Channel access method, device and storage medium

Abstract

The present application provides a channel access method, a device, and a storage medium, the channel access method applied to a first communication node includes: acquiring feedback information and an SL transmission type of a second SL transmission, the second SL transmission corresponding to a first SL transmission, the second SL transmission being a transmission performed within a channel occupancy time acquired using a first channel access type before the first SL transmission, identifying a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type, and adjusting the contention window corresponding to the first SL transmission according to the contention window adjustment policy, so as to cause the first communication node to perform channel access according to the contention window.

Description

[Technical field]

[0001] The present application relates to the field of communication technologies, for example, to a channel access method, device and storage medium. [Background technology]

[0002] SideLink (SL) communication runs on licensed or dedicated bands, for example, vehicle to anything (V2X) communication can run on bands dedicated to connected cars. With the development of SL communication, the need to transmit SL on unlicensed bands is also increasing. Summary of the Invention [Problem to be solved by the invention]

[0003] In order to avoid interference with devices of other systems, before transmitting SL in an unlicensed band, a channel access procedure, commonly called a Listen Before Talk (LBT) procedure, must be performed according to the relevant band usage standards. For SL transmission, the data transmission types include unicast, broadcast and groupcast. Therefore, how to adjust the contention window for different types of SL communication devices is a problem to be solved. [Means for solving the problem]

[0004] The embodiment of the present application is A channel access method applied to a first communication node, comprising: obtaining feedback information and an SL transmission type of a second sidelink (SL) transmission, the second SL transmission corresponding to a first SL transmission, the second SL transmission being a transmission performed within a channel occupancy time obtained using a first channel access type before the first SL transmission; determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type; and adjusting the contention window corresponding to the first SL transmission according to the contention window adjustment policy, so as to cause a first communication node to perform channel access according to the contention window. A channel access method is provided.

[0005] The embodiment of the present application is A channel access method applied to a second communication node, comprising: transmitting feedback information and an SL transmission type of a second SL transmission corresponding to the first SL transmission to a first communication node, so as to cause the first communication node to determine a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type; and adjusting the contention window corresponding to the first SL transmission according to the contention window adjustment policy, so as to cause the first communication node to perform channel access according to the contention window, wherein the second SL transmission is a transmission performed within a channel occupancy time obtained using the first channel access type before the first SL transmission. A channel access method is provided.

[0006] The embodiment of the present application is a communication module, a memory, and one or more processors, the communication module being configured to perform a communication interface with other communication nodes, the memory being configured to store one or more programs, the one or more programs being executed by the one or more processors causing the one or more processors to implement the method according to any one of the preceding embodiments; A channel access device is provided.

[0007] The embodiment of the present application is A computer program is stored, which, when executed by a processor, implements the method according to any one of the above embodiments. Provide a storage medium. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a schematic diagram showing the arrangement of one LBT time length according to an embodiment of the present application. [Diagram 2] FIG. 2 is a schematic diagram of the context between one first SL transmission and a second SL transmission according to an embodiment of the present application. [Diagram 3] FIG. 2 is a flow diagram of one channel access method according to an embodiment of the present application. [Figure 4] FIG. 4 is a flow diagram of another channel access method according to an embodiment of the present application. [Diagram 5] FIG. 2 is a structural block diagram of a channel access device according to an embodiment of the present application; [Figure 6] FIG. 2 is a structural block diagram of another channel access device according to an embodiment of the present application; [Figure 7] FIG. 2 is a structural schematic diagram of a channel access device according to an embodiment of the present application; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the present application will be described with reference to the drawings. Hereinafter, the present application will be described with reference to the drawings of the embodiments, and the examples given are merely for interpreting the present application, and are not intended to limit the scope of the present application.

[0010] Direct communication can also be called SL communication, and SL communication later refers to all direct communication. SL communication runs in licensed bands or dedicated bands, for example, V2X communication can run in bands dedicated to connected cars, and with the development of SL communication, the need to perform SL transmission in traditional unlicensed bands is also becoming stronger. In order to avoid interference with devices of other systems, before performing SL transmission in unlicensed bands, a channel access procedure, generally called an LBT procedure, must be performed according to the relevant band usage norms; generally, if it is determined that the detected channel resource is idle (LBT is successful) within the detection time length corresponding to the LBT procedure, the user equipment (UE) can continue to transmit, otherwise the UE must abandon transmission. NR-U (New Radio on Unlicensed band) defines multiple LBT procedures (which can also be called channel access procedures) to be applied to different scenes, and the duration of the LBT performed before transmission in this procedure may be a constant value (second channel access type, type 2) or a random value (first channel access type, type 1). For example, for the first channel access type, the LBT duration may be a random number, and one parameter related to this random number (defined as N) is the contention window (CW). However, the random number N of the LBT duration is generally initialized to a random number between [0, CW], and the value of CW is not constant and may correspond to different contention windows depending on the transmission situation and may correspond to different contention windows depending on the channel access priority.

[0011] A general LBT procedure (which may also be called a channel access procedure) occurs before a device (which may be a base station or a terminal) transmits, and its time span may be called an LBT time period (which may include one or more sensing slots). Figure 1 is a schematic diagram of an arrangement of one LBT time period according to an embodiment of the present application. As shown in Figure 1, if the channel is identified as idle within the LBT time period, the device can transmit.

[0012] When the LBT duration is a random value (the first channel access type, type1), the channel access can be divided into different channel access priority classes (CAPC), and the contention windows corresponding to different CAPCs may be different. p Let be the contention window for CAPC corresponding to channel access of p, and let CW p The minimum usable value of CW p,min And CW p The maximum usable value of CW p,max As an example, the longer the LBT time length, the longer the time required for channel access to be detected. For the LBT time length of the type 1 access, for one access process with priority p, the LBT is generally T d +N*T s1 where T d is the backoff time, N is a random integer, and T s1 is the time length of one LBT sensing slot (typically 9us), and [0,CW p ], and the larger the collision window, the longer the corresponding LBT time length will be with greater probability.

[0013] In the SL communication system, when traffic needs to be transmitted between devices, the traffic data between the devices is transmitted directly from the data source device to the target device without going through the transmission of other network devices, that is, it is a direct communication between the devices. SL communication includes multiple transmission types (cast types) as follows:

[0014] Unicast: For unicast, only one specific device is the receiver, and the receiver feeds back the received data, and the feedback may be ACK or NACK feedback, i.e., the receiver feeds back ACK if it receives correctly, and NACK if it receives incorrectly.

[0015] Groupcast: With groupcast, only one specific group of devices are receivers, and the receivers feed back the received data.

[0016] Groupcast type 1 (i.e., the first groupcast type): The feedback is only Non-Acknowledgement (NACK) feedback, i.e., the receiver does not feedback if it receives correctly, and feedbacks NACK information if it receives incorrectly. In one example, the sender uses the same resource to receive feedback information for all receivers. For example, all receivers use the same parameters when obtaining feedback resources, e.g., the same group member ID, so that the obtained feedback resources for all receivers are the same.

[0017] Groupcast type 2 (i.e., the second groupcast type): the feedback is an Acknowledgement (ACK) or NACK feedback, i.e., the receiver may feedback ACK information if it receives correctly, and NACK information if it receives incorrectly. In one example, the sender uses the same resource to receive the receiver's ACK feedback information and another resource to receive the receiver's NACK feedback information. For example, all receivers use the same parameters of one group when acquiring ACK feedback resources and the same parameters of another group when acquiring NACK feedback resources, e.g., all receivers use the same group member number x (member ID) to acquire ACK resources and the same group member number y (member ID) to acquire ACK resources, and the acquired ACK or NACK feedback resources of all receivers are the same.

[0018] Groupcast type 3 (i.e., the third groupcast type): The feedback is ACK or NACK feedback, i.e., the receiving side may feed back ACK information if it receives correctly, and NACK information if it receives incorrectly. And when the transmitting side receives feedback information from different receiving sides, it receives using each resource. For example, the receiving side uses a corresponding group of parameters when acquiring feedback resources, for example, one receiving side acquires feedback resources using its own group member number, and the group member number can be configured in the upper layer. By configuring different group member numbers, the feedback resources acquired by each receiving side may be different or orthogonal.

[0019] Broadcast: For broadcast, all surrounding UEs can be receivers, and the receivers do not feedback received data, i.e., there is no ACK or NACK feedback. Also, for groupcast and unicast, feedback can be disabled, i.e., the receivers of groupcast and unicast do not feedback.

[0020] For SL transmission, data transmission types include unicast, broadcast and groupcast, and a specific method of identifying or adjusting the contention window for SL communication is designed, which is used to solve the channel access problem of devices communicating in unlicensed bands, and includes methods for adjusting the contention window for different transmission types (unicast, groupcast, broadcast) in different situations.

[0021] In an embodiment of the present application, a contention window adjustment policy corresponding to a first SL transmission is determined based on the feedback information and SL transmission type of one or more second SL transmissions before the first SL transmission. Figure 2 is a schematic diagram of a context between one first SL transmission and a second SL transmission according to an embodiment of the present application. As shown in Figure 2, the second SL transmission is located before the first SL transmission.

[0022] In one example, as shown in FIG. 2, the UE performs the first channel access type (e.g., uses type 1 channel access) before transmitting an SL signal, which is referred to as a first SL transmission, and in one example, the channel access priority class of the first SL transmission is p. In one example, the UE performs one or more second SL transmissions at one timing before the first SL transmission, which may also be referred to as a reference SL transmission, and a transmission time period corresponding to the one or more second SL transmissions may be referred to as a reference time length. Based on different situations of the second SL transmission, a contention window adjustment policy corresponding to the first SL transmission is identified.

[0023] In one example, the second SL transmission is a transmission that occurs during a channel occupation time that the UE acquires using the first channel access type. In one example, the priority of the second SL transmission may be the same as the priority of the first SL transmission. In one example, the second SL transmission is a most recent transmission that occurs during a channel occupation time that the UE acquires using the first channel access type, or a first transmission that occurs during the acquired channel occupation time, or multiple transmissions that occur during the acquired channel occupation time.

[0024] In one example, the second SL transmission is an SL transmission that enables Hybrid Automatic Repeat reQuest (HARQ) feedback. In one example, the second SL transmission can correspond to one HARQ feedback type or cast type, which can be, for example, SL unicast (HARQ feedback type is unicast ACK / NACK), SL groupcast type 1 (HARQ feedback type is groupcast NACK only), or SL groupcast type 2 (HARQ feedback type is groupcast ACK / NACK) that enables HARQ feedback.

[0025] In one example, a feedback success rate of the second SL transmission is determined based on feedback information or a transmission type (cast type) of the second SL transmission, and in one example, whether the feedback success rate of the second SL transmission meets a requirement is determined, and further a contention window corresponding to the first SL transmission is adjusted based on whether the feedback success rate of the second SL transmission meets the requirement.

[0026] In one embodiment, Fig. 3 is a flow diagram of one channel access method according to an embodiment of the present application. This embodiment can be performed by a first communication node. However, the first communication node may be a terminal side (e.g., a user equipment). As shown in Fig. 3, this embodiment includes S310 to S330.

[0027] S310, obtaining feedback information and an SL transmission type of a second SL transmission corresponding to the first SL transmission.

[0028] The second SL transmission is a transmission performed within a channel occupancy time obtained using the first channel access type before the first SL transmission. In the embodiment, the feedback information is used to indicate whether the second communication node has successfully received traffic data transmitted from the first communication node. In the actual communication process, the feedback information includes at least one of ACK information and NACK information. If the second communication node has successfully received traffic data, the second communication node feeds back ACK information to the first communication node, and if the second communication node has not successfully received traffic data, the second communication node feeds back NACK information to the first communication node. However, the second communication node is the receiver of traffic data, and the first communication node is the transmitter of traffic data. In the embodiment, the SL transmission types include unicast, groupcast, and broadcast. In the actual operation process, in the broadcast scene, the second communication node, which is the receiver, does not feed back received traffic data, i.e., there is no feedback of ACK information or NACK information, so it will be described that the SL transmission types include unicast and groupcast.

[0029] S320, determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type.

[0030] The contention window adjustment policy is used to adjust the length value of the contention window corresponding to the first SL transmission. In one embodiment, the contention window adjustment policy includes one of a first adjustment policy used to adjust the window length value of the contention window to a minimum allowed value or a next smaller allowed window length value, a second adjustment policy used to adjust the window length value of the contention window to a next larger allowed window length value, and a third adjustment policy used to keep the window length value of the contention window unchanged. In an embodiment, the first adjustment policy may be an operation to decrease the window length value of the contention window corresponding to the first SL transmission, the second adjustment policy may be an operation to increase the window length value of the contention window corresponding to the first SL transmission, and the third adjustment policy may be an operation to keep the window length value of the contention window corresponding to the first SL transmission unchanged.

[0031] S330, adjusting a contention window corresponding to a first SL transmission according to a contention window adjustment policy, so as to cause the first communication node to perform channel access according to the contention window.

[0032] In an embodiment, after determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type of the second SL transmission, the window length value of the contention window corresponding to the first SL transmission is adjusted in accordance with the contention window adjustment policy so that the first communication node performs channel access in the unlicensed band in accordance with the adjusted contention window, thereby ensuring maximum utilization of the contention window and improving the channel access efficiency of the first SL transmission.

[0033] In one embodiment, the second SL transmission being a transmission occurring within the channel occupancy time obtained using the first channel access type prior to the first SL transmission includes one of the following: the second SL transmission being a most recent transmission occurring within the obtained channel occupancy time, the second SL transmission being a first transmission occurring within the obtained channel occupancy time, and the second SL transmission being a multiple transmission occurring within the obtained channel occupancy time. In an embodiment, if the second SL transmission is a multiple transmission occurring within the obtained channel occupancy time, the first communication node may average based on window length values ​​of the contention windows corresponding to all the second SL transmissions, and determine a contention window adjustment policy for the first SL transmission based on the average value.

[0034] In one embodiment, determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type includes determining a feedback success rate of the second SL transmission based on feedback information in the SL transmission type of the second SL transmission, and determining a contention window adjustment policy for the first SL transmission based on the feedback success rate and a preset feedback success rate threshold. In an embodiment, the feedback success rate of the second SL transmission can be expressed by the number of second SL transmissions whose feedback information is ACK information, and the preset feedback success rate threshold is used to represent whether the success rate requirement is met. If the feedback success rate reaches the preset feedback success rate threshold, the first communication node meets the success rate requirement, and if the feedback success rate does not reach the preset feedback success rate threshold, the first communication node does not meet the success rate requirement.

[0035] In one embodiment, determining a feedback success rate of the second SL transmission based on feedback information on the SL transmission type of the second SL transmission includes: determining that the second SL transmission is a unicast transmission type, determining a number of second SL transmissions whose feedback information is ACK information, and determining a feedback success rate of the second SL transmission based on the number of second SL transmissions whose feedback information is ACK information. In an embodiment, one second SL transmission carries one transmission block, and one transmission block corresponds to one feedback information. The number of second SL transmissions whose feedback information is ACK information may be the number of transmission blocks whose feedback information is ACK information.

[0036] In one embodiment, each of the second SL transmissions includes at least one data block, each of the data blocks corresponds to one feedback information, and the SL transmission type is a unicast transmission, and determining the feedback success rate of the second SL transmission based on the feedback information in the SL transmission type of the second SL transmission includes determining the number of data blocks in which the feedback information in the unicast transmission of the second SL transmission is ACK information, and determining the feedback success rate of the second SL transmission based on the number of data blocks of the ACK information. In an embodiment, each of the second SL transmissions includes one or more data blocks, and each of the data blocks can correspond to one feedback information, i.e., one second SL transmission can correspond to multiple feedback information. In an embodiment, the number of data blocks of the ACK information is equal to or greater than the number of second SL transmissions corresponding to the feedback information being ACK information. In an embodiment, when the SL transmission type is unicast and the feedback information may include ACK information and NACK information, the feedback success rate of the second SL transmission is determined.

[0037] In one embodiment, determining a contention window adjustment policy for the first SL transmission based on a feedback success rate and a preset feedback success rate threshold includes: The method includes one of: adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy when a feedback success rate of the second SL transmission reaches a preset feedback success rate threshold; adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy when a feedback success rate of the second SL transmission reaches a preset feedback success rate threshold; adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy when a feedback success rate of the second SL transmission does not reach the preset feedback success rate threshold; and adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy when a feedback success rate of the second SL transmission does not reach the preset feedback success rate threshold.

[0038] In an embodiment, adjusting the contention window corresponding to each channel access priority class according to the first adjustment policy or the second adjustment policy also includes adjusting the contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy or the second adjustment policy. In an embodiment, it is found that if the feedback success rate of the second SL transmission reaches a preset feedback success rate threshold, the window length value of the contention window currently corresponding to the second SL transmission is a little large and can be appropriately reduced, i.e., the contention window corresponding to each channel access priority class can be adjusted according to the first adjustment policy or the contention window corresponding to the channel access priority class corresponding to the first SL transmission; if the feedback success rate of the second SL transmission does not reach the preset feedback success rate threshold, it is found that the opening length value of the contention window currently corresponding to the second SL transmission is a little small and can be appropriately increased, i.e., the contention window corresponding to each channel access priority class can be adjusted according to the second adjustment policy or the contention window corresponding to the channel access priority class corresponding to the first SL transmission.

[0039] In one embodiment, determining the feedback success rate of the second SL transmission based on feedback information in the SL transmission type of the second SL transmission includes: determining that the second SL transmission is of a first groupcast type in which the feedback information is NACK information, determining the number of feedback information in the groupcast transmission, or determining whether the feedback information in the groupcast transmission is detected, and determining the feedback success rate of the second SL transmission based on the number of feedback information or whether the feedback information is detected. Here, the first groupcast type means that the SL transmission type is groupcast, and the feedback information includes NACK information fed back using the same resource. In the embodiment, determining the feedback success rate of the second SL transmission based on the number of feedback information in the groupcast transmission, or whether the feedback information in the groupcast transmission is detected.

[0040] In one embodiment, determining a contention window adjustment policy for the first SL transmission based on a feedback success rate and a preset feedback success rate threshold includes: The method includes one of: adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy, when a feedback success rate of the second SL transmission reaches a preset feedback success rate threshold; and adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy, when a feedback success rate of the second SL transmission does not reach a preset feedback success rate threshold.

[0041] In an embodiment, the first groupcast type is to only feed back NACK information. If no feedback information is detected in the second SL transmission, it is determined that the feedback success rate of the second SL transmission reaches a preset feedback success rate threshold. In an embodiment, if the feedback success rate of the second SL transmission reaches the preset feedback success rate threshold, the contention window corresponding to the channel access priority class corresponding to the first SL transmission can be adjusted according to the first adjustment policy or the second adjustment policy, i.e., the window length value of the contention window corresponding to the channel access priority class corresponding to the first SL transmission can be decreased or increased.

[0042] In one embodiment, determining a contention window adjustment policy for the first SL transmission based on a feedback success rate and a preset feedback success rate threshold includes: The method includes one of: adjusting the contention window corresponding to each channel access priority class according to a third adjustment policy, or adjusting the contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the third adjustment policy, when the feedback success rate of the second SL transmission reaches a preset feedback success rate threshold; adjusting the contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusting the contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy, when the feedback success rate of the second SL transmission does not reach the preset feedback success rate threshold. In an embodiment, the first groupcast type is to only feed back NACK information. If no feedback information is detected in the second SL transmission, it is found that the feedback success rate of the second SL transmission reaches the preset feedback success rate threshold. In an embodiment, when the feedback success rate of the second SL transmission reaches a preset feedback success rate threshold, the contention window corresponding to the channel access priority class corresponding to the first SL transmission can be adjusted according to the second adjustment policy or the third adjustment policy, i.e., the window length value of the contention window corresponding to the channel access priority class corresponding to the first SL transmission can be increased or maintained.

[0043] In one embodiment, determining a contention window adjustment policy for the first SL transmission based on a feedback success rate and a preset feedback success rate threshold includes: The method includes one of: adjusting the contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting the contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy, when the feedback success rate of the second SL transmission reaches a preset feedback success rate threshold; adjusting the contention window corresponding to each channel access priority class according to a third adjustment policy, or adjusting the contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the third adjustment policy, when the feedback success rate of the second SL transmission does not reach a preset feedback success rate threshold. In an embodiment, the first groupcast type is to only feed back NACK information. If no feedback information is detected in the second SL transmission, it is found that the feedback success rate of the second SL transmission reaches the preset feedback success rate threshold. In an embodiment, when the feedback success rate of the second SL transmission reaches a preset feedback success rate threshold, the contention window corresponding to the channel access priority class corresponding to the first SL transmission can be adjusted according to the first adjustment policy or the third adjustment policy, that is, the window length value of the contention window corresponding to the channel access priority class corresponding to the first SL transmission can be reduced or maintained.

[0044] In one embodiment, the second SL transmission adopts a second groupcast type, in which the feedback information is ACK information or NACK information, and determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type includes: The method includes one of: adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy, when the first communication node has received at least ACK information; and adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy, when the first communication node has not received ACK information. In an embodiment, when the second SL transmission adopts a second groupcast type, when only ACK information is received as feedback information for the second SL transmission, or when ACK information and NACK information are received, the contention window corresponding to each channel access priority class is adjusted according to a first adjustment policy, or the contention window corresponding to the channel access priority class corresponding to the first SL transmission is adjusted according to the first adjustment policy; when only NACK information is received as feedback information for the second SL transmission, or when no feedback information is received, the contention window corresponding to each channel access priority class is adjusted according to a second adjustment policy, or the contention window corresponding to the channel access priority class corresponding to the first SL transmission is adjusted according to the second adjustment policy.

[0045] In one embodiment, the second SL transmission employs a second groupcast type, which uses the same resource to feed back ACK or NACK information.

[0046] Determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type includes: The method includes one of: adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy, when the first communication node receives only an ACK message; adjusting a contention window corresponding to each channel access priority class according to a third adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the third adjustment policy, when the first communication node receives ACK information and NACK information; and adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy, when the first communication node does not receive ACK information. In an embodiment, when the second SL transmission adopts a second groupcast type, when only ACK information is received as feedback information for the second SL transmission, the contention window corresponding to each channel access priority class is adjusted according to a first adjustment policy, or the contention window corresponding to the channel access priority class corresponding to the first SL transmission is adjusted according to the first adjustment policy; when ACK information and NACK information are received as feedback information for the second SL transmission, the contention window corresponding to each channel access priority class is adjusted according to a third adjustment policy, or the contention window corresponding to the channel access priority class corresponding to the first SL transmission is adjusted according to the third adjustment policy; when only NACK information is received as feedback information for the second SL transmission or no feedback information is received, the contention window corresponding to each channel access priority class is adjusted according to the second adjustment policy, or the contention window corresponding to the channel access priority class corresponding to the first SL transmission is adjusted according to the second adjustment policy.

[0047] In one embodiment, the second SL transmission employs a second groupcast type, which is to feed back ACK information or NACK information using the same resource, and determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type includes: The method includes one of: adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy, when the first communication node receives only ACK information; and adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy, when the first communication node receives only NACK information, receives ACK information and NACK information simultaneously, or does not receive a feedback message. In an embodiment, when the second SL transmission adopts a second groupcast type, when only ACK information is received as feedback information for the second SL transmission, the contention window corresponding to each channel access priority class is adjusted according to a first adjustment policy, or the contention window corresponding to the channel access priority class corresponding to the first SL transmission is adjusted according to the first adjustment policy; when only NACK information is received as feedback information for the second SL transmission, ACK information and NACK information are received simultaneously, or no feedback message is received, the contention window corresponding to each channel access priority class is adjusted according to a second adjustment policy, or the contention window corresponding to the channel access priority class corresponding to the first SL transmission is adjusted according to the second adjustment policy.

[0048] In one embodiment, the second SL transmission adopts a third groupcast type, in which the second communication node uses a corresponding resource to feed back ACK information or NACK information, and determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type includes: The method includes: determining the number of feedback information in the groupcast transmission of the second SL transmission that is ACK information, the proportion of ACK information, the number of second communication nodes corresponding to the ACK information, or the proportion of second communication nodes corresponding to the ACK information; and determining a contention window adjustment policy of the first SL transmission based on the number of ACK information, the proportion of ACK information, the number of second communication nodes corresponding to the ACK information, or the proportion of second communication nodes corresponding to the ACK information. In an embodiment, when the SL transmission type of the second SL transmission is groupcast and each second communication node uses a corresponding resource to feed back ACK information or NACK information, the first communication node can accurately determine the number of second communication nodes that feed back ACK information and the number of second communication nodes that feed back NACK information. However, the number of ACK information is the same as the number of second communication nodes that correspond to the ACK information, and the proportion of ACK information is the same as the proportion of second communication nodes that correspond to the ACK information.

[0049] In one embodiment, determining a contention window adjustment policy for the first SL transmission based on the ACK information or a number of second communication nodes corresponding to the ACK information includes: The method includes one of: adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to a channel access priority class corresponding to a first SL transmission according to the first adjustment policy, when the number of the ACK information or the second communication nodes corresponding to the ACK information is equal to or greater than a first threshold value; and adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusting a contention window corresponding to a channel access priority class corresponding to a second SL transmission according to the first adjustment policy, when the number of the ACK information or the second communication nodes corresponding to the ACK information is less than a second threshold value, wherein the first threshold value is equal to or greater than a second threshold value. In an embodiment, if the number of ACK information or second communication nodes corresponding to the ACK information exceeds a first threshold value, the window length value of the contention window corresponding to the second SL transmission is found to be a little large, and the window length value can be appropriately decreased, i.e., the contention window corresponding to the respective channel access priority class can be adjusted according to the first adjustment policy, or the contention window corresponding to the channel access priority class corresponding to the first SL transmission can be adjusted according to the first adjustment policy. Correspondingly, if the number of ACK information or second communication nodes corresponding to the ACK information is less than a second threshold value, the window length value of the contention window corresponding to the second SL transmission is found to be a little small, and the window length value can be appropriately increased, i.e., the contention window corresponding to the respective channel access priority class can be adjusted according to the second adjustment policy, or the contention window corresponding to the channel access priority class corresponding to the first SL transmission can be adjusted according to the second adjustment policy. In an embodiment, the first threshold value may be the same as the second threshold value or may be greater than the second threshold value.Illustratively, the first threshold value and the second threshold value are integers greater than 1 and less than the total number of second communication nodes minus 1. Illustratively, the first threshold value and the second threshold value may be 1 or a positive integer less than the total number of second communication nodes minus 1.

[0050] In one embodiment, determining a contention window adjustment policy for the first SL transmission based on the ACK information or a proportion of second communication nodes responsive to the ACK information includes: The method includes one of: adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy, when the ACK information or a proportion of second communication nodes corresponding to the ACK information is equal to or greater than a third threshold value; and adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy, when the ACK information or a proportion of second communication nodes corresponding to the ACK information is less than a fourth threshold value, wherein the third threshold value is equal to or greater than the fourth threshold value. In an embodiment, if the ACK information or the proportion of the second communication nodes corresponding to the ACK information exceeds the third threshold value, the window length value of the contention window corresponding to the second SL transmission is found to be a little large, and the window length value can be appropriately decreased, i.e., the contention window corresponding to the respective channel access priority class can be adjusted according to the first adjustment policy, or the contention window corresponding to the channel access priority class corresponding to the first SL transmission can be adjusted according to the first adjustment policy. Correspondingly, if the ACK information or the proportion of the second communication nodes corresponding to the ACK information is less than the fourth threshold value, the window length value of the contention window corresponding to the second SL transmission is found to be a little small, and the window length value can be appropriately increased, i.e., the contention window corresponding to the respective channel access priority class can be adjusted according to the second adjustment policy, or the contention window corresponding to the channel access priority class corresponding to the first SL transmission can be adjusted according to the second adjustment policy. In an embodiment, the third threshold value may be the same as the fourth threshold value or may be greater than the fourth threshold value. Exemplarily, the third threshold value and the fourth threshold value are real numbers ranging from 0 to 1.For example, the third threshold value or the fourth threshold value may be 10% or 100%.

[0051] In one embodiment, the feedback information and the SL transmission type satisfy a preset feedback condition, and determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type includes: and adjusting a contention window corresponding to each channel access priority class according to the third adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the third adjustment policy. In an embodiment, when the second SL transmission is of a first groupcast type that enables feedback, the first communication node can adjust a contention window corresponding to each channel access priority class according to the third adjustment policy, or adjust a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the third adjustment policy.

[0052] In one embodiment, the feedback information and the SL transmission type satisfy a preset feedback condition, and determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type includes: determining a current busy level of a channel in which the first communication node exists, and determining a contention window adjustment policy for the first SL transmission based on the current busy level. In an embodiment, the current busy level of the channel may be a numerical value between 0 and 1. In an embodiment, the first communication node selects a target length of a contention window of a corresponding channel access priority class based on the measured current busy level, and then determines a contention window adjustment policy for the first SL transmission according to the target length of the contention window, and adjusts the current length of the contention window for the first SL transmission according to the contention window adjustment policy.

[0053] In one embodiment, determining a contention window adjustment policy for the first SL transmission based on a current busy level includes: The method includes determining a target length of a contention window corresponding to the first SL transmission based on a current busy level and a channel access priority class corresponding to the first SL transmission, and adjusting the contention window corresponding to the first SL transmission according to the target length of the contention window.

[0054] In one embodiment, determining a contention window adjustment policy for the first SL transmission based on a current busy level includes: The method includes: when the current busy level is equal to or greater than the first busy level threshold, adjusting the contention window corresponding to each channel access priority class according to the second adjustment policy, or adjusting the contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy; when the current busy level is less than the second busy level threshold, adjusting the contention window corresponding to each channel access priority class according to the first adjustment policy, or adjusting the contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy; when the current busy level is greater than the second busy level threshold and less than the first busy level threshold, adjusting the contention window corresponding to each channel access priority class according to the third adjustment policy, or adjusting the contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the third adjustment policy, wherein the first busy level threshold is equal to or greater than the second busy level threshold. In an embodiment, the first busy level threshold and the second busy level threshold may be the same value or different values, which are not limited and can be set according to actual circumstances.

[0055] In one embodiment, the preset feedback condition is: The second SL transmission includes one of: the second SL transmission being feedback information that does not enable feedback; the first SL transmission being feedback information that does not enable feedback; the first SL transmission being feedback information and an SL transmission type that enables feedback, and the SL transmission type being a unicast transmission, and the second communication node transmitting the feedback information using the same resource; the second SL transmission being an SL transmission type that enables feedback, and the first communication node not obtaining a feedback message; the first communication node not obtaining a feedback message for the second SL transmission, and the first SL transmission not including a retransmission; and the first communication node not obtaining a feedback message for the second SL transmission, and the first SL transmission being a transmission that is performed in a time window after the sensing time length corresponding to the second SL transmission.

[0056] In an embodiment, Figure 4 is a flow diagram of another channel access method according to an embodiment of the present application. This embodiment is applied to a second communication node. However, the second communication node may be a terminal (e.g., a user equipment). As shown in Figure 4, the channel access method in this embodiment includes S210.

[0057] S410 includes transmitting feedback information and an SL transmission type of a second SL transmission corresponding to the first SL transmission to the first communication node, so as to cause the first communication node to identify a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type, and adjusting a contention window corresponding to the first SL transmission according to the contention window adjustment policy, so as to cause the first communication node to perform channel access according to the contention window, wherein the second SL transmission is a transmission performed within a channel occupancy time obtained using the first channel access type before the first SL transmission.

[0058] In one embodiment, the second SL transmission being a transmission that occurs within the channel occupancy time obtained using the first channel access type prior to the first SL transmission includes one of the following: the second SL transmission being the most recent transmission that occurs within the obtained channel occupancy time; the second SL transmission being the first transmission that occurs within the obtained channel occupancy time; and the second SL transmission being a multiple transmission that occurs within the obtained channel occupancy time.

[0059] In one embodiment, the contention window adjustment policy includes one of a first adjustment policy used to adjust the window length value of the contention window to a minimum allowed value or a next smaller allowed window length value, a second adjustment policy used to adjust the window length value of the contention window to a next larger allowed window length value, and a third adjustment policy used to maintain the window length value of the contention window unchanged.

[0060] The interpretation of each parameter in the channel access method applied to the second communication node can be referred to in the description of the channel access method applied to the first communication node in the above embodiment, so it will not be repeated here.

[0061] In one embodiment, the SL transmission type of the second SL transmission is unicast transmission with feedback enabled, and the feedback information is ACK information and / or NACK information, and the process of determining the contention window adjustment policy of the first SL transmission is described as an example. In the embodiment, the HARQ feedback information of the second SL transmission is ACK information and / or NACK information, and the SL transmission type is unicast transmission with feedback enabled, and determining the success rate of the HARQ feedback of the second SL transmission and determining whether the success rate meets the requirements includes the following examples:

[0062] In one example, when each second SL transmission corresponds to one HARQ feedback information, i.e., HARQ feedback by SL transmission block is used, and the HARQ feedback information corresponding to at least one second SL transmission is ACK information, it is determined that the accuracy rate meets the requirement, where the satisfaction of the requirement means that a preset feedback success rate threshold is reached.

[0063] In one example, each of the one or more second SL transmissions includes at least one data block, and each of the data blocks corresponds to a respective HARQ feedback information, i.e., the HARQ feedback information according to the data block is used, and when the number or proportion of the data blocks whose HARQ feedback information is ACK information is equal to or greater than a threshold T, it is determined that the accuracy rate meets the requirement. In one example, the data block is one CB (code block), one CBG (code block group), or one data unit.

[0064] In one example, when it is determined that the accuracy rate meets the requirement (i.e., reaches a preset feedback success rate threshold), the UE adjusts a contention window corresponding to each channel access priority class according to a first adjustment policy. Adjusting the contention window corresponding to each channel access priority class also includes adjusting a contention window corresponding to a CAPC of the first SL transmission. In one example, when it is determined that the accuracy rate meets the requirement, the UE may adjust a contention window corresponding to a CAPC of the first SL transmission according to the first adjustment policy.

[0065] In one example, when it is determined that the accuracy rate does not meet the requirement (i.e., does not reach the preset feedback success rate threshold), the UE adjusts the contention window corresponding to each channel access priority class according to a second adjustment policy. Adjusting the contention window corresponding to each channel access priority class also includes adjusting the contention window corresponding to the CAPC of the first SL transmission. In one example, when it is determined that the accuracy rate does not meet the requirement, the UE may adjust the contention window corresponding to the CAPC of the first SL transmission according to the second adjustment policy.

[0066] In the embodiment of the later application, the UE adjusts the contention window, unless otherwise specified, refers to the UE adjusting the contention window corresponding to each channel access priority class or adjusting the contention window corresponding to the CAPC of the first SL transmission. In the embodiment of the later application, the groupcast may include a broadcast, for example, one broadcast enabling NACK feedback can also be called groupcast type 1.

[0067] In one embodiment, the SL transmission type of the second SL transmission is a groupcast transmission with feedback enabled, only NACK information is fed back using the same resource as feedback information, the first communication node is a transmitting UE, and the second communication node is a receiving UE as an example to describe a contention window adjustment policy determination process for the first SL transmission. In the embodiment, the HARQ feedback information of the second SL transmission is NACK information, and the SL transmission type is a first groupcast type with feedback enabled, and determining the success rate of the HARQ feedback of the second SL transmission and determining whether the success rate meets the requirements includes the following examples:

[0068] In one example, each second SL transmission corresponds to one HARQ feedback information, and can only feedback NACK information, but not ACK information.

[0069] For the first groupcast type, the transmitting UE cannot know exactly how many receiving UEs have fed back, and if the receiving UEs do not feed back, the transmitting UE cannot distinguish between the following several situations:

[0070] Situation 1: The receiving UE correctly receives the SL transmission and does not need to provide feedback.

[0071] Situation 2: The receiving UE detects but fails to receive the SL transmission, but cannot feed back a NACK because the channel is not contentioned.

[0072] Situation 3: The receiving UE does not detect the SL transmission, and therefore does not provide feedback, i.e., the receiving UE actually fails to receive.

[0073] In the embodiment, the transmitting UE erroneously determines that it has successfully received the situation 2 and the situation 3, but actually fails to receive the situation 2 and the situation 3. In addition, even if the transmitting UE can detect the NACK information for the first groupcast type, the transmitting UE cannot identify whether there are any receiving UEs that have received the situation correctly, and can only determine that there are some UEs that have not received the situation correctly. The transmitting UE cannot know the number of UEs that have received the situation correctly or the proportion of the UEs that have received the situation correctly to all the receiving UEs.

[0074] In one example, for x second SL transmissions, if the HARQ feedback information corresponding to at least x second SL transmissions is no feedback information, i.e., no feedback information is detected, it is determined that the accuracy rate meets the requirement. In one example, if the HARQ feedback information corresponding to the first or last second SL transmission is no feedback information, i.e., no feedback information is detected, it is determined that the accuracy rate meets the requirement.

[0075] In one example, if it is determined that the accuracy rate meets the requirement, the UE adjusts the contention window corresponding to each channel access priority class or adjusts the contention window corresponding to the CAPC of the first SL transmission according to a first adjustment policy, otherwise, the UE adjusts the contention window corresponding to each channel access priority class or adjusts the contention window corresponding to the CAPC of the first SL transmission according to a second adjustment policy. In this example, the UE adjusts the collision window according to a manner similar to unicast.

[0076] In one example, if it is determined that the accuracy rate meets the requirement, the UE adjusts the contention window corresponding to each channel access priority class or adjusts the contention window corresponding to the CAPC of the first SL transmission according to a third adjustment policy; if not, the UE adjusts the contention window corresponding to each channel access priority class or adjusts the contention window corresponding to the CAPC of the first SL transmission according to a second adjustment policy.

[0077] In one example, if it is determined that the accuracy rate meets the requirement, the UE adjusts the contention window corresponding to each channel access priority class or adjusts the contention window corresponding to the CAPC of the first SL transmission according to a first adjustment policy; if not, the UE adjusts the contention window corresponding to each channel access priority class or adjusts the contention window corresponding to the CAPC of the first SL transmission according to a third adjustment policy.

[0078] In one embodiment, the SL transmission type of the second SL transmission is a groupcast transmission with feedback enabled, the same resource is used to feed back ACK information and NACK information as feedback information, the first communication node is a transmitting UE, and the second communication node is a receiving UE, as an example, the contention window adjustment policy determining process of the first SL transmission is described. In the embodiment, the HARQ feedback information of the second SL transmission is ACK information and NACK information, the SL transmission type is a second groupcast type with feedback enabled, and determining the success rate of the HARQ feedback of the second SL transmission and determining whether the success rate meets the requirements includes the following examples:

[0079] In one example, each second SL transmission corresponds to one HARQ feedback information, and feedbacks NACK information when it is received incorrectly, and feedbacks ACK information when it is received correctly. In the second groupcast type, ACK information can be fed back, and is similar to the first groupcast type, and multiple receiving UEs feed back ACK information on the same resource or feedback NACK information on the same resource, and the transmitting UE cannot distinguish the receiving UEs. For the second groupcast type, the transmitting UE cannot know exactly how many receiving UEs have fed back ACK and how many receiving UEs have fed back NACK. In addition, the transmitting UE receiving HARQ feedback includes the following situations:

[0080] Situation 1: The receiving UE only receives ACK information.

[0081] Situation 2: The receiving UE only receives NACK information.

[0082] Situation 3: The receiving UE receives both ACK and NACK information.

[0083] Situation 4: The receiving UE has not received any feedback information.

[0084] In one example, if the feedback of the second SL transmission is situation 1 or 3, i.e., the feedback information includes at least ACK information, the UE adjusts the contention window corresponding to each channel access priority class according to the first adjustment policy, or adjusts the contention window corresponding to the CAPC of the first SL transmission; otherwise, the UE adjusts the contention window according to the second adjustment policy.

[0085] In one example, if the feedback of the second SL transmission is situation 1, the UE adjusts the contention window corresponding to each channel access priority class according to the first adjustment policy, or adjusts the contention window corresponding to the CAPC of the first SL transmission; if it is situation 3, the UE adjusts the contention window according to the third adjustment policy; if not, the UE adjusts the contention window according to the second adjustment policy.

[0086] In one example, if the feedback of the second SL transmission is situation 1, the UE adjusts the contention window corresponding to each channel access priority class according to the first adjustment policy, or adjusts the contention window corresponding to the CAPC of the first SL transmission; otherwise, the UE adjusts the contention window according to the second adjustment policy.

[0087] In one example, the second SL transmission is at least one, the first or the last second SL transmission of the one or more SL transmissions.

[0088] In one embodiment, the SL transmission type of the second SL transmission is a groupcast transmission with feedback enabled, and ACK information and NACK information are fed back using corresponding resources as feedback information, and the first communication node is a transmitting UE and the second communication node is a receiving UE as an example to describe the contention window adjustment policy determination process of the first SL transmission. In the embodiment, the HARQ feedback information of the second SL transmission is ACK information and NACK information, and the SL transmission type is a third groupcast type with feedback enabled, and determining the success rate of the HARQ feedback of the second SL transmission and determining whether the success rate meets the requirements includes the following examples:

[0089] In one example, each second SL transmission corresponds to one HARQ feedback information, and each receiving UE feeds back NACK information when it receives it incorrectly, and feeds back ACK information when it receives it correctly. Different from the first groupcast type and the second groupcast type, when the third groupcast type is adopted, each receiving UE feeds back ACK information or NACK information in each resource, and the transmitting UE knows the total number m of receiving UEs, for example, when the receiving UE knows that the total number of group members (group size) is m, the number of receiving UEs is m-1, excluding the transmitting UE itself. Similarly, the transmitting UE can know how many receiving UEs feed back ACK information and how many receiving UEs feed back NACK information by detecting the feedback. However, it is assumed that the number of detected ACK information is k.

[0090] In one example, if the number k of ACK information corresponding to the second SL transmission is greater than or equal to a threshold T1, the UE adjusts the contention window corresponding to each channel access priority class according to a first adjustment policy or adjusts the contention window corresponding to the CAPC of the first SL transmission; otherwise, the UE adjusts the contention window according to a second adjustment policy.

[0091] In one example, if the proportion of ACK information corresponding to the second SL transmission, i.e., the proportion of receiving UEs in all the groups of UEs that feed back ACK information, denoted by k / (m-1), is greater than or equal to a threshold T2, the UE adjusts the contention window corresponding to each channel access priority class according to a first adjustment policy or adjusts the contention window corresponding to the CAPC of the first SL transmission; otherwise, the UE adjusts the contention window according to a second adjustment policy.

[0092] In one embodiment, the above thresholds T1 and T2 are predefined, configured or pre-configured values. For example, T1 is usually a number from 1 to m-1, but in one special embodiment, T1 may be 1 or m-1, and T2 is usually a number from 0 to 1, for example, 10%, but in another special embodiment, T2 may be 100%, that is, all receiving UEs feeding back ACK is equivalent to meeting the condition of accuracy rate.

[0093] In one example, the second SL transmission includes one or more SL transmissions, at least one SL of the one or more SL transmissions, the first SL, or the last SL.

[0094] In one embodiment, the NACK information is fed back using the same resource as the HARQ feedback information of the second SL transmission, and the SL transmission type is the first group cast type that enables the feedback. In one example, the UE does not operate the collision window based on the accuracy rate, but may adjust the contention window based on the following method.

[0095] Scheme 1: In one example, if the second SL transmission is of a first groupcast type that enables feedback, adjust the contention window corresponding to the respective channel access priority class according to the third adjustment policy, or adjust the contention window corresponding to the CAPC of the first SL transmission, i.e., use the previous contention window without adjusting the contention window regardless of whether feedback is received.

[0096] Method 2: In one example, if the second SL transmission is of a first groupcast type that enables feedback, the UE determines the current busy level of the channel (CBR, channel busy ratio, or channel occupied ratio, changing the value from 0 to 1), and adjusts the contention window corresponding to each channel access priority class based on the busy level of the channel, or adjusts the contention window corresponding to the CAPC of the first SL transmission.

[0097] In one example, the size of the contention window corresponding to the busy level of different channels can be configured or pre-configured, taking CBR as an example and shown in Table 1 below, the UE uses Table 1 to select a suitable contention window for each channel access priority based on the measured channel busy level.

[0098] [Table 1]

[0099] Scheme 3: In one example, if the second SL transmission is of a first groupcast type that enables feedback, then at least one of the following is included:

[0100] A busy level threshold 1 of the channel (i.e., the first busy level threshold in the above embodiment) is configured or pre-configured, and when the busy level of the channel is equal to or greater than threshold 1, the UE adjusts the contention window corresponding to each channel access priority class according to the second adjustment policy, or adjusts the contention window corresponding to the CAPC of the first SL transmission.

[0101] A busy level threshold 2 of the channel (i.e., the second busy level threshold in the above embodiment) is configured or pre-configured, and when the busy level of the channel is below threshold 2, the UE adjusts the contention window corresponding to each channel access priority class according to the first adjustment policy, or adjusts the contention window corresponding to the CAPC of the first SL transmission.

[0102] When the busy level of the channel is between threshold 1 and threshold 2, the UE adjusts the contention window corresponding to each channel access priority class according to the third adjustment policy, or adjusts the contention window corresponding to the CAPC of the first SL transmission.

[0103] In one example, threshold 1 and threshold 2 may be the same value, ie, one threshold value need only be configured or pre-configured.

[0104] In one embodiment, if the HARQ feedback information of the second SL transmission is NACK information or the SL transmission type is the first groupcast type that enables feedback, the contention window adjustment policy defined using the current busy level in the above embodiment is also suitable for the following scenario, i.e., "the second SL transmission is of the first groupcast type that enables feedback" in the previous embodiment can be replaced with the following scenario:

[0105] Scene 1: The second SL transmission is of HARQ feedback information or SL transmission type that does not enable feedback, such as broadcast, unicast that disables feedback, groupcast, etc.

[0106] Scene 2: The first SL transmission is of HARQ feedback information or SL transmission type that does not enable feedback, such as broadcast, unicast that disables feedback, groupcast, etc.

[0107] Scene 3: The first SL transmission is of the first groupcast type with feedback enabled.

[0108] Scene 4: The second SL transmission is of a SL transmission type (cast type) that enables feedback, but the UE has not obtained the feedback result of the second SL transmission, i.e., the feedback result of the second SL transmission can be used.

[0109] Scene 5: The UE has not obtained the feedback result of the second SL transmission, and the first SL transmission does not include a retransmission or is a transmission that occurs within one time window (Tw) after the reference time length of the second SL transmission.

[0110] In one embodiment, Fig. 5 is a structural block diagram of one channel access device according to an embodiment of the present application. This embodiment is applied to a first communication node. As shown in Fig. 5, this embodiment includes an acquisition module 510, a determination module 520 and an adjustment module 530.

[0111] The acquiring module 510 is configured to acquire feedback information and a SL transmission type of a second SL transmission corresponding to a first sidelink SL transmission, the second SL transmission being a transmission that occurs within a channel occupancy time acquired using a first channel access type prior to the first SL transmission.

[0112] The identifying module 520 is configured to identify a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type.

[0113] The adjusting module 530 is configured to adjust a contention window corresponding to the first SL transmission according to the contention window adjustment policy, so as to cause the first communication node to perform channel access according to the contention window.

[0114] In one embodiment, the second SL transmission being a transmission that occurs within the channel occupancy time obtained using the first channel access type prior to the first SL transmission includes one of the following: the second SL transmission being the most recent transmission that occurs within the obtained channel occupancy time; the second SL transmission being the first transmission that occurs within the obtained channel occupancy time; and the second SL transmission being a multiple transmission that occurs within the obtained channel occupancy time.

[0115] In one embodiment, the contention window adjustment policy includes one of a first adjustment policy used to adjust the window length value of the contention window to a minimum allowed value or a next smaller allowed window length value, a second adjustment policy used to adjust the window length value of the contention window to a next larger allowed window length value, and a third adjustment policy used to maintain the window length value of the contention window unchanged.

[0116] In one embodiment, the identification module 520 includes: The present invention includes a first identification unit configured to identify a feedback success rate of the second SL transmission based on feedback information in an SL transmission type of the second SL transmission, and a second identification unit configured to identify a contention window adjustment policy of the first SL transmission based on the feedback success rate and a preset feedback success rate threshold.

[0117] In one embodiment, the first identification unit comprises: The communication device includes a first identifying subunit configured to identify that the second SL transmission is a unicast transmission type and to identify the number of second SL transmissions for which the feedback information is ACK information, and a second identifying subunit configured to identify a feedback success rate of the second SL transmissions based on the number of second SL transmissions for which the feedback information is ACK information.

[0118] In one embodiment, each of the second SL transmissions includes at least one data block, each of the data blocks corresponds to one feedback information, and the SL transmission type is a unicast transmission, and the first specific unit is: The present invention also includes a third specifying subunit configured to specify the number of data blocks whose feedback information in a unicast transmission of the second SL transmission is ACK information, and a fourth specifying subunit configured to specify a feedback success rate of the second SL transmission based on the number of data blocks of the ACK information.

[0119] In one embodiment, the second identification unit comprises: The method is configured to one of: adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy when a feedback success rate of the second SL transmission reaches a preset feedback success rate threshold; adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy when a feedback success rate of the second SL transmission reaches a preset feedback success rate threshold; adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy when a feedback success rate of the second SL transmission does not reach the preset feedback success rate threshold; and adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy when a feedback success rate of the second SL transmission does not reach the preset feedback success rate threshold.

[0120] In one embodiment, the first identification unit comprises: The second SL transmission is of a first groupcast type in which the feedback information is non-acknowledgement (NACK) information, and the fifth specifying subunit is configured to specify a number of feedback information in the groupcast transmission or to specify whether the feedback information in the groupcast transmission is detected, and a sixth specifying subunit is configured to specify a feedback success rate of the second SL transmission based on the number of feedback information or whether the feedback information is detected.

[0121] In one embodiment, the second identification unit comprises: The method is configured to one of: when a feedback success rate of the second SL transmission reaches a preset feedback success rate threshold, adjust a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjust a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy; when a feedback success rate of the second SL transmission does not reach a preset feedback success rate threshold, adjust a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjust a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy.

[0122] In one embodiment, the second identification unit comprises: The method is configured to one of: when a feedback success rate of the second SL transmission reaches a preset feedback success rate threshold, adjust a contention window corresponding to each channel access priority class according to a third adjustment policy, or adjust a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the third adjustment policy; when a feedback success rate of the second SL transmission does not reach a preset feedback success rate threshold, adjust a contention window corresponding to each channel access priority class according to the second adjustment policy, or adjust a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy.

[0123] In one embodiment, the second identification unit comprises: The method is configured to one of: adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, when a feedback success rate of the second SL transmission reaches a preset feedback success rate threshold, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy; and adjusting a contention window corresponding to each channel access priority class according to a third adjustment policy, when a feedback success rate of the second SL transmission does not reach a preset feedback success rate threshold, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the third adjustment policy.

[0124] In one embodiment, the second SL transmission adopts a second groupcast type, in which the feedback information is ACK information or NACK information, and the identifying module 520: The communication node is configured to one of: adjust a contention window corresponding to each channel access priority class according to a first adjustment policy, if the first communication node has received at least ACK information, or adjust a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy; and adjust a contention window corresponding to each channel access priority class according to a second adjustment policy, if the first communication node has not received ACK information, or adjust a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy.

[0125] In one embodiment, the second SL transmission employs a second groupcast type, which uses the same resource to feed back ACK or NACK information.

[0126] The identification module 520 is The communication node is configured to one of: adjust a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjust a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy, when the first communication node receives only an ACK message; adjust a contention window corresponding to each channel access priority class according to a third adjustment policy, or adjust a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the third adjustment policy, when the first communication node receives ACK information and NACK information; and adjust a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjust a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy, when the first communication node does not receive ACK information.

[0127] In one embodiment, the second SL transmission employs a second groupcast type, which uses the same resource to feed back ACK or NACK information.

[0128] The identification module 520 is The communication node is configured to one of: adjust a contention window corresponding to each channel access priority class according to a first adjustment policy, when the first communication node receives only ACK information, or adjust a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy; and adjust a contention window corresponding to each channel access priority class according to a second adjustment policy, when the first communication node receives only NACK information, receives ACK information and NACK information simultaneously, or does not receive a feedback message, adjust a contention window corresponding to each channel access priority class according to the second adjustment policy, or adjust a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy.

[0129] In one embodiment, the second SL transmission adopts a third groupcast type in which the second communication node feeds back ACK information or NACK information using the corresponding resource.

[0130] The identification module 520 is The present invention is provided with a third identification unit configured to identify the number of cases in which the feedback information in the groupcast transmission of the second SL transmission is ACK information, the proportion of the ACK information, the number of second communication nodes corresponding to the ACK information, or the proportion of second communication nodes corresponding to the ACK information, and a fourth identification unit configured to identify a contention window adjustment policy for the first SL transmission based on the number of ACK information, the proportion of the ACK information, the number of second communication nodes corresponding to the ACK information, or the proportion of second communication nodes corresponding to the ACK information.

[0131] In one embodiment, determining a contention window adjustment policy for the first SL transmission based on the ACK information or a number of second communication nodes corresponding to the ACK information includes: The method includes one of: adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to a channel access priority class corresponding to a first SL transmission according to the first adjustment policy, when the number of the ACK information or the second communication nodes corresponding to the ACK information is equal to or greater than a first threshold value; and adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusting a contention window corresponding to a channel access priority class corresponding to a second SL transmission according to the first adjustment policy, when the number of the ACK information or the second communication nodes corresponding to the ACK information is less than a second threshold value, wherein the first threshold value is equal to or greater than a second threshold value.

[0132] In one embodiment, determining a contention window adjustment policy for the first SL transmission based on the ACK information or a proportion of second communication nodes responsive to the ACK information includes: The method includes one of: adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy, when the ACK information or a proportion of second communication nodes corresponding to the ACK information is equal to or greater than a third threshold value; and adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy, when the ACK information or a proportion of second communication nodes corresponding to the ACK information is less than a fourth threshold value, wherein the third threshold value is equal to or greater than the fourth threshold value.

[0133] In one embodiment, the feedback information and the SL transmission type satisfy a preset feedback condition, and the identification module 520 is configured to adjust the contention window corresponding to each channel access priority class according to a third adjustment policy, or adjust the contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the third adjustment policy.

[0134] In one embodiment, the feedback information and the SL transmission type meet a preset feedback condition, and the identification module 520: The present invention also includes a fifth identification unit configured to identify a current busy level of a channel in which the first communication node exists, and a sixth identification unit configured to identify a contention window adjustment policy for the first SL transmission based on the current busy level.

[0135] In one embodiment, the sixth identification unit comprises: a seventh identifying subunit configured to identify a target length of a contention window corresponding to the first SL transmission based on a current busy level and a channel access priority class corresponding to the first SL transmission; and an adjusting subunit configured to adjust the contention window corresponding to the first SL transmission according to the target length of the contention window.

[0136] In one embodiment, the sixth identification unit comprises: the contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusts the contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy, if the current busy level is less than the second busy level threshold; the contention window corresponding to each channel access priority class according to the first adjustment policy, or adjusts the contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy, if the current busy level is greater than the second busy level threshold and less than the first busy level threshold; the contention window corresponding to each channel access priority class according to a third adjustment policy, or adjusts the contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the third adjustment policy, if the current busy level is greater than the second busy level threshold and less than the first busy level threshold, and the first busy level threshold is greater than or equal to the second busy level threshold.

[0137] In one embodiment, the preset feedback condition is: The second SL transmission includes one of: the second SL transmission being feedback information that does not enable feedback; the first SL transmission being feedback information that does not enable feedback; the first SL transmission being feedback information and an SL transmission type that enables feedback, and the SL transmission type being a unicast transmission, and the second communication node transmitting the feedback information using the same resource; the second SL transmission being an SL transmission type that enables feedback, and the first communication node not obtaining a feedback message; the first communication node not obtaining a feedback message for the second SL transmission, and the first SL transmission not including a retransmission; and the first communication node not obtaining a feedback message for the second SL transmission, and the first SL transmission being a transmission that is performed in a time window after the sensing time length corresponding to the second SL transmission.

[0138] The channel access device of this embodiment is configured to realize the channel access method applied to the first communication node of the embodiment shown in Figure 3, and since its realization principle and technical effect are similar, they will not be repeated here.

[0139] In an embodiment, Fig. 6 is a structural block diagram of another channel access device according to an embodiment of the present application. This embodiment is applied to a second communication node. As shown in Fig. 6, this embodiment includes a transmitter 610.

[0140] The transmitter 610 is configured to transmit feedback information and an SL transmission type of a second SL transmission corresponding to the first SL transmission to the first communication node, so as to cause the first communication node to identify a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type, and to adjust a contention window corresponding to the first SL transmission according to the contention window adjustment policy, so as to cause the first communication node to perform channel access according to the contention window, the second SL transmission being a transmission performed within a channel occupancy time obtained using the first channel access type before the first SL transmission.

[0141] The channel access device of this embodiment is configured to realize the channel access method applied to the second communication node of the embodiment shown in Figure 4, and since its realization principle and technical effect are similar, they will not be repeated here.

[0142] In one embodiment, FIG. 7 is a structural schematic diagram of a channel access device according to an embodiment of the present application. As shown in FIG. 7, the device according to the present application includes a processor 710, a memory 720, and a communication module 730. The number of processors 710 in the device may be one or more, and FIG. 7 takes one processor 710 as an example. The number of memories 720 in the device may be one or more, and FIG. 7 takes one memory 720 as an example. The processor 710, the memory 720, and the communication module 730 of the device may be connected by a bus or other manner, and FIG. 7 takes them as an example by a bus. In this embodiment, the device may be a terminal side (e.g., a user equipment).

[0143] The memory 720 may be configured to store software programs, computer-executable programs and modules, such as program instructions / modules corresponding to the device of any embodiment of the present application (e.g., the acquisition module 510, the identification module 520 and the adjustment module 530 in the channel access device) as a computer-readable storage medium. The memory 720 may include a program storage area capable of storing an operating system, an application program required for at least one function, and a data storage area capable of storing data generated by the use of the device. The memory 720 may also include a high-speed random access memory, and may also include a non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some examples, the memory 720 may include memories provided remotely to the processor 710, and these remote memories may be connected to the device by a network. Examples of the network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0144] The communication module 730 is configured to be used to provide a communication interface with other communication nodes.

[0145] When the channel access device is a first communication node, the provided device may be configured to perform a channel access method applied to the first communication node according to any of the above embodiments and may have corresponding functions and effects.

[0146] In the case where the channel access device is a second communication node, the provided device may be configured to perform a channel access method applied to the second communication node according to any of the above embodiments and may have functions and effects accordingly.

[0147] An embodiment of the present application further provides a storage medium including computer-executable instructions that, when executed by a computer processor, are used to perform a channel access method applied to a first communication node, the method including: obtaining feedback information and an SL transmission type of a second sidelink (SL) transmission corresponding to a first SL transmission, the SL transmission being a transmission that occurs within a channel occupancy time obtained using a first channel access type prior to the first SL transmission; determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type; and adjusting a contention window corresponding to the first SL transmission according to the contention window adjustment policy so as to cause the first communication node to perform channel access in accordance with the contention window.

[0148] An embodiment of the present application further provides a storage medium including computer-executable instructions used to perform a channel access method applied to a second communication node when executed by a computer processor, the method including: sending feedback information and an SL transmission type of a second SL transmission corresponding to the first SL transmission to the first communication node, so as to cause the first communication node to identify a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type; and adjusting a contention window corresponding to the first SL transmission according to the contention window adjustment policy, so as to cause the first communication node to perform channel access according to the contention window, the second SL transmission being a transmission performed within a channel occupancy time obtained using the first channel access type before the first SL transmission.

[0149] It should be appreciated by those skilled in the art that the term user equipment covers any suitable type of wireless user equipment, such as, for example, a mobile telephone, a portable data processing device, a portable web browser or a mobile station mounted on a vehicle.

[0150] In general, various embodiments of the present application may be implemented in hardware or special purpose circuits, software, logic, or any combination thereof. For example, and not limited to this application, some aspects may be implemented in hardware and other aspects may be implemented in firmware or software executable by a controller, microprocessor, or other computing device.

[0151] Embodiments of the present application may be implemented by a data processor of a mobile device executing computer program instructions, which may be implemented in hardware, for example in the entity of a processor, or a combination of software and hardware. The computer program instructions may be assembly instructions, Instruction Set Architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source or target code written in any combination of one or more programming languages.

[0152] Any logic flow block diagrams in the drawings of this application may represent program steps, or may represent interconnected logic circuits, modules and functions, or may represent a combination of program steps and logic circuits, modules and functions. Computer programs may be stored in memory. The memory may be of any type suitable for the local technology environment and may be implemented using any suitable data memory technology, such as, but not limited to, Read-Only Memory (ROM), Random Access Memory (RAM), optical memory devices and systems (Digital Video Disc (DVD) or Compact Disk (CD)), etc. Computer-readable media may include non-transitory storage media. Data processors may be of any type suitable for the local technology environment, such as, but not limited to, general purpose computers, special purpose computers, microprocessors, Digital Signal Processing (DSP), Application Specific Integrated Circuits (ASIC), Programmable Logic Devices (Field-Programmable Gate Arrays (FPGA) and processors with group core processor architectures.

Claims

1. A channel access method applied to a first communication node, comprising: obtaining feedback information and a SL transmission type of a second sidelink (SL) transmission, the second SL transmission corresponding to a first SL transmission and performed within a channel occupancy time obtained using a first channel access type before the first SL transmission; determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type; adjusting the contention window corresponding to the first SL transmission according to the contention window adjustment policy, so as to cause the first communication node to perform channel access according to the contention window. Channel access method.

2. The second SL transmission is a transmission performed within a channel occupancy time acquired using a first channel access type before the first SL transmission, The second SL transmission is a most recent transmission within the acquired channel occupancy time, the second SL transmission is a first transmission within the acquired channel occupancy time, or the second SL transmission is a multiple transmission within the acquired channel occupancy time. The method of claim 1.

3. The contention window adjustment policy includes one of a first adjustment policy used to adjust the window length value of the contention window to a minimum allowed value or a next smaller allowed window length value, a second adjustment policy used to adjust the window length value of the contention window to a next larger allowed window length value, and a third adjustment policy used to maintain the window length value of the contention window unchanged. The method of claim 1.

4. Determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type includes: determining a feedback success rate of the second SL transmission based on feedback information of the SL transmission type of the second SL transmission; determining a contention window adjustment policy for the first SL transmission based on the feedback success rate and a preset feedback success rate threshold. The method of claim 1.

5. Determining a feedback success rate of the second SL transmission based on feedback information of the SL transmission type of the second SL transmission includes: Identifying the second SL transmission as a unicast transmission type, and identifying a number of second SL transmissions whose feedback information is acknowledgement (ACK) information; determining a feedback success rate of the second SL transmission based on a number of second SL transmissions in which the feedback information is ACK information; The method according to claim 4.

6. Each of the second SL transmissions includes at least one data block, each of the data blocks corresponds to one feedback information, and the SL transmission type is a unicast transmission, and determining a feedback success rate of the second SL transmission based on feedback information of the SL transmission type of the second SL transmission includes: Identifying a number of data blocks whose feedback information in the unicast transmission of the second SL transmission is ACK information; determining a feedback success rate of the second SL transmission based on a number of data blocks of the ACK information; The method according to claim 4.

7. determining a contention window adjustment policy for the first SL transmission based on the feedback success rate and a preset feedback success rate threshold, adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy when a feedback success rate of the second SL transmission reaches a preset feedback success rate threshold; adjusting a contention window corresponding to a channel access priority class corresponding to the first SL transmission according to a first adjustment policy when a feedback success rate of the second SL transmission reaches a preset feedback success rate threshold; adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy when a feedback success rate of the second SL transmission does not reach a preset feedback success rate threshold; and adjusting a contention window corresponding to a channel access priority class corresponding to the first SL transmission according to a second adjustment policy when a feedback success rate of the second SL transmission does not reach a preset feedback success rate threshold. The method according to claim 5 or 6.

8. Determining a feedback success rate of the second SL transmission based on feedback information of the SL transmission type of the second SL transmission includes: The second SL transmission is of a first groupcast type in which feedback information is a non-acknowledgement (NACK) information, and determining a number of feedback information in the groupcast transmission or determining whether feedback information in the groupcast transmission is detected; determining a feedback success rate of the second SL transmission based on the number of feedback information or whether feedback information is detected. The method according to claim 4.

9. determining a contention window adjustment policy for the first SL transmission based on the feedback success rate and a preset feedback success rate threshold, When a feedback success rate of the second SL transmission reaches a preset feedback success rate threshold, adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy; and adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy when the feedback success rate of the second SL transmission does not reach a preset feedback success rate threshold. The method according to claim 8.

10. determining a contention window adjustment policy for the first SL transmission based on the feedback success rate and a preset feedback success rate threshold, When a feedback success rate of the second SL transmission reaches a preset feedback success rate threshold, adjusting a contention window corresponding to each channel access priority class according to a third adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the third adjustment policy; and adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy when the feedback success rate of the second SL transmission does not reach a preset feedback success rate threshold. The method according to claim 8.

11. determining a contention window adjustment policy for the first SL transmission based on the feedback success rate and a preset feedback success rate threshold, When a feedback success rate of the second SL transmission reaches a preset feedback success rate threshold, adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy; and adjusting a contention window corresponding to each channel access priority class according to a third adjustment policy when the feedback success rate of the second SL transmission does not reach a preset feedback success rate threshold. The method according to claim 8.

12. The second SL transmission adopts a second groupcast type in which feedback information is ACK information or NACK information; Determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type includes: If the first communication node has received at least ACK information, adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to a channel access priority class corresponding to the first SL transmission according to a first adjustment policy; if the first communication node does not receive ACK information, adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusting a contention window corresponding to a channel access priority class corresponding to the first SL transmission according to a second adjustment policy. The method of claim 1.

13. The second SL transmission employs a second groupcast type in which ACK information or NACK information is fed back using the same resource; Determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type includes: If the first communication node receives only an ACK message, adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to a channel access priority class corresponding to the first SL transmission according to a first adjustment policy; When the first communication node receives ACK information and NACK information, adjust a contention window corresponding to each channel access priority class according to a third adjustment policy, or adjust a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to a third adjustment policy; if the first communication node does not receive ACK information, adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusting a contention window corresponding to a channel access priority class corresponding to the first SL transmission according to a second adjustment policy. The method of claim 1.

14. The second SL transmission employs a second groupcast type in which ACK information or NACK information is fed back using the same resource; Determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type includes: If the first communication node receives only ACK information, adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to a channel access priority class corresponding to the first SL transmission according to a first adjustment policy; and adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to a second adjustment policy, when the first communication node receives only NACK information, receives ACK information and NACK information simultaneously, or does not receive a feedback message. The method of claim 1.

15. The second SL transmission adopts a third groupcast type in which a second communication node feeds back ACK information or NACK information using a corresponding resource; Determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type includes: Identifying the number of feedback information in the groupcast transmission of the second SL transmission that is ACK information, the proportion of ACK information, the number of second communication nodes corresponding to the ACK information, or the proportion of second communication nodes corresponding to the ACK information; determining a contention window adjustment policy for the first SL transmission based on the number of ACK information, the proportion of ACK information, the number of second communication nodes corresponding to the ACK information, or the proportion of second communication nodes corresponding to the ACK information; The method of claim 1.

16. Determining a contention window adjustment policy for the first SL transmission based on the ACK information or a number of second communication nodes corresponding to the ACK information includes: If the ACK information or a number of second communication nodes corresponding to the ACK information is equal to or greater than a first threshold value, adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy; and adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the second SL transmission according to a first adjustment policy, if the ACK information or a number of second communication nodes corresponding to the ACK information is less than a second threshold value, wherein the first threshold value is equal to or greater than the second threshold value. The method of claim 15.

17. Determining a contention window adjustment policy for the first SL transmission based on the ACK information or a proportion of second communication nodes corresponding to the ACK information includes: If the ACK information or a proportion of second communication nodes corresponding to the ACK information is equal to or greater than a third threshold value, adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy; adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to a second adjustment policy, if the ACK information or a proportion of second communication nodes corresponding to the ACK information is less than a fourth threshold value, and the third threshold value is equal to or greater than the fourth threshold value. The method of claim 15.

18. The feedback information and the SL transmission type satisfy a preset feedback condition, Determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type includes: adjusting a contention window corresponding to each channel access priority class according to a third adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to a third adjustment policy. The method of claim 1.

19. The feedback information and the SL transmission type satisfy a preset feedback condition, Determining a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type includes: determining a current busy level of a channel in which the first communication node resides; determining a contention window adjustment policy for the first SL transmission based on the current busy level. The method of claim 1.

20. determining a contention window adjustment policy for the first SL transmission based on the current busy level, determining a target length of a contention window corresponding to the first SL transmission based on the current busy level and a channel access priority class corresponding to the first SL transmission; and adjusting a contention window corresponding to the first SL transmission according to a target length of the contention window.

20. The method of claim 19.

21. determining a contention window adjustment policy for the first SL transmission based on the current busy level, If the current busy level is equal to or greater than a first busy level threshold, adjusting a contention window corresponding to each channel access priority class according to a second adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the second adjustment policy; If the current busy level is less than a second busy level threshold, adjusting a contention window corresponding to each channel access priority class according to a first adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to the first adjustment policy; adjusting a contention window corresponding to each channel access priority class according to a third adjustment policy, or adjusting a contention window corresponding to the channel access priority class corresponding to the first SL transmission according to a third adjustment policy, when the current busy level exceeds a second busy level threshold and is less than a first busy level threshold, and the first busy level threshold is equal to or greater than the second busy level threshold.

20. The method of claim 19.

22. The preset feedback condition is: the second SL transmission being of feedback information without enabling feedback; the first SL transmission being of feedback information that does not enable feedback; the first SL transmission is of feedback information enabling feedback and SL transmission type, and the SL transmission type is unicast transmission, and a second communication node transmits the feedback information using the same resource; the second SL transmission is of a feedback-enabled SL transmission type and the first communication node has not obtained a feedback message; and The first communication node has not obtained a feedback message of the second SL transmission, and the first SL transmission does not include a retransmission; the first communication node has not acquired a feedback message of the second SL transmission, and the first SL transmission is a transmission performed in a time window after a sensing time length corresponding to the second SL transmission. The method according to any one of claims 18 to 21.

23. A channel access method applied to a second communication node, comprising: transmitting feedback information and a SL transmission type of a second sidelink (SL) transmission corresponding to the first SL transmission to a first communication node, so as to cause the first communication node to determine a contention window adjustment policy for the first SL transmission based on the feedback information and the SL transmission type; and adjusting the contention window corresponding to the first SL transmission according to the contention window adjustment policy, so as to cause the first communication node to perform channel access according to the contention window; the second SL transmission is a transmission performed within a channel occupancy time obtained using a first channel access type before the first SL transmission; Channel access method.

24. A communication module, a memory, and at least one processor, the communication module is configured to provide a communication interface with other communication nodes; the memory is configured to store at least one program; When said at least one program is executed by said at least one processor, said at least one processor implements the channel access method according to any one of claims 1 to 22 or 23. Channel access device.

25. A computer program is stored which, when executed by a processor, implements the channel access method according to any one of claims 1 to 22 or 23. storage medium.

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