Sidelink feedback transmission enhancements

Abstract

Example embodiments of the present disclosure relate to sidelink feedback transmission enhancements. The first device obtains sidelink control information for a sidelink transmission with feedback associated with the same feedback occasion of the first device. The first device also obtains a respective value of at least one channel access parameter associated with feedback of the sidelink transmission based on the sidelink control information. The first device also determines a value of feedback of the at least one channel access parameter for transmitting the sidelink transmission on the same feedback opportunity of the first device as a function of a corresponding value of the at least one channel access parameter. In this manner, sidelink feedback transmissions may be enhanced.

Description

Technical Field

[0001] Various example embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly to methods, devices, apparatuses, and computer-readable storage media for sidelink (SL) feedback transmission enhancement. Background Art

[0002] With the rapid development of communication technology, communication systems can support various types of services for terminal devices, such as SL transmission between terminal devices. In recent communication technologies, it has been proposed that terminal devices can use resources such as shared frequency bands of unlicensed spectrum for SL transmission. For example, a terminal device may be required to access resources in an unlicensed spectrum by performing a channel access procedure to use the resources for SL operation. In some cases, a terminal device that receives an SL transmission via resources in an unlicensed spectrum may send feedback to a terminal device that performs the SL transmission. Work is in progress to introduce enhancements to SL feedback transmission. Summary of the invention

[0003] In a first aspect of the present disclosure, a first device is provided. The first device includes: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, cause the first device to at least perform: obtaining sidelink control information of a sidelink transmission having feedback associated with the same feedback opportunity as the first device; based on the sidelink control information, obtaining a corresponding value of at least one channel access parameter associated with the feedback of the sidelink transmission; and determining the value of at least one channel access parameter as a function of the corresponding value of at least one channel access parameter, the value being used to send feedback of the sidelink transmission on the same feedback opportunity of the first device.

[0004] In a second aspect of the present disclosure, a second device is provided. The second device includes: at least one processor; and at least one memory storing instructions, which, when executed by the at least one processor, cause the second device to at least perform: sending channel access configuration information to the first device, the channel access configuration information including at least one of the following: a function for determining the value of at least one channel access parameter from a plurality of values ​​of at least one channel access parameter, the value of the at least one channel access parameter being used to send feedback of a sidelink transmission of the first device; a mapping rule between a sidelink transmission priority and an associated value of at least one channel access parameter for feedback associated with the sidelink transmission; a threshold number for determining whether the value of at least one channel access parameter is to be updated based on the function; or a broadcast type rule for determining whether the value of at least one channel access parameter is to be updated based on the function.

[0005] In a third aspect of the present disclosure, a method is provided. The method includes: obtaining, at a first device, sidelink control information of a sidelink transmission having feedback associated with a same feedback opportunity of the first device; obtaining, based on the sidelink control information, a corresponding value of at least one channel access parameter associated with the feedback of the sidelink transmission; and determining a value of the at least one channel access parameter as a function of the corresponding value of the at least one channel access parameter, the value being used to send feedback of the sidelink transmission on the same feedback opportunity of the first device.

[0006] In a fourth aspect of the present disclosure, a method is provided. The method includes: sending channel access configuration information to a first device at a second device, the channel access configuration information including at least one of the following: a function for determining a value of at least one channel access parameter from a plurality of values ​​of the at least one channel access parameter, the value of the at least one channel access parameter being used to send feedback of a sidelink transmission of the first device; a mapping rule between a sidelink transmission priority and an associated value of at least one channel access parameter for feedback associated with the sidelink transmission; a threshold number for determining whether the value of the at least one channel access parameter is to be updated based on the function; or a broadcast type rule for determining whether the value of the at least one channel access parameter is to be updated based on the function.

[0007] In a fifth aspect of the present disclosure, a first device is provided. The first device includes: a component for obtaining sidelink control information of a sidelink transmission having feedback associated with the same feedback opportunity of the first device; a component for obtaining a corresponding value of at least one channel access parameter associated with the feedback of the sidelink transmission based on the sidelink control information; and a component for determining the value of the at least one channel access parameter as a function of the corresponding value of the at least one channel access parameter, the value being used to send feedback of the sidelink transmission on the same feedback opportunity of the first device.

[0008] In a sixth aspect of the present disclosure, a second device is provided. The second device includes: a component for sending channel access configuration information to the first device, the channel access configuration information including at least one of the following: a function for determining the value of at least one channel access parameter from a plurality of values ​​of the at least one channel access parameter, the value of the at least one channel access parameter being used to send feedback of a sidelink transmission of the first device; a mapping rule between a sidelink transmission priority and an associated value of at least one channel access parameter for feedback associated with the sidelink transmission; a threshold number for determining whether the value of at least one channel access parameter is to be updated based on the function, or a broadcast type rule for determining whether the value of at least one channel access parameter is to be updated based on the function.

[0009] In a seventh aspect of the present disclosure, a computer-readable medium is provided, wherein the computer-readable medium includes instructions stored thereon, and the instructions are used to cause a device to at least execute the method according to the third aspect.

[0010] In an eighth aspect of the present disclosure, a computer-readable medium is provided, wherein the computer-readable medium includes instructions stored thereon, and the instructions are used to cause a device to at least execute the method according to the fourth aspect.

[0011] It should be understood that the abstract is not intended to identify the key or essential features of the embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0013] Figure 1 An example communication environment is shown in which example embodiments of the present disclosure may be implemented;

[0014] Figure 2 shows a signaling diagram for communication according to some example embodiments of the present disclosure;

[0015] Figure 3A , Figure 3B and Figure 3C Some examples of SL transmission with channel access procedure are shown;

[0016] Figure 4 shows example SL time slots according to some example embodiments of the present disclosure;

[0017] Figure 5A and Figure 5B shows an example mapping between SL transmission and SL feedback according to some example embodiments of the present disclosure;

[0018] Figure 6 A flow chart illustrating a process for determining a channel access procedure for feedback transmission according to some example embodiments of the present disclosure;

[0019] Figure 7 A flowchart showing a method implemented at a first device according to some example embodiments of the present disclosure is shown;

[0020] Figure 8 A flowchart showing a method implemented at a second device according to some example embodiments of the present disclosure is shown;

[0021] Fig. 9 shows a simplified block diagram of a device suitable for implementing an example embodiment of the present disclosure; and

[0022] Fig.10 A block diagram of an example computer-readable medium is shown according to some example embodiments of the present disclosure.

[0023] Throughout the drawings, the same or similar reference numerals refer to the same or similar elements. DETAILED DESCRIPTION

[0024] The principles of the present disclosure will now be described with reference to some example embodiments. It should be understood that these embodiments are only for illustrative purposes and are helpful for those skilled in the art to understand and implement the present disclosure without implying any limitation on the scope of the present disclosure. The embodiments described herein can be implemented in various ways different from the ways described below.

[0025] In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0026] References in this disclosure to "one embodiment," "an embodiment," "an example embodiment," etc. indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes the particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it is considered to be within the purview of those skilled in the art to affect such feature, structure, or characteristic in conjunction with other embodiments, whether or not explicitly described.

[0027] It should be understood that although the terms "first", "second", etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the exemplary embodiments, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0028] As used herein, “at least one of: ” and “at least one of ” and similar expressions (wherein a list of two or more elements is connected by “and” or “or”) refer to at least any one of the elements, or at least any two or more of the elements, or at least all of the elements.

[0029] As used herein, unless explicitly stated, performing a step “in response to A” does not mean performing the step immediately after “A” occurs, but may include one or more intermediate steps.

[0030] The terms used herein are used only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments. As used herein, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms as well. It should also be understood that when used herein, the terms "comprises", "comprising", "has", "having", "includes", and / or "including" specify the presence of features, elements, and / or parts, etc., but do not exclude the presence or addition of one or more other features, elements, parts, and / or combinations thereof.

[0031] As used in this application, the term "circuitry" may refer to one or more or all of the following: (a) hardware circuit implementation only (e.g., implementation only in analog and / or digital circuitry) and (b) hardware circuit implementation only (e.g., implementation only in analog and / or digital circuitry). (b) a combination of hardware circuitry and software, such as (where applicable): (i) a combination of analog and / or digital hardware circuits and software / firmware; and (ii) any portion of a hardware processor with software (including a digital signal processor, software, and memory that work together to enable a device such as a mobile phone or server to perform various functions), and (c) a hardware circuit and / or processor that requires software (e.g., firmware) for operation, such as a microprocessor or a portion of a microprocessor, but the software may not be present when not required for operation.

[0032] This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of only a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to a particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in a server, cellular network device, or other computing or network device.

[0033] As used herein, the term "communication network" refers to a network that complies with any suitable communication standard, such as New Radio (NR), Long Term Evolution (LTE), Advanced LTE (LTE-A), Wideband Code Division Multiple Access (WCDMA), High Speed ​​Packet Access (HSPA), Narrowband Internet of Things (NB-IoT), etc. In addition, the communication between the terminal device and the network device in the communication network can be performed according to any suitable generation communication protocol, including but not limited to the first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) communication protocol and / or any other protocol currently known or developed in the future. The embodiments of the present disclosure can be applied to various communication systems. In view of the rapid development of communication, there are of course communication technologies and systems of future types that can implement the present disclosure. The scope of the present disclosure should not be considered to be limited to the above-mentioned system.

[0034] As used herein, the term "network device" refers to a node in a communication network, via which a terminal device accesses the network and receives services from it. A network device may refer to a base station (BS) or an access point (AP), for example, a NodeB (NodeB or NB), an evolved NodeB (eNodeB or eNB), a NR NB (also referred to as a gNB), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), a repeater, an integrated access and backhaul (IAB) node, a low-power node (e.g., a femto, a micro), a non-terrestrial network (NTN) or a non-terrestrial network device (such as a satellite network device, a low earth orbit (LEO) satellite and a geosynchronous orbit (GEO) satellite, an aircraft network device), etc., depending on the terminology and technology applied. In some example embodiments, a radio access network (RAN) split architecture includes a centralized unit (CU) and a distributed unit (DU) at an IAB donor node. An IAB node includes a mobile terminal (IAB-MT) portion that behaves similarly to a UE toward a parent node, and a DU portion of an IAB node behaves similarly to a base station toward a next-hop IAB node.

[0035] The term "terminal device" refers to any terminal device capable of wireless communication. As an example and not limitation, a terminal device may also be referred to as a communication device, a user equipment (UE), a user station (SS), a portable subscriber station, a mobile station (MS), or an access terminal (AT). The terminal device may include, but is not limited to, a mobile phone, a cellular phone, a smart phone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet computer, a wearable terminal device, a personal digital assistant (PDA), a portable computer, a desktop computer, an image capture terminal device (e.g., a digital camera), a game terminal device, a music storage and playback facility, a vehicle-mounted wireless terminal device, a wireless endpoint, a mobile station, a laptop embedded device (LEE), a laptop mounted device (LME), a USB dongle, a smart device, a wireless customer premises equipment (CPE), an Internet of Things (IoT) device, a watch or other wearable device, a head mounted display (HMD), a vehicle, a drone, medical equipment and applications (e.g., remote surgery), industrial equipment and applications (e.g., robots and / or other wireless devices operating in industrial and / or automated processing chain environments), consumer electronic devices, equipment operating on commercial and / or industrial wireless networks, etc. In some example embodiments, the terminal device may include a device performing device-to-device (D2D) communication (also referred to as a D2D device). Alternatively or additionally, in some example embodiments, the terminal device may also include a device performing vehicle-to-everything (V2X) communication (also referred to as a V2X device). V2X communication may include, but is not limited to, vehicle-to-infrastructure (V2I) communication, vehicle-to-network (V2N) communication, vehicle-to-vehicle (V2V) communication, vehicle-to-pedestrian (V2P) communication, or vehicle-to-device (V2D) communication. The terminal device may also correspond to the mobile terminal (MT) portion of an IAB node (e.g., a relay node). In the following description, the terms "terminal device", "communication device", "terminal", "user equipment" and "UE" may be used interchangeably.

[0036] As used herein, the term "resource", "transmission resource", "resource block", "physical resource block" (PRB), "uplink resource" or "downlink resource" may refer to any resource used to perform communication (e.g., communication between a terminal device and a network device), such as a resource in the time domain, a resource in the frequency domain, a resource in the spatial domain, a resource in the code domain, or any other resource that enables communication. In the following, unless explicitly stated, resources in the frequency domain and the time domain will be used as examples of transmission resources for describing some example embodiments of the present disclosure. Note that the example embodiments of the present disclosure are also applicable to other resources in other domains. Example Environment

[0037] Figure 1An example communication environment 100 is shown in which example embodiments of the present disclosure may be implemented. In the communication environment 100, a device 110 has a particular coverage area, which may be referred to as a service area or cell 102. One or more devices may be located inside or outside of the cell 102. As shown, a device 120 and a device 130 are located inside the cell 102 and therefore can communicate with the device 110. A device 140 is located outside of the cell 102 and therefore cannot obtain service from the device 110.

[0038] exist Figure 1 In the example of , device 120 and device 130 may include terminal devices, and device 110 may include a network device serving the terminal device. Device 140 may also include a terminal device. In some example embodiments, if device 110 is a network device and device 120 or device 130 is a terminal device, the link from device 120 (or device 130) to device 110 is referred to as an uplink (UL), and the link from device 110 to device 120 (or device 130) is referred to as a downlink (DL).

[0039] In some example embodiments, different terminal devices may establish communication connections with each other. For example, device 120 and device 130 inside cell 102 (in coverage) may establish communication connections with each other. In addition, device 140 outside cell 102 (out of coverage) may also establish communication connections with device 120 and / or device 130 inside cell 102. In some example embodiments, a terminal device such as device 120, 130 or 140 may establish communication connections with multiple other terminal devices. Communication between terminal devices may be referred to as sidelink (SL) communication.

[0040] During SL communication, different terminal devices can communicate data and control information with each other. For example, if an SL connection is established between terminal devices, a terminal device can communicate data and control information with more than one terminal device. In SL communication, a terminal device that performs transmission (e.g., device 120 (or device 130 or device 140)) is referred to as a transmitting (TX) device (or transmitter), and a terminal device that receives transmission (e.g., device 130 (or device 120 or device 140)) is referred to as a receiving (RX) device (or receiver).

[0041] SL communication can support one or more communication methods, including unicast communication, multicast communication and broadcast communication. SL can include one or more logical channels, including but not limited to physical side link control channel (PSCCH), physical side link shared channel (PSSCH), physical side link feedback channel (PSFCH), physical side link discovery channel (PSDCH) and physical side link broadcast channel (PSBCH).

[0042] It should be understood that Figure 1 The number of devices and their connections shown in the figure is for illustration purposes only and does not imply any limitation. The communication environment 100 may include any suitable number of devices for implementing the example embodiments of the present disclosure. Although not shown, it should be understood that one or more additional devices may be located in the cell 102, and one or more additional cells may be deployed in the communication environment 100.

[0043] Hereinafter, for the purpose of illustration, some example embodiments are described as having device 110 operating as a network device and devices 120, 130, and 140 operating as terminal devices. However, in some example embodiments, the operations described in conjunction with the terminal device may be implemented at a network device or other device, and the operations described in conjunction with the network device may be implemented at a terminal device or other device.

[0044] The communication in the communication environment 100 may be implemented according to any suitable communication protocol, including but not limited to cellular communication protocols of the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G), the fifth generation (5G), the sixth generation (6G), etc., wireless local area network communication protocols such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11, etc., and / or any other protocol currently known or developed in the future. In addition, the communication may utilize any suitable wireless communication technology, including but not limited to: code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), frequency division duplex (FDD), time division duplex (TDD), multiple input multiple output (MIMO), orthogonal frequency division multiple access (OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM) and / or any other technology currently known or developed in the future.

[0045] As described above, a terminal device may use resources in an unlicensed spectrum (such as a shared radio frequency band) to perform SL transmissions. For example, a terminal device may be required to access resources in an unlicensed spectrum by performing a channel access procedure to use the resources for SL operations. In some cases, a terminal device that receives a SL transmission via resources in an unlicensed spectrum may send feedback to a terminal device that performs the SL transmission. For example, a TX terminal device may send hybrid automatic repeat request (HARQ) feedback on the SL from a terminal device that is an intended recipient of a PSSCH transmission (i.e., an RX terminal device) to a terminal device that performs a PSSCH transmission (i.e., a TX terminal device).

[0046] In some cases, when sending SL feedback such as HARQ feedback, the RX terminal device also needs to access resources in the unlicensed spectrum.The resources used for SL feedback (such as PSFCH) can be derived from the resource location of the SL transmission (such as PSCCH or PSSCH).

[0047] In some methods, the RX terminal device may use the channel occupancy time (COT) initiated by the TX terminal device to send SL feedback. A priority value or priority level may be assigned to PSFCH transmission or reception. Th priority value or priority level may reflect latency requirements and may be associated as described in the 3rd Generation Partnership Project (3GPP) Technical Specification (TS). For example, for PSFCH transmission or reception with HARQ feedback (such as HARQ acknowledgment (ACK) information), the priority value for PSFCH may be equal to the priority value indicated by the side link control information (SCI) format 1-A associated with the PSFCH. For another example, for PSFCH transmission with conflicting information, the priority value for PSFCH may be equal to the minimum priority value determined by the corresponding SCI format 1-A for conflicting resources. For another example, for PSFCH reception with conflicting information, the priority value for PSFCH may be equal to the priority value determined by the corresponding SCI format 1-A for conflicting resources.

[0048] However, in some cases, the TX-initiated COT is not available for RX transmission, so the RX terminal device needs to initiate COT for SL feedback transmission. In this case, a channel access priority needs to be associated with the SL feedback transmission. Such channel access priority can be used in a channel access procedure (such as a listen-before-talk (LBT) type 1 procedure) to initiate COT. However, there is a lack of an efficient way to associate appropriate channel access priorities for SL feedback transmission.

[0049] In some methods, the channel access priority of the PSFCH transmission (such as the channel access priority category (CAPC)) may depend on the priority value of the corresponding SL transmission (e.g., PSCCH or PSSCH transmission) indicated by SCI format 1-A. In other words, the channel access priority of the PSFCH transmission may be associated with the data priority. Consider a scenario where terminal device A sends a data packet with a priority value p to the RX terminal device. A PSCCH / PSSCH A, and terminal device B sends a PSCCH / PSSCH A with priority value p to the RX terminal device. B (with p A The RX terminal device may send feedback associated with PSCCH / PSSCH A or PSCCH / PSSCH B on the PSFCH opportunity.

[0050] However, if the RX terminal device is associated with a CAPC with a high p value (for low priority information), it has a higher probability of failing LBT and may miss PSFCH transmissions, resulting in HARQ-ACK misdetection problems such as unnecessary retransmissions or non-acknowledgement (NACK) to ACK misinterpretation if the NACK-only HARQ option is used. In addition, if the RX terminal device is associated with a CAPC with a low p value (for high priority information), it has a higher chance of acquiring the channel when the contention window is low, but may suffer LBT failures to the detriment of other devices also competing for the channel. For example, assuming p B <p A , if an RX terminal device sending feedback associated with PSCCH / PSSCH B uses a low CAPC / smaller contention window (CW), and another RX terminal device sending feedback associated with PSCCH / PSSCH A uses a high CAPC / larger CW, the former RX terminal device is able to complete the LBT process to send PSFCH.

[0051] In some methods, such as in the new radio (NR) unlicensed (NR-U) design, several channel access priority association methods are proposed. For example, for an UL configuration grant, the lowest priority of the logical channel (LCH) multiplexed in a transport block (TB) is selected. When a signaling radio bearer (SRB) is multiplexed in a TB on a configuration grant (CG), the CAPC of the SRB can be used. For another example, for an UL grant case, the terminal device can assume a CAPC of p=4 within a COT initiated by a network device, and for a COT initiated by a terminal device, the terminal device can select a channel access priority based on data priority. For DL ​​assignments, the physical uplink control channel (PUCCH) can use the highest CAPC. In some methods, this NR-U design can be applied in SL feedback transmission. However, the NR-U design does not consider the SL multicast scenario in which multiple RX terminal devices must send feedback to a TX terminal device. If the NR-U design is adopted, one low priority transmission from a TX terminal device will trigger many RX terminal devices competing for channels with other devices. This is unfair to other devices using unlicensed spectrum.

[0052] In order to enhance SL feedback transmission, it is desirable to associate or select appropriate channel access parameter values, such as appropriate channel access priority for SL feedback transmission. Working principles and example signaling for communication

[0053] As described above, enhancing SL feedback transmission in unlicensed spectrum is challenging. According to some example embodiments of the present disclosure, a scheme for SL feedback transmission enhancement is provided. In the scheme, a first device obtains an SCI for SL transmissions associated with the same feedback timing (such as the same PSFCH timing). The first device determines a corresponding value of at least one channel access parameter associated with the feedback of the SL transmission based on the obtained SCI. For example, the at least one channel access parameter may include a channel access priority for the SL feedback. The first device selects a value for at least one channel access parameter by using a function of the corresponding value of the at least one channel access parameter of the received SL transmission.

[0054] In this way, an appropriate channel access priority can be associated with the SL feedback transmission. By associating the channel access priority, the chances of a successful channel access process when multiple SL feedbacks are multiplexed in the same time slot will therefore be improved. In addition, such an approach uses unlicensed spectrum to achieve better fairness towards other devices.

[0055] Example embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0056] Figure 2 2 shows a signaling diagram 200 for communication according to some example embodiments of the present disclosure. Figure 2 As shown, the signaling diagram 200 involves a first device 201 and a second device 202. In some example embodiments, the first device 201 may include a terminal device such as Figure 1 In some example embodiments, the second device 202 may include a network device such as a Figure 1 Alternatively, in some example embodiments, the second device 202 may include a terminal device different from the first device 201, such as Figure 1 Another one of device 120, device 130 or device 140 in.

[0057] Despite Figure 2 , a first device 201 and a second device 202 are shown, but it should be understood that there may be multiple first devices that perform similar operations as described below with respect to the first device 201 and multiple second devices that perform similar operations as described below with respect to the second device 202.

[0058] In operation, the second device 202 may send 210 configuration information to the first device 201. For example, the second device 202 may send 210 channel access configuration information to the first device 201.

[0059] In an example where the second device 202 comprises a network device, the second device 202 may send 210 the channel access configuration information and the resource pool configuration. For example, in a mode 1 SL transmission, the second device 202 may send the resource pool configuration together with the channel access configuration information to the first device 201 .

[0060] In an example where the second device 202 includes a terminal device, the second device 202 may send (210) channel access configuration information via a SL synchronization signal / physical broadcast channel (PBCH) block (SSB), via an SCI, via PC5 radio resource control (RRC), or any other suitable method.

[0061] In some example embodiments, the first device 201 may receive (215) configuration information such as channel access configuration information. Details regarding the channel access configuration information will be described below.

[0062] In some example embodiments, the first device 201 may receive 220 SL transmissions. For example, the first device 201 may receive 220 SL transmissions from other terminal devices. In examples where the second device 202 comprises a terminal device, the first device 201 may receive 220 SL transmissions from the second device 202.

[0063] In some example embodiments, the SL transmission may be performed on a shared frequency band such as an unlicensed frequency band (also referred to as an unlicensed spectrum). In this case, before sending the SL transmission to the first device 201, the other terminal devices need to perform a channel access procedure to initiate a channel occupation time (COT). The channel access procedure may include LBT. An example of a channel access procedure is described below.

[0064] As described above, in order to operate on a shared band such as an unlicensed band, different channel access procedures including LBT may be used prior to performing SL transmissions by the terminal device. For example, in order to pass LBT, the device needs to observe the shared band as available for a number of consecutive clear channel assessment (CCA) slots. In sub-7 GHz bands, the duration of a slot may be 9 μs. For example, if the measured power (i.e., the energy collected during a CCA slot) is below a predetermined threshold, the device may determine that the shared band is available in that CCA slot. There are several types of channel access procedures, which will be referenced in detail below. Figure 3A-3C Give a description.

[0065] like Figure 3AAs shown, when the initiating device 310 intends to use resources on the shared radio frequency band to perform a transmission to the responding device 320, the initiating device 310 needs to obtain permission to access the shared radio frequency band for a certain period of time, which is also referred to as the channel occupation time (COT) 340 by applying the channel access process. As used herein, the term "initiating device" may refer to a device that initiates a transmission to one or more other devices and obtains the COT for the transmission. As used herein, the term "responding device" may refer to a device to which the initiating device performs a transmission.

[0066] In some example embodiments, the channel access procedure may be an “extended” LBT procedure (e.g., an LBT Type 1 (also referred to as Type 1 LBT) procedure or a Type 1 channel access procedure) in which the shared radio frequency band is sensed to be idle for the duration of a sensing interval determined based on the contention window. After the initiator device 310 successfully completes the LBT Type 1 check, the initiator device 310 may perform a transmission during the COT 340.

[0067] If the initiator device 310 decides to perform a new transmission within the COT 340 after the initial transmission, the initiator device 310 may perform an additional channel access procedure within the COT 340. In this case, the channel access procedure may include a "reduced" LBT procedure (e.g., an LBT Type 2 (also referred to as a Type 2 LBT) procedure or a Type 2 channel access procedure) in which the initiator device 310 may need to monitor the shared RF band for a smaller period of time than an "extended" LBT procedure (e.g., an LBT Type 1 procedure). Figure 3B An example of performing an LBT Type 2 process by the initiator device 310 prior to a new transmission performed within the COT 340 is shown.

[0068] like Figure 3B As shown, after completing the LBT Type 1 process, the initiator device 310 performs an initial transmission 350. Thereafter, the initiator device 310 may intend to perform a new transmission 352 within the COT 340. Figure 3B As shown, the initiating device 310 may need to perform an LBT Type 2 procedure prior to performing the transmission 352 in order to check that the shared radio frequency band is available for communication.

[0069] There are several types of LBT Type 2 procedures that can be selected based on the time gap between two transmissions to be performed within the COT. As an example, the LBT Type 2 procedure can include an LBT Type 2A procedure, an LBT Type 2B procedure, and an LBT Type 2C procedure. The channel access procedure to be performed is determined based on the duration of the time gap 360 between transmissions 350 and 352. For example, if the duration of the time gap 360 is greater than or equal to 25 μs, the initiator device 310 can perform an LBT Type 2A (referred to as "25 μs LBT") procedure. If the duration of the time gap 360 is equal to 16 μs, the initiator device 310 can perform an LBT Type 2B (referred to as "16 μs LBT") procedure. If the duration of the time gap 360 is less than 16 μs, the initiator device 310 can perform an LBT Type 2C procedure, which may not require the execution of an LTB procedure. That is, if the LBT Type 2C procedure is selected, the initiator device 310 can directly perform the transmission 352 without actually performing the channel access procedure.

[0070] In some example embodiments, the initiator device 310 that has acquired the COT 340 may share the COT 340 with one or more other devices (e.g., the responding device 320) communicating therewith. In order to share the COT 340 with the responding device 320, the initiator device 310 may inform the responding device 320 (e.g., via control signaling) about the duration of the COT 340. With the COT sharing mechanism, the responding device 320 is able to perform transmissions within the COT 340 through a “reduced” LBT process. Note that when the responding device 320 performs a transmission, the responding device 320 becomes the initiator device.

[0071] Figure 3C An example of performing an LBT Type 2 process prior to transmission by a responding device 320 within a COT 340 is shown. Figure 3C As shown, after completing the LBT Type 1 process, the initiating device 310 performs a transmission 350. Thereafter, the responding device 320 may intend to perform a transmission 370 within the COT 340. Figure 3C As shown, responding device 320 may perform an LBT Type 2 procedure prior to transmission 370 to check that the shared radio frequency band is available for communication.

[0072] The LBT Type 2 procedure to be performed by responding device 320 may be selected based on the duration of time gap 380 between transmissions 350 and 370. For example, if the duration of time gap 380 is greater than or equal to 25 μs, responding device 320 may perform an LBT Type 2A procedure. If the duration of time gap 380 is equal to 16 μs, responding device 320 may perform an LBT Type 2B procedure. If the duration of time gap 380 is less than 16 μs, responding device 320 may perform an LBT Type 2C procedure, and thus may directly perform transmission 370. In some cases, if responding device 320 initiates its transmission outside of COT 340, it may be necessary to use an “extended” LBT procedure to acquire a new COT.

[0073] Through the above discussion, based on the time gap between two transmissions performed by the same device or two devices in the case of COT sharing, a device may select various types of channel access procedures.

[0074] Still reference Figure 2 . If the initiating device initiates the COT, the initiating device may send a SL transmission to the first device 201. The first device 201 may receive (220) the SL transmission from the initiating device. It should be understood that the first device 201 may receive (220) the SL transmission from any suitable number of initiating devices. Alternatively or additionally, the first device 201 may also receive (220) the SL transmission in a COT initiated by the first device 201 itself and shared with another device. In some example embodiments, the first device 201 may receive (220) SL transmissions from different devices in the vicinity of the first device 201 for different RX devices or groups of RX devices.

[0075] In some example embodiments, the first device 201 obtains (225) SCI for SL transmissions having feedback associated with the same feedback opportunity of the first device 201. For example, the first device 201 may monitor the SCI for the SL transmissions. For example, the feedback for the SL transmissions may include a PSFCH transmission. In some example embodiments, the feedback opportunity may include a feedback slot, such as a PSFCH slot. In some example embodiments, the SCI may follow a 2-stage SCI structure. For example, a stage 1 SCI (also referred to as SCI format 1-A) may be carried by a PSCCH.

[0076] SCI format 1-A may include information required to determine resource allocation for the PSSCH and decode the stage 2 SCI. Stage 2 SCI (such as SCI format 2-A or SCI format 2-B) may be carried by the PSSCH (multiplexed with the sidelink shared channel (SL-SCH)). Stage 2 SCI may include control information for HARQ feedback in unicast or multicast. It should be understood that stage 1 SCI and stage 2 SCI may also include other suitable information. Examples of additional information included in the SCI are described below.

[0077] In some example embodiments, SCI format 1-A may be used for scheduling of PSSCH and stage 2 SCI on PSSCH. The following information is sent via SCI format 1-A: - Priority—3 bits; - Frequency resource assignment—When the value of the higher layer parameter sl-MaxNumPerReserve is configured as 2, bit; otherwise, when the value of the higher layer parameter sl-MaxNumPerReserve is configured as 3, Bit; - Time Resource Assignment—5 bits when the value of the higher layer parameter sl-MaxNumPerReserve is configured as 2; otherwise, 9 bits when the value of the higher layer parameter sl-MaxNumPerReserve is configured as 3; -Resource reservation period bits, where N rsv_period is the number of entries in the higher layer parameter sl-ResourceReservePeriodList; otherwise 0 bit; -DMRS Mode— bits, where N pattern is the number of DMRS patterns configured by the higher layer parameter sl-PSSCH-DMRS-TimePatternList; if sl-PSSCH-DMRS-TimePatterList is not configured, it is 0 bit; - Stage 2 SCI format—2 bits, as defined in Table 1 below; - Beta_offset indicator—2 bits provided by the higher layer parameter sl-BetaOffsets2ndSCI; - Number of DMRS ports—1 bit; - Modulation and coding scheme—5 bits; - Additional MCS table indicator - 1 bit if one MCS table is configured by the higher layer parameter sl-Additional-MCS-Table; 2 bits if two MCS tables are configured by the higher layer parameter sl-Additional-MCS-Table; otherwise, 0 bit; -PSFCH overhead indication—1 bit if higher layer parameter sl-PSFCH-Period=2 or 4; otherwise, 0 bit; - Reserved—The number of bits determined by the higher layer parameter sl-NumReservedBits, where the value is set to zero. Table 1 Phase 2 SCI format Values ​​of the Phase 2 SCI Format fields Phase 2 SCI Format 00 SCI Format 2-A 01 SCI Format 2-B 10 Reserve 11 Reserve

[0078] In some example embodiments, SCI format 2-A has the following information: HARQ process number, new data indicator, redundancy version, source ID, destination ID, HARQ feedback enable / disable indicator, broadcast type indicator, and CSI request. SCI format 2-B may have the following information: HARQ process number, new data indicator, redundancy version, source ID, destination ID, HARQ feedback enable / disable indicator, area ID, and communication range requirement.

[0079] It should be understood that the above examples of SCI Format 1, SCI Format 2-A, and SCI Format 2-B are shown for illustration purposes only and do not imply any limitation.

[0080] As described above, the Phase 2 SCI may include control information for HARQ feedback in unicast or multicast. In some example embodiments, the following HARQ feedback options may be configured for multicast. The first option is HARQ feedback with NACK only. In this first option, all terminal devices in the group share a single PSFCH resource. If no NACK is received in the shared PSFCH resource, the TX device determines an ACK. The RX device decides whether to send feedback based on the distance between the TX device and the RX device. This option can be used for any group size and can be used when a group is formed without any higher layer group management.

[0081] The second option is ACK / NACK HARQ feedback. In this second option, each RX device uses a dedicated PSFCH resource. The TX device determines ACK only when all expected ACKs are received and no NACKs are received. The group member ID and source ID are used for implicit determination of PSFCH resources. This option can be used only when the group parameters (group size, member ID) are provided by the upper layer and when the group size is not greater than the number of candidate PSFCH resources associated with the PSSCH resource.

[0082] In some example embodiments, the first device 201 obtains (230) a corresponding value of at least one channel access parameter associated with the feedback of the SL transmission based on the obtained SCI. For example, the at least one channel access parameter may include at least one of the following: a channel access priority class (CAPC), or a size of a contention window (CW). Alternatively or additionally, the at least one channel access parameter may include a channel access procedure type, such as an LBT type.

[0083] Taking CAPC as an example channel access parameter, the first device 201 may obtain (230) a corresponding value of at least one channel access parameter based on an explicit CAPC indication included in the first or second stage SCI. Alternatively or additionally, in some example embodiments, the first device 201 may obtain (230) a corresponding value of at least one channel access parameter based on a corresponding data priority of the SL transmission and an association rule between the CAPC and the data priority. The association rule may be indicated in the SCI. In the case of determining the value of the CAPC, the value of the size of the CW may also be determined based on an association rule between the CAPC and the size of the CW.

[0084] In some example embodiments, the first device 201 may also determine a value of the size of the CW based on the obtained SCI, and determine a value of the CAPC based on the value of the size of the CW. It should be understood that the above method for obtaining a value of at least one channel access parameter is for illustrative purposes only, and any suitable method for obtaining a value of at least one channel access parameter may be applied. In some example embodiments, the obtained value of at least one channel access parameter may be stored by the first device 201.

[0085] In some example embodiments, the first device 201 may determine (235) whether to send feedback of the received SL transmission on the same feedback opportunity of the first device 201 based on the obtained SCI. For example, the SCI may include information about whether to send feedback of the SL transmission. In addition, in some example embodiments, the SCI may also include resource pool configuration information. For example, the resource pool configuration information may include information for the first device 201 to decode the SL transmission. The resource pool configuration information may include information such as the number of subchannels, the number of physical resource blocks (PRBs) per subchannel, the number of symbols in the PSCCH, which time slots have the PSFCH, and any other suitable configuration.

[0086] Figure 4An example SL time slot 401 with PSCCH / PSSCH and PSFCH is shown. The SL time slot can be configured by the resource pool configuration information in the SCI. As shown, a PSFCH opportunity 405 (such as the last symbol) can be included in the time slot 401. The PSFCH can enable HARQ feedback on the SL from the device that is the intended recipient of the PSSCH transmission (i.e., the RX device) to the device that performs the transmission (i.e., the TX device). Within the PSFCH, the Zadoff-Chu sequence in one PRB is repeated over two orthogonal frequency division multiplexing (OFDM) symbols. The Zadoff-Chu sequence as the base sequence is (pre)configured per SL resource pool.

[0087] In some example embodiments, HARQ feedback resources (such as PSFCH) can be derived from the resource location of PSCCH / PSSCH. For PSSCH to HARQ timing, there is a configuration parameter K with time slot units. The time timing for PSFCH can be determined based on K. For a PSSCH transmission with its last symbol in time slot n, the HARQ feedback can be in time slot n+a, where a is the smallest integer greater than or equal to K, provided that time slot n+a contains PSFCH resources. A time gap of at least K time slots allows RX device processing delays to be taken into account when decoding PSCCH and generating HARQ feedback. K can be equal to 2 or 3 or any other suitable value, and a single value of K can be (pre)configured per resource pool.

[0088] Figure 5A An example mapping between SL transmission and SL feedback according to some example embodiments of the present disclosure is shown. The mapping may be configured by the SCI. Figure 5A In the example of , K may be equal to 2. As shown, PSSCH 510 (PSSCH 2) is mapped to a set of M PRBs (Mset PRBs) 515 in PSFCH opportunity 530. In addition, PSSCH 520 (PSSCH 12) is mapped to Mset PRBs 525. In some example embodiments, PSFCH may be configured with a priority value.

[0089] In some example embodiments, in the case of ACK / NACK feedback for groupcast communication or in the case of different PSSCH transmissions in the same subchannel, a set of Mset PRBs associated with a subchannel is shared among multiple RX devices. For each PRB available for PSFCH, there are Q cyclic shift pairs available to support ACK or NACK feedback for Q RX UEs within the PRB. The first device 201 can determine which PRB and cyclic shift pair should be used to send its HARQ feedback based on the PSFCH index i. For example, the first device 201 can use the first cyclic shift or the second cyclic shift from the cyclic shift pair associated with the selected PSFCH index i to send a NACK or ACK, respectively. By selecting the PSFCH with index i by the RX device, the TX device can distinguish the HARQ feedback of different RX devices. In some example embodiments, prioritization of simultaneous PSFCH transmission / reception can be applied. In other words, the first device 201 can determine the channel access priority for SL feedback.

[0090] Still reference Figure 2 The first device 201 may determine (235) to send feedback for SL transmission based on the configuration information included in the SCI. It should be understood that the first device 201 may determine (235) whether to send SL feedback using any suitable method.

[0091] In some example embodiments, the first device 201 may determine (240) whether the first device 201 needs to initiate a COT for SL feedback transmission. For example, if there is already an available COT for the first device 201, the first device 201 may use the COT to send the SL feedback. In some example embodiments, the COT being available means that there should be an initiating COT that ends after the transmit symbol of the PSFCH. In some example embodiments, the first device 201 may use a channel access procedure, such as an LBT type 2 procedure for transmitting the PSFCH. For example, the first device 201 may determine which type of channel access procedure to perform based on the configuration in the SCI.

[0092] In some example embodiments, if a previous COT initiated by another device or by the first device 201 itself is not available, the first device 201 may need to initiate a COT. For example, the first device 201 may perform a channel access procedure, such as a type 1 channel access procedure (e.g., LBT type 1) to initiate a COT. In other words, if no COT is available for the first device 201 to perform SL transmission, the first device 201 may perform a channel access procedure to initiate a COT. Example Channel Access Prioritization

[0093] In order to perform the channel access process, the first device 201 needs to determine the value of at least one channel access parameter for sending feedback of SL transmission on the same feedback timing of the first device 201. For example, the first device 201 can determine the channel access priority for SL feedback. As used herein, the value of at least one channel access parameter for sending feedback of SL transmission determined by the first device 201 may also be referred to as a "target value". The first device 201 may apply the target value or determined value of at least one channel access parameter to send feedback of SL transmission.

[0094] In some example embodiments, the first device 201 determines (245) a value (also referred to as a target value) of at least one channel access parameter as a function of a corresponding value of the at least one channel access parameter for sending feedback of the SL transmission on the same feedback opportunity of the first device 201. In some example embodiments, the function for determining the target value of the at least one channel access parameter may be preconfigured or predefined.

[0095] Alternatively or additionally, in some example embodiments, the function may be configured by the second device 202. For example, as described above, the second device 202 may send (210) channel access configuration information to the first device 201. The first device 201 may receive (215) the channel access configuration information from the second device 202. In some example embodiments, the channel access configuration information may include a function for determining a target value for at least one channel access parameter. For example, the function may indicate that a minimum value or a maximum value among a plurality of values ​​for the at least one channel access parameter is to be selected as the target value for the at least one parameter.

[0096] Alternatively or additionally, in some example embodiments, the function may indicate a calculation for determining a target value based on a plurality of values. For example, the function may indicate obtaining an average value or a weighted average value. For another example, the function may indicate sorting a plurality of values ​​in ascending or descending order, and selecting a value with a target sorting order as the target value. In some example embodiments, the function may also indicate a threshold value. A value above the threshold value or, alternatively, a value below the threshold value may be determined as the target value. It should be understood that the above examples of functions for determining a target value are for illustrative purposes only, and any suitable function may be applied to determine the target value.

[0097] In an example where at least one channel access parameter includes CAPC, the function may instruct the first device 201 to select the minimum CAPC (corresponding to the highest priority) or the maximum CAPC (corresponding to the lowest priority). It should be understood that, in the case where the target value for CAPC is determined, the target value for the size of the CW and any other channel access parameter may also be determined based on the association rules between the target value for CAPC and different channel access parameters.

[0098] In an example where at least one channel access parameter includes the size of a CW, the function may instruct the first device 201 to select a minimum CW or a maximum CW. It should be understood that, in the case where a target value for the CW size is determined, the target values ​​for the CAPC and any other channel access parameter may also be determined based on the target value for the size of the CW and the association rules between different channel access parameters. In this case, the size of the CW for SL transmission with a specific CAPC may be adjusted based on the number of HARQ transmission failures. For example, the first device 201 may use the following Table 2 to determine the value of one of the channel access parameters based on the value of another channel access parameter. Table 2 Channel access parameters In Table 2, the contention window length in the CCA slot associated with each CAPC has a minimum value (CW min,p ) and maximum value (CW max,p ). The duration of COT is determined by T ulmcot,p Given.

[0099] Figure 5B An example mapping between SL transmission and SL feedback according to some example embodiments of the present disclosure is shown. Figure 5B In FIG. 5 , CAPC is used as an example of at least one channel access parameter. As shown in the figure, PSSCH 560 is mapped to Mset PRB 565 in PSFCH opportunity 580. In addition, PSSCH 570 is mapped to Mset PRB 575 in PSFCH opportunity 580. The CAPC of PSSCH 570 is p A , and the CAPC of PSSCH 570 is p B In this case, the first device 201 may determine (245) the target value P of the CAPC by using a function indicating selection of a minimum value. That is, the first device 201 may determine (245) the target value P of the CAPC from p A and p B By selecting the minimum value of CAPC, the first device can take advantage of the fact that another SL-U device can access the feedback channel with a higher priority, thereby increasing the chance that multiple PSFCHs are sent together.

[0100] It should be understood that Figure 5B The example of target value determination in is for illustrative purposes only and does not imply any limitation. In other embodiments, the function may vary. At least one channel access parameter may include a parameter other than CAPC.

[0101] Still reference Figure 2In some example embodiments, the first device 201 may be pre-configured with a function set for determining a target value. The function set may include selecting a minimum value, selecting a maximum value, selecting an average value, etc. In this case, the channel access configuration information may include a function index associated with a corresponding function in the function set. The first device 201 may select a corresponding function from the function set based on the received channel access configuration information.

[0102] By configuring different functions for different devices, the channel access priority for feedback from different devices can be adjusted. In this way, one device can downgrade the channel access priority for feedback based on selecting a lower priority function to benefit other devices competing for the channel.

[0103] Alternatively or additionally, the channel access configuration information may include a mapping rule between the SL transmission priority and the value of at least one channel access parameter for feedback associated with the SL transmission. For example, the priority indicated in the SCI may be mapped to the CAPC in the following manner: a priority of value 1 or 2 may be mapped to a CAPC with p equal to 1, a priority of value 3 or 4 may be mapped to a CAPC with p equal to 2, a priority of value 5 or 6 may be mapped to a CAPC with p equal to 3, and a priority with a value greater than 6 may be mapped to a CAPC with p equal to 4. It should be understood that the above mapping rules and example values ​​and CAPCs are for illustrative purposes only and do not imply any limitation. Any suitable mapping rules may be included in the channel access configuration information.

[0104] In some example embodiments, the channel access configuration information may include a threshold number for determining whether a target value of at least one channel access parameter is to be updated based on a function. In this case, if the first device 201 determines that the number of multiple feedback transmissions on the same feedback opportunity exceeds the threshold number, the first device 201 may determine the target value based on the function. For example, in an example where the function indicates the minimum value (i.e., the highest priority) of the CAPC is selected, if the first device 201 determines that the number of feedback transmissions on the same feedback opportunity exceeds the threshold number, the first device 201 may upgrade the target value to indicate a higher transmission priority of the feedback. For another example, in an example where the function indicates the maximum value (i.e., the lowest priority) of the CAPC is selected, if the first device 201 determines that the number of feedback transmissions on the same feedback opportunity exceeds the threshold number, the first device 201 may downgrade the target value to indicate a lower transmission priority of the feedback.

[0105] By introducing a threshold number, the channel access priority for SL feedback can be adjusted. In this way, it may be beneficial to reduce the HARQ-ACK problem when a large amount of feedback needs to be sent in a shared channel or an unlicensed channel.

[0106] In some example embodiments, the channel access configuration information may include a broadcast type rule for determining whether a target value of at least one channel access parameter is to be updated based on a function. For example, the broadcast type rule may include a first rule: the first SL transmission includes a unicast transmission, and the second transmission includes at least one of a unicast transmission requesting feedback or a multicast transmission requesting feedback.

[0107] Alternatively or additionally, the broadcast type rule may include a second rule: the first SL transmission includes a multicast transmission, and the second transmission includes a multicast transmission requesting feedback. In this case, if the first device 201 determines that at least one of the first SL transmission or the second SL transmission of the SL transmission satisfies the broadcast type rule, the first device 201 may update the target value based on a function. For example, if the first SL transmission satisfies the broadcast type rule, the first device 201 may update the target value based on a function. For another example, if any SL transmission having feedback associated with the same timing as the feedback of the first SL transmission satisfies the broadcast type rule, the first device 201 may update the target value based on a function.

[0108] Examples of channel access configuration information have been described. It is understood that at least one of the above examples, such as a function, a mapping rule, a threshold number, or a multicast type rule, can be included in the channel access configuration information. The channel access configuration information can also include any other suitable information related to the channel access parameters or the channel access process.

[0109] In the case where at least one channel access parameter is determined, the first device 201 can perform (250) a type 1 channel access procedure, such as an LBT type 1 procedure. The details of the LBT type 1 procedure have been referred to in Figure 3A In some example embodiments, if the type 1 channel access procedure passes, the first device 201 may send (255) feedback associated with the received SL transmission. For example, the first device 201 may send (255) PSFCH to a device that sends a SL transmission with feedback to the first device 201.

[0110] In some example embodiments, if first device 201 detects another SL transmission after the type 1 channel access procedure for the first feedback transmission at the same feedback opportunity and before the first feedback transmission, first device 201 may compare the second value of the at least one channel access parameter of the other feedback of the other SL transmission with the target value. If first device 201 determines that the second value of the at least one channel access parameter of the other feedback of the other SL transmission is associated with a second transmission priority that is higher than the first transmission priority of the first feedback transmission, first device 201 may reduce the duration for the type 1 channel access procedure.

[0111] For example, if the first device 201 has started an LBT process for sending a PSFCH after decoding a first PSCCH / PSSCH, and then the first device 201 detects a second PSCCH / PSSCH associated with a higher priority (e.g., a lower CAPC or a lower CW size) that allows upgrading channel access parameters, the first device 201 may decrement the backoff counter for the LBT by D, where D is the difference between the CW size for the ongoing LBT and the CW size to be used for the LBT with upgraded channel access parameters. In this way, the duration for the channel access process may be adjusted based on the channel access priority. In some example embodiments, the function for determining the target value may be applied to channel access parameters acquired from a PSCCH or PSSCH in the same time slot or in a time slot until the start of the LBT. In this case, the channel access duration adjustment may not be applied.

[0112] An example of channel access priority determination has been described above. With the determined target value of the channel access priority, the chance of LBT success can be improved when multiple PSFCHs are multiplexed in the same time slot. In addition, since the channel access parameters may not be upgraded to an unnecessary extent, better fairness to other devices such as other radio access technologies (RATs) may result. Example Process

[0113] Figure 6 6 is a flowchart of a process 600 for determining a channel access procedure for feedback transmission according to some example embodiments of the present disclosure. According to some example embodiments of the present disclosure, the process 600 may be implemented at the first device 201. For the purpose of discussion, Figure 2 The process is described from the perspective of the first device 201 in FIG.

[0114] At block 605, the first device 201 may start selecting at least one channel access parameter for next feedback. The time interval between the current time slot and the next feedback time slot is higher than a time gap threshold. For example, the time gap threshold may be a minimum time gap, such as sl-MinTimeGapPSFCH or K time slots. The time gap threshold may be determined by Figure 2 The second device 202 in the embodiment of the present invention is configured. For example, the time gap threshold can be configured by the SCI. For another example, the time gap threshold can be configured by the SL resource configuration from the network device. As described above, at least one channel access parameter may include the size of the CAPC, the CW, or other suitable channel access parameters. The feedback may include the PSFCH. The feedback time slot may include the PSFCH time slot or the PSFCH opportunity.

[0115] At box 610, the first device 201 may detect a SL transmission in the current SL time slot. For example, the first device 201 may monitor the PSCCH or PSSCH in the current SL time slot. At box 615, the first device 201 may determine whether a SL transmission is detected in the SL time slot. For example, the first device 201 may determine whether any PSCCH or PSSCH is detected in the SL time slot. If the first device 201 does not detect any SL transmission (such as PSCCH or PSSCH) at box 615, the first device 201 may proceed to the next SL time slot at box 625. For example, the first device 201 may detect a SL transmission in the next PSCCH or PSSCH time slot at box 625.

[0116] In some example embodiments, if the first device 201 detects a SL transmission at block 615, then at block 620, the first device 201 may obtain a value for at least one channel access parameter for feedback associated with the SL transmission. For example, the first device 201 may obtain and store a value for at least one channel access parameter for a PSFCH associated with a PSCCH or PSSCH transmission. The at least one channel access parameter may include a CAPC, a CW size, or any other suitable parameter. At block 625, the first device 201 may proceed to the next SL time slot. For example, the first device 201 will go to the next SL time slot to monitor the PSCCH or PSSCH.

[0117] At block 630, the first device 201 may determine whether the time interval between the current SL time slot and the next feedback time slot is greater than a time gap threshold. For example, the time gap threshold may be a minimum time gap, such as sl-MinTimeGapPSFCH or K time slots. The time gap threshold may be determined by Figure 2 The second device 202 in the network may be configured. For example, the time gap threshold may be configured by the SCI. For another example, the time gap threshold may be configured by the SL resource configuration from the network device.

[0118] In some example embodiments, if at block 630, the first device 201 determines that the time interval is above the time gap threshold, the first device 201 may continue to detect SL transmissions in the current SL time slot at block 610. By introducing the time gap threshold, the processing delay of the first device 201 is allowed to be taken into account when decoding the PSCCH and generating HARQ feedback.

[0119] In some example embodiments, if at block 630, first device 201 determines that the time interval does not exceed the time gap threshold, then at block 635, first device 201 may determine whether there is feedback to send. For example, first device 201 may determine whether there is a PSFCH to be sent by first device 201 in the next feedback time slot or feedback opportunity. This determination may be made based on the SCI.

[0120] In some example embodiments, if at block 635, first device 201 determines that there is feedback to be sent, then at block 640, first device 201 may determine whether there is a COT available for feedback transmission. For example, first device 201 may determine whether a COT previously initiated by first device 201 itself or by another device is still available for SL transmission by first device 201. COT availability means that there should be an initiated COT that ends after the transmission symbol of the PSFCH.

[0121] In some example embodiments, if at block 640, the first device 201 determines that COT is available, then at block 645, the first device 201 may send feedback using LBT Type 2. For example, the first device 201 may send PSFCH using LBT Type 2. Figure 3B and Figure 3C An example of a processed type 2 LBT is described and will not be repeated here. In some example embodiments, in the case of performing LBT type 2 for transmitting PSFCH, the first device 201 may select a value (also referred to as a target value) of at least one channel access parameter for the next feedback slot at block 605.

[0122] In some example embodiments, if at block 640, the first device 201 determines that COT is not available, then at block 650, the first device 201 determines a target value for at least one channel parameter. For example, the first device 201 determines the target value for at least one channel parameter as a function of a corresponding value of at least one channel access parameter associated with the feedback of the SL transmission. Figure 2 The function used to determine the target value is described and will not be repeated here.

[0123] Using the target value of at least one channel access parameter, the first device 201 can perform a type 1 channel access procedure, such as LBT type 1, by using the target value of at least one channel access parameter. If the first device 201 initiates a COT through the type 1 channel access procedure, the first device 201 can send SL feedback such as PSFCH by using the initiated COT.

[0124] In some example embodiments, upon determining a target value for at least one channel access parameter for a current time slot, first device 201 may select a target value for at least one channel access parameter for a next feedback time slot at block 605. A time interval between the current time slot and the next feedback time slot is greater than a time gap threshold. For example, first device 201 may perform blocks 610-650 for a next PSFCH time slot.

[0125] Alternatively or additionally, in some example embodiments, if the first device 201 determines that there is no feedback to transmit at block 635, the first device 201 may select a target value for at least one channel access parameter for the next feedback slot at block 605. The time interval between the current slot and the next feedback slot is above the time gap threshold. For example, the first device 201 may perform blocks 610-650 for the next PSFCH slot.

[0126] It should be understood that process 600 may be repeated in any SL time slot. Process 600 may be performed continuously or cyclically by first device 201. First device 201 may continue to monitor SL time slots and attempt to determine a value of at least one channel access parameter corresponding to feedback (such as PSFCH).

[0127] Already referenced Figure 6 An example process for SL feedback transmission according to the present disclosure is described. It should be understood that Figure 6 The process in is for illustrative purposes only and does not imply any limitation. Process 600 may include additional steps, or some steps in process 600 may be omitted. By using SL feedback transmission with determined target values ​​of channel access parameters, the chance of LBT success can be improved when multiple PSFCHs are multiplexed in the same time slot. In addition, since the channel access parameters may not be updated to an unnecessary extent, better fairness to other devices such as other radio access technologies (RATs) may result. Example Method

[0128] Figure 7 FIG. 7 is a flowchart of an example method 700 implemented at a first device according to some example embodiments of the present disclosure. For example, the first device may include a terminal device. For the purpose of discussion, Figure 2 Method 700 is described from the perspective of the first device 201.

[0129] At block 710 , the first device 201 obtains sidelink control information for a sidelink transmission having feedback associated with a same feedback opportunity of the first device 201 .

[0130] At block 720, the first device 201 obtains a corresponding value of at least one channel access parameter associated with feedback of the sidelink transmission based on the sidelink control information. For example, in some exemplary embodiments, the at least one channel access parameter includes at least one of the following: a channel access priority class, or a size of a contention window.

[0131] In some exemplary embodiments, obtaining a corresponding value of at least one channel access parameter associated with feedback of a side link transmission includes one of: obtaining a corresponding value of at least one channel access parameter based on an explicit channel access priority category indication included in the side link control information; or obtaining a corresponding value of at least one channel access parameter based on a corresponding data priority of the side link transmission and an association rule between the channel access priority category and the data priority, wherein the association rule is indicated in the side link control information.

[0132] At block 730, the first device 201 determines the value of at least one channel access parameter as a function of the corresponding value of the at least one channel access parameter, the value being used to transmit feedback of the sidelink transmission on the same feedback opportunity of the first device. For example, the first device 201 may determine the value of at least one channel access parameter as a function by at least one of: selecting a minimum value among the corresponding values ​​as the value; or selecting a maximum value among the corresponding values ​​as the value.

[0133] In some example embodiments, determining a value of at least one channel access parameter includes: determining that a number of multiple feedback transmissions on the same feedback opportunity exceeds a threshold number; and determining the value according to the function based on determining that the number of feedback transmissions exceeds the threshold number.

[0134] Alternatively or additionally, in some example embodiments, determining the value of at least one channel access parameter includes: determining that at least one of the first side link transmission or the second side link transmission of the side link transmission satisfies a broadcast type rule; and determining the value according to the function based on determining that at least one of the first side link transmission or the second side link transmission satisfies the broadcast type rule. For example, in some example embodiments, the broadcast type rule includes at least one of the following: a first rule: the first side link transmission includes a unicast transmission, and the second transmission includes at least one of a unicast transmission requesting feedback or a multicast transmission requesting feedback; or a second rule: the first side link transmission includes a multicast transmission, and the second transmission includes a multicast transmission requesting feedback.

[0135] In some example embodiments, determining the value of at least one channel access parameter includes: determining that a channel occupancy time is not available for multiple feedback transmissions for sidelink transmissions; and based on determining that the channel occupancy time is not available, determining the value of at least one channel access parameter, the value of the at least one channel access parameter being used for a type 1 channel access process for feedback transmissions on the same feedback opportunity.

[0136] In some example embodiments, method 700 further includes: determining that a second value of at least one channel access parameter of another feedback of the other side link transmission is associated with a second transmission priority based on detecting another side link transmission after a type 1 channel access procedure for a first feedback transmission at the same feedback opportunity and before the first feedback transmission, wherein the second transmission priority is higher than the first transmission priority of the first feedback transmission; and reducing the duration for the type 1 channel access procedure based on determining that the second value is associated with the second transmission priority that is higher than the first transmission priority.

[0137] In some example embodiments, method 700 further includes receiving channel access configuration information from second device 202. The channel access configuration information may include at least one of the following: a function for determining a value of at least one channel access parameter, a mapping rule between a sidelink transmission priority and an associated value of at least one channel access parameter for feedback associated with the sidelink transmission, a threshold number for determining whether the value of at least one channel access parameter is to be updated based on a function, or a broadcast type rule for determining whether the value of at least one channel access parameter is to be updated based on a function. In some example embodiments, second device 202 may include a terminal device. Alternatively, in some example embodiments, second device 202 may include a network device.

[0138] Figure 8 A flowchart of an example method 800 implemented at a second device according to some example embodiments of the present disclosure is shown. For the purpose of discussion, Figure 2 Method 800 is described from the perspective of second device 202 in FIG. In some example embodiments, second device 202 may include a terminal device or a network device.

[0139] At block 810, the second device 202 sends channel access configuration information to the first device 201. In some exemplary embodiments, the second device 202 may include a terminal device or a network device, and the first device 201 may include a terminal device.

[0140] In some example embodiments, the channel access configuration information includes at least one of the following: a function for determining a value of at least one channel access parameter from a plurality of values ​​of the at least one channel access parameter, the value of the at least one channel access parameter being used to send feedback of a side link transmission of a first device; a mapping rule between a side link transmission priority and an associated value of at least one channel access parameter for feedback associated with the side link transmission; a threshold number for determining whether the value of at least one channel access parameter is to be updated based on the function; or a broadcast type rule for determining whether the value of at least one channel access parameter is to be updated based on the function.

[0141] In some example embodiments, the function may indicate whether a minimum value or a maximum value of at least one channel access parameter is to be selected.

[0142] It should be understood that method 700 or method 800 may include additional blocks not shown and / or may omit some of the shown blocks, and the scope of the present disclosure is not limited in this regard. Example devices, equipment, and media

[0143] In some example embodiments, a first device (eg, Figure 2 The first device 201 in the method 700 may include components for performing the corresponding operations of the method 700. The components may be implemented in any suitable form. For example, the components may be implemented in a circuit or a software module. The first device may be implemented as or included in Figure 2 In the first device 201.

[0144] In some example embodiments, the first device includes: a component for obtaining sidelink control information for a sidelink transmission having feedback associated with the same feedback opportunity as the first device; a component for obtaining a corresponding value of at least one channel access parameter associated with the feedback of the sidelink transmission based on the sidelink control information; and a component for determining the value of the at least one channel access parameter as a function of the corresponding value of the at least one channel access parameter, wherein the value is used to send the feedback of the sidelink transmission on the same feedback opportunity of the first device.

[0145] In some example embodiments, the means for obtaining a corresponding value of at least one channel access parameter associated with feedback of the sidelink transmission includes one of: means for obtaining the corresponding value of the at least one channel access parameter based on an explicit channel access priority category indication included in the sidelink control information; or means for obtaining the corresponding value of the at least one channel access parameter based on the corresponding data priority of the sidelink transmission and an association rule between the channel access priority category and the data priority, the association rule being indicated in the sidelink control information. For example, in some example embodiments, the at least one channel access parameter includes at least one of: a channel access priority category, or a size of a contention window.

[0146] In some example embodiments, the means for determining the value of at least one channel access parameter as a function of corresponding values ​​of at least one channel access parameter includes at least one of the following: means for selecting a minimum value among the corresponding values ​​as the value; or means for selecting a maximum value among the corresponding values ​​as the value.

[0147] In some example embodiments, means for determining a value of at least one channel access parameter includes means for determining that a number of multiple feedback transmissions on the same feedback opportunity exceeds a threshold number; and means for determining the value according to a function based on determining that the number of feedback transmissions exceeds the threshold number.

[0148] Alternatively or additionally, in some example embodiments, the means for determining the value of at least one channel access parameter includes: means for determining that at least one of the first side link transmission or the second side link transmission of the side link transmission satisfies a broadcast type rule; and means for determining the value according to a function based on determining that at least one of the first side link transmission or the second side link transmission satisfies the broadcast type rule. For example, in some example embodiments, the broadcast type rule includes at least one of the following: a first rule: the first side link transmission includes a unicast transmission, and the second transmission includes at least one of a unicast transmission requesting feedback or a multicast transmission requesting feedback; or a second rule: the first side link transmission includes a multicast transmission, and the second transmission includes a multicast transmission requesting feedback.

[0149] In some example embodiments, the means for determining a value of at least one channel access parameter includes: means for determining that a channel occupancy time is not available for a plurality of feedback transmissions for a sidelink transmission; and means for determining a value of the at least one channel access parameter based on determining that the channel occupancy time is not available. The value of the at least one channel access parameter may be used for a type 1 channel access procedure for feedback transmissions on the same feedback opportunity.

[0150] In some example embodiments, the first device also includes: a component for determining that a second value of at least one channel access parameter of another feedback of the other side link transmission is associated with a second transmission priority based on detecting another side link transmission after a type 1 channel access procedure for the first feedback transmission at the same feedback opportunity and before the first feedback transmission, wherein the second transmission priority is higher than the first transmission priority of the first feedback transmission; and a component for reducing the duration of the type 1 channel access procedure based on determining that the second value is associated with a second transmission priority that is higher than the first transmission priority.

[0151] In some example embodiments, the first device may further include: a component for receiving channel access configuration information from the second device. The channel access configuration information may include at least one of the following: a function for determining a value of at least one channel access parameter, a mapping rule between a sidelink transmission priority and an associated value of at least one channel access parameter for feedback associated with the sidelink transmission, a threshold number for determining whether the value of at least one channel access parameter is to be updated based on the function, or a broadcast type rule for determining whether the value of at least one channel access parameter is to be updated based on the function.

[0152] In some example embodiments, the first device comprises a terminal device, and the second device comprises a terminal device or a network device.

[0153] In some example embodiments, the first apparatus further comprises means for performing other operations in some example embodiments of the method 700 or the first device 201. In some example embodiments, the means comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the execution of the first apparatus.

[0154] In some example embodiments, a second device (eg, Figure 2 The second device 202 in the method 800 may include components for performing the corresponding operations of the method 800. The components may be implemented in any suitable form. For example, the components may be implemented in a circuit or a software module. The second device may be implemented as or included in Figure 2 In the second device 202.

[0155] In some example embodiments, the second device includes: a component for sending channel access configuration information to the first device. In some example embodiments, the channel access configuration information includes at least one of the following: a function for determining a value of at least one channel access parameter from a plurality of values ​​of the at least one channel access parameter, the value of the at least one channel access parameter being used to send feedback of a sidelink transmission of the first device; a mapping rule between a sidelink transmission priority and an associated value of at least one channel access parameter for feedback associated with the sidelink transmission; a threshold number for determining whether the value of the at least one channel access parameter is to be updated based on the function; or a broadcast type rule for determining whether the value of the at least one channel access parameter is to be updated based on the function.

[0156] In some example embodiments, the function may indicate whether a minimum value or a maximum value of at least one channel access parameter is to be selected.

[0157] In some exemplary embodiments, the first device includes a terminal device, and the second device includes a terminal device or a network device.

[0158] In some example embodiments, the second apparatus further comprises means for performing other operations in some example embodiments of the method 800 or the second device 202. In some example embodiments, the means comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the execution of the second apparatus.

[0159] Fig. 9 900 is a simplified block diagram of a device suitable for implementing an example embodiment of the present disclosure. The device 900 may be provided to implement a communication device, such as Figure 1 The device 110, 120, 130 or 140 shown, or as Figure 2 The first device 201 or the second device 202 is shown. As shown in the figure, the device 900 includes one or more processors 910, one or more memories 920 coupled to the processor 910, and one or more communication modules 940 coupled to the processor 910.

[0160] The communication module 940 is used for two-way communication. The communication module 940 has one or more communication interfaces to facilitate communication with one or more other modules or devices. The communication interface may represent any interface necessary for communicating with other network elements. In some example embodiments, the communication module 940 may include at least one antenna.

[0161] As non-limiting examples, processor 910 may be of any type suitable for a local technology network, and may include one or more of the following: a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Device 900 may have multiple processors, such as application specific integrated circuit chips that are time slaved to a clock that is synchronized with a main processor.

[0162] The memory 920 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 924, electrically programmable read-only memory (EPROM), flash memory, hard disk, compact disk (CD), digital video disk (DVD), optical disk, laser disk, and other magnetic storage and / or optical storage. Examples of volatile memories include, but are not limited to, random access memory (RAM) 922 and other volatile memories that will not persist during a power outage.

[0163] The computer program 930 includes computer executable instructions executed by the associated processor 910. The instructions of the program 930 may include instructions for performing the operations / actions of some example embodiments of the present disclosure. The program 930 may be stored in a memory, such as ROM 924. The processor 910 may perform any suitable actions and processes by loading the program 930 into the RAM 922.

[0164] The exemplary embodiments of the present disclosure may be implemented by a program 930 so that the device 900 may execute the Figure 2 and Figures 6 to 8 Any process of the present disclosure discussed. The exemplary embodiments of the present disclosure may also be implemented by hardware or a combination of software and hardware.

[0165] In some example embodiments, the program 930 may be tangibly contained in a computer-readable medium, which may be included in the device 900 (such as in the memory 920) or in other storage devices accessible by the device 900. The device 900 may load the program 930 from the computer-readable medium to the RAM 922 for execution. In some example embodiments, the computer-readable medium may include any type of non-transitory storage medium, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc. As used herein, the term "non-transitory" is a limitation of the medium itself (i.e., tangible rather than a signal), not a limitation on data storage persistence (e.g., RAM versus ROM).

[0166] Fig.10An example of a computer readable medium 1000 is shown, which may be in the form of a CD, DVD or other optical storage disc. The computer readable medium 1000 has a program 930 stored thereon.

[0167] Generally, various embodiments of the present disclosure may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure are shown and described as block diagrams, flow charts, or using some other graphical representations, it should be understood that the blocks, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general hardware or controllers or other computing devices, or some combination thereof, in non-limiting examples.

[0168] Some example embodiments of the present disclosure also provide at least one computer program product tangibly stored on a computer-readable medium (such as a non-volatile computer-readable medium). The computer program product includes computer executable instructions, such as those instructions included in a program module, executed in a device on a target physical or virtual processor to perform any method as described above. Typically, a program module includes routines, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The functionality of a program module can be combined or split between program modules as needed in various embodiments. Machine executable instructions for program modules can be executed in local or distributed devices. In distributed devices, program modules can be located in local and remote storage media.

[0169] The program code for executing the method of the present disclosure can be written in any combination of one or more programming languages. The program code can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device so that the program code, when executed by the processor or controller, causes the realization of the function / operation specified in the flow chart and / or block diagram. The program code can be executed entirely on the machine, partially on the machine, as an independent software package, partially on the machine and partially on a remote machine, or completely on a remote machine or server.

[0170] In the context of the present disclosure, computer program codes or related data may be carried by any suitable carrier to enable a device, apparatus or processor to perform various processes and operations as described above. Examples of carriers include signals, computer readable media, etc.

[0171] The computer readable medium may be a computer readable signal medium or a computer readable storage medium. The computer readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared or semiconductor systems, devices or apparatuses, or any suitable combination of the foregoing. More specific examples of computer readable storage media would include an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage component, a magnetic storage component, or any suitable combination of the foregoing.

[0172] In addition, although the operations are depicted in a particular order, this should not be understood as requiring such operations to be performed with the specific item shown or with the sequential item, or performing all the operations shown, to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the above discussion, these details should not be interpreted as limitations on the scope of the present disclosure, but should be interpreted as descriptions of features that may be specific to a specific embodiment. Unless explicitly stated, certain features described in the context of a separate embodiment may also be implemented in combination in a single embodiment. On the contrary, unless explicitly stated, the various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable sub-combination.

[0173] Although the disclosure has been described in language specific to structural features and / or methodological acts, it should be understood that the disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A first device, comprising: at least one processor; as well as at least one memory storing instructions that, when executed by the at least one processor, cause the first device to at least perform: obtaining sidelink control information for a sidelink transmission having feedback associated with a same feedback opportunity as the first device; obtaining, based on the sidelink control information, a corresponding value of at least one channel access parameter associated with the feedback of the sidelink transmission; as well as A value of the at least one channel access parameter is determined as a function of the corresponding value of the at least one channel access parameter, the value being used to send the feedback of the sidelink transmission on the same feedback opportunity of the first device.

2. The first device of claim 1 , wherein determining the value of the at least one channel access parameter as a function of the corresponding value of the at least one channel access parameter comprises one of: select the minimum value among the corresponding values ​​as the value; or The maximum value among the corresponding values ​​is selected as the value.

3. The first device according to claim 1 or claim 2, wherein the first device is further configured to perform: Receive channel access configuration information from the second device, where the channel access configuration information includes at least one of the following: said function for determining said value of said at least one channel access parameter, a mapping rule between a sidelink transmission priority and an associated value of said at least one channel access parameter for said feedback associated with said sidelink transmission, a threshold number for determining whether the value of the at least one channel access parameter is to be updated based on the function, or A broadcast type rule is used to determine whether the value of the at least one channel access parameter is to be updated based on the function.

4. The first device according to any one of claims 1 to 3, wherein determining the value of the at least one channel access parameter comprises: determining that a number of the plurality of feedback transmissions on the same feedback opportunity exceeds a threshold number; as well as Based on determining that the number of feedback transmissions exceeds the threshold number, the value is determined according to the function.

5. The first device according to any one of claims 1 to 4, wherein determining the value of the at least one channel access parameter comprises: determining that at least one of the first sidelink transmission or the second sidelink transmission of the sidelink transmission satisfies a broadcast type rule; as well as Based on determining that at least one of the first transmission or the second transmission satisfies the broadcast type rule, the value is determined according to the function.

6. The first device according to claim 5, wherein the broadcast type rule comprises at least one of the following: First rule: the first sidelink transmission comprises a unicast transmission, and the second transmission comprises at least one of a unicast transmission requesting feedback or a multicast transmission requesting feedback, or Second rule: the first sidelink transmission comprises a multicast transmission, and the second transmission comprises a multicast transmission requesting feedback.

7. The first device according to any one of claims 1 to 6, wherein determining the value of the at least one channel access parameter comprises: determining that a channel occupancy time is unavailable for a plurality of feedback transmissions of the sidelink transmission; as well as Based on determining that the channel occupancy time is unavailable, determining the value of the at least one channel access parameter, the value of the at least one channel access parameter being used for a type 1 channel access procedure for the feedback transmission on the same feedback opportunity.

8. The first device of claim 7, wherein the first device is further configured to perform: Determining, based on another side link transmission after the type 1 channel access procedure for the first feedback transmission detected at the same feedback opportunity and before the first feedback transmission, that a second value of the at least one channel access parameter of another feedback of the other side link transmission is associated with a second transmission priority, the second transmission priority being higher than the first transmission priority of the first feedback transmission; and Based on determining that the second value is associated with the second transmission priority that is higher than the first transmission priority, a duration for the type 1 channel access procedure is reduced.

9. The first device according to any one of claims 1 to 8, wherein the at least one channel access parameter comprises at least one of the following: Channel access priority class, or The size of the contention window.

10. The first device according to any one of claims 1 to 9, wherein obtaining the corresponding value of the at least one channel access parameter associated with the feedback of the sidelink transmission comprises one of: obtaining the corresponding value of the at least one channel access parameter based on an explicit channel access priority class indication included in the sidelink control information; or The corresponding value of the at least one channel access parameter is obtained based on the corresponding data priority of the side link transmission and the association rule between the channel access priority category and the data priority, and the association rule is indicated in the side link control information.

11. The first device according to any one of claims 1 to 10, wherein the first device comprises a terminal device, and the second device comprises another terminal device or a network device.

12. A second device, comprising: at least one processor; as well as at least one memory storing instructions that, when executed by the at least one processor, cause the second device to at least perform: Sending channel access configuration information to the first device, where the channel access configuration information includes at least one of the following: a function for determining a value of at least one channel access parameter from a plurality of values ​​of the at least one channel access parameter, the value of the at least one channel access parameter being used to send feedback of a sidelink transmission of the first device, a mapping rule between a sidelink transmission priority and an associated value of said at least one channel access parameter for said feedback associated with said sidelink transmission, a threshold number for determining whether the value of the at least one channel access parameter is to be updated based on the function, or A broadcast type rule is used to determine, based on the function, that the value of the at least one channel access parameter is to be updated.

13. The second device of claim 12, wherein the function indicates whether a minimum value or a maximum value of the at least one channel access parameter is to be selected.

14. The second device according to claim 12 or claim 13, wherein the first device comprises a terminal device and the second device comprises a further terminal device or a network device.

15. A method comprising: obtaining, at a first device, sidelink control information for a sidelink transmission having feedback associated with a same feedback opportunity as the first device; obtaining, based on the sidelink control information, a corresponding value of at least one channel access parameter associated with the feedback of the sidelink transmission; as well as A value of the at least one channel access parameter is determined as a function of the corresponding value of the at least one channel access parameter, the value being used to send the feedback of the sidelink transmission on the same feedback opportunity of the first device.

16. A method comprising: Sending channel access configuration information to the first device at the second device, where the channel access configuration information includes at least one of the following: a function for determining a value of at least one channel access parameter from a plurality of values ​​of the at least one channel access parameter, the value of the at least one channel access parameter being used to send feedback of a sidelink transmission of the first device, a mapping rule between a sidelink transmission priority and an associated value of said at least one channel access parameter for said feedback associated with said sidelink transmission, a threshold number for determining whether the value of the at least one channel access parameter is to be updated based on the function, or A broadcast type rule is used to determine, based on the function, that the value of the at least one channel access parameter is to be updated.

17. A first device, comprising: means for obtaining sidelink control information for a sidelink transmission having feedback associated with a same feedback opportunity as the first apparatus; means for obtaining, based on the sidelink control information, a respective value of at least one channel access parameter associated with the feedback of the sidelink transmission; as well as means for determining a value of said at least one channel access parameter as a function of said corresponding value of at least one channel access parameter, said value being used to send said feedback of said sidelink transmission on said same feedback opportunity of said first apparatus.

18. A second device, comprising: A component for sending channel access configuration information to a first device, wherein the channel access configuration information includes at least one of the following: a function for determining a value of at least one channel access parameter from a plurality of values ​​of the at least one channel access parameter, the value of the at least one channel access parameter being used to send feedback of a sidelink transmission of the first apparatus; a mapping rule between a sidelink transmission priority and an associated value of said at least one channel access parameter for said feedback associated with said sidelink transmission, a threshold number for determining whether the value of the at least one channel access parameter is to be updated based on the function, or A broadcast type rule is used to determine, based on the function, that the value of the at least one channel access parameter is to be updated.

19. A computer-readable medium comprising instructions stored thereon, the instructions being configured to cause an apparatus to at least perform the method according to claim 15 or the method according to claim 16.

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