermore, in the above-described case, a new reference duration may be defined such that the reference duration includes at least one PSSCH based on HARQ feedback retransmission, as shown in Figures 4 and 5. Figure 4 is a schematic diagram of the transmission provided by an embodiment of the present application, part two. Figure 5 is a schematic diagram of the transmission provided by an embodiment of the present application, part three.

[0058] In Figure 4, the reference duration still starts from the beginning position of COT1, and the end position is the end position of the PSSCH transmission, i.e., the end position of slot 4.

[0059] In Figure 5, all SL transmissions based on blind retransmission are excluded from the reference duration, and the start position of the reference duration is the start position of the PSSCH based on HARQ feedback retransmission, i.e., the start position of slot 4. The PSSCH based on HARQ feedback retransmission may be a unicast transmission. For cases where the PSSCH based on HARQ feedback retransmission is a groupcast transmission, refer to the embodiment of CWS adjustment corresponding to NACK-only groupcast transmission in this application and the embodiment of CWS adjustment corresponding to ACK / NACK based groupcast transmission described later.

[0060] Alternatively, CWS may be adjusted sequentially based on SL transmissions based on all blind retransmissions within COT1. During the initial transmission, CWS is maintained unchanged. For the first retransmission, CWS is adjusted to min(CW×2+1,CWmax). For the second retransmission, CWS is adjusted to min(CW×2+1,CWmax) based on the previous adjustments. This process is repeated by analogy. Once all retransmissions are complete, CWS is adjusted to CWmin. In other words, if all blind retransmissions can be completed within COT1, Tx UE can adjust CWS to CWmin in slot7. If all blind retransmissions cannot be completed within COT1, Tx UE adjusts CWS in slot7 according to the number of blind retransmissions performed.

[0061] The above-mentioned blind retransmission mechanism includes initial transmission and retransmission. In SL, blind retransmission refers to transmissions where the higher layer (MAC) instructs that HARQ feedback transmitted via TB be disabled, transmissions performed within a resource pool where a PSFCH is not deployed, or transmissions where the SCI (Sidelink Control Information) scheduling the PSFCH transmission instructs that HARQ feedback should not be performed.

[0062] Embodiments of this application provide a method for adjusting the CWS based on feedback of the first transmission or transmission within a first reference period when a terminal accesses a channel by Type 1 channel access and the first transmission is a sidelink SL transmission based on a blind retransmission mechanism. According to this method, the SL UE can rationally adjust the CWS when accessing an unlicensed band channel, thereby avoiding transmission collisions and improving transmission efficiency.

[0063] If the first transmission is optionally a channel status information CSI request or an Inter-UE coordination request transmission, the step of adjusting the contention window size CWS based on the first transmission is: When a corresponding channel status information report (CSI report) or user-device collaboration information (Inter-UE coordination information) is received, the default setting is ACK, and the CWS is adjusted to CWmin. If a CSI report or Inter-UE coordination information is not received within the CSI feedback window, the CWS is maintained without modification. If a CSI report is not received after the CSI feedback time delay has been exceeded or the CSI feedback window has timed out, the procedure includes at least one of the following steps: adjusting the CWS to min(CW×2+1,CWmax), CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0064] In this case, although the first transmission falls within the first reference period, it is not necessary to refer to the feedback of the first transmission. Instead, the CWS is adjusted based on whether or not the corresponding response information, i.e., the CSI report or Inter-UE coordination information, has been received after the first transmission.

[0065] If the first transmission is optionally a physical sidelink feedback channel PSFCH or a sidelink synchronization signal block S-SSB transmission, the step of adjusting the contention window size CWS based on the first transmission is: This includes a step to either maintain the CWS without changing it or to always maintain the CWS at CWmin, where CWmin is the minimum value of the contention window.

[0066] In this case, the first transmission is included within the first reference period, and the CWS is directly adjusted depending on the type of the first transmission, i.e., whether it is PSFCH or S-SSB.

[0067] If the first transmission is optionally a NACK-only groupcast transmission, the step of adjusting the contention window size CWS based on feedback from the first transmission or transmissions within the first reference period includes at least one of the following a), b), c), and d):

[0068] a) Maintain the CWS without making any changes. If the first transmission is a NACK-only groupcast transmission, either do not define a reference duration, or make the reference duration that includes the NACK-only groupcast transmission an invalid reference duration, i.e., maintain the CWS without changing it.

[0069] b) Adjust CWS based on the received NACK feedback. In other words, the terminal adjusts the CWS based on the NACK of the data transmitted within the reference duration.

[0070] The optional step of adjusting the CWS based on the received NACK feedback is: When NACK is received, the CWS is adjusted to min(CW×2+1,CWmax), If no feedback is received for a NACK-only groupcast transmission, the CWS must be maintained unchanged, and this includes at least one of the following steps: CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0071] In this case, the first transmission is included within the first reference period.

[0072] c) If the second transmission includes ACK / NACK based groupcast transmission and / or physical sidelink shared channel PSSCH unicast transmission, adjust the contention window size CWS based on feedback of the transmission within the first reference period.

[0073] If the first transmission is a NACK-only groupcast transmission, the Reference duration is defined as follows: Defined as the period from the start of the COT to the end of the first unicast SL transmission (burst) that has completed transmission across all allocated resources, i.e., the first reference period includes both the first and second transmissions, or Defined as the period from the start of the COT to the end of the first ACK / NACK based groupcast-based SL transmission (burst) that successfully transmitted across all allocated resources; that is, the first and second transmissions are included within the first reference period, or Defined as the length of the first unicast SL transmission (burst) completed across all allocated resources, i.e., the second transmission is included within the first reference period.

[0074] By defining the above Reference duration, the defined Reference duration will include at least one unicast SL transmission or an ACK / NACK based groupcast SL transmission.

[0075] If the second transmission includes an ACK / NACK based groupcast transmission, the step of adjusting the contention window size CWS based on feedback of the transmission within the first reference period is: Steps include adjusting the CWS based on the received ACK and / or NACK, The process includes at least one of the following steps: adjusting the CWS based on feedback of all ACKs and / or NACKs from one transmission block TB.

[0076] The optional step of adjusting the CWS based on the received ACK and / or NACK is: If the number of received ACKs exceeds X, the CWS is adjusted to CWmin. If the received NACK exceeds Y, the CWS is adjusted to min(CW×2+1,CWmax), The process includes at least one of the following steps: if the received ACK or NACK is Z1 to Z2, maintain the CWS without changing it. X, Y, Z1, and Z2 are all numbers between 0 and 1 (exclusive of 0), or X, Y, Z1, and Z2 are all integers greater than or equal to 0. CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0077] The optional step of adjusting the CWS based on feedback of all ACKs and / or NACKs of one transmission block TB is: If all of the TB feedback is ACK, the step is to adjust CWS to CWmin, If at least one of the TB feedbacks is NACK, the step is to adjust CWS to min(CW×2+1,CWmax), The process includes at least one of the following steps: if the total number of received ACKs is less than the number of receiving terminals, adjust CWS to min(CW×2+1,CWmax); CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0078] If the second transmission includes a unicast PSSCH transmission, the step of adjusting the contention window size CWS based on feedback of the transmission within the first reference period is: If HARQ-ACK feedback is received after the last update of CWS, and at least one ACK exists in the HARQ-ACK within the most recent COT reference period, the step is to adjust CWS to CWmin. If HARQ-ACK feedback is received after the last CWS update, and no ACKs exist in the HARQ-ACK within the most recent COT reference period, the CWS is adjusted to min(CW×2+1,CWmax). If no HARQ-ACK feedback has been received since the last update of the CWS, and the terminal transmission does not include a retransmission, or the terminal transmission is within Tw hours after the earliest COT reference period since the last update of the CWS, the step is to maintain the CWS unchanged. The procedure includes at least one of the following steps: if no HARQ-ACK feedback is received after the last update of the CWS, and the terminal transmission includes a retransmission, and the terminal transmission is not within Tw hours after the earliest COT reference period after the last update of the CWS, then adjust the CWS to min(CW×2+1,CWmax); Tw = max(Xms, length of transmission burst starting from the reference period of the earliest COT + 1ms), where X = 5 or 10, CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0079] The previous CWS update refers to the CWS adjustment immediately preceding the current Type 1 channel access.

[0080] d) Adjust the CWS based on the received ACK and / or NACK, the ACK being transmitted by a different PSFCH resource than the NACK.

[0081] In this embodiment, transmission resources are allocated for ACK and NACK feedback, respectively; that is, ACK is transmitted by a different PSFCH resource than NACK. For example, all Rx UEs feed back ACK on one PSFCH resource, and all Rx UEs feed back NACK on another PSFCH resource, and the terminal adjusts the CWS based on the received ACK and / or NACK.

[0082] Optionally, the step of adjusting the CWS based on the received ACK and / or NACK is: If an ACK is received but a NACK is not, the step is to adjust CWS to CWmin, If NACK is received but ACK is not received, the CWS is adjusted to min(CW×2+1,CWmax), If both ACK and NACK are received, the steps are to either maintain the CWS without changing it or adjust the CWS to min(CW×2+1,CWmax), If no feedback is received, include at least one of the following steps: maintain CWS as is. CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0083] The following explains, with specific examples, how to adjust CWS when the first transmission is a NACK-only groupcast transmission.

[0084] Figure 6 is a schematic diagram of the transmission provided by an embodiment of the present application, number four. As shown in Figure 6, the Tx UE transmits a NACK-only groupcast PSSCH and a unicast PSSCH into COT1, respectively. When the UE performs a Type 1 LBT in slot 7 to reacquire the channel, it needs to adjust the CWS based on the feedback of the PSSCH transmitted within the reference duration. In one embodiment, a reference duration containing only a NACK-only groupcast PSSCH is made an invalid reference duration, or in this case, no reference duration is defined and the CWS is maintained unchanged.

[0085] In another embodiment, a new reference duration may be defined, as shown in Figures 7 and 8. Figure 7 is a schematic diagram (number five) of the transmission provided by an embodiment of the present application, and Figure 8 is a schematic diagram (number six) of the transmission provided by an embodiment of the present application. The new reference duration includes at least one unicast PSSCH transmission. The start position of the reference duration may be the start position of COT1, or it may be the start position of the first unicast PSSCH that has completed transmission on all allocated resources. The end position of the reference duration is the end position of the first unicast PSSCH that has completed transmission on all allocated resources.

[0086] Embodiments of this application provide a method for adjusting the CWS based on feedback of the first transmission or transmissions within a first reference period when a terminal accesses a channel by Type 1 channel access and the first transmission is a NACK-only groupcast transmission. According to this method, the SL UE can rationally adjust the CWS when accessing an unlicensed band channel, thereby avoiding transmission collisions and improving transmission efficiency.

[0087] If the first or second transmission is an ACK / NACK based groupcast transmission, the step of adjusting the contention window size CWS based on feedback of transmissions within the first reference period includes at least one of a) and b) below.

[0088] a) Adjust the CWS based on the received ACK and / or NACK.

[0089] The optional step of adjusting the CWS based on the received ACK and / or NACK is: If the number of received ACKs exceeds X, the CWS is adjusted to CWmin. If the received NACK exceeds Y, the CWS is adjusted to min(CW×2+1,CWmax), The process includes at least one of the following steps: if the received ACK or NACK is Z1 to Z2, maintain the CWS without changing it. X, Y, Z1, and Z2 are all numbers between 0 and 1 (exclusive of 0), or X, Y, Z1, and Z2 are all integers greater than or equal to 0. CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0090] For example, if a Tx UE accesses a channel via Type 1 channel access and the reference duration within the preceding COT includes an ACK / NACK based groupcast transmission, different Rx UEs will use different PSFCHs to perform HARQ feedback, and the Tx UE will receive multiple HARQ feedbacks. The Tx UE may adjust its CWS based on the proportion of HARQ feedback received. If the number of received ACKs exceeds X, adjust the CWS to CWmin. If the number of received NACKs exceeds Y, adjust the CWS to min(CW×2+1,CWmax). If the number of received ACKs or NACKs is between Z1 and Z2, maintain the CWS unchanged. Here, X, Y, Z1, and Z2 are between 1 and 0 (inclusive), and the values ​​of X, Y, and Z1 or Z2 may be the same, i.e., X=Y=Z1 / Z2. Also, the adjustment criteria X, Y, and Z1 or Z2 may be the number of received ACKs or NACKs, i.e., the values ​​of X, Y, and Z1 or Z2 are integers of 0 or greater.

[0091] b) Adjust the CWS based on the feedback of all ACKs and / or NACKs from one transmission block TB.

[0092] The optional step of adjusting the CWS based on feedback of all ACKs and / or NACKs of one transmission block TB is: If all of the TB feedback is ACK, the step is to adjust CWS to CWmin, If at least one of the TB feedbacks is NACK, the step is to adjust CWS to min(CW×2+1,CWmax), The process includes at least one of the following steps: if the total number of received ACKs is less than the number of receiving terminals, adjust CWS to min(CW×2+1,CWmax); CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0093] Embodiments of this application provide a method for adjusting the CWS based on feedback of transmissions within a first reference period when a terminal accesses a channel by Type 1 channel access and the first or second transmission is an ACK / NACK based groupcast transmission. According to this method, the SL UE can rationally adjust the CWS when accessing an unlicensed band channel, thereby avoiding transmission collisions and improving transmission efficiency.

[0094] In some selective embodiments, if the first or second transmission is a physical sidelink shared channel PSSCH unicast transmission, the step of adjusting the contention window size CWS based on feedback of the transmission within the first reference period is: If HARQ-ACK feedback is received after the last update of CWS, and at least one ACK exists in the HARQ-ACK within the most recent COT reference period, the step is to adjust CWS to CWmin. If HARQ-ACK feedback is received after the last CWS update, and no ACKs exist in the HARQ-ACK within the most recent COT reference period, the CWS is adjusted to min(CW×2+1,CWmax). If no HARQ-ACK feedback has been received since the last update of the CWS, and the terminal transmission does not include a retransmission, or the terminal transmission is within Tw hours after the earliest COT reference period since the last update of the CWS, the step is to maintain the CWS unchanged. The procedure includes at least one of the following steps: if no HARQ-ACK feedback is received after the last update of the CWS, and the terminal transmission includes a retransmission, and the terminal transmission is not within Tw hours after the earliest COT reference period after the last update of the CWS, then adjust the CWS to min(CW×2+1,CWmax); Tw = max(Xms, length of transmission burst starting from the reference period of the earliest COT + 1ms), where X = 5 or 10, CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window. "After the last CWS update" refers to the CWS adjustment immediately preceding the current Type 1 channel access. Note that if the first or second transmission is a physical sidelink shared channel PSSCH unicast transmission, the reference duration is: a) The period from the start position of the first COT to the end position of the first slot where at least one PSSCH has completed transmission across all allocated resources, or b) The period from the start of the first COT to the end of the first transmission burst, which includes PSSCH that has been transmitted on all allocated resources, or c) Defined as the period from the starting position of the first COT to the earliest ending position of a) and b), or, d) If a first COT contains a PSSCH but does not contain any PSSCH that has completed transmission on all allocated resources, the reference duration is defined as the duration of the first transmission burst in which the UE contains a PSSCH within the first COT.

[0095] If a terminal accesses a channel via Type 1 channel access and receives HARQ-ACK feedback after the last update of the CWS, a) If there is at least one ACK in the HARQ-ACK corresponding to PSSCH within the reference duration of the latest COT, adjust CWS to CWmin. b) Otherwise, adjust CWS to min(CW×2+1, CWmax).

[0096] If a terminal accesses the channel via Type 1 channel access and has not received HARQ-ACK feedback since the last update of the CWS, a) If the terminal transmission does not include retransmissions or the terminal transmission is within Tw time after the earliest COT reference period since the last update of the CWS, maintain the CWS unchanged. Tw = max(Xms, length of transmission burst starting from the reference period of the earliest COT + 1ms), where X = 5 or 10, and X = 5 if regulation cannot ensure that no other techniques exist, otherwise X = 10. b) Otherwise, adjust CWS to min(CW×2+1, CWmax).

[0097] Embodiments of this application provide a method for adjusting the CWS based on feedback of transmissions within a first reference period when a terminal accesses a channel by Type 1 channel access, and the first or second transmission is a unicast PSSCH. According to this method, the SL UE can rationally adjust the CWS when accessing an unlicensed band channel, thereby avoiding transmission collisions and improving transmission efficiency.

[0098] In each of the above embodiments, the values ​​of CW, CWmin, and CWmax are all associated with the channel access priority class CAPC; that is, CW may be CWp, and it represents the CWS value when CAPC=p. CWmin,p represents the minimum CWS value when CAPC=p, and CWmax,p represents the maximum CWS value when CAPC=p.

[0099] The method for adjusting a contention window provided by the embodiments of this application may be implemented by a contention window adjusting device. In the embodiments of this application, the contention window adjusting device provided by the embodiments of this application will be described by giving an example in which the contention window adjustment method is implemented by the contention window adjusting device.

[0100] Figure 9 is a schematic diagram of the structure of a contention window adjustment device provided by an embodiment of this application, and as shown in Figure 9, the contention window adjustment device 900 is When a terminal accesses a channel via Type 1 channel access, it includes an adjustment unit 910 for adjusting the contention window size CWS based on feedback from a first transmission or a transmission within a first reference period. The first reference period includes the first transmission and / or the second transmission, The first transmission or the second transmission is Sidelink SL transmission based on a blind retransmission mechanism, Sending a channel status information CSI request or an Inter-UE coordination request for cooperation between user devices, Physical sidelink feedback channel PSFCH or sidelink synchronous signal block S-SSB transmission, Groupcast transmission that feeds back only negative responses as NACK-only, Affirmative / negative response-based ACK / NACK-based group cast transmission, Includes at least one of the following: physical sidelink shared channel PSSCH unicast transmission.

[0101] In the embodiments of this application, when a terminal accesses a channel via Type 1 channel access, a new reference duration is defined for transmissions on the unlicensed band that have no feedback or have special feedback, such as blind retransmissions, unicast, and groupcast transmissions of SLs, and by adjusting the CWS based on the feedback of the first transmission or transmissions within the first reference duration, the SL UE can reasonably adjust the CWS when accessing channels on the unlicensed band, thereby avoiding transmission collisions and improving transmission efficiency.

[0102] Optionally, the first reference period is: The period from the start position of the first channel occupancy time (COT) to the first position, The period from the starting position of the first COT to the second position, The period from the starting position of the first COT to the position where the first position and the second position end earliest, The period of the first transmission burst within the first COT, which includes the first transmission or the second transmission, Including at least one of the first COTs, The first position is the end position of the first slot in which at least one of the first or second transmissions has been completed on all allocated resources, and the second position is the end position of the first transmission burst in which the first or second transmission has been completed on all allocated resources. The first COT mentioned above is the COT before accessing the channel via Type 1 channel access.

[0103] Optionally, the second transmission occurs after the first transmission, and the first transmission is of a different type than the second transmission.

[0104] Optionally, if the first transmission is a sidelink SL transmission based on a blind retransmission mechanism, the step of adjusting the contention window size CWS based on feedback of the first transmission or transmissions within the first reference period is: Maintaining CWS without changing it, This involves sequentially adjusting the CWS according to the adjustment rules corresponding to ACK and NACK, treating each retransmission as one NACK, and considering the completion of all retransmissions as an ACK. If the second transmission includes an ACK / NACK based groupcast transmission or a physical sidelink shared channel PSSCH unicast transmission, then the CWS includes at least one of the following: adjusting the CWS based on feedback of the transmission within the first reference period.

[0105] Embodiments of this application provide a method for adjusting the CWS based on feedback of the first transmission or transmission within a first reference period when a terminal accesses a channel by Type 1 channel access and the first transmission is a sidelink SL transmission based on a blind retransmission mechanism. According to this method, the SL UE can rationally adjust the CWS when accessing an unlicensed band channel, thereby avoiding transmission collisions and improving transmission efficiency.

[0106] If the first transmission is optionally a channel status information CSI request or an Inter-UE coordination request transmission, adjusting the contention window size CWS based on the first transmission is: When a corresponding channel status information report (CSI report) or user-device collaboration information (Inter-UE coordination information) is received, the CWS will be adjusted to CWmin. If a CSI report or Inter-UE coordination information is not received within the CSI feedback window, the CWS will be maintained without modification. If a CSI report is not received after the CSI feedback time delay has been exceeded or the CSI feedback window has timed out, the CWS will be adjusted to min(CW×2+1,CWmax), which includes at least one of the following: CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0107] If the first transmission is optionally a physical sidelink feedback channel PSFCH or a sidelink synchronous signal block S-SSB transmission, adjusting the contention window size CWS based on the first transmission is: This includes a step to either maintain the CWS without changing it or to always maintain the CWS at CWmin, where CWmin is the minimum value of the contention window.

[0108] If the first transmission is a NACK-only groupcast transmission, adjusting the contention window size CWS based on feedback from the first transmission or transmissions within the first reference period is: Maintaining CWS without changing it, Adjusting the CWS based on the received NACK feedback, If the second transmission includes ACK / NACK based groupcast transmission and / or physical sidelink shared channel PSSCH unicast transmission, the CWS is adjusted based on feedback of the transmission within the first reference period. Adjusting the CWS based on the received ACK and / or NACK, wherein the ACK is transmitted by a PSFCH resource different from the NACK, comprising at least one of these.

[0109] Embodiments of this application provide a method for adjusting the CWS based on feedback of the first transmission or transmissions within a first reference period when a terminal accesses a channel by Type 1 channel access and the first transmission is a NACK-only groupcast transmission. According to this method, the SL UE can rationally adjust the CWS when accessing an unlicensed band channel, thereby avoiding transmission collisions and improving transmission efficiency.

[0110] If the first or second transmission is an ACK / NACK based groupcast transmission, adjusting the contention window size CWS based on the feedback of the transmission within the first reference period is: Adjusting the CWS based on the received ACK and / or NACK, This includes at least one of the following: adjusting the CWS based on feedback of all ACKs and / or NACKs of a single transmission block TB.

[0111] Embodiments of this application provide a method for adjusting the CWS based on feedback of transmissions within a first reference period when a terminal accesses a channel by Type 1 channel access and the first or second transmission is an ACK / NACK based groupcast transmission. According to this method, the SL UE can rationally adjust the CWS when accessing an unlicensed band channel, thereby avoiding transmission collisions and improving transmission efficiency.

[0112] Optionally, sequentially adjusting the CWS according to the adjustment regulations corresponding to the aforementioned ACK and NACK is: For each retransmission, adjust CWS to min(CW×2+1,CWmax), After all retransmissions are complete, this includes at least one of the following: adjusting CWS to CWmin, CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0113] Optionally, adjusting the CWS based on the received NACK feedback is: If NACK is received, adjust CWS to min(CW×2+1,CWmax), If feedback is not received for NACK-only groupcast transmission, this includes at least one of the following: maintaining the CWS unchanged. CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0114] Optionally, adjusting the CWS based on the received ACK and / or NACK is: If an ACK is received but a NACK is not, adjust CWS to CWmin. If NACK is received but ACK is not received, adjust CWS to min(CW×2+1,CWmax), If both ACK and NACK are received, either maintain the CWS without changing it, or adjust the CWS to min(CW×2+1,CWmax), If no feedback is received, we will maintain CWS without making any changes, including at least one of the following: CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0115] Optionally, adjusting the CWS based on the received ACK and / or NACK is: If the number of received ACKs exceeds X, adjust CWS to CWmin, If the received NACK exceeds Y, adjust CWS to min(CW×2+1,CWmax), If the received ACK or NACK is Z1 to Z2, the CWS is maintained without change, which includes at least one of the following: X, Y, Z1, and Z2 are all numbers between 0 and 1 (exclusive of 0), or X, Y, Z1, and Z2 are all integers greater than or equal to 0. CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0116] Optionally, adjusting the CWS based on the feedback of all ACKs and / or NACKs of one of the aforementioned transmission blocks TB is: If all of the TB feedback is ACK, adjust CWS to CWmin, If at least one of the TB feedbacks is NACK, adjust CWS to min(CW×2+1,CWmax), This includes at least one of the following: if the total number of received ACKs is less than the number of receiving terminals, adjust CWS to min(CW×2+1,CWmax), CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0117] If the first or second transmission is a physical sidelink shared channel PSSCH unicast transmission, adjusting the contention window size CWS based on the feedback of the transmission within the first reference period is: If HARQ-ACK feedback is received after the last CWS update, and at least one ACK is present in the HARQ-ACK within the most recent COT reference period, adjust CWS to CWmin. If HARQ-ACK feedback is received after the last CWS update, and no ACK is present in the HARQ-ACK within the most recent COT reference period, adjust CWS to min(CW×2+1,CWmax), If no HARQ-ACK feedback is received after the last CWS update, and the terminal transmission does not include retransmissions, or the terminal transmission is within Tw hours after the earliest COT reference period after the last CWS update, the CWS should be maintained unchanged. If no HARQ-ACK feedback is received after the last update of the CWS, and the terminal transmission includes a retransmission, and the terminal transmission is not within Tw hours after the earliest COT reference period after the last update of the CWS, then adjust the CWS to min(CW×2+1,CWmax), which includes at least one of the following: Tw = max(Xms, length of transmission burst starting from the reference period of the earliest COT + 1ms), where X = 5 or 10, CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0118] Embodiments of this application provide a method for adjusting the CWS based on feedback of transmissions within a first reference period when a terminal accesses a channel by Type 1 channel access, and the first or second transmission is a unicast PSSCH. According to this method, the SL UE can rationally adjust the CWS when accessing an unlicensed band channel, thereby avoiding transmission collisions and improving transmission efficiency.

[0119] Examples of the present application Contention window adjustment device provided byThis may be an electronic device such as an electronic device equipped with an operating system, or it may be a component within an electronic device such as an integrated circuit or a chip. This electronic device may be a terminal or other device other than a terminal. Exemplaryly, a terminal may include, but is not limited to, the types of terminals 11 described above, and other devices may be servers, network attached storage (NAS), etc., and are not specifically limited by the embodiments of this application.

[0120] The contention window adjustment device provided by the embodiments of this application can implement each process realized by the embodiments of the methods shown in Figures 2 to 8 and achieve similar technical effects, and to avoid duplication, a detailed explanation is omitted here.

[0121] Optionally, as shown in Figure 10, an embodiment of this application further provides a communication device 1000 including a processor 1001 and a memory 1002, wherein the memory 1002 stores a program or command executable by the processor 1001. For example, if this communication device 1000 is a terminal, when the program or command is executed by the processor 1001, each step of the embodiment of the contention window adjustment method described above can be realized and similar technical effects can be achieved. If this communication device 1000 is a network-side device, when the program or command is executed by the processor 1001, each step of the embodiment of the contention window adjustment method described above can be realized and similar technical effects can be achieved, and to avoid redundancy, the explanation is omitted here.

[0122] Embodiments of this application further provide a terminal including a processor and a communication interface, the processor being used to adjust the contention window size CWS based on feedback of a first transmission or transmission within a first reference period when the terminal accesses a channel by Type 1 channel access, the first reference period including the first transmission and / or second transmission, the first transmission or the second transmission including at least one of a sidelink SL transmission based on a blind retransmission mechanism, a channel state information CSI request or an Inter-UE coordination request transmission between user devices, a physical sidelink feedback channel PSFCH or sidelink synchronization signal block S-SSB transmission, a NACK-only groupcast transmission, an ACK / NACK based groupcast transmission, and a physical sidelink shared channel PSSCH unicast transmission. Embodiments of this terminal correspond to embodiments of the terminal-side method described above, and each implementation process and means of embodiments of the method described above is applicable to embodiments of this terminal and can achieve similar technical effects. Specifically, Figure 11 is a schematic diagram of the hardware structure of a terminal realizing embodiments of this application.

[0123] The terminal 1100 includes, but is not limited to, some of the following components: a radio frequency unit 1101, a network module 1102, an audio output unit 1103, an input unit 1104, a sensor 1105, a display unit 1106, a user input unit 1107, an interface unit 1108, a memory 1109, and a processor 1110.

[0124] As those skilled in the art will understand, the terminal 1100 may further include a power supply (e.g., a battery) to power each component, and the power supply may be logically connected to the processor 1110 by a power management system, thereby enabling functions such as charge / discharge management and power consumption management by the power management system. The terminal structure shown in Figure 11 is not an limitation on the terminal, and the terminal may include more or fewer components than the number of components shown, or combinations of several components, or different arrangements of components, which are omitted from this explanation.

[0125] In the embodiments of this application, the input unit 1104 may include a graphics processing unit (GPU) 11041 and a microphone 11042. Graphics Processing Unit It should be understood that 11041 processes still images or video image data acquired by an image capture device (e.g., a camera) in video capture mode or image capture mode. The display unit 1106 may include a display panel 11061, which can be configured in the form of a liquid crystal display, organic light-emitting diodes, etc. The user input unit 1107 includes at least one of a touch panel 11071 and other input devices 11072. The touch panel 11071 is also called a touchscreen. The touch panel 11071 may include two parts: a touch detection device and a touch controller. Other input devices 11072 may include, but are not limited to, a physical keyboard, function keys (e.g., volume control buttons, switch buttons, etc.), a trackball, a mouse, or an operating lever, and are not described here.

[0126] In the embodiments of this application, the radio frequency unit 1101 can receive downlink data from network-side equipment and then transmit it to the processor 1110 for processing. The radio frequency unit 1101 can also transmit uplink data to network-side equipment. Typically, the radio frequency unit 1101 includes, but is not limited to, an antenna, amplifier, transceiver, coupler, low-noise amplifier, duplexer, etc.

[0127] Memory 1109 may be used to store software programs or commands and various data. Memory 1109 may include a first storage area mainly for storing programs or commands and a second storage area for storing data, the first storage area may store an operating system, an application program or command necessary for at least one function (e.g., audio playback function, image playback function, etc.). Memory 1109 may also include volatile memory or non-volatile memory, or memory 1109 may include both volatile and non-volatile memory. Non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (Erasable PROM, EPROM), electrically erasable programmable read-only memory (Electrically EPROM, EEPROM), or flash memory. The volatile memory may be random access memory (RAM), static random access memory (Static RAM, SRAM), dynamic random access memory (DRAM), synchronous random access memory (Synchronous DRAM, SDRAM), double data rate synchronous random access memory (Double Data Rate SDRAM, DDRSDRAM), enhanced synchronous random access memory (Enhanced SDRAM, ESDRAM), synchronous random access memory (Synchlink DRAM, SLDRAM), and direct Rambus random access memory (Direct Rambus RAM, DRRAM). The memory 1109 in the embodiments of this application includes, but is not limited to, these memories and any other suitable type of memory.

[0128] The processor 1110 may include one or more processing units. Optionally, the processor 1110 integrates an application processor and a modem processor. The application processor primarily handles operations related to the operating system, user interface, and application programs, while the modem processor primarily handles wireless communication signals, such as a baseband processor. It should be understood that the above-mentioned modem processor does not necessarily have to be integrated into the processor 1110.

[0129] The processor 1110 is used to adjust the contention window size CWS based on feedback of a first transmission or transmission within a first reference period when a terminal accesses a channel by Type 1 channel access, the first reference period includes the first transmission and / or a second transmission, the first transmission or the second transmission includes at least one of the following: a sidelink SL transmission based on a blind retransmission mechanism; a channel state information CSI request or an Inter-UE coordination request transmission; a physical sidelink feedback channel PSFCH or sidelink synchronization signal block S-SSB transmission; a groupcast transmission that feeds back only negative responses NACK-only; an acknowledgment / negative response based ACK / NACK groupcast transmission; and a physical sidelink shared channel PSSCH unicast transmission.

[0130] In the embodiments of this application, when a terminal accesses a channel via Type 1 channel access, a new reference duration is defined for transmissions on the unlicensed band that have no feedback or have special feedback, such as blind retransmissions, unicast, and groupcast transmissions of SLs, and by adjusting the CWS based on the feedback of the first transmission or transmissions within the first reference duration, the SL UE can reasonably adjust the CWS when accessing channels on the unlicensed band, thereby avoiding transmission collisions and improving transmission efficiency.

[0131] Optionally, the first reference period is: The period from the start position of the first channel occupancy time (COT) to the first position, The period from the starting position of the first COT to the second position, The period from the starting position of the first COT to the position where the first position and the second position end earliest, The period of the first transmission burst within the first COT, which includes the first transmission or the second transmission, Including at least one of the first COTs, The first position is the end position of the first slot in which at least one of the first or second transmissions has been completed on all allocated resources, and the second position is the end position of the first transmission burst in which the first or second transmission has been completed on all allocated resources. The first COT mentioned above is the COT before accessing the channel via Type 1 channel access.

[0132] Optionally, the second transmission occurs after the first transmission, and the first transmission is of a different type than the second transmission.

[0133] Optionally, if the first transmission is a sidelink SL transmission based on a blind retransmission mechanism, adjusting the contention window size CWS based on feedback from the first transmission or transmissions within the first reference period is: Maintaining CWS without changing it, This involves sequentially adjusting the CWS according to the adjustment rules corresponding to ACK and NACK, treating each retransmission as one NACK, and considering the completion of all retransmissions as an ACK. If the second transmission includes an ACK / NACK based groupcast transmission or a physical sidelink shared channel PSSCH unicast transmission, then the CWS includes at least one of the following: adjusting the CWS based on feedback of the transmission within the first reference period.

[0134] Embodiments of this application provide a method for adjusting the CWS based on feedback of the first transmission or transmission within a first reference period when a terminal accesses a channel by Type 1 channel access and the first transmission is a sidelink SL transmission based on a blind retransmission mechanism. According to this method, the SL UE can rationally adjust the CWS when accessing an unlicensed band channel, thereby avoiding transmission collisions and improving transmission efficiency.

[0135] If the first transmission is optionally a channel status information CSI request or an Inter-UE coordination request transmission, adjusting the contention window size CWS based on the first transmission is: When a corresponding channel status information report (CSI report) or user-device collaboration information (Inter-UE coordination information) is received, the CWS will be adjusted to CWmin. If a CSI report or Inter-UE coordination information is not received within the CSI feedback window, the CWS will be maintained without modification. If a CSI report is not received after the CSI feedback time delay has been exceeded or the CSI feedback window has timed out, the CWS will be adjusted to min(CW×2+1,CWmax), which includes at least one of the following: CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0136] If the first transmission is optionally a physical sidelink feedback channel PSFCH or a sidelink synchronous signal block S-SSB transmission, adjusting the contention window size CWS based on the first transmission is: This includes a step to either maintain the CWS without changing it or to always maintain the CWS at CWmin, where CWmin is the minimum value of the contention window.

[0137] If the first transmission is a NACK-only groupcast transmission, adjusting the contention window size CWS based on feedback from the first transmission or transmissions within the first reference period is: Maintaining CWS without changing it, Adjusting the CWS based on the received NACK feedback, If the second transmission includes ACK / NACK based groupcast transmission and / or physical sidelink shared channel PSSCH unicast transmission, the CWS is adjusted based on feedback of the transmission within the first reference period. Adjusting the CWS based on the received ACK and / or NACK, wherein the ACK is transmitted by a PSFCH resource different from the NACK, comprising at least one of these.

[0138] Embodiments of this application provide a method for adjusting the CWS based on feedback of the first transmission or transmissions within a first reference period when a terminal accesses a channel by Type 1 channel access and the first transmission is a NACK-only groupcast transmission. According to this method, the SL UE can rationally adjust the CWS when accessing an unlicensed band channel, thereby avoiding transmission collisions and improving transmission efficiency.

[0139] If the first or second transmission is an ACK / NACK based groupcast transmission, adjusting the contention window size CWS based on the feedback of the transmission within the first reference period is: Adjusting the CWS based on the received ACK and / or NACK, This includes at least one of the following: adjusting the CWS based on feedback of all ACKs and / or NACKs of a single transmission block TB.

[0140] Embodiments of this application provide a method for adjusting the CWS based on feedback of transmissions within a first reference period when a terminal accesses a channel by Type 1 channel access and the first or second transmission is an ACK / NACK based groupcast transmission. According to this method, the SL UE can rationally adjust the CWS when accessing an unlicensed band channel, thereby avoiding transmission collisions and improving transmission efficiency.

[0141] Optionally, sequentially adjusting the CWS according to the adjustment regulations corresponding to the aforementioned ACK and NACK is: For each retransmission, adjust CWS to min(CW×2+1,CWmax), After all retransmissions are complete, this includes at least one of the following: adjusting CWS to CWmin, CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0142] Optionally, adjusting the CWS based on the received NACK feedback is: If NACK is received, adjust CWS to min(CW×2+1,CWmax), If feedback is not received for NACK-only groupcast transmission, this includes at least one of the following: maintaining the CWS unchanged. CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0143] Optionally, adjusting the CWS based on the received ACK and / or NACK is: If an ACK is received but a NACK is not, adjust CWS to CWmin. If NACK is received but ACK is not received, adjust CWS to min(CW×2+1,CWmax), If both ACK and NACK are received, either maintain the CWS without changing it, or adjust the CWS to min(CW×2+1,CWmax), If no feedback is received, we will maintain CWS without making any changes, including at least one of the following: CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0144] Optionally, adjusting the CWS based on the received ACK and / or NACK is: If the number of received ACKs exceeds X, adjust CWS to CWmin, If the received NACK exceeds Y, adjust CWS to min(CW×2+1,CWmax), If the received ACK or NACK is Z1 to Z2, the CWS is maintained without change, which includes at least one of the following: X, Y, Z1, and Z2 are all numbers between 0 and 1 (exclusive of 0), or X, Y, Z1, and Z2 are all integers greater than or equal to 0. CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0145] Optionally, adjusting the CWS based on the feedback of all ACKs and / or NACKs of one of the aforementioned transmission blocks TB is: If all of the TB feedback is ACK, adjust CWS to CWmin, If at least one of the TB feedbacks is NACK, adjust CWS to min(CW×2+1,CWmax), This includes at least one of the following: if the total number of received ACKs is less than the number of receiving terminals, adjust CWS to min(CW×2+1,CWmax), CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0146] If the first or second transmission is a physical sidelink shared channel PSSCH unicast transmission, adjusting the contention window size CWS based on the feedback of the transmission within the first reference period is: If HARQ-ACK feedback is received after the last CWS update, and at least one ACK is present in the HARQ-ACK within the most recent COT reference period, adjust CWS to CWmin. If HARQ-ACK feedback is received after the last CWS update, and no ACK is present in the HARQ-ACK within the most recent COT reference period, adjust CWS to min(CW×2+1,CWmax), If no HARQ-ACK feedback is received after the last CWS update, and the terminal transmission does not include retransmissions, or the terminal transmission is within Tw hours after the earliest COT reference period after the last CWS update, the CWS should be maintained unchanged. If no HARQ-ACK feedback is received after the last update of the CWS, and the terminal transmission includes a retransmission, and the terminal transmission is not within Tw hours after the earliest COT reference period after the last update of the CWS, then adjust the CWS to min(CW×2+1,CWmax), which includes at least one of the following: Tw = max(Xms, length of transmission burst starting from the reference period of the earliest COT + 1ms), where X = 5 or 10, CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0147] Embodiments of this application provide a method for adjusting the CWS based on feedback of transmissions within a first reference period when a terminal accesses a channel by Type 1 channel access, and the first or second transmission is a unicast PSSCH. According to this method, the SL UE can rationally adjust the CWS when accessing an unlicensed band channel, thereby avoiding transmission collisions and improving transmission efficiency.

[0148] Embodiments of this application further provide a readable storage medium in which a program or command is stored, and when the program or command is executed by a processor, it implements each of the embodiments of the contention window adjustment method described above and achieves similar technical effects, and for the sake of avoiding redundancy, a description is omitted here.

[0149] The processor is the processor installed in the terminal described in the above embodiment. The readable storage medium includes, for example, a computer-readable storage medium such as a computer read-only memory ROM, a random access memory RAM, a magnetic disk, or an optical disk.

[0150] Embodiments of this application further provide a chip that includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor executes a program or command and is used to implement each process of the embodiment of the contention window adjustment method described above, and which can achieve similar technical effects, and for the sake of avoiding redundancy, a description is omitted here.

[0151] It should be understood that the chip described in the embodiments of this application may also be called a system-on-a-chip, system chip, chip system, or SoC.

[0152] Embodiments of this application further provide computer programs / program products that, when stored in a storage medium and executed by at least one processor, implement each of the above-described embodiments of the contention window adjustment method and achieve similar technical effects, and to avoid redundancy, are omitted here from further explanation.

[0153] In this specification, the terms “includes,” “equipped with,” or any other variation thereof are intended to include non-exclusive inclusion, so that a process, method, article, or apparatus containing a set of elements includes not only those elements but also other elements not explicitly stated, or elements specific to such process, method, article, or apparatus. Unless otherwise specified, an element limited by the expression “includes one…” does not preclude the existence of other identical elements in a process, method, article, or apparatus containing that element. Furthermore, it should be noted that the scope of methods and apparatus in embodiments of this application is not limited to performing functions in the order shown or considered, but may further include performing functions almost simultaneously or in reverse order depending on such functions. For example, the described methods may be performed in an order different from the order described, and various steps may be added, omitted, or combined. Also, features described with reference to some examples may be combined in other examples.

[0154] From the above description of the embodiments, it will be clear to those skilled in the art that the methods of the above embodiments can be realized by a combination of software and a necessary general-purpose hardware platform, and of course, they may also be realized by hardware, but in many cases the former is a more preferred embodiment. Based on this understanding, the technical means of the present application may be embodied substantially or in part in the form of a computer software product, which is stored in a storage medium (e.g., ROM / RAM, magnetic disk, optical disk) and includes a plurality of commands for causing a terminal (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to perform the method of each embodiment of the present application.

[0155] Although embodiments of this application have been described above with reference to the attached drawings, this application is not limited to the above-described specific embodiments. The above-described specific embodiments are not restrictive but merely illustrative. Those skilled in the art can, by the suggestions of this application, create various other forms without departing from the spirit of this application and the scope of protection of the claims, and all of these fall within the scope of protection of this application.

Claims

1. A method for adjusting the contention window, When a terminal accesses a channel via Type1 channel access, the process includes the step of adjusting the contention window size CWS based on feedback from a first transmission or a transmission within a first reference period. The first reference period includes the first transmission and / or the second transmission, The first transmission or the second transmission is Channel status information CSI request or user device cooperation request Inter-UE coordination request transmission, Physical sidelink feedback channel PSFCH or sidelink synchronous signal block S-SSB transmission, Group cast transmission that only provides NACK-only feedback for negative responses, A method for adjusting a contention window, comprising at least one of acknowledgment / negation response-based ACK / NACK-based group cast transmission.

2. The first transmission or the second transmission is Sidelink SL transmission based on a blind retransmission mechanism, A method for adjusting a contention window according to claim 1, further comprising at least one of the following: a physical sidelink shared channel PSSCH unicast transmission.

3. The first reference period is, The period from the start position of the first channel occupancy time COT to the first position, The period from the start position of the first channel occupancy time COT to the second position, The period from the start position of the first channel occupancy time COT to the earliest ending position among the first and second positions, The period of the first transmission burst, which includes the first transmission or the second transmission, within the first channel occupancy time COT, The first channel occupancy time COT includes at least one of the above, The first position is the end position of the first slot in which at least one of the first transmissions or the second transmission has been completed on all allocated resources, and the second position is the end position of the first transmission burst in which the first transmission or the second transmission has been completed on all allocated resources. The contention window adjustment method according to claim 1, wherein the first channel occupancy time COT is the channel occupancy time COT before accessing the channel by Type1 channel access.

4. The method for adjusting a contention window according to claim 3, wherein the second transmission occurs after the first transmission, and the type of the first transmission is different from the type of the second transmission.

5. If the first transmission is a sidelink SL transmission based on a blind retransmission mechanism, the step of adjusting the contention window size CWS based on feedback of the first transmission or transmissions within the first reference period is: Steps to maintain CWS without changing it, A step of sequentially adjusting the CWS in accordance with the adjustment regulations corresponding to ACK and NACK, wherein each retransmission is considered as one NACK, and the completion of all retransmissions is considered as an ACK, A method for adjusting a contention window according to claim 1, comprising at least one of the steps of adjusting the CWS based on feedback of transmissions within a first reference period, if the second transmission includes an ACK / NACK-based groupcast transmission or a physical sidelink shared channel PSSCH unicast transmission.

6. The step of sequentially adjusting the CWS in accordance with the adjustment regulations corresponding to ACK and NACK, respectively, Each retransmission involves the step of adjusting CWS to min(CW×2+1, CWmax), After all retransmissions are complete, the step includes at least one of the following: adjusting CWS to CWmin, The method for adjusting a contention window according to claim 5, wherein CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

7. If the first transmission is a channel state information CSI request or an Inter-UE coordination request transmission, the step of adjusting the contention window size CWS based on the first transmission is: When a corresponding channel status information report (CSI report) or user-device collaboration information (Inter-UE coordination information) is received, the CWS is adjusted to CWmin. If a CSI report or Inter-UE coordination information is not received within the CSI feedback window time, the CWS is maintained unchanged. The process includes at least one of the following steps: if a CSI report is not received after the CSI feedback time delay has been exceeded or the CSI feedback window has timed out, adjust the CWS to min(CW × 2 + 1, CW max); The method for adjusting a contention window according to claim 1, wherein CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

8. If the first transmission is a physical sidelink feedback channel PSFCH or a sidelink synchronization signal block S-SSB transmission, the step of adjusting the contention window size CWS based on the first transmission is: A method for adjusting a contention window according to claim 1, comprising the step of keeping CWS unchanged or keeping CWS always at CWmin, where CWmin is the minimum value of the contention window.

9. If the first transmission is a NACK-only groupcast transmission, the step of adjusting the contention window size CWS based on feedback of the first transmission or transmissions within the first reference period is: Steps to maintain CWS without changing it, Steps include adjusting the CWS based on the received NACK feedback, If the second transmission includes ACK / NACK-based groupcast transmission and / or physical sidelink shared channel PSSCH unicast transmission, the steps include adjusting the CWS based on feedback of the transmission within the first reference period, A method for adjusting a contention window according to claim 1, comprising at least one of the steps of adjusting the CWS based on received ACK and / or NACK, wherein the ACK is transmitted by a PSFCH resource different from the NACK.

10. The step of adjusting the CWS based on the received NACK feedback is: When NACK is received, the step is to adjust CWS to min(CW×2+1, CWmax), If no feedback is received for a NACK-only groupcast transmission, the process includes at least one of the following steps: The method for adjusting a contention window according to claim 9, wherein CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

11. The step of adjusting the CWS based on the received ACK and / or NACK is: If ACK is received but NACK is not, the step is to adjust CWS to CWmin, If NACK is received and ACK is not received, the step is to adjust CWS to min(CW×2+1, CWmax), If both ACK and NACK are received, the steps are to either maintain the CWS without changing it or adjust the CWS to min(CW×2+1, CWmax), If no feedback is received, the CWS will be maintained unchanged, including at least one of the following steps: The method for adjusting a contention window according to claim 9, wherein CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

12. If the first transmission or the second transmission is an ACK / NACK-based groupcast transmission, the step of adjusting the contention window size CWS based on feedback of the transmission within the first reference period is: Steps include adjusting the CWS based on the received ACK and / or NACK, A method for adjusting a contention window according to claim 3, comprising at least one of the steps of adjusting the CWS based on feedback from all ACKs and / or NACKs of a single transmission block TB.

13. The step of adjusting the CWS based on the received ACK and / or NACK is: If the received ACK exceeds X, the step is to adjust CWS to CWmin, If the received NACK exceeds Y, the step is to adjust CWS to min(CW×2+1, CWmax), If the received ACK or NACK is Z1 to Z2, the step includes at least one of the following: The method for adjusting a contention window according to claim 12, wherein X, Y, Z1, and Z2 are all numbers between 0 and 1, or X, Y, Z1, and Z2 are all integers greater than or equal to 0, CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

14. The step of adjusting the CWS based on the feedback of all ACKs and / or NACKs of one transmission block TB is: If all feedback of the aforementioned transmission block TB is ACK, the step is to adjust CWS to CWmin, If at least one feedback of the aforementioned transmission block TB is NACK, the step of adjusting CWS to min(CW × 2 + 1, CW max), The process includes at least one of the following steps: if the total number of received ACKs is less than the number of receiving terminals, adjust CWS to min(CW×2+1, CWmax); The method for adjusting a contention window according to claim 12, wherein CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

15. If the first transmission or the second transmission is a physical sidelink shared channel PSSCH unicast transmission, the step of adjusting the contention window size CWS based on feedback of the transmission within the first reference period is: If HARQ-ACK feedback is received after the last update of CWS, and at least one ACK exists within the reference period of the most recent channel occupancy time (COT), the step of adjusting CWS to CWmin, If HARQ-ACK feedback is received after the last update of CWS, and there is no ACK in HARQ-ACK within the reference period of the most recent channel occupancy time COT, the step is to adjust CWS to min(CW×2+1, CWmax), If no HARQ-ACK feedback has been received since the last update of the CWS, and the terminal transmission does not include retransmissions, or the terminal transmission is within Tw hours after the earliest channel occupancy time (COT) reference period since the last update of the CWS, the step is to maintain the CWS unchanged. The procedure includes at least one of the following steps: if no HARQ-ACK feedback is received after the last update of CWS, and the terminal transmission includes a retransmission, and the terminal transmission is not within Tw hours after the earliest channel occupancy time COT reference period after the last update of CWS, then adjust CWS to min(CW×2+1, CWmax); A method for adjusting a contention window according to claim 2, wherein Tw = max(Xms, length of transmission burst starting from the reference period of the earliest channel occupancy time COT + 1ms), X = 5 or 10, CW is the value of the contention window before adjustment, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

16. A terminal comprising a processor and memory, wherein the memory stores a program or command executable by the processor, and when the program or command is executed by the processor, a step of the contention window adjustment method according to any one of claims 1 to 15 is realized.

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