CN119678616A - Sidelink feedback transmission enhancement - Google Patents

Abstract

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

Description

Side link feedback transmission enhancement

Technical Field

Various example embodiments of the present disclosure relate generally to the field of telecommunications and, more particularly, relate to methods, apparatus, devices, and computer readable storage media for Side Link (SL) feedback transmission enhancement.

Background

With the rapid development of communication technology, a communication system 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 a terminal device can use resources such as a shared band of unlicensed spectrum for SL transmission. For example, a terminal device may be required to access resources in the unlicensed spectrum by performing a channel access procedure to use the resources for SL operation. In some cases, a terminal device receiving SL transmissions via resources in the unlicensed spectrum may send feedback to the terminal device performing the SL transmissions. Work is underway to introduce enhancements to SL feedback transmission.

Disclosure of Invention

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 that, when executed by the at least one processor, cause the first device to at least obtain side link control information for a side link transmission having feedback associated with a same feedback occasion of the first device, obtain a corresponding value of at least one channel access parameter associated with feedback for the side link transmission based on the side link control information, and determine 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 for the side link transmission on the same feedback occasion of the first device.

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 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, the channel access configuration information including at least one of 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 the first device, a mapping rule between a side link transmission priority and an associated value of the at least one channel access parameter for feedback associated with the side link 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.

In a third aspect of the present disclosure, a method is provided. The method includes obtaining, at a first device, side link control information for a side link transmission having feedback associated with a same feedback occasion of the first device, obtaining, based on the side link control information, a respective value of at least one channel access parameter associated with the feedback for the side link transmission, and determining the value of the at least one channel access parameter as a function of the respective value of the at least one channel access parameter, the value being used to send the feedback for the side link transmission on the same feedback occasion of the first device.

In a fourth aspect of the present disclosure, a method is provided. The method includes transmitting, at a second device, channel access configuration information to a first device, the channel access configuration information including at least one of 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 transmit feedback for a side link transmission of the first device, a mapping rule between a side link transmission priority and an associated value of the at least one channel access parameter for feedback associated with the side link 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.

In a fifth aspect of the present disclosure, a first apparatus is provided. The first apparatus includes means for obtaining side link control information for a side link transmission having feedback associated with a same feedback occasion of the first apparatus, means for obtaining respective values of at least one channel access parameter associated with the feedback for the side link transmission based on the side link control information, and means for determining the values of the at least one channel access parameter as a function of the respective values of the at least one channel access parameter, the values being used to send the feedback for the side link transmission on the same feedback occasion of the first apparatus.

In a sixth aspect of the present disclosure, a second apparatus is provided. The second apparatus includes means for transmitting channel access configuration information to the first apparatus, the channel access configuration information including at least one of 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 transmit feedback for a side link transmission of the first apparatus, a mapping rule between a side link transmission priority and an associated value of the at least one channel access parameter for feedback associated with the side link 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.

In a seventh aspect of the present disclosure, a computer readable medium is provided. The computer readable medium comprising instructions stored thereon for causing an apparatus to perform at least the method according to the third aspect.

In an eighth aspect of the present disclosure, a computer-readable medium is provided. The computer readable medium includes instructions stored thereon for causing an apparatus to perform at least the method according to the fourth aspect.

It should be understood that the abstract section is not intended to identify key or essential features of the embodiments of the disclosure, nor is it intended to be used to limit the scope of the disclosure. Other features of the present disclosure will become apparent from the following description.

Drawings

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

FIG. 1 illustrates an example communication environment in which example embodiments of the present disclosure may be implemented;

Fig. 2 illustrates a signaling diagram for communication according to some example embodiments of the present disclosure;

Fig. 3A, 3B, and 3C illustrate some examples of SL transmissions with channel access procedures;

fig. 4 illustrates an example SL slot according to some example embodiments of the present disclosure;

fig. 5A and 5B illustrate example mappings between SL transmissions and SL feedback according to some example embodiments of the present disclosure;

Fig. 6 illustrates a flowchart of a process for determining a channel access procedure for feedback transmission, according to some example embodiments of the present disclosure;

fig. 7 illustrates a flowchart of a method implemented at a first device, according to some example embodiments of the present disclosure;

Fig. 8 illustrates a flowchart of a method implemented at a second device, according to some example embodiments of the present disclosure;

FIG. 9 shows a simplified block diagram of a device suitable for practicing the exemplary embodiments of this disclosure, and

Fig. 10 illustrates a block diagram of an example computer-readable medium, according to some example embodiments of the present disclosure.

The same or similar reference numbers will be used throughout the drawings to refer to the same or like elements.

Detailed Description

Principles of the present disclosure will now be described with reference to some example embodiments. It should be understood that these examples are for illustrative purposes only and to assist those skilled in the art in understanding and practicing the present disclosure, and are not meant to limit the scope of the present disclosure in any way. The embodiments described herein may be implemented in various ways other than those described below.

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.

References in the present disclosure to "one embodiment," "an example embodiment," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It will 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, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term "and/or" includes any and all combinations of one or more of the listed terms.

As used herein, "at least one of the following" < list of two or more elements > "and" < at least one of the list of two or more elements > "and similar expressions (where the list of two or more elements are connected by" and "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.

As used herein, unless explicitly stated otherwise, performing a step "in response to a" does not mean that the step is performed immediately after "a" occurs, but may include one or more intermediate steps.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," comprising, "" includes, "" including, "" having, "" includes, "" including, "" containing, "" having, "" including, "" containing, "" component, "" element, "" means having the feature, element, component, and/or the like, as used herein, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof.

As used in this disclosure, the term "circuitry" may refer to one or more or all of (a) hardware-only circuit implementations (e.g., implementations within analog and/or digital circuits only) and

(B) A combination of hardware circuitry and software, for example (if applicable):

(i) Combination of analog and/or digital hardware circuitry and software/firmware, and

(Ii) Any portion of a hardware processor having software (including digital signal processors, software, and memory that work together to cause a device such as a mobile phone or server to perform various functions), and (c) hardware circuitry and/or a processor, such as a microprocessor or a portion of a microprocessor, that requires software (e.g., firmware) for operation, but software may not exist when not required for operation.

This definition of circuit applies to all uses of this term in this application, including in any claims. As a further example, as used in this disclosure, the term circuitry also encompasses hardware-only circuitry or a processor (or multiple processors) or an implementation of hardware circuitry or a portion of a processor and its attendant software and/or firmware. The term circuitry also encompasses, for example and if applicable to the 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.

As used herein, the term "communication network" refers to a network that conforms to any suitable communication standard, such as New Radio (NR), long Term Evolution (LTE), LTE-advanced (LTE-a), wideband Code Division Multiple Access (WCDMA), high Speed Packet Access (HSPA), narrowband internet of things (NB-IoT), and the like. Furthermore, communication between the terminal device and the network device in the communication network may be performed according to any suitable generational communication protocol, including, but not limited to, first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) communication protocols, and/or any other protocols currently known or developed in the future. Embodiments of the present disclosure may be applied in various communication systems. In view of the rapid development of communications, there are, of course, future types of communication technologies and systems that can implement the present disclosure. The scope of the present disclosure should not be considered limited to the systems described above.

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 therefrom. Network devices may refer to Base Stations (BS) or Access Points (APs), e.g., node BS (NodeB or NB), evolved NodeB (eNodeB or eNB), NR NB (also known as gNB), remote Radio Unit (RRU), radio Head (RH), remote Radio Head (RRH), repeater, integrated Access and Backhaul (IAB) nodes, low power nodes (e.g., femto, pico), non-terrestrial network (NTN) or non-terrestrial network devices (such as satellite network devices, low Earth Orbit (LEO) satellites and geosynchronous orbit (GEO) satellites, aircraft network devices), 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. The IAB node includes a mobile terminal (IAB-MT) portion that behaves like a UE towards a parent node, while the DU portion of the IAB node behaves like a base station towards a next hop IAB node.

The term "terminal device" refers to any terminal device capable of wireless communication. By way of example, and not limitation, a terminal device may also be referred to as a communication device, a User Equipment (UE), a Subscriber Station (SS), a portable subscriber station, a Mobile Station (MS), or an Access Terminal (AT). The terminal devices may include, but are not limited to, mobile phones, cellular phones, smart phones, voice over IP (VoIP) phones, wireless local loop phones, tablet computers, wearable terminal devices, personal Digital Assistants (PDAs), portable computers, desktop computers, image capture terminal devices (e.g., digital cameras), gaming terminal devices, music storage and playback appliances, in-vehicle wireless terminal devices, wireless endpoints, mobile stations, laptop embedded devices (LEEs), laptop mounted devices (LMEs), USB dongles, smart devices, wireless Customer Premises Equipment (CPE), internet of things (IoT) devices, watches or other wearable devices, head Mounted Displays (HMDs), vehicles, drones, medical devices and applications (e.g., tele-surgery), industrial devices and applications (e.g., robots and/or other wireless devices operating in an industrial and/or automated processing chain environment), consumer electronic devices, devices operating on a commercial and/or industrial wireless network, and the like. In some example embodiments, the terminal device may include a device (also referred to as a D2D device) that performs device-to-device (D2D) communication. Alternatively or additionally, in some example embodiments, the terminal device may also include a device in vehicle-to-everything (V2X) communication (also referred to as a V2X device). The V2X communication may include, but is not limited to, a vehicle-to-infrastructure (V2I) communication, a vehicle-to-network (V2N) communication, a vehicle-to-vehicle (V2V) communication, a vehicle-to-pedestrian (V2P) communication, or a vehicle-to-device (V2D) communication. The terminal device may also correspond to a Mobile Terminal (MT) part 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.

As used herein, the terms "resource," "transmission resource," "resource block," "physical resource block" (PRB), "uplink resource," or "downlink resource" may refer to any resource used to perform communications (e.g., communications between a terminal device and a network device), such as resources in the time domain, resources in the frequency domain, resources in the spatial domain, resources in the code domain, or any other resource that enables communications, and the like. Hereinafter, 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 example embodiments of the present disclosure are equally applicable to other resources in other domains.

Example Environment

FIG. 1 illustrates an example communication environment 100 in which example embodiments of the present disclosure may be implemented. In the communication environment 100, the 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 cell 102. As shown, device 120 and device 130 are located inside cell 102 and thus may communicate with device 110. Device 140 is located outside of cell 102 and therefore cannot obtain service from device 110.

In the example of fig. 1, devices 120 and 130 may comprise terminal devices, and device 110 may comprise network devices serving the terminal devices. The 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 the Uplink (UL) and the link from device 110 to device 120 (or device 130) is referred to as the Downlink (DL).

In some example embodiments, different terminal devices may establish a communication connection with each other. For example, device 120 and device 130 within cell 102 (in coverage) may establish a communication connection with each other. In addition, devices 140 outside of cell 102 (outside of coverage) may also establish communication connections with devices 120 and/or devices 130 inside of cell 102. In some example embodiments, a terminal device, such as device 120, 130, or 140, may establish a communication connection with a plurality of other terminal devices. The communication between the terminal devices may be referred to as Side Link (SL) communication.

During SL communication, different terminal devices can communicate data and control information with each other. For example, if a SL connection is established between terminal devices, the terminal devices may communicate data and control information with more than one terminal device. In SL communication, a terminal device that performs transmission, such as device 120 (or device 130 or device 140), is referred to as a Transmit (TX) device (or transmitter), and a terminal device that receives transmission, such as device 130 (or device 120 or device 140), is referred to as a Receive (RX) device (or receiver).

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

It should be understood that the number of devices and their connections shown in fig. 1 is for illustration purposes only and does not imply any limitation. Communication environment 100 may include any suitable number of devices for implementing example embodiments of the present disclosure. Although not shown, it is to be appreciated that one or more additional devices can reside within the cell 102 and that one or more additional cells can be deployed within the communication environment 100.

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

Communication in communication environment 100 may be implemented in accordance with any suitable communication protocol including, but not limited to, first generation (1G), second generation (2G), third generation (3G), fourth generation (4G), fifth generation (5G), sixth generation (6G), etc., cellular communication protocols, wireless local area network communication protocols such as Institute of Electrical and Electronics Engineers (IEEE) 802.11, etc., and/or any other protocols 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.

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

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

In some approaches, the RX terminal device may transmit the SL feedback using a Channel Occupation Time (COT) initiated by the TX terminal device. A priority value or priority level may be assigned to PSFCH for transmission or reception. The Th priority value or priority level may reflect latency requirements and may be associated as described in the 3 rd generation partnership project (3 GPP) Technical Specification (TS). For example, for PSFCH transmissions or receptions with HARQ feedback, such as HARQ Acknowledgement (ACK) information, the priority value for PSFCH may be equal to the priority value indicated by side link control information (SCI) format 1-a associated with PSFCH. For another example, for PSFCH transmissions 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 the conflicting resource. 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 the conflicting resource.

However, in some cases, 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, channel access priority needs to be associated with SL feedback transmission. Such channel access priorities may be used in a channel access procedure, such as a Listen Before Talk (LBT) type 1 procedure, to initiate the COT. However, there is a lack of an efficient way to correlate the appropriate channel access priorities for SL feedback transmissions.

In some approaches, the channel access priority of PSFCH transmissions, such as Channel Access Priority Class (CAPC), may depend on a 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 PSFCH transmissions may be associated with a data priority. Consider the scenario where terminal device a sends a PSCCH/PSSCH a with priority value p _A to an RX terminal device and terminal device B sends a PSCCH/PSSCH B with priority value p _B (different from p _A) to an RX terminal device. Both PSCCH/PSCCH a and PSCCH/pscsch B are associated with the same PSFCH occasions. The RX terminal device may send feedback associated with PSCCH/PSCCH a or PSCCH/pscsch B on the PSFCH occasion.

However, if the RX terminal device is associated with CAPC of 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 unacknowledged (NACK) to ACK misinterpretation if only NACK HARQ options are used. Furthermore, if an RX terminal device is associated with CAPC of low p-value (for high priority information), it has a higher chance to acquire the channel when the contention window is lower, but may compromise LBT failures of other devices that also contend for the channel. For example, assuming p _B<p_A, if an RX terminal device that sends feedback associated with PSCCH/PSSCH B uses a low CAPC/smaller Contention Window (CW) and another RX terminal device that sends feedback associated with PSCCH/PSSCH A uses a high CAPC/larger CW, then the former RX terminal device can complete the LBT procedure to send PSFCH.

In some approaches, such as in New Radio (NR) unlicensed (NR-U) designs, several channel access priority association approaches are proposed. For example, for UL configuration grant, the lowest priority of Logical Channels (LCHs) multiplexed in a Transport Block (TB) is selected. CAPC of the Signaling Radio Bearers (SRBs) may be used when multiplexed in the TBs on the Configuration Grant (CG). For another example, for the UL grant case, the terminal device may assume CAPC of p=4 within the network device initiated COT, and for the terminal device initiated COT, the terminal device may select the channel access priority based on the data priority. For DL assignment, the Physical Uplink Control Channel (PUCCH) may use the highest CAPC. In some approaches, this NR-U design may be applied in SL feedback transmission. However, the NR-U design does not take into account the SL multicast scenario where multiple RX terminal devices have to send feedback to the TX terminal device. If the NR-U design is employed, one low priority transmission from the TX terminal equipment will trigger many RX terminal equipment competing for channels with other equipment. This is unfair to other devices using unlicensed spectrum.

To enhance SL feedback transmissions, it is desirable to associate or select appropriate channel access parameter values, such as appropriate channel access priorities for the SL feedback transmissions.

Working principle and example signaling for communication

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 this scheme, the first device obtains SCI of the SL transmission associated with the same feedback occasion (such as the same PSFCH occasion). The first device determines a respective value of at least one channel access parameter associated with 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 of the SL feedback. The first device selects a value for the at least one channel access parameter by using a function of a corresponding value of the at least one channel access parameter of the received SL transmission.

In this way, appropriate channel access priorities may be associated with SL feedback transmissions. By associating channel access priorities, the chance of the channel access procedure being successful when multiplexing multiple SL feedbacks in the same time slot will thus be improved. In addition, such methods use unlicensed spectrum to achieve better fairness towards other devices.

Example embodiments of the present disclosure are described in detail below with reference to the attached drawing figures.

Fig. 2 illustrates a signaling diagram 200 for communication according to some example embodiments of the present disclosure. As shown in fig. 2, the signaling diagram 200 relates to a first device 201 and a second device 202. In some example embodiments, the first device 201 may include a terminal device, such as one of the devices 120, 130, or 140 in fig. 1. In some example embodiments, the second device 202 may include a network device, such as the device 110 in fig. 1. Alternatively, in some example embodiments, the second device 202 may comprise a different terminal device than the first device 201, such as another one of the devices 120, 130, or 140 in fig. 1.

Although one first device 201 and one second device 202 are shown in fig. 2, it should be understood that there may be multiple first devices performing similar operations as described below with respect to the first device 201 and multiple second devices performing similar operations as described below with respect to the second device 202.

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.

In examples where the second device 202 includes a network device, the second device 202 may send (210) channel access configuration information with a resource pool configuration. For example, in mode 1SL transmission, the second device 202 may send the resource pool configuration to the first device 201 along with channel access configuration information.

In examples where the second device 202 comprises a terminal device, the second device 202 may send (210) the channel access configuration information via a SL synchronization signal/Physical Broadcast Channel (PBCH) block (SSB), via SCI, via PC5 Radio Resource Control (RRC), or any other suitable method.

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.

In some example embodiments, the first device 201 may receive (220) the SL transmission. 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) the SL transmission from the second device 202.

In some example embodiments, SL transmissions may be performed over 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 the channel access procedure will be described below.

As described above, in order to operate on a shared frequency band such as an unlicensed frequency band, a different channel access procedure including LBT may be used before SL transmission is performed by a terminal device. For example, to pass LBT, a device needs to observe a shared frequency band as available for multiple consecutive Clear Channel Assessment (CCA) slots. In the sub-7GHz band, the duration of the time 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 a shared frequency band is available in the CCA slot. There are several types of channel access procedures, which will be described with reference to fig. 3A-3C.

As shown in fig. 3A, when the initiating device 310 intends to perform a transmission to the responding device 320 using resources on the shared radio frequency band, the initiating device 310 needs to acquire a license to access the shared radio frequency band for a period of time, also referred to as a Channel Occupation Time (COT) 340 by applying a channel access procedure. 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 an initiating device performs a transmission.

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

If the initiating device 310 decides to perform a new transmission within the COT 340 after the initial transmission, the initiating device 310 may perform additional channel access procedures within the COT 340. In this case, the channel access procedure may include a "reduced" LBT procedure (e.g., a LBT type 2 (also referred to as a type 2 LBT) procedure or a type 2 channel access procedure) in which the initiating device 310 may need to monitor the shared radio frequency band for a smaller period of time than an "extended" LBT procedure (e.g., a LBT type 1 procedure). Fig. 3B shows an example of an LBT type 2 procedure performed by initiating device 310 prior to a new transmission performed within COT 340.

As shown in fig. 3B, after completing the LBT type 1 procedure, initiating device 310 performs an initial transmission 350. Thereafter, the initiating device 310 may want to perform a new transmission 352 within the COT 340. As shown in fig. 3B, the initiating device 310 may need to perform an LBT type 2 procedure before performing transmission 352 in order to check that the shared radio frequency band is available for communication.

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 may 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 time gap 360 is greater than or equal to 25 μs, initiating device 310 may perform an LBT type 2A (referred to as a "25 μs LBT") procedure. If the duration of time gap 360 is equal to 16 μs, initiating device 310 may perform an LBT type 2B (referred to as a "16 μs LBT") procedure. If the duration of time gap 360 is less than 16 μs, initiating device 310 may perform an LBT type 2C procedure, which may not require the performance of an LTB procedure. That is, if the LBT type 2C procedure is selected, the originating device 310 may directly perform the transmission 352 without actually performing the channel access procedure.

In some example embodiments, the initiating 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) with which it communicates. To share the COT 340 with the responding device 320, the initiating device 310 may notify (e.g., via control signaling) the responding device 320 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 procedure. Note that when the responding device 320 performs transmission, the responding device 320 becomes an initiating device.

Fig. 3C shows an example of performing an LBT type 2 procedure prior to transmission by the responding device 320 within the COT 340. As shown in fig. 3C, after completing the LBT type 1 procedure, initiating device 310 performs a transmission 350. The responding device 320 may then intend to perform transmission 370 within the COT 340. As shown in fig. 3C, the responding device 320 may perform an LBT type 2 procedure prior to transmission 370 to check that the shared radio frequency spectrum band is available for communication.

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

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

Still referring to fig. 2. If the initiating device initiates a COT, the initiating device may send a SL transmission to the first device 201. The first device 201 may receive (220) a SL transmission from an originating device. It should be appreciated that the first device 201 may receive (220) SL transmissions 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.

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

SCI format 1-a may include information needed to determine the resource allocation of the PSSCH and to 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 a side link shared channel (SL-SCH)). The stage 2 SCI may include control information for HARQ feedback in unicast or multicast. It should be appreciated that the stage 1 SCI and the stage 2 SCI may also include other suitable information. An example of the additional information included in the SCI will be described below.

In some example embodiments, SCI format 1-A may be used for PSSCH and stage 2 SCI scheduling 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 to be 2 Bit, otherwise, when the value of the higher layer parameter sl-MaxNumPerReserve is configured to be 3Bits;

-time resource assignment-5 bits when the value of the higher layer parameter sl-MaxNumPerReserve is configured as 2, or 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 if the higher layer parameter sl-MultiReserveResource is configured, otherwise 0 bits;

-DMRS pattern- Bits, where N _pattern is the number of DMRS patterns configured by higher layer parameter sl-PSSCH-DMRS-TIMEPATTERNLIST, 0 bits if sl-PSSCH-DMRS-TIMEPATTERLIST is not configured;

stage 2 SCI format-2 bits, as defined in table 1 below;

-beta_offset indicator-2 bits provided by higher layer parameter sl-BetaOffsets2 ndSCI;

-number of DMRS ports-1 bit;

-modulation and coding scheme-5 bits;

-an 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, -0 bits otherwise;

-PSFCH overhead indication-1 bit if higher layer parameter sl-PSFCH-Period = 2 or 4, otherwise 0 bit;

reservation-number of bits determined by higher layer parameters sl-NumReservedBits, where the value is set to zero.

TABLE 1 stage 2 SCI Format

Value of SCI format field at stage 2	SCI format at stage 2
		00	SCI Format 2-A
01	SCI Format 2-B
		10	Reservation
11	Reservation

In some example embodiments, SCI format 2-A has information of a HARQ process number, a new data indicator, a redundancy version, a source ID, a destination ID, a HARQ feedback enable/disable indicator, a broadcast type indicator, and a CSI request. SCI format 2-B may have information of HARQ process number, new data indicator, redundancy version, source ID, destination ID, HARQ feedback enable/disable indicator, region ID, and communication range requirement.

It should be understood that the above examples of SCI format 1, SCI format 2-a, and SCI format 2-B are shown for illustrative purposes only and are not meant to be limiting in any way.

As described above, the 2 nd stage 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 multicasting. The first option is NACK-only HARQ feedback. In this first option, all terminal devices in the group share a single PSFCH resource. If no NACK is received in the shared PSFCH resources, the TX device determines an ACK. The RX device decision whether to send feedback may be 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 forming groups without any higher layer group management.

The second option is ACK/NACK HARQ feedback. In this second option, each RX device uses dedicated PSFCH resources. The TX device determines an ACK only if 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 may 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.

In some example embodiments, the first device 201 obtains (230) a respective value of at least one channel access parameter associated with 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 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 comprise a channel access procedure type, such as an LBT type.

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 the explicit CAPC indication included in the stage 1 or 2 SCI. Alternatively or additionally, in some example embodiments, the first device 201 may obtain (230) a respective value of the at least one channel access parameter based on a respective data priority of the SL transmission and an association rule between CAPC and the data priority. The association rule may be indicated in the SCI. In the case of determining the value CAPC, the value of the size of the CW may also be determined based on an association rule between CAPC and the size of the CW.

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 CAPC based on the value of the size of the CW. It should be appreciated that the above-described method for obtaining the value of the at least one channel access parameter is for illustrative purposes only, and any suitable method for obtaining the value of the at least one channel access parameter may be applied. In some example embodiments, the obtained value of the at least one channel access parameter may be stored by the first device 201.

In some example embodiments, the first device 201 may determine (235) whether to send feedback of the received SL transmission on the same feedback occasion of the first device 201 based on the obtained SCI. For example, the SCI may include information regarding whether to send feedback for SL transmissions. Furthermore, 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 slots have PSFCH, and any other suitable configuration.

Fig. 4 shows an example SL slot 401 with PSCCH/psch and PSFCH. The SL slot may be configured by the resource pool configuration information in the SCI. As shown, PSFCH opportunities 405 (such as the last symbol) may be included in the slot 401. PSFCH HARQ feedback may be enabled on SL from the device that is the intended recipient of the PSSCH transmission (i.e., the RX device) to the device performing the transmission (i.e., the TX device). Within 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.

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

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

In some example embodiments, the set of Mset PRB associated with a subchannel is shared among multiple RX devices, either in the case of ACK/NACK feedback for multicast communications or in the case of different PSSCH transmissions in the same subchannel. 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 may determine which PRB and cyclic shift pair should be used to transmit its HARQ feedback based on PSFCH index i. For example, the first device 201 may use the first cyclic shift or the second cyclic shift from the cyclic shift pair associated with the selected PSFCH index i in order to transmit a NACK or an ACK, respectively. By the RX device selecting the PSFCH with index i, the TX device can distinguish between HARQ feedback of different RX devices. In some example embodiments, prioritization of simultaneous PSFCH transmit/receive may be applied. In other words, the first device 201 may determine a channel access priority for SL feedback.

Still referring to fig. 2. The first device 201 may determine 235 to send feedback of the SL transmission based on configuration information included in the SCI. It should be appreciated that the first device 201 may use any suitable method to determine 235 whether to send SL feedback.

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 available COT for the first device 201, the first device 201 may use COT to send SL feedback. In some example embodiments, the COT availability means that there should be an initiating COT ending after PSFCH's transmitted symbol. In some example embodiments, the first device 201 may use a channel access procedure, such as an LBT type 2 procedure for transmitting PSFCH. For example, the first device 201 may determine which type of channel access procedure to perform based on the configuration in the SCI.

In some example embodiments, the first device 201 may need to initiate a COT if a previous COT initiated by the other device or by the first device 201 itself is not available. 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 COT. In other words, if there is no COT available for the first device 201 to perform SL transmission, the first device 201 may perform a channel access procedure to initiate the COT.

Example channel Access priority determination

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

In some example embodiments, the first device 201 determines (245) a value (also referred to as a target value) of the at least one channel access parameter as a function of a corresponding value of the at least one channel access parameter, the value being used to send feedback of the SL transmission on the same feedback occasion 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.

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) 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 of the at least one channel access parameter. For example, the function may indicate that a minimum or maximum of a plurality of values of the at least one channel access parameter is to be selected as the target value of the at least one parameter.

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 that an average or weighted average is obtained. For another example, the function may instruct to sort the plurality of values in ascending or descending order and select the value having the target sort 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 appreciated that the above examples of functions for determining the target value are for illustration purposes only, and that any suitable function may be applied to determine the target value.

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

In examples where the at least one channel access parameter includes a size of CW, the function may instruct the first device 201 to select a minimum CW or a maximum CW. It should be appreciated that where the target value for the CW size is determined, the target values for CAPC and any other channel access parameters may also be determined based on the target value for the CW size and the association rules between the different channel access parameters. In this case, the size of the CW having the SL transmission of a particular CAPC may be adjusted based on the number of HARQ transmission failures. For example, the first device 201 may determine a value of one of the channel access parameters based on a value of another channel access parameter using the following table 2.

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 a maximum value (CW _max,p). The duration of COT is given by T _ulmcot,p.

Fig. 5B illustrates an example mapping between SL transmission and SL feedback according to some example embodiments of the present disclosure. In fig. 5B CAPC is used as an example of at least one channel access parameter. As shown, PSSCH 560 is mapped to Mset PRB 565 in PSFCH opportunities 580. In addition, PSSCH 570 is mapped to Mset PRB 575 in PSFCH opportunities 580. CAPC of PSSCH 570 was p _A, and CAPC of PSSCH 570 was p _B. In this case, the first device 201 may determine (245) the target value P of CAPC by using a function indicating that the minimum value is selected. That is, the first device 201 may select the minimum value from p _A and p _B. By selecting the minimum of CAPC, the first device can access the feedback channel with another SL-U device with higher priority, and thus can increase the chance that multiple PSFCH are transmitted together.

It should be understood that the example of target value determination in fig. 5B is for illustration purposes only and does not imply any limitation. In other embodiments, the function may vary. The at least one channel access parameter may include parameters other than CAPC.

Still referring to fig. 2. In some example embodiments, the first device 201 may be preconfigured with a set of functions for determining the target value. The set of functions may include selecting a minimum value, selecting a maximum value, selecting an average value, and the like. In this case, the channel access configuration information may include function indexes associated with respective functions in the function set. The first device 201 may select a respective function from the set of functions based on the received channel access configuration information.

By configuring different functions for different devices, the channel access priority of the feedback for the different devices may be adjusted. In this way, one device may downgrade the channel access priority for feedback based on a function that selects a lower priority to facilitate other devices competing for the channel.

Alternatively or additionally, the channel access configuration information may comprise a mapping rule between the SL transmission priority and a value of at least one channel access parameter for feedback associated with the SL transmission. For example, the priority indicated in SCI may be mapped to CAPC in such a way that a priority of 1 or 2 may be mapped to CAPC with p equal to 1, a priority of 3 or 4 may be mapped to CAPC with p equal to 2, a priority of 5 or 6 may be mapped to CAPC with p equal to 3, and a priority of greater than 6 may be mapped to CAPC with p equal to 4. It should be understood that the mapping rules and example values and CAPC described above are for illustrative purposes only and are not meant to be limiting in any way. Any suitable mapping rule may be included in the channel access configuration information.

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

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

In some example embodiments, the channel access configuration information may include a broadcast type rule for determining whether a target value of the at least one channel access parameter is to be updated based on the function. For example, the broadcast type rule may include a first rule that the first SL 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.

Alternatively or additionally, the broadcast type rule may include a second rule that the first SL transmission comprises a multicast transmission and the second transmission comprises 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 the function. For example, if the first SL transmission satisfies the broadcast type rule, the first device 201 may update the target value based on the function. For another example, the first device 201 may update the target value based on a function if any SL transmission having feedback associated with the same occasion as the feedback of the first SL transmission satisfies the broadcast type rule.

Examples of channel access configuration information have been described. It will be appreciated that at least one of the above examples, such as a function, a mapping rule, a threshold number, or a multicast type rule, may be included in the channel access configuration information. The channel access configuration information may also include any other suitable information related to channel access parameters or channel access procedures.

In case at least one channel access parameter is determined, the first device 201 may perform (250) a type 1 channel access procedure, such as an LBT type 1 procedure. Details of the LBT type 1 procedure have been described with reference to fig. 3A and are not repeated here. 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 SL transmissions with feedback to the first device 201.

In some example embodiments, if the first device 201 detects another SL transmission after the type 1 channel access procedure for the first feedback transmission on the same feedback occasion and prior to the first feedback transmission, the 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 the first device 201 determines that the second value of the at least one channel access parameter of the further feedback of the further SL transmission is associated with a second transmission priority being higher than the first transmission priority of the first feedback transmission, the first device 201 may decrease the duration for the type 1 channel access procedure.

For example, if the first device 201 has started an LBT procedure for transmitting PSFCH after decoding the first PSCCH/PSSCH, then the first device 201 detects a second PSCCH/PSSCH associated with a higher priority (e.g., a lower CAPC or lower CW size) that allows for an upgrade of channel access parameters, the first device 201 may decrement the back-off counter of the LBT by D, where D is the difference between the CW size for the ongoing LBT and the CW size that would be used for the LBT with the upgraded channel access parameters. In this way, the duration for the channel access procedure 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 obtained from the PSCCH or PSSCH in the same time slot or up to the time slot before the start of LBT. In this case, channel access duration adjustment may not be applied.

Examples of channel access priority determination have been described above. With the determined target value of the channel access priority, the chance of LBT success can be increased when multiplexing a plurality PSFCH in the same slot. Furthermore, since channel access parameters may not be upgraded to unnecessary levels, better fairness to other devices, such as other Radio Access Technologies (RATs), may result.

Example procedure

Fig. 6 illustrates 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 discussion purposes, the process will be described from the perspective of the first device 201 in fig. 2.

At block 605, the first device 201 may begin selection of at least one channel access parameter for the next feedback. The time interval between the current time slot and the next feedback time slot is above the time gap threshold. For example, the time slot threshold may be a minimum time slot, such as sl-MINTIMEGAPPSFCH or K slots. The time gap threshold may be configured by the second device 202 in fig. 2. For example, the time gap threshold may be configured by the SCI. As another example, the time slot threshold may be configured from a SL resource configuration from the network device. As described above, the at least one channel access parameter may include a cap, a size of a CW, or other suitable channel access parameters. The feedback may include PSFCH. The feedback slots may include PSFCH slots or PSFCH occasions.

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

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

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 above a time gap threshold. For example, the time slot threshold may be a minimum time slot, such as sl-MINTIMEGAPPSFCH or K slots. The time gap threshold may be configured by the second device 202 in fig. 2. For example, the time gap threshold may be configured by the SCI. As another example, the time gap threshold may be configured from a SL resource configuration from the network device.

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

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

In some example embodiments, if at block 635 the first device 201 determines that there is feedback to send, at block 640 the first device 201 may determine whether there is a COT available for feedback transmission. For example, the first device 201 may determine whether the COT previously initiated by the first device 201 itself or by other devices is still available for SL transmissions by the first device 201. COT available means that there should be an initiating COT ending after PSFCH's transmit symbol.

In some example embodiments, if the first device 201 determines that COT is available at block 640, the first device 201 may send feedback using LBT type 2 at block 645. For example, the first device 201 may transmit PSFCH using LBT type 2. Examples of type 2LBT of processing are described with respect to fig. 3B and 3C and are not repeated here. In some example embodiments, in the case of performing LBT type 2 for transmission 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.

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

With the target value of the at least one channel access parameter, the first device 201 may perform a type 1 channel access procedure, e.g., LBT type 1, by using the target value of the at least one channel access parameter. If the first device 201 initiates a COT through a type 1 channel access procedure, the first device 201 may transmit SL feedback such as PSFCH by using the initiated COT.

In some example embodiments, where a target value of at least one channel access parameter for the current time slot is determined, the first device 201 may select the target value of at least one channel access parameter for the next feedback time slot at block 605. The time interval between the current time slot and the next feedback time slot is above the time gap threshold. For example, the first device 201 may perform blocks 610-650 for the next PSFCH slot.

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 of at least one channel access parameter for the next feedback slot at block 605. The time interval between the current time slot and the next feedback time slot is above the time gap threshold. For example, the first device 201 may perform blocks 610-650 for the next PSFCH slot.

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

An example process for SL feedback transmission according to the present disclosure has been described with reference to fig. 6. It should be understood that the process in fig. 6 is for illustration purposes only and does not imply any limitation. The process 600 may include additional steps or some steps in the process 600 may be omitted. By using SL feedback transmission with a determined target value of the channel access parameter, the chance of LBT success can be increased when multiplexing multiple PSFCH in the same time slot. Furthermore, since 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

Fig. 7 illustrates 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 comprise a terminal device. For discussion purposes, the method 700 will be described from the perspective of the first device 201 in fig. 2.

At block 710, the first device 201 obtains side link control information for side link transmissions having feedback associated with the same feedback opportunity of the first device 201.

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

In some exemplary embodiments, obtaining the respective value of the at least one channel access parameter associated with the feedback of the side link transmission comprises obtaining the respective value of the at least one channel access parameter based on an explicit channel access priority class indication included in the side link control information or obtaining the respective value of the at least one channel access parameter based on the respective data priority of the side link transmission and an association rule between the channel access priority class and the data priority, the association rule being indicated in the side link control information.

At block 730, the first device 201 determines a value of the at least one channel access parameter as a function of a corresponding value of the at least one channel access parameter, the value being used to convey feedback of the side chain transmission on the same feedback occasion of the first device. For example, the first device 201 may determine the value of the at least one channel access parameter as a function by at least one of selecting a minimum value of the respective values as the value, or selecting a maximum value of the respective values as the value.

In some example embodiments, determining the value of the at least one channel access parameter includes determining that a number of the plurality of feedback transmissions over the same feedback occasion 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.

Alternatively or additionally, in some example embodiments, determining the value of the 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 a first rule that the first side link 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 a second rule that the first side link transmission comprises a multicast transmission and the second transmission comprises a multicast transmission requesting feedback.

In some example embodiments, determining the value of the at least one channel access parameter includes determining that a channel occupancy time is not available for a plurality of feedback transmissions of the side link transmission and determining the 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 being used for a type 1 channel access procedure for the feedback transmissions on the same feedback occasion.

In some example embodiments, the 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 the other side link transmission after the type 1 channel access procedure for the first feedback transmission on the same feedback occasion and prior to the first feedback transmission, wherein the second transmission priority is higher than the first transmission priority of the first feedback transmission, and reducing a 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.

In some example embodiments, the method 700 further comprises receiving channel access configuration information from the second device 202. The channel access configuration information may include at least one of a function for determining a value of the at least one channel access parameter, a mapping rule between the side link transmission priority and an associated value of the at least one channel access parameter for feedback associated with the side link 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. In some example embodiments, the second device 202 may comprise a terminal device. Alternatively, in some example embodiments, the second device 202 may comprise a network device.

Fig. 8 illustrates a flowchart of an example method 800 implemented at a second device, according to some example embodiments of the present disclosure. For discussion purposes, the method 800 will be described from the perspective of the second device 202 in fig. 2. In some example embodiments, the second device 202 may include a terminal device or a network device.

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

In some example embodiments, the channel access configuration information includes at least one of 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 for the side link transmission of the first device, a mapping rule between a side link transmission priority and an associated value of the at least one channel access parameter for feedback associated with the side link 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.

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

It should be understood that method 700 or method 800 may include additional blocks not shown and/or that some of the blocks shown may be omitted, and that the scope of the present disclosure is not limited in this respect.

Example apparatus, devices, and media

In some example embodiments, a first apparatus (e.g., first device 201 in fig. 2) capable of performing any of methods 700 may include means for performing the respective operations of method 700. The components may be implemented in any suitable form. For example, the components may be implemented in circuitry or software modules. The first means may be implemented or comprised in the first device 201 of fig. 2.

In some example embodiments, a first apparatus includes means for obtaining side link control information for a side link transmission having feedback associated with a same feedback occasion of the first apparatus, means for obtaining respective values of at least one channel access parameter associated with the feedback for the side link transmission based on the side link control information, and means for determining the values of the at least one channel access parameter as a function of the respective values of the at least one channel access parameter, the values being used to send the feedback for the side link transmission on the same feedback occasion of the first apparatus.

In some example embodiments, the means for obtaining the respective value of the at least one channel access parameter associated with the feedback of the side link transmission comprises one of means for obtaining the respective value of the at least one channel access parameter based on an explicit channel access priority class indication included in the side link control information, or means for obtaining the respective value of the at least one channel access parameter based on the respective data priority of the side link transmission and an association rule between the channel access priority class and the data priority, the association rule being indicated in the side link control information. For example, in some example embodiments, the at least one channel access parameter includes at least one of a channel access priority class, or a size of a contention window.

In some example embodiments, the means for determining the value of the at least one channel access parameter as a function of the respective value of the at least one channel access parameter comprises at least one of means for selecting a minimum value of the respective values as the value, or means for selecting a maximum value of the respective values as the value.

In some example embodiments, the means for determining the value of the at least one channel access parameter comprises means for determining that a number of the plurality of feedback transmissions over the same feedback occasion 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.

Alternatively or additionally, in some example embodiments, the means for determining the value of the at least one channel access parameter comprises means for determining that at least one of a first side link transmission or a second side link transmission of the side link transmission meets 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 meets the broadcast type rule. For example, in some example embodiments, the broadcast type rule includes at least one of a first rule that the first side link 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 a second rule that the first side link transmission comprises a multicast transmission and the second transmission comprises a multicast transmission requesting feedback.

In some example embodiments, the means for determining the value of the at least one channel access parameter comprises means for determining that a channel occupancy time is not available for a plurality of feedback transmissions of the side link transmission, and means for determining the 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 transmission on the same feedback occasion.

In some example embodiments, the first apparatus further comprises means 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, wherein the second transmission priority is higher than the first transmission priority of the first feedback transmission, and means for reducing a duration for the type 1 channel access procedure based on determining that the second value is associated with the second transmission priority higher than the first transmission priority, based on detecting the other side link transmission after the type 1 channel access procedure for the first feedback transmission on the same feedback occasion and prior to the first feedback transmission.

In some example embodiments, the first apparatus may further include means for receiving channel access configuration information from the second apparatus. The channel access configuration information may include at least one of a function for determining a value of the at least one channel access parameter, a mapping rule between the side link transmission priority and an associated value of the at least one channel access parameter for feedback associated with the side link 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.

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

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 component includes at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause execution of the first apparatus.

In some example embodiments, a second apparatus (e.g., second device 202 in fig. 2) capable of performing any of the methods 800 may include means for performing the respective operations of the methods 800. The components may be implemented in any suitable form. For example, the components may be implemented in circuitry or software modules. The second means may be implemented or comprised in the second device 202 of fig. 2.

In some example embodiments, the second apparatus includes means for transmitting channel access configuration information to the first apparatus. In some example embodiments, the channel access configuration information includes at least one of 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 for the side link transmission of the first device, a mapping rule between a side link transmission priority and an associated value of the at least one channel access parameter for feedback associated with the side link 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.

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

In some exemplary embodiments, the first device comprises a terminal device and the second device comprises a terminal device or a network device.

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 component includes at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause execution of the second apparatus.

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

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

By way of non-limiting example, the processor 910 may be of any type suitable to a local technology network and may include one or more of general purpose computers, special purpose computers, microprocessors, digital Signal Processors (DSPs), and processors based on a multi-core processor architecture. The device 900 may have multiple processors, such as application specific integrated circuit chips that are time dependent to a clock synchronized to the master processor.

Memory 920 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memory include, but are not limited to, read-only memory (ROM) 924, electrically programmable read-only memory (EPROM), flash memory, a hard disk, an optical disk (CD), a Digital Video Disk (DVD), an optical disk, a laser disk, and other magnetic and/or optical storage. Examples of volatile memory include, but are not limited to, random Access Memory (RAM) 922 and other volatile memory that will not persist during power failure.

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

Example embodiments of the present disclosure may be implemented by the program 930 such that the device 900 may perform any of the processes of the present disclosure as discussed with reference to fig. 2 and 6-8. Example embodiments of the present disclosure may also be implemented by hardware or a combination of software and hardware.

In some example embodiments, the program 930 may be tangibly embodied in a computer-readable medium, which may be included in the device 900 (such as in the memory 920) or other storage device accessible by the device 900. Device 900 may load program 930 from a computer-readable medium into 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, and the like. As used herein, the term "non-transitory" is a limitation of the medium itself (i.e., tangible rather than signals), and not a limitation of data storage persistence (e.g., RAM versus ROM).

Fig. 10 shows an example of a computer readable medium 1000, which may be in the form of a CD, DVD or other optical storage disc. Computer-readable medium 1000 has program 930 stored thereon.

In general, the various embodiments of the disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of the embodiments of the disclosure are illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, in non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

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 comprises computer executable instructions such as those included in program modules, being executed in a device on a target physical or virtual processor to perform any of the methods described above. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within local or distributed devices. In distributed devices, program modules may be located in both local and remote memory storage media.

Program code for carrying out the methods of the present disclosure may be written in any combination of one or more programming languages. Program code may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus such that the program code, when executed by the processor or controller, results in the implementation of the functions/operations specified in the flowchart and/or block diagram. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of this disclosure, computer program code or related data may be carried by any suitable carrier to enable an apparatus, device, or processor to perform the various processes and operations described above. Examples of carriers include signals, computer readable media, and the like.

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, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of a computer-readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, 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 disc read-only memory (CD-ROM), an optical storage component, a magnetic storage component, or any suitable combination of the foregoing.

Moreover, although operations are depicted in a particular order, this should not be understood as requiring that such operations be performed by specific ones of the illustrated operations, or by sequential ones of the illustrated operations, or that all of the illustrated operations be performed to achieve desirable results. In some cases, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are included in the above discussion, these details should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments can also be implemented in combination in a single embodiment unless explicitly stated. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination unless explicitly stated otherwise.

Although the disclosure has been described in language specific to structural features and/or methodological acts, it is to 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 (19)

1. A first device, comprising: at least one processor; and 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; and 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; and 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; and 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: A 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 channel occupancy time is unavailable for a plurality of feedback transmissions of the sidelink transmission; and 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 being 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; and 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; and 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 corresponding value of at least one channel access parameter associated with the feedback of the sidelink transmission; and 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 the 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.