Method for Adjusting a Contention Window and a 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 and Terminal for Adjusting a Contention Window", which was filed on July 20, 2022, and 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 and terminal for adjusting a contention window.

Background Art

[0003] In future communication systems, the unlicensed band can assist communication operators in expanding their services as a supplement to the licensed band. To maintain consistency with the deployment in the 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 the base station (gNB) and the terminal (User Equipment, UE), since 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), in order 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] When performing contention window size (CWS) adjustment for a sidelink (SL) transmission channel in an unlicensed band, it is necessary to determine the definition of the corresponding reference duration. However, for characteristics in SL such as, for example, blind retransmission, PSFCH transmission, groupcast transmission in SL, etc., where there is no feedback or transmission with special feedback, regulations and methods related to CWS adjustment do not yet exist in the related art.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Embodiments of the present application provide a contention window adjustment method and a terminal that can solve problems related to CWS adjustment of SL transmission on an unlicensed band.

Means for Solving the Problems

[0006] In a first aspect, a method for adjusting a contention window, applied to a terminal, comprising: When the terminal accesses the channel by Type1 channel access, adjusting the contention window size CWS based on feedback of a first transmission or a transmission within a first reference duration, wherein the first transmission and / or a second transmission are included within the first reference duration, the first transmission or the second transmission is a sidelink (SL) transmission based on a blind retransmission mechanism, a transmission of a channel state information (CSI) request or an inter-user equipment coordination request (Inter-UE coordination request), a transmission of a physical sidelink feedback channel (PSFCH) or a sidelink synchronization signal block (S-SSB), NACK-only groupcast transmission, and ACK / NACK based groupcast transmission, and A method is provided that includes at least one of physical sidelink shared channel PSSCH unicast transmission.

[0007] In a second aspect, a contention window adjustment device, When a terminal accesses a channel by Type1 channel access, it includes an adjustment unit for adjusting a contention window size CWS based on feedback of a first transmission or a transmission within a first reference period. The first transmission and / or a second transmission are included within the first reference period, The first transmission or the second transmission is Sidelink SL transmission based on a blind retransmission mechanism, and Channel state information CSI request or inter-user equipment coordination request Inter-UE coordination request transmission, and Physical sidelink feedback channel PSFCH or sidelink synchronization signal block S-SSB transmission, and NACK-only groupcast transmission, and ACK / NACK based groupcast transmission, and A contention window adjustment device is provided that includes at least one of physical sidelink shared channel PSSCH unicast transmission.

[0008] In a third aspect, a terminal is provided that includes a processor and a memory, the memory stores a program or command executable by the processor, and when the program or command is executed by the processor, the steps of the method described in the first aspect are realized.

[0009] On the fourth side, it includes a processor and a communication interface. When the terminal accesses the channel through Type 1 channel access, the processor is used to adjust the contention window size CWS based on the feedback of the first transmission or the transmission within the first reference period. The first reference period includes the first transmission and / or the second transmission. The first transmission or the second transmission includes at least one of sidelink SL transmission based on a blind retransmission mechanism, transmission of a channel state information CSI request or an inter-user equipment coordination request Inter-UE coordination request, transmission of a physical sidelink feedback channel PSFCH or a sidelink synchronization signal block S-SSB, NACK-only groupcast transmission, ACK / NACK based groupcast transmission, and unicast transmission of a physical sidelink shared channel PSSCH, and provides a terminal.

[0010] On the fifth side, a program or command is stored. When the program or command is executed by a processor, it realizes the steps of the contention window adjustment method described in the first side, and provides a readable storage medium.

[0011] On the sixth side, it includes a processor and a communication interface. The communication interface is coupled to the processor. The processor executes a program or command and is used to realize the contention window adjustment method described in the first side, and provides a chip.

[0012] On the seventh side, it is stored in a storage medium and, when executed by at least one processor, realizes the steps of the contention window adjustment method described in the first side, and provides a computer program / program product.

Advantages of the Invention

[0013] In the embodiments of the present application, when a terminal accesses a channel through Type1 channel access, a new reference duration is defined for feedback such as blind retransmission, unicast, and groupcast transmission of SL on an unlicensed band without feedback or with special feedback, and the CWS is adjusted based on the feedback of the first transmission or the transmission within the first reference duration. In this way, when accessing the channel of the unlicensed band, the SL UE can reasonably adjust the CWS, avoid transmission collisions, and improve the transmission efficiency at the same time.

Brief Description of the Drawings

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Best Mode for Carrying Out the Invention

[0015] In the following, while referring to the accompanying drawings in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly described. Naturally, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art shall fall within the protection scope of the present application.

[0016] In the description and claims of the present application, terms such as "first", "second", etc. are for distinguishing similar objects and not for indicating a specific order or sequence. To enable the embodiments of the present application to be implemented in an order other than the order illustrated or described herein, the terms used in this way are, in some cases, interchangeable, and the objects distinguished by "first" and "second" are generally of the same type, without limiting the number of objects. For example, the first object may be one or a plurality. It should be understood that this is the case. Also, "and" in the description and claims indicates at least one of the connected objects, and the symbol " / " generally indicates that the related objects before and after are in an "or" relationship.

[0017] It should be noted that the technology described in the embodiments of the present application is not limited to the Long Time 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 the present application are always used interchangeably. The described technology may be used in the above-described systems and wireless technologies, and may also be used in other systems and wireless technologies. In the following description, for the purpose of illustration, the New Radio (NR) system is described, and the NR terms are used in most of the following descriptions. However, these technologies are also applicable beyond the NR system, for example, to the 6 th Generation (6G) communication system.

[0018] FIG. 1 shows a block diagram of a wireless communication system to which the embodiments of the present application are applicable. The wireless communication system includes a terminal 11 and a network-side device 12. The terminal 11 may be a mobile phone, a tablet personal computer, a laptop computer (also called a notebook computer), a personal digital assistant (PDA), a palm-top computer, a netbook, an ultra-mobile personal computer (UMPC), a mobile Internet device (MID), an augmented reality (AR) / virtual reality (VR) device, a robot, a wearable device, a vehicle-mounted device (VUE), a pedestrian terminal (PUE), a smart home (a home device with a wireless communication function, such as a refrigerator, a TV, a washing machine, or furniture), a game console, a personal computer (PC), a terminal-side device such as a cash dispenser or a kiosk terminal. The wearable device may include a smart watch, a smart bracelet, smart earphones, smart glasses, a smart accessory (such as a smart bracelet, a smart hand chain, a smart ring, a smart necklace, a smart ankle bracelet, a smart anklet), a smart band, a smart garment, etc. Note that the embodiments of the present application do not limit the specific type of the terminal 11. The network-side device 12 may include an access network device or a core network device. The access network device 12 may also be referred to as a wireless access network device, a radio access network (RAN), a wireless access network function, or a wireless access network unit.The access network device 12 may include a base station, a WLAN access point, or a WiFi node, etc. The base station may be referred to as Node B, evolved Node B (eNB), access point, Base Transceiver Station (BTS), radio base station, radio transceiver, Basic Service Set (BSS), Extended Service Set (ESS), home B node, home evolved B node, Transmitting Receiving Point (TRP), or other appropriate terms in the field. As long as the same technical effects are achieved, the base station is not limited to specific technical terms. In the embodiments of this application, only the base station in the NR system is taken as an example for description, but the specific type of the base station is not limited.The core network device may include at least one of, but is not limited to, a core network node, a core network function, a Mobility Management Entity (MME), an Access and Mobility Management Function (AMF), a Session Management Function (SMF), a User Plane Function (UPF), a Policy Control Function (PCF), a Policy and Charging Rules Function (PCRF) unit, an Edge Application Server Discovery Function (EASDF), a Unified Data Management (UDM), a Unified Data Repository (UDR), a Home Subscriber Server (HSS), a Centralized network configuration (CNC), a Network Repository Function (NRF), a Network Exposure Function (NEF), a Local NEF (or L-NEF), a Binding Support Function (BSF), an Application Function (AF), etc. In the embodiments of this application, only the core network device in the NR system is taken as an example for explanation, 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 first when transmitting information, it performs energy detection (ED) on surrounding nodes. If the detected power is lower than 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. The transmission node may be a base station, a UE, a WiFi AP, etc. The channel occupancy time COT after the transmission node starts transmission shall not exceed the MCOT. Also, according to the occupied channel bandwidth (OCB) regulation, in the unlicensed band, the transmission node needs to occupy at least 70% (60 GHz) or 80% (5 GHz) of the bandwidth of the entire band in each transmission. In NR Unlicensed (NRU) technology based on NR, the commonly used types of LBT are classified into Type1, Type2A, Type2B, and Type2C. Type1 LBT is a channel listening mechanism based on back-off. When the transmission node listens that the channel is busy, it performs back-off and continues to listen until it listens that the channel is idle. Type2C is a type where the transmission node does not perform LBT, that is, no LBT or immediate transmission. Type2A and Type2B LBT are one-shot LBT, that is, the node performs LBT once before transmission, transmits when the channel is idle, and does not transmit when the channel is busy. As the difference between Type2A LBT and Type2B LBT, in Type2A, LBT is performed within 25 us and is suitable when the gap between two transmissions is 25 us or more when sharing COT, while in Type2B, LBT is performed within 16 us and is suitable when the gap between two transmissions is 16 us when sharing COT. Furthermore, Type2 LBT is suitable for LAA / eLAA / FeLAA, and when the gap between two transmissions is 25 us or more when sharing COT, the eNB and UE may use Type2 LBT. Also, in frequency range 2-2, the types of LBT are Type1, Type2, and Type3. Type1 is a channel listening mechanism based on back-off, Type2 is one-shot LBT, which performs LBT for 5 us within 8 us, and Type3 does not perform LBT. A downlink DL / uplink UL transmission burst is a set of transmissions with a gap within 16 us transmitted from a base station or a UE. For transmissions within the same DL / UL transmission burst, the base station or the UE may transmit directly without performing LBT after the gap. If the gap between transmissions exceeds 16 us, it may be regarded as a separate DL / UL transmission burst.

[0021] II. CWS Adjustment When the UE accesses the channel by Type1 channel access, it can adjust the CWS based on the Hybrid automatic repeat request (HARQ) / acknowledgement (ACK) of the data transmitted within the reference duration. When there is a new HARQ feedback, the CWS is adjusted using the feedback of the most recent COT. When the HARQ feedback is ACK, the CW is set to CWmin. When the HARQ feedback is Non-ACKnowledgement (NACK), the CW is set to min(CW×2 + 1, CWmax). In other cases, the CW is maintained without change. The reference duration is the channel occupancy time from the start position of the COT to the first slot including at least one Physical Uplink Shared Channel (PUSCH) that has been transmitted and completed on all allocated resources, or the channel occupancy time from the start position of the COT to the first transmission burst including the PUSCH that has been transmitted and completed on all allocated resources.

[0022] III. SL Sidelink (SL) transmission refers to data transmission between terminals (User Equipment, UE) that is carried out directly at the physical layer. LTE sidelink performs communication based on broadcast and can support basic security communication for vehicle-to-everything (V2X), but it cannot be applied to other V2X services with higher levels. The 5G NR system can support more comprehensive service types by supporting more advanced sidelink transmission designs such as unicast, multicast, or groupcast. Before each SL transmission, a symbol for automatic gain control (AGC) is required, and after each SL transmission, a symbol for gap is required. The symbol for AGC is usually the repeated transmission of the next symbol such as the Physical Sidelink Control Channel (PSCCH) / Physical Sidelink Shared Channel (PSSCH) or Physical Sidelink Feedback Channel (PSFCH). The SL UE can start PSCCH / PSSCH or PSFCH transmission only at a fixed position within a slot.

[0023] Hereinafter, with reference to the accompanying drawings, the adjustment method of the contention window and the terminal provided by the embodiments of the present application will be described in detail by means of several embodiments and their application scenarios.

[0024] Figure 2 is a schematic flowchart of the adjustment method of the contention window provided by the embodiments of the present application. As shown in Figure 2, the adjustment method of the contention window provided by the embodiments of the present application is as follows. When the terminal accesses the channel by Type1 channel access, it includes step 200 of adjusting the contention window size CWS based on the feedback of the first transmission or the transmission within the first reference period. The first transmission and / or the second transmission are included within the first reference period. The first transmission or the second transmission is Sidelink (SL) transmission based on a blind retransmission mechanism, transmission of a Channel State Information (CSI) request or an Inter-UE coordination request, transmission of a Physical Sidelink Feedback Channel (PSFCH) or a Sidelink Synchronization Signal and PBCH block (S-SSB), groupcast transmission that feeds back only negative acknowledgments (NACK-only), groupcast transmission based on acknowledgments / negative acknowledgments (ACK / NACK), and includes at least one of unicast Physical Sidelink Shared Channel (PSSCH) transmissions.

[0025] It should be understood that this application provides a method for adjusting CWS when there is no feedback such as blind retransmission of SL or groupcast in an unlicensed band, or when there is a transmission with special feedback, and when there is a unicast PSSCH transmission in an unlicensed band. Thereby, the SL terminal can reasonably adjust the CWS when accessing the channel in the unlicensed band, avoid transmission collisions, and at the same time improve the transmission efficiency.

[0026] It should be understood that the groupcast transmission in this application is groupcast PSSCH transmission, that is, NACK-only groupcast PSSCH transmission and ACK / NACK based groupcast PSSCH transmission.

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

[0028] Optionally, when the first transmission is a channel state information CSI request or an inter-user equipment coordination request Inter-UE coordination request transmission, the CWS is adjusted based on the first transmission.

[0029] Optionally, when 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, when the first transmission is NACK-only groupcast transmission, the CWS is adjusted based on the feedback of the first transmission or the transmission within the first reference period.

[0031] Optionally, when the first transmission is ACK / NACK based groupcast transmission, the CWS is adjusted based on the feedback of the transmission within the first reference period.

[0032] Optionally, when the first transmission is unicast PSSCH transmission, the CWS is adjusted based on the feedback of the transmission within the first reference period.

[0033] Optionally, the step of adjusting the CWS based on the feedback of the transmission within the first reference period includes the step of adjusting the CWS based on the feedback of the second transmission. The second transmission is after the first transmission, and the type of the first transmission is different from the type of the second transmission.

[0034] Optionally, the first reference period is the period from the start position of the first COT to the first position, and the period from the start position of the first COT to the second position, and the period from the start position of the first COT to the position that ends earliest among the first position and the second position, and the period of the first transmission burst including the first transmission or the second transmission within the first COT, and includes at least one of the first COT and the first position is the end position of the first slot where all transmissions of at least one of the first transmission or the second transmission are completed, and the second position is the end position of the first transmission burst including the first transmission or the second transmission where all allocated resources are transmitted, the first COT is the COT before accessing the channel by Type1 channel access, that is, the first COT may be understood as a past COT. Further, 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 alternative embodiments, the second transmission is later than the first transmission, and the type of the first transmission is different from the type of the second transmission. For example, sidelink (SL) transmission based on a blind retransmission mechanism, channel state information request or user equipment cooperation 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 alternative embodiments, the first transmission is performed starting from the start position of the first COT.

[0037] Optionally, when 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 the feedback of the first transmission or the transmissions within the first reference period includes at least one of the following a), b), and c).

[0038] a) Maintain the CWS without change. In one embodiment, for a COT whose start position includes SL transmission based on a blind retransmission mechanism, no reference duration is defined, that is, the CWS is maintained without change.

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

[0040] b) Treat each retransmission as a NACK, and treat the completion of all retransmissions as an ACK, and sequentially adjust the CWS according to the adjustment rules corresponding to the ACK and the NACK respectively. Optionally, the step of sequentially adjusting the CWS according to the adjustment rules corresponding to the ACK and the NACK respectively In each retransmission, a step of adjusting the CWS to min(CW × 2 + 1, CWmax); including at least one of the steps of adjusting the CWS to CWmin after all retransmissions are completed, where 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 previous update of the CWS and there is at least one ACK in the HARQ-ACK corresponding to the PSSCH within the reference duration of the most recent COT, the CWS is adjusted to CWmin; otherwise, the CWS is adjusted to min(CW × 2 + 1, CWmax).

[0042] Note that in the Nth retransmission, the CWS is adjusted based on the CWS at the (N - 1)th retransmission.

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

[0044] It should be understood that when the first transmission is an SL transmission based on a blind retransmission mechanism, the reference duration is defined as the period including the first transmission and the second transmission, or the period including the second transmission. That is, it is defined as the period from the start position of the first COT to the end position of the first HARQ retransmission mechanism-based SL transmission or transmission burst completed on all allocated resources, that is, the first and second transmissions are included within the first reference period, or it is defined as the length of the first HARQ retransmission mechanism-based SL transmission or SL transmission burst completed on all allocated resources, that is, the first reference period includes the second transmission.

[0045] By defining the above Reference duration, SL transmissions based on at least one HARQ retransmission mechanism will be included within the defined Reference duration.

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

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

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

[0049] It should be understood that when the first reference period includes a second transmission and the second transmission is ACK / NACK based groupcast transmission or unicast PSSCH transmission, the CWS is adjusted based on the feedback of the transmission within the first reference period.

[0050] When the second transmission is ACK / NACK based groupcast transmission, the step of adjusting the CWS based on the feedback of the transmission within the first reference period is the step of adjusting the CWS based on the received ACK and / or NACK, and includes at least one of the step of adjusting the CWS based on the feedback of all ACKs and / or NACKs of one transmission block TB.

[0051] Optionally, the step of adjusting the CWS based on the received ACK and / or NACK is when the received ACK exceeds X, the step of adjusting the CWS to CWmin, and when the received NACK exceeds Y, the step of adjusting the CWS to min(CW×2 + 1, CWmax). When the received ACK or NACK is Z1 to Z2, it includes at least one of the steps of maintaining the CWS without changing it. X, Y, Z1, and Z2 are all numbers between 0 and 1 inclusive, 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] Optionally, the step of adjusting the CWS based on all ACKs and / or NACKs feedback of one transmission block TB includes When all feedbacks of the TB are ACKs, the step of adjusting the CWS to CWmin, and When at least one feedback of the TB is a NACK, the step of adjusting the CWS to min(CW × 2 + 1, CWmax), and When the total number of received ACKs is less than the number of receiving terminals, it includes at least one of the steps of 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.

[0053] When the second transmission is a unicast PSSCH transmission, the step of adjusting the CWS based on the feedback of the transmission within the first reference period includes When HARQ-ACK feedback is received after the previous update of the CWS and there is at least one ACK in the HARQ-ACKs within the reference period of the most recent COT, the step of adjusting the CWS to CWmin, and When HARQ-ACK feedback is received after the previous update of the CWS and there is no ACK in the HARQ-ACKs within the reference period of the most recent COT, the step of adjusting the CWS to min(CW × 2 + 1, CWmax). If no HARQ-ACK feedback is received after the previous update of the CWS, and the transmission of the terminal does not include retransmission or the transmission of the terminal is within Tw hours after the reference period of the earliest COT after the previous update of the CWS, the step of maintaining the CWS without change; If no HARQ-ACK feedback is received after the previous update of the CWS, and the transmission of the terminal includes retransmission and the transmission of the terminal is not within Tw hours after the reference period of the earliest COT after the previous update of the CWS, at least one of the steps of adjusting the CWS to min(CW×2 + 1, CWmax); Tw = max(Xms, the length of the transmission burst starting from the reference period of the earliest COT + 1 ms), X = 5 or 10, CW is the value before the adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window. The transmission at the terminal is unicast PSSCH transmission.

[0054] After the previous update of the CWS means the CWS adjustment immediately before the current Type1 channel access.

[0055] Hereinafter, the method for adjusting the CWS when the first transmission is a sidelink SL transmission based on the blind retransmission mechanism will be described by way of a specific example.

[0056] Figure 3 is one of the schematic diagrams of transmission provided by the embodiments of the present application. As shown in Figure 3, the Tx UE performs blind retransmission including one initial transmission and three retransmissions within COT1, and then performs PSSCH transmission based on HARQ feedback retransmission. When the Tx UE performs Type1 LBT at slot7 to obtain a new COT, it is necessary to adjust the CWS based on the feedback of the transmission within COT1. The reference duration can be determined according to the prior art, for example, it may be slot0. In the blind retransmission mechanism, since there is no HARQ feedback, there is no feedback regarding the SL transmission within the reference duration, and this reference duration may be regarded as an invalid reference duration. Alternatively, in this case, the reference duration is not defined. That is, when the SL transmission based on blind retransmission is included in the previous COT, it is maintained without changing the CWS.

[0057] Furthermore, in the above-mentioned case, as shown in Figures 4 and 5, a new reference period may be defined such that at least one PSSCH based on HARQ feedback retransmission is included within the reference duration. Figure 4 is the second of the schematic diagrams of transmission provided by the embodiments of the present application. Figure 5 is the third of the schematic diagrams of transmission provided by the embodiments of the present application.

[0058] In Figure 4, the reference duration still starts from the start position of COT1, and the end position is the end position of the PSSCH transmission, that is, the end position of slot4.

[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 unicast transmission. For the case where the PSSCH based on HARQ feedback retransmission is groupcast transmission, refer to the embodiments of CWS adjustment corresponding to NACK-only groupcast transmission in this application and the embodiments of CWS adjustment corresponding to ACK / NACK based groupcast transmission described later.

[0060] Also, based on all SL transmissions based on blind retransmission within COT1, the CWS may be adjusted sequentially. In the initial transmission, the CWS is maintained without change. In the first retransmission, the CWS is adjusted to min(CW×2 + 1, CWmax). In the second retransmission, based on the previous adjustments, the CWS is adjusted to min(CW×2 + 1, CWmax). By analogy, when all retransmissions are completed, the CWS is adjusted to CWmin. That is, if all blind retransmissions can be completed within COT1, the Tx UE can adjust the CWS to CWmin in slot 7. If all blind retransmissions cannot be completed within COT1, the Tx UE adjusts the CWS according to the number of executions of blind retransmission in slot 7.

[0061] Note that the transmissions based on the above blind retransmission mechanism include the initial transmission and retransmissions. Blind retransmission in SL refers to the transmission where it is indicated by the upper layer (MAC) that the HARQ feedback transmitted for this TB is disabled, the transmission performed within a resource pool where no PSFCH is arranged, or the transmission where it is indicated by the SCI (Sidelink control information, SCI) that schedules this PSSCH transmission not to perform HARQ feedback.

[0062] In an embodiment of the present application, when a terminal accesses a channel through Type1 channel access, if the first transmission is a sidelink SL transmission based on a blind retransmission mechanism, a method for adjusting the CWS based on the feedback of the first transmission or the transmission within the first reference period is provided. According to this method, the SL UE can reasonably adjust the CWS when accessing the channel of the unlicensed band, avoid transmission collisions, and improve transmission efficiency at the same time.

[0063] Optionally, when the first transmission is a transmission of a channel state information CSI request or an inter-user equipment cooperation request Inter-UE coordination request, the step of adjusting the contention window size CWS based on the first transmission is When receiving the corresponding channel state information report CSI report or inter-user equipment cooperation information Inter-UE coordination information, by default, it is regarded as ACK, and the step of adjusting the CWS to CWmin; When not receiving the CSI report or Inter-UE coordination information within the CSI feedback window time, the step of maintaining the CWS without change; When not receiving the CSI report after exceeding the CSI feedback time delay or when the CSI feedback window times out, the step of adjusting the CWS to min(CW×2 + 1, CWmax), including at least one of them, CW is the value before the adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0064] Note that in this case, although the first transmission is included within the first reference period, there is no need to refer to the feedback of the first transmission, and the CWS is adjusted according to whether the corresponding response information, that is, CSI report or Inter-UE coordination information, is received after transmitting the first transmission.

[0065] Optionally, when 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 includes the step of maintaining the CWS without change or always maintaining the CWS at CWmin, where CWmin is the minimum value of the contention window.

[0066] Note that in this case, the first transmission is included within the first reference period, and the CWS is directly adjusted according to the type of the first transmission, that is, whether it is a PSFCH or an S-SSB.

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

[0068] a) Maintain the CWS without change. When the first transmission is a NACK-only groupcast transmission, do not define the reference duration, or regard the reference duration including the NACK-only groupcast transmission as an invalid reference duration, that is, maintain the CWS without change.

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

[0070] Optionally, the step of adjusting the CWS based on the received NACK feedback is When receiving a NACK, adjusting the CWS to min(CW×2 + 1, CWmax), and when not receiving the feedback of NACK - only groupcast transmission, maintaining the CWS without change, including at least one of these steps, where CW is the value before adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0071] Note that in this case, the first transmission is included within the first reference period.

[0072] c) When 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 the feedback of the transmission within the first reference period.

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

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

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

[0076] Optionally, the step of adjusting CWS based on the received ACK and / or NACK is When the received ACK exceeds X, the step of adjusting CWS to CWmin, and When the received NACK exceeds Y, the step of adjusting CWS to min(CW×2 + 1, CWmax), and When the received ACK or NACK is between Z1 and Z2, includes at least one of the step of maintaining CWS without change, X, Y, Z1, Z2 are all numbers between 0 and 1, or X, Y, Z1, Z2 are all integers greater than or equal to 0, CW is the value before adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0077] Optionally, the step of adjusting CWS based on the feedback of all ACKs and / or NACKs of one transmission block TB is When all the feedback of the TB is ACK, the step of adjusting the CWS to CWmin; When at least one feedback of the TB is NACK, the step of adjusting the CWS to min(CW×2 + 1, CWmax); including at least one of the step of adjusting the CWS to min(CW×2 + 1, CWmax) when the total number of received ACKs is less than the number of receiving terminals; CW is the value before the adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0078] When the second transmission includes a unicast PSSCH transmission, the step of adjusting the contention window size CWS based on the feedback of the transmission within the first reference period is: When HARQ-ACK feedback is received after the previous update of the CWS and there is at least one ACK in the HARQ-ACK within the reference period of the most recent COT, the step of adjusting the CWS to CWmin; When HARQ-ACK feedback is received after the previous update of the CWS and there is no ACK in the HARQ-ACK within the reference period of the most recent COT, the step of adjusting the CWS to min(CW×2 + 1, CWmax); When HARQ-ACK feedback is not received after the previous update of the CWS and the transmission of the terminal does not include a retransmission or the transmission of the terminal is within Tw hours after the reference period of the earliest COT after the previous update of the CWS, the step of maintaining the CWS without change; When HARQ-ACK feedback is not received after the previous update of the CWS and the transmission of the terminal includes a retransmission and the transmission of the terminal is not within Tw hours after the reference period of the earliest COT after the previous update of the CWS, including at least one of the step of adjusting the CWS to min(CW×2 + 1, CWmax); Tw = max(Xms, the length of the transmission burst starting from the reference period of the earliest COT + 1 ms), where X = 5 or 10, CW is the value before the adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0079] After the previous update of CWS, it means the CWS adjustment immediately before the current Type1 channel access.

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

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

[0082] Optionally, the step of adjusting CWS based on the received ACK and / or NACK includes When an ACK is received and no NACK is received, the step of adjusting CWS to CWmin; When a NACK is received and no ACK is received, the step of adjusting CWS to min(CW × 2 + 1, CWmax); When both ACK and NACK are received, the step of maintaining CWS without change or adjusting CWS to min(CW × 2 + 1, CWmax); When no feedback is received, the step of maintaining CWS without change, including at least one of these steps. CW is the value before the adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0083] The following describes, by way of specific examples, the method for adjusting the CWS when the first transmission is a NACK-only groupcast transmission.

[0084] FIG. 6 is a fourth schematic diagram of a transmission provided according to an embodiment of the present application. As shown in FIG. 6, the Tx UE transmits a NACK-only groupcast PSSCH and a unicast PSSCH respectively within COT1. When the UE performs Type1 LBT at slot7 to reacquire the channel, it is necessary to adjust the CWS based on the feedback of the PSSCH transmitted within the reference duration. In one embodiment, the reference duration including only the NACK-only groupcast PSSCH is regarded as an invalid reference duration, or in this case, the reference duration is not defined and the CWS is maintained without change.

[0085] In another embodiment, as shown in FIGS. 7 and 8, a new reference duration may be defined. FIG. 7 is a fifth schematic diagram of a transmission provided according to an embodiment of the present application, and FIG. 8 is a sixth schematic diagram of a transmission provided according to an embodiment of the present application. At least one unicast PSSCH transmission is included within the new reference duration. The start position of the reference duration may be the start position of COT1 or the start position of the first unicast PSSCH completed on all the allocated resources. The end position of the reference duration is the end position of the first unicast PSSCH completed on all the allocated resources.

[0086] Embodiments of the present application provide a method for adjusting the CWS based on the feedback of the first transmission or the transmission within the first reference period when the terminal accesses the channel by Type1 channel access and the first transmission is a NACK-only group cast transmission. According to this method, the SL UE can reasonably adjust the CWS when accessing the unlicensed band channel, avoiding transmission collisions and improving transmission efficiency at the same time.

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

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

[0089] Optionally, the step of adjusting the CWS based on the received ACK and / or NACK includes When the received ACK exceeds X, adjusting the CWS to CWmin; When the received NACK exceeds Y, adjusting the CWS to min(CW×2 + 1, CWmax); When the received ACK or NACK is between Z1 and Z2, maintaining the CWS without change, including at least one of them, X, Y, Z1, and Z2 are all numbers between 0 and 1 or all integers greater than or equal to 0. CW is the value before the adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0090] For example, when the Tx UE accesses the channel by Type1 channel access and the reference duration within the previous COT includes ACK / NACK based groupcast transmission, different Rx UEs perform HARQ feedback using different PSFCHs, and the Tx UE receives multiple HARQ feedbacks. The Tx UE may adjust the CWS based on the ratio of the received HARQ feedbacks. When the received ACK exceeds X, the CWS is adjusted to CWmin. When the received NACK exceeds Y, the CWS is adjusted to min(CW×2 + 1, CWmax). When the received ACK or NACK is between Z1 and Z2, the CWS is maintained without change. Here, X, Y, Z1, and Z2 are between 0 and 1, and the values of X, Y, and Z1 or Z2 may be the same, that is, X = Y = Z1 / Z2. Also, X, Y, and Z1 or Z2 serving as the adjustment criteria may be the number of received ACKs or NACKs, that is, the values of X, Y, and Z1 or Z2 are integers greater than or equal to 0.

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

[0092] Optionally, the step of adjusting the CWS based on all ACKs and / or NACKs feedback for one transmission block TB is When all feedbacks for the TB are ACKs, the step of adjusting the CWS to CWmin, and When at least one feedback for the TB is a NACK, the step of adjusting the CWS to min(CW×2 + 1, CWmax), and When the total number of received ACKs is less than the number of receiving terminals, including at least one of the step of adjusting the CWS to min(CW×2 + 1, CWmax), CW is the value before adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0093] In an embodiment of the present application, when a terminal accesses a channel by Type1 channel access, if the first transmission or the second transmission is an ACK / NACK-based groupcast transmission, a method for adjusting the CWS based on the feedback of the transmission within the first reference period is provided. According to this method, the SL UE can reasonably adjust the CWS when accessing the channel of the unlicensed band, avoid transmission collisions, and at the same time improve the transmission efficiency.

[0094] In some alternative embodiments, when 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 the feedback of the transmission within the first reference period is as follows: If an HARQ-ACK feedback is received after the previous update of the CWS and at least one ACK exists in the HARQ-ACK within the reference period of the most recent COT, adjusting the CWS to CWmin; If an HARQ-ACK feedback is received after the previous update of the CWS and no ACK exists in the HARQ-ACK within the reference period of the most recent COT, adjusting the CWS to min(CW×2 + 1, CWmax); If no HARQ-ACK feedback is received after the previous update of the CWS and the transmission of the terminal does not include a retransmission or the transmission of the terminal is within Tw hours after the reference period of the earliest COT after the previous update of the CWS, maintaining the CWS without change; If no HARQ-ACK feedback is received after the previous update of the CWS and the transmission of the terminal includes a retransmission and the transmission of the terminal is not within Tw hours after the reference period of the earliest COT after the previous update of the CWS, adjusting the CWS to min(CW×2 + 1, CWmax), including at least one of the above steps. Tw = max(Xms, the length of the transmission burst starting from the reference period of the earliest COT + 1 ms), where X = 5 or 10, CW is the value before the adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window. After the previous update of CWS, it means the CWS adjustment immediately before the current Type1 channel access. Note that when the first transmission or the 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 transmission is completed on all resources to which at least one PSSCH is assigned, or b) the period from the start position of the first COT to the end position of the first transmission burst that includes the PSSCH whose transmission is completed on all assigned resources, or c) defined as the period from the start position of the first COT to the earliest ending position among a) and b), or d) if the first COT contains a PSSCH but does not contain any PSSCH whose transmission is completed on all assigned resources, the reference duration is defined as the duration of the first transmission burst that contains a PSSCH within the first COT by the UE.

[0095] When the terminal accesses the channel by Type1 channel access and receives HARQ-ACK feedback after the previous update of CWS, a) If there is at least one ACK among the HARQ-ACKs corresponding to the 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 the terminal accesses the channel by Type1 channel access and does not receive a HARQ-ACK feedback after the previous update of the CWS, a) If the retransmission is not included in the transmission of the terminal or the transmission of the terminal is within Tw hours after the reference period of the earliest COT after the previous update of the CWS, maintain the CWS without change. Tw = max(Xms, the length of the transmission burst starting from the reference period of the earliest COT + 1ms), where X = 5 or 10. If it cannot be ensured that there are no other technologies by regulation, X = 5; otherwise, X = 10. b) Otherwise, adjust the CWS to min(CW×2 + 1, CWmax).

[0097] The embodiments of the present application provide a method for adjusting the CWS based on the feedback of the transmission within the first reference period when the terminal accesses the channel by Type1 channel access and the first transmission or the second transmission is a unicast PSSCH. According to this method, the SL UE can reasonably adjust the CWS when accessing the channel of the unlicensed band, avoid transmission collisions, and improve the transmission efficiency at the same time.

[0098] In addition, 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, indicating the value of CWS when CAPC = p. CWmin,p indicates the minimum value of CWS when CAPC = p, and CWmax,p indicates the maximum value of CWS when CAPC = p.

[0099] The method for adjusting a contention window provided by an embodiment of the present application may have an execution entity as a contention window adjustment device. In an embodiment of the present application, an example in which the method for adjusting a contention window is executed by a contention window adjustment device is given to describe the contention window adjustment device provided by the embodiment of the present application.

[0100] FIG. 9 is a structural schematic diagram of a contention window adjustment device provided by an embodiment of the present application. As shown in FIG. 9, the contention window adjustment device 900 includes an adjustment unit 910 for adjusting a contention window size CWS based on feedback of a first transmission or a transmission within a first reference period when a terminal accesses a channel by Type1 channel access, wherein the first transmission and / or a second transmission are included within the first reference period, the first transmission or the second transmission is a sidelink SL transmission based on a blind retransmission mechanism, a channel state information CSI request or an inter-user equipment coordination request Inter-UE coordination request transmission, a physical sidelink feedback channel PSFCH or a sidelink synchronization signal block S-SSB transmission, a groupcast transmission that feeds back only negative acknowledgments NACK-only, a groupcast transmission based on acknowledgments / negative acknowledgments ACK / NACK, and at least one of a physical sidelink shared channel PSSCH unicast transmission.

[0101] In the embodiments of the present application, when a terminal accesses a channel by means of Type1 channel access, a new reference duration is defined for blind retransmission of SL, unicast, groupcast transmission, etc. on an unlicensed band without feedback or for transmission with special feedback, and the CWS is adjusted based on the feedback of the first transmission or the transmission within the first reference duration, so that the SL UE can reasonably adjust the CWS when accessing the channel of the unlicensed band, avoid transmission collisions, and improve the transmission efficiency at the same time.

[0102] Optionally, the first reference duration is the period from the start position of the first channel occupancy time COT to the first position, and the period from the start position of the first COT to the second position, and the period from the start position of the first COT to the position that ends earliest among the first position and the second position, and the period of the first transmission burst including the first transmission or the second transmission within the first COT, and includes at least one of the first COT, the first position is the end position of the first slot where all transmissions to which at least one of the first transmission or the second transmission is assigned are completed, and the second position is the end position of the first transmission burst including the first transmission or the second transmission where all transmissions assigned are completed, the first COT is the COT before accessing the channel by means of Type1 channel access.

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

[0104] Optionally, when 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 the feedback of the first transmission or the transmission within the first reference period is maintaining the CWS without change; sequentially adjusting the CWS according to the adjustment rules corresponding to ACK and NACK respectively, regarding each retransmission as one NACK, and regarding the completion of all retransmissions as ACK; including at least one of adjusting the CWS based on the feedback of the transmission within the first reference period when the second transmission includes ACK / NACK based groupcast transmission or physical sidelink shared channel PSSCH unicast transmission.

[0105] The embodiments of the present application provide a method for adjusting the CWS based on the feedback of the first transmission or the transmission within the first reference period when the first transmission is a sidelink SL transmission based on a blind retransmission mechanism when the terminal accesses the channel by Type1 channel access. According to this method, the SL UE can reasonably adjust the CWS when accessing the unlicensed band channel, avoid transmission collisions, and improve the transmission efficiency at the same time.

[0106] Optionally, when the first transmission is a channel state information CSI request or an inter-user equipment coordination request Inter-UE coordination request transmission, the adjustment of the contention window size CWS based on the first transmission is adjusting the CWS to CWmin when receiving the corresponding channel state information report CSI report or inter-user equipment coordination information Inter-UE coordination information; If CSI report or Inter-UE coordination information is not received within the CSI feedback window time, maintain the CWS without changing it, including at least one of the following: when the CSI feedback time delay is exceeded or the CSI report is not received after the CSI feedback window times out, adjust the CWS to min(CW×2 + 1, CWmax), where CW is the value before the adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0107] Optionally, when the first transmission is a physical sidelink feedback channel PSFCH or sidelink synchronization signal block S-SSB transmission, adjusting the contention window size CWS based on the first transmission includes maintaining the CWS without changing it or always maintaining the CWS at CWmin, where CWmin is the minimum value of the contention window.

[0108] Optionally, when the first transmission is a NACK-only groupcast transmission, adjusting the contention window size CWS based on the feedback of the first transmission or the transmission within the first reference period includes maintaining the CWS without changing it, adjusting the CWS based on the received NACK feedback, when the second transmission includes ACK / NACK based groupcast transmission and / or physical sidelink shared channel PSSCH unicast transmission, adjusting the CWS based on the feedback of the transmission within the first reference period, and adjusting the CWS based on the received ACK and / or NACK, where the ACK is transmitted by a PSFCH resource different from the NACK, including at least one of the above.

[0109] When a terminal accesses a channel through Type1 channel access, if the first transmission is a NACK-only group cast transmission, embodiments of the present application provide a method for adjusting the CWS based on the feedback of the first transmission or the transmission within the first reference period. According to this method, the SL UE can reasonably adjust the CWS when accessing the unlicensed band channel, avoiding transmission collisions and improving transmission efficiency at the same time.

[0110] Optionally, when the first transmission or the second transmission is an ACK / NACK based group cast transmission, adjusting the contention window size CWS based on the feedback of the transmission within the first reference period includes adjusting the CWS based on the received ACK and / or NACK, and adjusting the CWS based on the feedback of all ACKs and / or NACKs of one transmission block TB, at least one of which is included.

[0111] When a terminal accesses a channel through Type1 channel access, if the first transmission or the second transmission is an ACK / NACK based group cast transmission, embodiments of the present application provide a method for adjusting the CWS based on the feedback of the transmission within the first reference period. According to this method, the SL UE can reasonably adjust the CWS when accessing the unlicensed band channel, avoiding transmission collisions and improving transmission efficiency at the same time.

[0112] Optionally, sequentially adjusting the CWS according to the adjustment rules corresponding to the ACK and NACK respectively includes adjusting the CWS to min(CW×2 + 1, CWmax) in each retransmission, and after all retransmissions are completed, adjusting the CWS to CWmin, at least one of which is included. 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 described above When a NACK is received, adjusting the CWS to min(CW × 2 + 1, CWmax), and when no feedback for NACK-only groupcast transmission is received, maintaining the CWS without change, includes at least one of 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 described above When an ACK is received and no NACK is received, adjusting the CWS to CWmin, and when a NACK is received and no ACK is received, adjusting the CWS to min(CW × 2 + 1, CWmax), and when both ACK and NACK are received, maintaining the CWS without change or adjusting the CWS to min(CW × 2 + 1, CWmax), and when no feedback of any kind is received, maintaining the CWS without change, includes at least one of 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 described above When the received ACK exceeds X, adjusting the CWS to CWmin, and When the received NACK exceeds Y, adjust the CWS to min(CW×2 + 1, CWmax), and include at least one of maintaining the CWS without change when the received ACK or NACK is within Z1 to Z2, where all of X, Y, Z1, and Z2 are numbers between 0 and 1 inclusive, or all of X, Y, Z1, and Z2 are 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 all ACK and / or NACK feedbacks of the one transmission block TB includes adjusting the CWS to CWmin when all feedbacks of the TB are ACK, and adjusting the CWS to min(CW×2 + 1, CWmax) when at least one feedback of the TB is NACK, and include at least one of adjusting the CWS to min(CW×2 + 1, CWmax) when the total number of received ACKs is less than the number of receiving terminals, where 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] Optionally, when the first transmission or the 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 includes adjusting the CWS to CWmin when HARQ-ACK feedback is received after the previous update of the CWS and at least one ACK exists in the HARQ-ACKs within the most recent COT reference period, If a HARQ-ACK feedback is received after the previous update of the CWS and there is no ACK in the HARQ-ACK within the reference period of the most recent COT, adjust the CWS to min(CW×2 + 1, CWmax). If a HARQ-ACK feedback is not received after the previous update of the CWS and the transmission of the terminal does not include a retransmission or the transmission of the terminal is within Tw hours after the reference period of the earliest COT after the previous update of the CWS, maintain the CWS without change. Include at least one of the following: If a HARQ-ACK feedback is not received after the previous update of the CWS and the transmission of the terminal includes a retransmission and the transmission of the terminal is not within Tw hours after the reference period of the earliest COT after the previous update of the CWS, adjust the CWS to min(CW×2 + 1, CWmax). Tw = max(Xms, the length of the transmission burst starting from the reference period of the earliest COT + 1ms), X = 5 or 10, CW is the value before the adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0118] The embodiments of this application provide a method for adjusting the CWS based on the feedback of the transmission within the first reference period when the terminal accesses the channel by Type1 channel access and the first transmission or the second transmission is a unicast PSSCH. According to this method, the SL UE can reasonably adjust the CWS when accessing the channel in the unlicensed band, avoid transmission collisions, and at the same time improve the transmission efficiency.

[0119] In the embodiments of the present application, it may be an electronic device such as an electronic device equipped with an operating system, or a component within an electronic device such as an integrated circuit or a chip. This electronic device may be a terminal or other devices other than terminals. Exemplarily, the terminal may include the types of the above-described terminal 11, but is not limited thereto, and other devices may be a server, a Network Attached Storage (NAS), etc., and are not specifically limited by the embodiments of the present application.

[0120] The contention window adjustment device provided by the embodiments of the present application realizes each process realized by the method embodiments in FIGS. 2 to 8 and can achieve the same technical effects. To avoid duplication, the description is omitted here.

[0121] Optionally, as shown in FIG. 10, the embodiments of the present application further provide a communication device 1000 including a processor 1001 and a memory 1002. The memory 1002 stores a program or command executable by the processor 1001. For example, when this communication device 1000 is a terminal, when the program or command is executed by the processor 1001, each step of the method embodiment for adjusting the contention window described above is realized, and the same technical effects can be achieved. When this communication device 1000 is a network-side device, when the program or command is executed by the processor 1001, each step of the method embodiment for adjusting the contention window described above is realized, and the same technical effects can be achieved. To avoid duplication, the description is omitted here.

[0122] An embodiment of the present application further provides a terminal including a processor and a communication interface. When the terminal accesses a channel through Type1 channel access, the processor is used to adjust the contention window size CWS based on the feedback of the first transmission or the transmission within the first reference period. The first reference period includes the first transmission and / or the second transmission. 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 an inter-user equipment coordination request Inter-UE coordination request, a transmission of a physical sidelink feedback channel PSFCH or a sidelink synchronization signal block S-SSB, a NACK-only group cast transmission, an ACK / NACK based group cast transmission, and a physical sidelink shared channel PSSCH unicast transmission. This embodiment of the terminal corresponds to the embodiment of the above-mentioned terminal-side method. Each implementation process and realization means of the embodiment of the above-mentioned method can all be applied to this embodiment of the terminal and can achieve the same technical effect. Specifically, FIG. 11 is a schematic diagram of the hardware structure of a terminal for realizing an embodiment of the present application.

[0123] This terminal 1100 includes at least some of the members such as 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, but is not limited thereto.

[0124] As can be understood by those skilled in the art, the terminal 1100 may further include a power source (e.g., a battery) for supplying power to each component. The power source may be logically connected to the processor 1110 by a power management system, whereby functions such as charge and discharge management and power consumption management can be realized by the power management system. The terminal structure shown in FIG. 11 is not a limitation on the terminal. The terminal may include more or fewer components than the number of components shown, or a combination of some components, or different arrangements of components, which will not be described here for the sake of brevity.

[0125] In the embodiments of the present application, the input unit 1104 may include a graphics processing unit (GPU) 11041 and a microphone 11042. It should be understood that the graphics processor 11041 processes the still image or video image data acquired by an image capture device (e.g., a camera) in a video capture mode or an image capture mode. The display unit 1106 may include a display panel 11061, and the display panel 11061 may be configured in the form of a liquid crystal display, an organic light-emitting diode, or the like. 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 touch screen. The touch panel 11071 may include two parts: a touch detection device and a touch controller. The 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, and an operation lever, which will not be described here for the sake of brevity.

[0126] In an embodiment of the present application, after receiving downlink data from a network-side device, the radio frequency unit 1101 can transmit it to the processor 1110 for processing. Also, the radio frequency unit 1101 can transmit uplink data to the network-side device. Usually, the radio frequency unit 1101 includes, but is not limited to, an antenna, an amplifier, a transceiver, a coupler, a low-noise amplifier, a duplexer, etc.

[0127] Memory 1109 may be used to store software programs or commands and various data. Memory 1109 may mainly include a first storage area for storing programs or commands and a second storage area for storing data. The first storage area may store an operating system, application programs or commands required for at least one function (such as a voice playback function, an image playback function, etc.). Also, Memory 1109 may include volatile memory or non-volatile memory, or Memory 1109 may include both volatile memory and non-volatile memory. The non-volatile memory may be a Read-Only Memory (ROM), Programmable ROM (PROM), Erasable PROM (EPROM), Electrically EPROM (EEPROM) or flash memory. The volatile memory may be a Random Access Memory (RAM), Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDRSDRAM), Enhanced SDRAM (ESDRAM), Synchlink DRAM (SLDRAM) and Direct Rambus RAM (DRRAM). The Memory 1109 in the embodiments of the present application includes these memories and any other suitable types of memories, but is not limited thereto.

[0128] Processor 1110 may include one or more processing units. Optionally, processor 1110 is an integration of an application processor and a modem processor. The application processor mainly processes operations related to the operating system, user interface, application programs, etc., and the modem processor mainly processes wireless communication signals, for example, a baseband processor. It should be understood that the above modem processor may not be integrated into processor 1110.

[0129] When the terminal accesses the channel by Type1 channel access, processor 1110 is used to adjust the contention window size CWS based on the feedback of the transmission during the first transmission or the first reference period, and the first transmission and / or the second transmission are included in the first reference period. 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 an inter-UE coordination request, a transmission of a physical sidelink feedback channel PSFCH or a sidelink synchronization signal block S-SSB, a group cast transmission that feeds back only negative acknowledgments NACK-only, a group cast transmission based on acknowledgments / negative acknowledgments ACK / NACK, and a unicast transmission of a physical sidelink shared channel PSSCH.

[0130] In an embodiment of the present application, when a terminal accesses a channel through Type1 channel access, a new reference duration is defined for transmissions such as blind retransmission of SL, unicast, and groupcast on an unlicensed band without feedback or with special feedback, and the CWS is adjusted based on the feedback of the first transmission or the transmission within the first reference duration, so that the SL UE can reasonably adjust the CWS when accessing the channel of the unlicensed band, avoid transmission collisions, and improve the transmission efficiency at the same time.

[0131] Optionally, the first reference duration is the period from the start position of the first channel occupancy time COT to the first position, and the period from the start position of the first COT to the second position, and the period from the start position of the first COT to the earliest ending position among the first position and the second position, and the period of the first transmission burst including the first transmission or the second transmission within the first COT, and includes at least one of the first COT, the first position is the end position of the first slot where all transmissions to which at least one of the first transmission or the second transmission is assigned are completed, and the second position is the end position of the first transmission burst including the first transmission or the second transmission where all transmissions assigned are completed, the first COT is the COT before accessing the channel through Type1 channel access.

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

[0133] Optionally, when the first transmission is a sidelink (SL) transmission based on a blind retransmission mechanism, adjusting the contention window size (CWS) based on the feedback of the first transmission or the transmissions within the first reference period is maintaining the CWS without change; sequentially adjusting the CWS according to adjustment rules corresponding to ACK and NACK respectively, considering each retransmission as one NACK and considering that all retransmissions are completed as an ACK; including at least one of adjusting the CWS based on the feedback of the transmissions within the first reference period when the second transmission includes ACK / NACK based groupcast transmission or physical sidelink shared channel (PSSCH) unicast transmission.

[0134] An embodiment of this application provides a method for adjusting the CWS based on the feedback of the first transmission or the transmissions within the first reference period when the first transmission is a sidelink (SL) transmission based on a blind retransmission mechanism when a terminal accesses a channel through Type 1 channel access. According to this method, the SL UE can reasonably adjust the CWS when accessing a channel in an unlicensed band, avoiding transmission collisions and improving transmission efficiency at the same time.

[0135] Optionally, when the first transmission is a transmission of a channel state information (CSI) request or an inter-user equipment coordination request (Inter-UE coordination request), adjusting the contention window size (CWS) based on the first transmission is adjusting the CWS to CWmin when receiving the corresponding channel state information report (CSI report) or inter-user equipment coordination information (Inter-UE coordination information); maintaining the CWS without change when not receiving the CSI report or the Inter-UE coordination information within the CSI feedback window time; If a CSI report is not received after exceeding the CSI feedback time delay or when the CSI feedback window times out, it includes at least one of adjusting the CWS to min(CW×2 + 1, CWmax), where 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] Optionally, when the first transmission is a physical sidelink feedback channel PSFCH or a sidelink synchronization signal block S-SSB transmission, adjusting the contention window size CWS based on the first transmission includes maintaining the CWS without change or always maintaining the CWS at CWmin, where CWmin is the minimum value of the contention window.

[0137] Optionally, when the first transmission is a NACK-only groupcast transmission, adjusting the contention window size CWS based on the feedback of the first transmission or the transmission within the first reference period includes maintaining the CWS without change; adjusting the CWS based on the received NACK feedback; when the second transmission includes ACK / NACK based groupcast transmission and / or physical sidelink shared channel PSSCH unicast transmission, adjusting the CWS based on the feedback of the transmission within the first reference period; adjusting the CWS based on the received ACK and / or NACK, where the ACK is transmitted by a PSFCH resource different from the NACK, including at least one of them.

[0138] Embodiments of this application provide a method for adjusting the contention window size (CWS) based on the feedback of the first transmission or the transmission within the first reference period when the terminal accesses the channel by Type 1 channel access and the first transmission is a NACK-only group cast transmission. According to this method, the SL UE can reasonably adjust the CWS when accessing the unlicensed band channel, avoiding transmission collisions and improving transmission efficiency at the same time.

[0139] Optionally, when the first transmission or the second transmission is an ACK / NACK based group cast transmission, adjusting the contention window size CWS based on the feedback of the transmission within the first reference period includes: adjusting the CWS based on the received ACK and / or NACK; and adjusting the CWS based on the feedback of all ACKs and / or NACKs of one transmission block (TB), at least one of which is included.

[0140] Embodiments of this application provide a method for adjusting the contention window size (CWS) based on the feedback of the transmission within the first reference period when the terminal accesses the channel by Type 1 channel access and the first transmission or the second transmission is an ACK / NACK based group cast transmission. According to this method, the SL UE can reasonably adjust the CWS when accessing the unlicensed band channel, avoiding transmission collisions and improving transmission efficiency at the same time.

[0141] Optionally, sequentially adjusting the CWS according to the adjustment rules corresponding to the ACK and NACK respectively includes: in each retransmission, adjusting the CWS to min(CW×2 + 1, CWmax); and after all retransmissions are completed, adjusting the CWS to CWmin, at least one of which is included. 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 described above When a NACK is received, adjusting the CWS to min(CW × 2 + 1, CWmax), and when feedback for NACK-only groupcast transmission is not received, maintaining the CWS without change, includes at least one of 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 described above When an ACK is received and no NACK is received, adjusting the CWS to CWmin, and when a NACK is received and no ACK is received, adjusting the CWS to min(CW × 2 + 1, CWmax), and when both an ACK and a NACK are received, maintaining the CWS without change or adjusting the CWS to min(CW × 2 + 1, CWmax), and when no feedback is received, maintaining the CWS without change, includes at least one of 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 described above When the received ACK exceeds X, adjusting the CWS to CWmin, and When the received NACK exceeds Y, adjust the CWS to min(CW×2 + 1, CWmax), and include at least one of maintaining the CWS without change when the received ACK or NACK is between Z1 and Z2, where 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.

[0145] Optionally, adjusting the CWS based on all ACK and / or NACK feedbacks of the one transmission block TB includes adjusting the CWS to CWmin when all feedbacks of the TB are ACK, and adjusting the CWS to min(CW×2 + 1, CWmax) when at least one feedback of the TB is NACK, and include at least one of adjusting the CWS to min(CW×2 + 1, CWmax) when the total number of received ACKs is less than the number of receiving terminals, where 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] Optionally, when the first transmission or the 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 includes adjusting the CWS to CWmin when HARQ-ACK feedback is received after the previous update of the CWS and at least one ACK exists in the HARQ-ACK within the most recent COT reference period, If a HARQ-ACK feedback is received after the previous update of the CWS and there is no ACK in the HARQ-ACK within the reference period of the most recent COT, adjust the CWS to min(CW × 2 + 1, CWmax). If a HARQ-ACK feedback is not received after the previous update of the CWS and there is no retransmission in the transmission of the terminal or the transmission of the terminal is within Tw hours after the reference period of the earliest COT after the previous update of the CWS, maintain the CWS without change. If a HARQ-ACK feedback is not received after the previous update of the CWS and there is retransmission in the transmission of the terminal, and the transmission of the terminal is not within Tw hours after the reference period of the earliest COT after the previous update of the CWS, include at least one of adjusting the CWS to min(CW × 2 + 1, CWmax). Tw = max(Xms, the length of the transmission burst starting from the reference period of the earliest COT + 1ms), X = 5 or 10, CW is the value before the adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

[0147] The embodiments of this application provide a method for adjusting the CWS based on the feedback of the transmission within the first reference period when the terminal accesses the channel by Type1 channel access and the first transmission or the second transmission is a unicast PSSCH. According to this method, the SL UE can reasonably adjust the CWS when accessing the channel in the unlicensed band, avoiding transmission collisions and at the same time improving the transmission efficiency.

[0148] The embodiments of this application further provide a readable storage medium in which a program or command is stored. When the program or command is executed by a processor, each process of the embodiment of the above-described method for adjusting the contention window is realized, and the same technical effects can be achieved. To avoid duplication, the description is omitted here.

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

[0150] The embodiments of the present application include a processor and a communication interface, the communication interface is coupled to the processor, the processor executes a program or a command, and is used to implement each process of the embodiment of the above-described method for adjusting a contention window, and further provides a chip that can achieve the same technical effect. To avoid duplication, the description is omitted here.

[0151] It should be understood that the chip described in the embodiments of the present application may also be referred to as a system-on-chip, a system chip, a chip system, or an SoC, etc.

[0152] The embodiments of the present application are stored in a storage medium and, when executed by at least one processor, implement each process of the embodiment of the above-described method for adjusting a contention window and can achieve the same technical effect, and further provide a computer program / program product. To avoid duplication, the description is omitted here.

[0153] In addition, in this specification, the terms "comprising", "including" or any other variation thereof are intended to include non-exclusive inclusion, such that a process, method, article or apparatus comprising a series of elements includes not only those elements but also other elements not expressly listed or elements inherent to such a process, method, article or apparatus. Unless otherwise specified, the elements limited by the expression "comprising one..." do not exclude the further existence of the same other elements in the process, method, article or apparatus comprising the element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the indicated order or the considered order, and may further include performing functions substantially simultaneously or in the reverse order according to such functions. For example, the described method may be performed in an order different from the described order, and various steps may be added, omitted or combined. Also, the features described with reference to some examples may be combined in other examples.

[0154] From the description of the above embodiments, those skilled in the art can clearly understand that the methods of the above examples can be realized by a combination of software and the necessary general-purpose hardware platform. Of course, it may also be realized by hardware, but in many cases, the former is a more preferred embodiment. Based on such an understanding, the technical means of this application, in essence or the part contributing to the prior art, may be embodied in the form of a computer software product. The computer software product is stored in a storage medium (such as 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 execute the methods described in each embodiment of this application.

[0155] The embodiments of the present application have been described above with reference to the accompanying drawings. However, the present application is not limited to the above specific embodiments. The above specific embodiments are not restrictive but merely illustrative. Those skilled in the art can, based on the suggestion of the present application, create various other aspects without departing from the spirit of the present application and the scope of protection of the claims. All of these fall within the protection scope of the present application.

Claims

1. A method for adjusting a contention window, comprising: when a terminal accesses a channel by Type 1 channel access, adjusting a contention window size (CWS) based on feedback of a first transmission or a transmission within a first reference period; wherein the first reference period includes the first transmission and / or a second transmission; wherein the first transmission or the second transmission includes: a sidelink (SL) transmission based on a blind retransmission mechanism; a transmission of a channel state information (CSI) request or an inter-user equipment (UE) coordination request; a transmission of a physical sidelink feedback channel (PSFCH) or a sidelink synchronization signal block (S-SSB); a groupcast transmission that feeds back only negative acknowledgments (NACK-only); a groupcast transmission based on positive / negative acknowledgments (ACK / NACK-based); and at least one of a physical sidelink shared channel (PSSCH) unicast transmission.

2. The first reference period includes: a period from a start position of a first channel occupancy time (COT) to a first position; a period from the start position of the first COT to a second position; a period from the start position of the first COT to a position that ends earliest among the first position and the second position; a period of a first transmission burst that includes the first transmission or the second transmission within the first COT; and at least one of the first COT; wherein the first position is an end position of a first slot in which all resources allocated for at least one of the first transmission or the second transmission are transmitted, and the second position is an end position of a first transmission burst that includes the first transmission or the second transmission and is transmitted on all allocated resources; wherein the first COT is a COT before accessing the channel by Type 1 channel access. The method according to claim 1.

3. The method according to claim 2, wherein the second transmission is after the first transmission, and the type of the first transmission is different from the type of the second transmission.

4. When 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 the feedback of the first transmission or the transmission within the first reference period is as follows: The step of maintaining the CWS without changing it; The step of sequentially adjusting the CWS according to the adjustment rules corresponding to ACK and NACK respectively, regarding each retransmission as one NACK, and regarding the completion of all retransmissions as an ACK; The method according to any one of claims 1 to 3, including at least one of the following: when the second transmission includes ACK / NACK based groupcast transmission or physical sidelink shared channel PSSCH unicast transmission, the step of adjusting the CWS based on the feedback of the transmission within the first reference period.

5. The step of sequentially adjusting the CWS according to the adjustment rules corresponding to ACK and NACK respectively is as follows: In each retransmission, the step of adjusting the CWS to min(CW×2 + 1, CWmax); Including at least one of the following steps: after all retransmissions are completed, the step of adjusting the CWS to CWmin; CW is the value before the adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window. The method according to claim 4.

6. When the first transmission is the transmission of channel state information CSI request or inter-user equipment coordination request Inter-UE coordination request, the step of adjusting the contention window size CWS based on the first transmission is as follows: When receiving the corresponding channel state information report CSI report or inter-user equipment coordination information Inter-UE coordination information, the step of adjusting the CWS to CWmin; When not receiving the CSI report or Inter-UE coordination information within the CSI feedback window time, the step of maintaining the CWS without changing it. If a CSI Report is not received after exceeding the CSI feedback time delay or when the CSI feedback window times out, including at least one of the steps of adjusting the CWS to min(CW × 2 + 1, CWmax), The method 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.

7. When 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 includes The method according to claim 1, including the step of maintaining the CWS without change or always maintaining the CWS at CWmin, where CWmin is the minimum value of the contention window.

8. When the first transmission is a NACK-only groupcast transmission, the step of adjusting the contention window size CWS based on the feedback of the first transmission or the transmission within the first reference period includes The step of maintaining the CWS without change; The step of adjusting the CWS based on the received NACK feedback; When the second transmission includes an ACK / NACK based groupcast transmission and / or a physical sidelink shared channel PSSCH unicast transmission, the step of adjusting the CWS based on the feedback of the transmission within the first reference period; The method according to any one of claims 1 to 3, including at least one of the step of adjusting the CWS based on the received ACK and / or NACK, wherein the ACK is transmitted by a PSFCH resource different from the NACK.

9. The step of adjusting the CWS based on the received NACK feedback includes When a NACK is received, the step of adjusting the CWS to min(CW × 2 + 1, CWmax); The method according to claim 1, including at least one of the step of maintaining the CWS without change when the feedback of the NACK-only groupcast transmission is not received. The method according to claim 8, wherein CW is the value before adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

10. The step of adjusting CWS based on the received ACK and / or NACK comprises when an ACK is received and no NACK is received, adjusting CWS to CWmin; when a NACK is received and no ACK is received, adjusting CWS to min(CW×2 + 1, CWmax); when both an ACK and a NACK are received, maintaining CWS without change or adjusting CWS to min(CW×2 + 1, CWmax); including at least one of the steps of maintaining CWS without change when no feedback is received, The method according to claim 8, wherein CW is the value before adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window.

11. When 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 the feedback of the transmission within the first reference period comprises the step of adjusting CWS based on the received ACK and / or NACK; The method according to any one of claims 2 to 4, 8, including at least one of the steps of adjusting CWS based on the feedback of all ACKs and / or NACKs of one transmission block TB.

12. The step of adjusting CWS based on the received ACK and / or NACK comprises when the received ACK exceeds X, adjusting CWS to CWmin; when the received NACK exceeds Y, adjusting CWS to min(CW×2 + 1, CWmax); including at least one of the steps of maintaining CWS without change when the received ACK or NACK is between Z1 and Z2. 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. The method according to claim 11.

13. The step of adjusting CWS based on all ACK and / or NACK feedbacks of one transmission block TB includes: When all feedbacks of the TB are ACK, the step of adjusting CWS to CWmin; When at least one feedback of the TB is NACK, the step of adjusting CWS to min(CW × 2 + 1, CWmax); When the total number of received ACKs is less than the number of receiving terminals, including at least one of the steps of adjusting 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. The method according to claim 11.

14. When the first transmission or the second transmission is physical sidelink shared channel PSSCH unicast transmission, the step of adjusting the contention window size CWS based on the feedback of the transmission within the first reference period includes: When HARQ-ACK feedback is received after the previous update of CWS and at least one ACK exists in the HARQ-ACK within the reference period of the most recent COT, the step of adjusting CWS to CWmin; When HARQ-ACK feedback is received after the previous update of CWS and no ACK exists in the HARQ-ACK within the reference period of the most recent COT, the step of adjusting CWS to min(CW × 2 + 1, CWmax); When HARQ-ACK feedback is not received after the previous update of CWS and the transmission of the terminal does not include retransmission or the transmission of the terminal is within Tw time after the reference period of the earliest COT after the previous update of CWS, the step of maintaining CWS without change. If no HARQ-ACK feedback is received after the previous update of the CWS, and retransmission is included in the transmission of the terminal, and the transmission of the terminal is not within Tw time after the reference period of the earliest COT after the previous update of the CWS, it includes at least one of the steps of adjusting the CWS to min(CW×2 + 1, CWmax). Tw = max(Xms, the length of the transmission burst starting from the reference period of the earliest COT + 1ms), X = 5 or 10, CW is the value before the adjustment of the contention window, CWmin is the minimum value of the contention window, CWmax is the maximum value of the contention window, the method according to any one of claims 2 to 4, 8.

15. When the terminal accesses the channel by Type 1 channel access, it includes an adjustment unit for adjusting the contention window size CWS based on the feedback of the first transmission or the transmission within the first reference period. The first transmission and / or the second transmission are included within the first reference period. The first transmission or the second transmission is sidelink SL transmission based on a blind retransmission mechanism, transmission of a channel state information CSI request or an inter-user equipment coordination request Inter-UE coordination request, physical sidelink feedback channel PSFCH or sidelink synchronization signal block S-SSB transmission, groupcast transmission that feeds back only negative acknowledgments NACK-only, groupcast transmission based on positive acknowledgment / negative acknowledgment ACK / NACK based, a contention window adjustment device including at least one of physical sidelink shared channel PSSCH unicast transmission.

16. 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 COT to the second position, the period from the start position of the first COT to the position that ends earliest among the first position and the second position, the period of the first transmission burst including the first transmission or the second transmission within the first COT, including at least one of the first COT. The first position is the end position of the first slot in which all transmissions of at least one of the first transmission or the second transmission are completed on all allocated resources, and the second position is the end position of the first transmission burst including the first transmission or the second transmission that is completed on all allocated resources. The apparatus according to claim 15, wherein the first COT is a COT before accessing the channel by Type1 channel access. **Claim 17** The apparatus according to claim 16, wherein the second transmission is later than the first transmission, and the type of the first transmission is different from the type of the second transmission. **Claim 18** When the first transmission is a sidelink SL transmission based on a blind retransmission mechanism, adjusting the contention window size CWS based on the feedback of the first transmission or the transmission within the first reference period is maintaining the CWS without changing it; sequentially adjusting the CWS according to adjustment rules corresponding to ACK and NACK respectively, regarding each retransmission as one NACK, and regarding the completion of all retransmissions as an ACK; The apparatus according to any one of claims 15 to 17, including at least one of adjusting the CWS based on the feedback of the transmission within the first reference period when the second transmission includes an ACK / NACK based groupcast transmission or a physical sidelink shared channel PSSCH unicast transmission. **Claim 19** Sequentially adjusting the CWS according to the adjustment rules corresponding to the ACK and NACK respectively is including at least one of adjusting the CWS to min(CW×2 + 1, CWmax) in each retransmission; adjusting the CWS to CWmin after all retransmissions are completed, where CW is the value before adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window. The apparatus according to claim 18. **Claim 20** When the first transmission is a transmission of a channel state information CSI request or an inter - UE coordination request, adjusting the contention window size CWS based on the first transmission is When receiving the corresponding channel state information report CSI report or inter-user equipment collaboration information Inter-UE coordination information, adjusting the CWS to CWmin, and When not receiving the CSI report or Inter-UE coordination information within the CSI feedback window time, maintaining the CWS without change, and When not receiving the CSI report after exceeding the CSI feedback time delay or when the CSI feedback window times out, adjusting the CWS to min(CW × 2 + 1, CWmax), including at least one of the above, The CW is the value before adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window. The apparatus according to claim 15.

21. When the first transmission is a physical sidelink feedback channel PSFCH or sidelink synchronization signal block S-SSB transmission, adjusting the contention window size CWS based on the first transmission includes Maintaining the CWS without change or always maintaining the CWS at CWmin. CWmin is the minimum value of the contention window. The apparatus according to claim 15.

22. When the first transmission is a NACK-only groupcast transmission, adjusting the contention window size CWS based on the feedback of the first transmission or the transmission within the first reference period includes Maintaining the CWS without change, and Adjusting the CWS based on the received NACK feedback, and When the second transmission includes an ACK / NACK based groupcast transmission and / or a physical sidelink shared channel PSSCH unicast transmission, adjusting the CWS based on the feedback of the transmission within the first reference period, and Adjusting the CWS based on the received ACK and / or NACK, wherein the ACK is transmitted by a PSFCH resource different from the NACK. The apparatus according to any one of claims 15 to 17 includes at least one of the above.

23. Adjusting the CWS based on the received NACK feedback includes When a NACK is received, adjust the CWS to min(CW × 2 + 1, CWmax), and include at least one of maintaining the CWS without change when no feedback for NACK - only group - cast transmission is received, where 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, the apparatus according to claim 22.

24. Adjusting the CWS based on the received ACK and / or NACK includes when an ACK is received and no NACK is received, adjusting the CWS to CWmin, and when a NACK is received and no ACK is received, adjusting the CWS to min(CW × 2 + 1, CWmax), and when both ACK and NACK are received, maintaining the CWS without change or adjusting the CWS to min(CW × 2 + 1, CWmax), and when no feedback is received, maintaining the CWS without change, where 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, the apparatus according to claim 22.

25. When the first transmission or the second transmission is an ACK / NACK based group - cast transmission, adjusting the contention window size CWS based on the feedback of the transmission within the first reference period includes adjusting the CWS based on the received ACK and / or NACK, and including at least one of adjusting the CWS based on the feedback of all ACKs and / or NACKs of one transmission block TB, the apparatus according to any one of claims 16 to 18, 22.

26. Adjusting the CWS based on the received ACK and / or NACK includes when the received ACK exceeds X, adjusting the CWS to CWmin, and when the received NACK exceeds Y, adjusting the CWS to min(CW × 2 + 1, CWmax), and when the received ACK or NACK is between Z1 and Z2, maintaining the CWS without change, including at least one of these. ​ 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. The apparatus according to claim 25.

27. Adjusting CWS based on all ACK and / or NACK feedbacks of the one transmission block TB includes when all feedbacks of the TB are ACK, adjusting CWS to CWmin; when at least one feedback of the TB is NACK, adjusting CWS to min(CW × 2 + 1, CWmax); including at least one of adjusting CWS to min(CW × 2 + 1, CWmax) when the total number of received ACKs is less than the number of receiving terminals; 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. The apparatus according to claim 25.

28. When the first transmission or the 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 includes when HARQ-ACK feedback is received after the previous update of CWS and at least one ACK exists in the HARQ-ACKs within the reference period of the most recent COT, adjusting CWS to CWmin; when HARQ-ACK feedback is received after the previous update of CWS and no ACK exists in the HARQ-ACKs within the reference period of the most recent COT, adjusting CWS to min(CW × 2 + 1, CWmax); when HARQ-ACK feedback is not received after the previous update of CWS and the transmission of the terminal does not include retransmission or the transmission of the terminal is within Tw time after the reference period of the earliest COT after the previous update of CWS, maintaining CWS without change. If no HARQ-ACK feedback is received after the previous update of the CWS, and retransmission is included in the transmission of the terminal, and the transmission of the terminal does not occur within Tw hours after the reference period of the earliest COT after the previous update of the CWS, at least one of adjusting the CWS to min(CW×2 + 1, CWmax) is included. Tw = max(Xms, the length of the transmission burst starting from the reference period of the earliest COT + 1ms), where X = 5 or 10, CW is the value before the adjustment of the contention window, CWmin is the minimum value of the contention window, and CWmax is the maximum value of the contention window. The apparatus according to any one of claims 16 to 18 and 22.

29. Including a processor and a memory, the memory stores a program or command executable by the processor. When the program or command is executed by the processor, it realizes the steps of the method for adjusting the contention window according to any one of claims 1 to 14. A terminal.

30. A readable storage medium storing a program or command. When the program or command is executed by a processor, it realizes the steps of the method for adjusting the contention window according to any one of claims 1 to 14.

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