Channel occupancy time sharing for sidelink transmissions

Abstract

Example embodiments of the present disclosure relate to a terminal device, method, apparatus, and computer readable storage medium for channel occupancy time sharing for sidelink transmissions. The first terminal device initiates COT by executing an LBT process associated with the CAPC; sending an indication of COT for SL transmission among the plurality of terminal devices to the plurality of terminal devices; and detecting the SL transmission during the COT. In this way, the first terminal device may know information of SL transmission (s) during the COT, and for example, the information may be used to adjust the CW. Therefore, the communication efficiency of SL transmission can be improved.

Description

Technical Field

[0001] Example embodiments of the present disclosure relate generally to the field of telecommunications, and in particular, to terminal devices, methods, apparatuses, and computer-readable storage media for channel occupancy time sharing for sidelink transmissions. Background Art

[0002] Given the scarcity and expense of bandwidth in the licensed spectrum, and the growing need for data transmission capacity, there is growing interest in offloading at least some communications traffic to the unlicensed spectrum. Listen before talk (LBT) has been proposed, where a device that intends to perform a transmission needs to first successfully complete an LBT check before being able to initiate a transmission. LBT may also be referred to as clear channel assessment (CCA).

[0003] Support for sidelinks in unlicensed spectrum (SL-U) was proposed for study and specification, and sidelink enhancements still need to be considered. Summary of the invention

[0004] In general, example embodiments of the present disclosure provide a solution for channel occupancy time sharing for sidelink transmissions.

[0005] In a first aspect, a first terminal device is provided. The first terminal device comprises at least one processor and at least one memory storing instructions, which when executed by the at least one processor causes the first terminal device to at least: initiate a channel occupation time (COT) by performing a listen-before-talk (LBT) procedure associated with a channel access priority class (CAPC); send an indication of the COT for a sidelink (SL) transmission between the plurality of terminal devices to a plurality of terminal devices; and detect the SL transmission during the COT.

[0006] In a second aspect, a second terminal device is provided. The second terminal device comprises at least one processor and at least one memory storing instructions, which, when executed by the at least one processor, causes the second terminal device to at least: send service information to at least one of a first terminal device or a network device; receive an indication of a channel occupancy time (COT) initiated by the first terminal device from the first terminal device; and send a sidelink (SL) transmission to a third terminal device during the COT.

[0007] In a third aspect, a network device is provided. The network device includes at least one processor and at least one memory storing instructions, wherein when the instructions are executed by the at least one processor, the network device at least: sends an initiation command to a first terminal device instructing the first terminal device to initiate a channel occupation time (COT), wherein the initiation command includes at least one of the following items: a channel access priority category (CAPC), multiple identifiers of multiple terminal devices, service information of a side link (SL) transmission between multiple terminal devices, or timing information for initiating COT.

[0008] In a fourth aspect, a method performed by a first terminal device is provided. The method comprises: at the first terminal device, initiating a channel occupancy time (COT) by performing a listen-before-talk (LBT) procedure associated with a channel access priority class (CAPC); sending an indication of the COT for a sidelink (SL) transmission between the plurality of terminal devices to a plurality of terminal devices; and detecting the SL transmission during the COT.

[0009] In a fifth aspect, a method performed by a second terminal device is provided. The method comprises: at the second terminal device, sending service information to at least one of a first terminal device or a network device; receiving an indication of a channel occupancy time (COT) initiated by the first terminal device from the first terminal device; and sending a sidelink (SL) transmission to a third terminal device during the COT.

[0010] In a sixth aspect, a method performed by a network device is provided. The method includes: sending an initiation command to the first terminal device to instruct the first terminal device to initiate a channel occupation time (COT), the initiation command including at least one of the following items: a channel access priority category (CAPC), multiple identifiers of multiple terminal devices, service information of a side link (SL) transmission between multiple terminal devices, or timing information for initiating COT.

[0011] In a seventh aspect, an apparatus is provided. The apparatus comprises: means for initiating a channel occupancy time (COT) at a first terminal device by performing a listen-before-talk (LBT) procedure associated with a channel access priority class (CAPC); means for sending an indication of the COT for a sidelink (SL) transmission between the plurality of terminal devices to a plurality of terminal devices; and means for detecting a SL transmission during the COT.

[0012] In an eighth aspect, an apparatus is provided. The apparatus comprises: means for sending service information at a second terminal device to at least one of a first terminal device or a network device; means for receiving from the first terminal device an indication of a channel occupancy time (COT) initiated by the first terminal device; and means for sending a sidelink (SL) transmission to a third terminal device during the COT.

[0013] In a ninth aspect, an apparatus is provided. The apparatus includes: a component for sending an initiation command to a first terminal device to instruct the first terminal device to initiate a channel occupation time (COT), the initiation command including at least one of the following items: a channel access priority category (CAPC), multiple identifiers of multiple terminal devices, service information of a side link (SL) transmission between multiple terminal devices, or timing information for initiating COT.

[0014] In a tenth aspect, a non-transitory computer-readable medium including program instructions is provided, the program instructions being used to cause an apparatus to at least perform the method of any one of the fifth to eighth aspects.

[0015] In an eleventh aspect, a computer program comprising instructions is provided, which, when executed by an apparatus, causes the apparatus to at least perform the method of any one of the fifth to eighth aspects.

[0016] In a twelfth aspect, a first terminal device is provided. The first terminal device comprises: an initiating circuit configured to initiate a COT by executing an LBT process associated with a CAPC; a sending circuit configured to send a COT indication for SL transmission between the multiple terminal devices to multiple terminal devices; and a detecting circuit configured to detect SL transmission during the COT.

[0017] In a thirteenth aspect, a second terminal device is provided. The second terminal device comprises: a sending circuit configured to send service information to at least one of a first terminal device or a network device; a receiving circuit configured to receive an indication of a COT initiated by the first terminal device from the first terminal device; and a sending circuit configured to send an SL transmission to a third terminal device during the COT.

[0018] In a fourteenth aspect, a network device is provided. The network device includes: a sending circuit configured to send an initiation command to a first terminal device, instructing the first terminal device to initiate a channel occupation time (COT), the initiation command including at least one of the following items: a channel access priority category (CAPC), multiple identifiers of multiple terminal devices, service information of a side link (SL) transmission between multiple terminal devices, or timing information for initiating COT.

[0019] It should be understood that the invention summary is not intended to identify the key or essential features of the embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Some example embodiments will now be described with reference to the accompanying drawings, in which:

[0021] Figure 1A shows an example of a network environment in which some example embodiments of the present disclosure may be implemented;

[0022] Figure 1B and Figure 1C Two example scenarios are shown in which some example embodiments of the present disclosure may be implemented;

[0023] Figure 2A shows an example diagram of a CCA slot in which some example embodiments of the present disclosure may be implemented;

[0024] Figure 2B An example diagram showing acquisition of a COT by an initiator device via a Type 1 LBT in which some example embodiments of the present disclosure may be implemented;

[0025] Figure 3A Some examples of a Type 1 LBT CW count-down process are shown in which some example embodiments of the present disclosure may be implemented;

[0026] Figure 3B Some examples of allowed clearances for a Type 2 LBT in which some example embodiments of the present disclosure may be implemented are shown;

[0027] Figure 3C shows an example of the relationship between the LBT bandwidth and the sub-channel bandwidth for SL-U in which some example embodiments of the present disclosure may be implemented;

[0028] Figure 4A shows an example of a process flow according to some example embodiments of the present disclosure;

[0029] Figure 4B Another example of a process flow according to some example embodiments of the present disclosure is shown;

[0030] Figure 5 Another example of a process flow according to some example embodiments of the present disclosure is shown;

[0031] Figure 6 shows an example frame structure according to some example embodiments of the present disclosure;

[0032] Figure 7A flowchart of a method implemented at a first terminal device according to some example embodiments of the present disclosure is shown;

[0033] Figure 8 A flowchart of a method implemented at a second terminal device according to some example embodiments of the present disclosure is shown;

[0034] Fig. 9 A flowchart of a method implemented at a network device according to some example embodiments of the present disclosure is shown;

[0035] Fig.10 shows a simplified block diagram of a device suitable for implementing some example embodiments of the present disclosure;

[0036] Fig.11 A block diagram illustrating an example of a computer readable medium according to some example embodiments of the present disclosure is shown.

[0037] Throughout the drawings, the same or similar reference numerals refer to the same or similar elements. DETAILED DESCRIPTION

[0038] The principles of the present disclosure will now be described with reference to some example embodiments. It should be understood that these embodiments are described for illustrative purposes only and to help those skilled in the art understand and implement the present disclosure, and are not intended to limit the scope of the present disclosure in any way. The disclosure described herein can be implemented in various ways except as follows.

[0039] 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.

[0040] References in this disclosure to "one embodiment," "an embodiment," "an example embodiment," and the like indicate that the described embodiment may include a particular feature, structure, or characteristic, but not every embodiment must include the particular feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it is considered to be within the knowledge of those skilled in the art to affect that feature, structure, or characteristic in conjunction with other embodiments (whether or not explicitly described).

[0041] It should be understood that although the terms "first" and "second" and the like 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 may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the example embodiments. As used herein, the term "and / or" includes any and all combinations of one or more of the listed terms.

[0042] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit exemplary embodiments. As used herein, unless the context clearly indicates otherwise, the singular forms "one", "an" and "the" are also intended to include their plural forms. It will also be understood that the terms "include", "include", "have", "have", "include" and / or "include" used in this article indicate the existence of features, elements and / or parts, but do not exclude the existence or increase of one or more other features, elements, parts and / or their combinations. As used herein, "at least one of the following: <list of two or more elements>" and "at least one of <list of two or more elements>" and similar terms, wherein the list of two or more elements is connected by "and" or "or", meaning at least any one element, or at least any two or more elements, or at least all elements.

[0043] As used in this application, the term "circuitry" may refer to one or more or all of the following:

[0044] (a) hardware circuit implementation only (e.g., implementation in analog and / or digital circuits only), and

[0045] (b) a combination of hardware circuitry and software, such as (where applicable):

[0046] (i) a combination of analog and / or digital hardware circuits with software / firmware, and

[0047] (ii) any portion of a hardware processor with software (including a digital signal processor), software and memory that work together to enable a device such as a mobile phone or server to perform various functions; and

[0048] (c) Hardware circuits and / or processors, such as a microprocessor or a portion of a microprocessor, that require software (such as firmware) to operate, but where software is not required for operation, the software may not be present.

[0049] This definition of circuitry applies to all uses of this term in this application, including in any claims. As another example, as used in this application, the term circuitry also covers implementations of only a hardware circuit or processor (or multiple processors) or portions of a hardware circuit or processor and its (or its) accompanying software and / or firmware. The term circuitry also covers (for example and if applicable to a particular claim element) a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in a server, cellular network device or other computing or network device.

[0050] As used herein, the term "communication network" refers to a network that complies with any suitable communication standard, such as Long Term Evolution (LTE), Advanced LTE (LTE-A), Wideband Code Division Multiple Access (WCDMA), High Speed ​​Packet Access (HSPA), Narrowband Internet of Things (NB-IoT), etc. In addition, the communication between the terminal equipment and the network equipment in the communication network can be performed according to any suitable generation of communication protocols, including but not limited to the first generation (1G), the second generation (2G), 2.5G, 2.75G, the third generation (3G), the fourth generation (4G), 4.5G, the future fifth generation communication protocol (5G), and / or any other protocol currently known or developed in the future. The embodiments of the present disclosure can be applied to various communication systems. In view of the rapid development of communication, there will certainly be future types of communication technologies and systems that can be used to embody the present disclosure. The scope of the present disclosure should not be considered to be limited to the above-mentioned systems.

[0051] As used herein, the term "network device" refers to a node in a communication network through which a terminal device accesses the network and receives services from it. Depending on the terminology and technology applied, a network device can be a base station (BS) or an access point (AP), for example, a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), a new radio (NR), a NB (also known as a gNB), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), an integrated access and backhaul (IAB) node, a relay, a low-power node such as a femto, a pico, etc.

[0052] The term "terminal device" refers to any terminal device capable of wireless communication. As an example and not limitation, a terminal device may also be referred to as a communication device, a user equipment (UE), a subscriber station (SS), a portable subscriber station, a mobile station (MS), or an access terminal (AT). The terminal device may include, but is not limited to, a mobile phone, a cellular phone, a smart phone, a voice over IP (VoIP) phone, a wireless local loop phone, a tablet computer, a wearable terminal device, a personal digital assistant (PDA), a portable computer, a desktop computer, an image capture terminal device (such as a digital camera), a game terminal device, a music storage and playback device, a vehicle-mounted wireless terminal device, a wireless endpoint, a mobile station, a laptop embedded device (LEE), a laptop mounted device (LME), USB doogles, smart devices, wireless client equipment (CPE), an Internet of Things (IoT) device, a machine type communication (MTC) device, a watch or other wearable device, a head mounted display (HMD), a vehicle, an unmanned aircraft, medical equipment and applications (such as remote surgery), industrial equipment and applications (such as robots and / or other wireless devices running in industrial and / or automated processing environments). In the following description, the terms "terminal device", "communication device", "terminal", "user equipment" and "UE" may be used interchangeably.

[0053] In Release 18, it is proposed to study and specify support for sidelinks on unlicensed spectrum. The following text box describes some non-limiting introductory information of SL-U that can be used in some example embodiments of the present disclosure.

[0054]

[0055]

[0056] In the sub-7GHz unlicensed band, the coexistence of New Radio (NR) and other systems (such as Institute of Electrical and Electronics Engineers (IEEE) 802.11) is ensured via the LBT channel access mechanism. A user equipment (UE) that plans to perform a sidelink (SL) transmission needs to successfully complete the LBT check first before being able to initiate the same transmission. In some embodiments, the UE may be referred to as a SL UE.

[0057] For operation in unlicensed bands, a SL UE can obtain the "right" to access a channel (in other words, to initiate a COT) by itself for SL transmission via a Type 1 LBT within a specific time period represented as the channel occupation time (COT), or be shared by a COT initiated by another UE to acquire the channel for SL transmission via a "simplified" LBT procedure (e.g., Type 2 LBT). Obviously, the "simplified" LBT (i.e., Type 2A / 2B / 2CLBT) procedure will be friendly to SL UEs (e.g., sensor devices, low-cost MTC devices, or even low-cost terminal devices) in terms of power consumption, latency, and capability requirements. To this end, it makes sense if a device with at least Type 1 LBT capability can initiate a COT and then share the COT with other SL UEs for SL transmission in unlicensed bands.

[0058] Example embodiments of the present disclosure provide a solution for SL-U. In particular, the first terminal device can initiate COT by executing an LBT process associated with a channel access priority category (CAPC), share the COT with other terminal devices, and further detect (multiple) sidelink transmissions during the COT. In this way, the first terminal device can obtain information about (multiple) sidelink transmissions during the COT, and, for example, the information can be used to adjust the CW. Thereby, the communication efficiency of SL transmission can be improved. The principles and some example embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0059] Figure 1A An example of a network environment 100 in which some example embodiments of the present disclosure may be implemented is shown. The network environment 100 may include a first terminal device 110, a plurality of terminal devices 120, and a network device 130. The network device 130 may provide a wireless access cell through which the first terminal device 110 and each of the plurality of terminal devices 120 may communicate with the network device 130. In some example embodiments, the network device 130 may be a gNB providing a 3GPP NR cell. In other example embodiments, the network device 130 may be an eNB providing an LTE cell. The air interface through which the first terminal device 110, the plurality of terminal devices 120, and the network device 130 communicate may be compatible with 3GPP technical specifications, such as technical specifications defining a fifth generation (5G) NR system standard.

[0060] like Figure 1AAs shown, multiple terminal devices 120 include terminal device 120-1, terminal device 120-2, ..., and terminal device 120-M. It should be noted that the number M can be any suitable natural number. It should be understood that the number of network devices and terminal devices is only for illustrative purposes and does not imply any limitation. Network environment 100 may include any suitable number of network devices and terminal devices suitable for implementing embodiments of the present disclosure. It should be noted that some example embodiments of the present disclosure can be implemented without the presence of network device 130.

[0061] The first terminal device 110 and the multiple terminal devices 120 may also communicate directly with each other via a sidelink interface. The sidelink interface may alternatively be referred to as a ProSe interface, a device-to-device (D2D) interface, a user-to-user (U2U) interface, or a ProSe communication 5 (PC5) interface. In some example embodiments, the network environment 100 may be deployed within a vehicle communication system. In the vehicle communication system, the first terminal device 110 and the multiple terminal devices 120 may communicate with each other using cellular vehicle-to-everything (V2X) communication. V2X may involve vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-network (VTN), or vehicle-to-pedestrian (V2P) communication. Therefore, although Figure 1A The first terminal device 110 and the plurality of terminal devices 120 are shown as mobile phones, but the first terminal device 110 and the plurality of terminal devices 120 may be any type of user equipment.

[0062] In some example embodiments, a transmission link between the first terminal device 110 and any one of the plurality of terminal devices 120 may be represented as a sidelink (SL).

[0063] It should be understood that Figure 1A The network environment 100 shown in FIG. 1 is for illustration purposes only and does not mean any limitation to the scope of the present disclosure. For example, in other embodiments, the first terminal device 110 may be replaced by another network device (eg, a base station).

[0064] The communication in the network environment 100 may be implemented according to any appropriate (multiple) communication protocols, including but not limited to cellular communication protocols such as the first generation (1G), the second generation (2G), the third generation (3G), the fourth generation (4G) and the fifth generation (5G), wireless local area network communication protocols (such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11, etc.), and / or any other protocol currently known or developed in the future. In addition, the communication may utilize any appropriate 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 multiplexing (OFDM), discrete Fourier transform spread OFDM (DFT-s-OFDM), and / or any other technology currently known or developed in the future.

[0065] In the following description, the first terminal device 110 may be used as a head device among the plurality of terminal devices 120. In some example embodiments, the first terminal device 110 may be referred to as a cluster head (CH) device, and the plurality of terminal devices 120 may be referred to as cluster member (CM) devices. In some embodiments, the plurality of terminal devices 120 may be divided into one or more clusters according to a cluster configuration from the network device 130. In some embodiments, the first terminal device 110 and the plurality of terminal devices 120 may be within the coverage of the network device 130.

[0066] Figure 1B 1 shows an example of a network environment 105 in which some example embodiments of the present disclosure may be implemented. The network environment 105 may include a first terminal device 110 and terminal devices 120-1 to 120-5. Figure 1B As shown, the first terminal device 110 and the terminals 120 - 1 to 120 - 5 are located in a car. Figure 1B Two clusters are shown in FIG. 1 , wherein the first cluster includes terminal devices 120 - 1 and 120 - 2 , and the second cluster includes terminal devices 120 - 3 to 120 - 5 .

[0067] In some example embodiments, the first terminal device 110 (CH device) may be responsible for obtaining LBT clearance of the COT of multiple terminal devices 120-1 to 120-5 (i.e., one or more groups of CM devices) that are the target of the in-vehicle SL communication scenario. In some examples, each of the multiple terminal devices 120-1 to 120-5 may be a sensor device, a low-cost MTC device, or a low-cost UE terminal device. In some examples, each of the multiple terminal devices 120-1 to 120-5 may have a capacity limitation for LBT operation. For example, for cost reduction at the multiple terminal devices 120-1 to 120-5, only type 2 LBT (e.g., type 2C LBT) is supported.

[0068] It should be understood that Figure 1B The illustrated network environment 105 is for illustration purposes only and is not intended to limit the scope of the present disclosure in any way. For example, in other embodiments, a network device 130 may exist.

[0069] For example, the first terminal device 110 and the plurality of terminal devices 120 may be located in other scenarios. As a non-limiting example, the first terminal device 110 may be a device with smart home technology, such as an air conditioner or refrigerator in a home, may have LBT capabilities, and may act as a CH device. The plurality of terminal devices 120 may be sensors installed in home curtains. In some examples, the first terminal device 110 may be responsible for obtaining unauthorized channel access for the plurality of terminal devices 120, such as sensors for opening / closing home curtains.

[0070] Figure 1C 1 shows an example of a network environment 115 in which some example embodiments of the present disclosure may be implemented. The network environment 115 may include a first terminal device 110 and terminal devices 120-1 to 120-5. Figure 1C As shown, it is assumed that data transmission can be performed between terminal devices 120-1 and 120-2, and another data transmission can be performed between terminal devices 120-3 and 120-4. Figure 1C In addition, there may be control signaling from the first terminal device 110 to any one of the terminal devices 120-1 to 120-4, which is shown as a solid line in FIG. Figure 1C Indicated by dotted line.

[0071] In some example embodiments, the transmission channel between two different terminal devices may be any of the following: a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), or a physical sidelink feedback channel (PSFCH).

[0072] It should be understood that Figure 1C The network environment 115 shown is for illustration purposes only and does not imply any limitation on the scope of the present disclosure. For example, in other embodiments, there may be a network device 130. For example, in other embodiments, there may be a data transmission from the first terminal device 110 to one of the terminal devices 120-1 to 120-5.

[0073] For a terminal device to pass the LBT check, it needs to observe the available channels for multiple consecutive durations. The total duration of the consecutive durations may be referred to as the contention window (CW) duration. One of the durations within the CW duration may be referred to as a CCA slot or a sensing slot, and the length of the CCA slot may be represented as T sl . Figure 2A An example diagram 210 of a CCA time slot in sub-7 GHz is shown. As shown in FIG. 2 , the length of the CCA time slot 214 is T sl =9μs.

[0074] In some example embodiments, if the measured power is below a specified threshold, the terminal device may consider the channel to be available in the CCA slot. Figure 2A , the terminal device may measure the duration 212 (eg Figure 2A The power within 4μs in the channel, and if the measured power is lower than the threshold, the terminal device can determine that the channel is available. In some embodiments, the threshold may depend on the operating frequency band and / or geographical area, and the present disclosure is not limited in this regard.

[0075] In the context of the present disclosure, the term "initiating device" may be a device that uses a Type 1 LBT process to initiate a COT for sidelink transmission, and the term "responding device" may be a device that uses a simplified LBT type to share a COT for sidelink transmission. In the context of the present disclosure, the terms "sidelink (SL) transmission" and "SL communication" may be used interchangeably. In the context of the present disclosure, the term "Type 1 LBT" may also be referred to as LBT Type 1, extended LBT, etc., and the term "Type 2 LBT" may also be referred to as LBT Type 2, simplified LBT, etc. In some embodiments, extended LBT and simplified LBT may refer to those described in TS37.213 and are not repeated here.

[0076] When a terminal device (initiating device) initiates communication, the terminal device can perform Type 1 LBT in order to obtain the right to access the channel within a specific time period, that is, initiate COT. Figure 2B An example diagram 220 is shown of a COT being acquired by an initiator device via a Type 1 LBT. Figure 2BAs shown, the initiating device may perform Type 1 LBT during a CW duration 222 and may perform communications during a subsequent COT 224 .

[0077] In some example embodiments, the maximum duration of the COT and the size of the CW duration may depend on the channel access priority class (CAPC) associated with the traffic of the terminal device, as shown in Table 1. In some embodiments, control plane traffic (such as PSCCH) is transmitted when p=1, while user plane traffic has p>1.

[0078] Table 1

[0079]

[0080]

[0081] For a detailed description of Table 1, please refer to "Table 4.2.1-1: Channel Access Priority Category (CAPC) for UL" in TS.37.213, so it will not be repeated here. In some examples, the size of the CW duration can refer to the number of CCA time slots within the CW duration. For example, the size of the CW duration can be expressed as N, where N is an integer. In some examples, the size of the CW duration can be referred to as the size of the CW, the CW size, or simply CW. It should be understood that the CW within the CCA time slot associated with each CAPC can have a minimum value (CW min,p ) and maximum value (CW max,p ), and the duration of COT can be obtained from T in Table 1 ulmcot,p Table 1 describes the Type 1 LBT details that can be adopted in SL and used for Uu uplink (UL) case. However, it should be understood that the Type 1 LBT parameters or any other parameters for downlink (DL) case can also be adopted in SL and will not be repeated here.

[0082] Figure 3A 1 shows some examples of a Type 1 LBT CW countdown process 310 in which some example embodiments of the present disclosure may be implemented. In some example embodiments, Figure 3A As shown in (a) of FIG. 1 , if the delay time (denoted as T d ) period, the CW countdown process is performed. When neither the delay time nor the countdown is interrupted (i.e., the channel is not detected as busy during the sensing time slot), the Type 1 LBT ends and SL transmission can be performed subsequently. In some example embodiments, such as Figure 3A As shown in (b) in FIG. 1 , if the delay time is interrupted, that is, the channel is detected as busy during the delay time sensing time slot, another delay time is further detected until it is idle. In some example embodiments, as Figure 3AAs shown in (c) in FIG. 1 , if the channel is detected as idle during the delay time and the countdown is interrupted, that is, the channel is detected as busy during the sensing time slot of the countdown (in the CCA time slot (T sl ) in the LBT check fails), the countdown will stop and will resume if the channel is deemed idle during another delay time. In some embodiments, Figure 3A The N in is the number of CCA slots that are required to be considered idle before the contention window countdown is completed.

[0083] In NR-U, before a Type 1 LBT procedure associated with a channel access priority class p, the terminal device shall maintain a contention window value CW p and can adjust the CW used for its transmission p In some embodiments, the terminal device may adjust the CW based on the success or failure of reception of (multiple) PUSCHs within the previous COT as specified in TS 37.213 (e.g., UL HARQ-ACK feedback). p .

[0084] In some embodiments, once the Type 1 LBT is successfully completed, the initiator device can obtain the COT with the maximum duration associated with the corresponding CAPC, and thus the initiator device can perform the transmission. In some embodiments, the obtained COT is still valid even if the initiator device suspends its transmission. In some embodiments, if the initiator device wants to perform a new transmission within the obtained COT, it still needs to perform the simplified LBT process.

[0085] In some example embodiments, the initiating device may share the acquired COT with its intended recipients, i.e., the responding device(s). To this end, the initiating device shall inform (e.g., via control signaling) the responding device about the remaining duration of the COT. If the responding device wants to perform a transmission with the initiating device, the responding device may decide which type of LBT it should apply based on the shared COT from the initiating device. In some examples, if the intended transmission of the responding device falls within the COT, the responding device may perform a simplified LBT.

[0086] Figure 3B Some examples of allowed clearances for a Type 2 LBT 320 are shown in which some example embodiments of the present disclosure may be implemented. Figure 3B (a), (b) and (c) show the case where the gap is between two transmissions from the initiating UE, while (d), (e) and (f) show the case where the gap is between two different transmissions from the initiating UE and the responding UE, respectively.

[0087] In some other example embodiments, the simplified LBT may also be referred to as a Type 2 LBT, and may include a Type 2A LBT, a Type 2B LBT, and a Type 2C LBT:

[0088] ●Type 2A (25μs LBT) – such as Figure 3B (c) and (f) in FIG. 5 are for a SL transmission within the acquired COT (i.e., a SL transmission after another SL transmission) when the gap between the two SL transmissions is ≥ 25 μs;

[0089] ● Type 2B (16μs LBT) – e.g. Figure 3B , which are shown in (b) and (e) in FIG. 5 , for a SL transmission within the acquired COT (ie, a SL transmission after another SL transmission) when the gap is exactly equal to 16 μs.

[0090] ●Type 2C (no LBT) – e.g. Figure 3B As shown in (a) and (d) in FIG. 5 , it is used for SL transmission within the acquired COT (i.e., SL transmission after another SL transmission) when the gap is <16 μs and the allowed duration of SL transmission is ≤584 μs.

[0091] In some other example embodiments, if the expected subsequent transmission falls outside the acquired COT, another Type 1 LBT should be performed to acquire a new COT.

[0092] In some example embodiments, for single carrier operation of SL in Release 16 or Release 17, the terminal device will make its resource selection based on the sensing results of the resource pool (RP) for resource allocation (RA) mode 2. In some examples, the RP can be further divided into sub-channels in the frequency domain, and each sub-channel can be composed of a set of at least 10 consecutive non-overlapping physical resource blocks (PRBs) in a time slot. In some embodiments, resource allocation, sensing and resource selection for SL RA mode 2 can be performed in units of sub-channels.

[0093] In some example embodiments, the LBT bandwidth in the frequency domain is typically 20 MHz in Release 16 NR-U. In some embodiments, the 20 MHz LBT bandwidth may correspond to an RP bandwidth with multiple subchannels for SL operation in unlicensed spectrum. Figure 3C An example of a relationship 330 between LBT bandwidth and subchannel bandwidth for SL-U is shown in which some example embodiments of the present disclosure may be implemented. Figure 3C As shown, by assuming that the subcarrier spacing (SCS) is 30kHz, 5 subchannels are configured in the transmitter / receiver (TX / RX) RP, and each subchannel may consist of 10 PRBs.

[0094] In addition, multiple sub-channels can be allocated to different terminal devices for SL communication.

[0095] Based on the above description, for unlicensed band operation, the terminal device can acquire a channel by itself via Type 1 LBT to initiate a COT, or the terminal device can acquire a channel within a COT shared by another terminal device via Type 2 LBT. It can be understood that Type 2 LBT will be preferred for the terminal device in terms of power consumption, latency, and capability requirements. Fig.10 The principles and some exemplary embodiments of the present disclosure are described in detail.

[0096] Figure 4A An example of a process flow 400 according to some example embodiments of the present disclosure is shown. For the purpose of discussion, reference will be made to Figure 1A Processing flow 400 is described. Processing flow 400 involves first terminal device 110, terminal device 120-1 and terminal device 120-2. In some embodiments, terminal device 120-1 may be referred to as a second terminal device, and terminal device 120-2 may be referred to as a third terminal device. It should be understood that although Figure 1A The processing flow 400 is described in the network environment 100, but the processing flow can also be applied to other communication scenarios.

[0097] In the process flow 400, the first terminal device 110 initiates 410 COT by executing an LBT process associated with the CAPC. In some embodiments, the LBT process may be a Type 1 LBT process, or may also be referred to as Type 1 LBT. In some embodiments, the first terminal device 100 has Type 1 LBT capability.

[0098] In some example embodiments, the first terminal device 110 may receive an initiation command from the network device 130, and initiate the COT based on the initiation command. Figure 5 Those discussed.

[0099] In some example embodiments, the CAPC may be a fixed CAPC. In some examples, the CAPC may be predefined at first terminal device 110. In some other examples, the CAPC may be preconfigured by network device 130. For example, network device 130 may determine the CAPC during cluster configuration and send the CAPC to first terminal device 110.

[0100] In some examples, the predefined or preconfigured CAPC may be the lowest CAPC among a plurality of preconfigured CAPCs. In this way, the first terminal device 110 may always give priority access to the terminal device 120.

[0101] In some examples, the predefined or preconfigured CAPC may be the highest CAPC among a plurality of preconfigured CAPCs. In this way, the first terminal device 110 may give lower (compared to the lowest CAPC) priority access to the terminal device 120, but the initiated COT may be longer.

[0102] In some example embodiments, the CAPC may be determined based on the service information. For example, the CAPC may be determined by the first terminal device 110 or may be determined by the network device 130 .

[0103] In some examples, at least one of the terminal devices 120 may send service information to the first terminal device 110, so the first terminal device 110 may receive service information from at least one of the terminal devices 120, and the first terminal device 110 may determine the CAPC based on the received service information.

[0104] In some other examples, at least one of the terminal devices 120 may send the service information to the network device 130, so the network device 130 may receive the service information from at least one of the terminal devices 120. The network device 130 may also send the service information to the first terminal device 110, so the first terminal device 110 may receive the service information and may determine the CAPC based on the received service information.

[0105] In some other examples, the network device 130 may determine the service information based on the categories of the plurality of terminal devices 120, for example during cluster configuration. The network device 130 may send the determined service information to the first terminal device 110, so the first terminal device 110 may receive the service information and may determine the CAPC based on the received service information.

[0106] In some embodiments, the first terminal device 110 may determine the CAPC based on the received service information and further based on one or more of the following: channel load, expected COT.

[0107] In some other examples, at least one of the terminal devices 120 may send service information to the network device 130, so the network device 130 may receive the service information from at least one of the terminal devices 120, and the network device 130 may also determine the CAPC based on the received service information. The network device 130 may also send the determined CAPC to the first terminal device 110, so the first terminal device 110 may receive the CAPC.

[0108] In some other examples, the network device 130 may determine the service information based on the categories of the plurality of terminal devices 120, for example during cluster configuration. The network device 130 may determine the CAPC based on the determined service information. The network device 130 may also send the determined CAPC to the first terminal device 110 so that the first terminal device 110 may receive the CAPC.

[0109] In some example embodiments, the CAPC may be determined by first terminal device 110. In some examples, first terminal device 110 may select the CAPC from a plurality of pre-configured CAPCs.

[0110] For example, the selected CAPC may be the highest CAPC among multiple pre-configured CAPCs. In some examples, if the first terminal device 110 does not know the service information of the multiple terminal devices 120, the first terminal device 110 may select the highest CAPC.

[0111] In some embodiments, the plurality of preconfigured CAPCs may include 1, 2, 3, and 4 as shown in Table 1. In some embodiments, the service information sent from at least one of the terminal devices 120 to the first terminal device 110 may be carried in a buffer status report (BSR). In some embodiments, the service information may indicate a service type (or types) associated with a category of the plurality of terminal devices 120.

[0112] In some embodiments, a default CAPC may be stored (or predefined or preconfigured) at the first terminal device 110. In some embodiments, there may be the same default CAPC at multiple terminal devices 120.

[0113] In some example embodiments, the first terminal device 110 may initiate (or determine) a COT. In some examples, the first terminal device 110 may determine the maximum COT and the size of the CW (between the minimum contention window and the maximum contention window) based on the CAPC; and the first terminal device 110 may perform a type 1 LBT based on the CW to initiate a COT.

[0114] In the process flow 400, the first terminal device 110 sends 420 an indication of COT 421 to a plurality of terminal devices 120, and as shown in FIG4 , the plurality of terminal devices 120 include terminal device 120-1 and terminal device 120-2. Thus, terminal device 120-1 may receive 422 an indication of COT 421, and terminal device 120-2 may receive 424 an indication of COT 421.

[0115] In some embodiments, the indication of COT 421 may be sent via control signaling, such as sidelink control information (SCI) or sequence-based signaling.

[0116] Alternatively or additionally, the first terminal device 110 may send an indication of the CAPC to the plurality of terminal devices 120. In some embodiments, the indication of the CAPC may be sent via control signaling. In some embodiments, the indication of the COT and the indication of the CAPC may be carried in the same signaling.

[0117] In some example embodiments, first terminal device 110 may not send an indication of the CAPC to multiple terminal devices 120. In some examples, if the CAPC determined by first terminal device 110 is the same as a default CAPC, the CAPC may not be indicated, which may reduce signaling overhead.

[0118] In some example embodiments, it is assumed that there is a SL transmission to be initiated by terminal device 120-1.Alternatively or additionally, terminal device 120-1 may determine 430 a traffic type of the SL transmission to be performed during the COT.

[0119] In some embodiments, if an indication of a CAPC is sent, the terminal device 120 - 1 may determine a service type of SL transmission to be performed based on the indicated CAPC.

[0120] In some embodiments, if there is no indication of a CAPC sent from the first terminal device 110, the terminal device 120-1 may determine a default (or predefined or preconfigured) CAPC, and further determine a service type of SL transmission to be performed based on the default CAPC.

[0121] In process flow 400, terminal device 120-1 sends 440 a SL transmission 442 to terminal device 120-2 during a COT. On the other side of the communication, terminal device 120-2 receives 444 the SL transmission 442. Specifically, terminal device 120-1 may send 442 the SL transmission based on resource selection and the indicated COT.

[0122] In some example embodiments, the SL transmission 442 performed within the COT may be limited to the traffic type determined at 430. In some example embodiments, the SL transmission 442 within the COT may be limited to multicast and / or unicast transmission, and the present disclosure is not limited in this regard. In some example embodiments, the SL transmission 442 may be sent via the PSCCH or PSSCH, and the present disclosure is not limited in this regard.

[0123] Terminal device 120-2 sends 450 SL-transmitted feedback information 452 to terminal device 120-1. Thus, terminal device 120-1 receives 454 feedback information 452. In some example embodiments, feedback information 452 may be sent via a PSCCH or a PSFCH.

[0124] Alternatively or additionally, the terminal device 120 - 1 or the terminal device 120 - 2 may perform another SL transmission after the Type 2 LBT process within the indicated COT.

[0125] In this way, the first terminal device 110 with at least type 1 LBT capability can initiate a COT, and the COT can be shared with other terminal devices 120 for SL transmission in an unlicensed band. Therefore, the terminal device 120 does not need to perform type 1 LBT, and the power consumption at the terminal device 120 can be reduced.

[0126] Continue to refer Figure 4A , the first terminal device 110 detects 460 the SL transmission during the COT. In some example embodiments, the first terminal device 110 may detect the SL transmission and determine a detection result.

[0127] In some example embodiments, the detection result may include one or more of the following: an SCI associated with the SL transmission, HARQ feedback information for the SL transmission, or a channel energy level for the SL transmission. Alternatively or additionally, the first terminal device 110 may determine input information based at least on the detection result, wherein the input information may be used for CW adjustment.

[0128] In some embodiments, the first terminal device 110 may monitor SL transmissions (PSCCH and / or PSFCH) within the COT. In some examples, the first terminal device 110 may monitor SCI exchanges (i.e., PSCCH) within the cluster based on an identifier (ID) of the terminal device 120. For example, the first terminal device 110 may detect whether the terminal device 120 is able to transmit during the COT, and the first terminal device 110 may further use the detection information in the SCI as part of the input information.

[0129] In some embodiments, the first terminal device 110 may detect resource allocations for SL transmissions (PSSCH) of the terminal device 120 within the COT. In some embodiments, the first terminal device 110 may monitor HARQ feedback information (PSFCH) based on the resource allocations. In some examples, the first terminal device 110 may include the HARQ feedback information as part of the input information.

[0130] In some embodiments, the first terminal device 110 may detect the channel energy level by sensing the channel at a predetermined time. In some examples, the first terminal device 110 may sense the channel for the detected energy level during the COT and use the detected energy level as part of the input information. For example, by detecting the energy in the channel at a predetermined time, the first terminal device 110 may determine whether the terminal device (e.g., terminal device 120-2) successfully received the SL transmission 442. In other words, the detected energy may implicitly indicate whether the SL transmission 442 was successful.

[0131] Alternatively or additionally, the first terminal device 110 performs 470 a CW adjustment based on the input information.In some embodiments, the first terminal device 110 may adjust the CW associated with the CAPC according to at least one predefined rule.

[0132] In some embodiments, the first terminal device 110 may reset the size of the CW to an initial value based on one or more of the following items: the number of acknowledgments (ACKs) indicated by the HARQ feedback information exceeds a threshold value of the number of ACKs, the ratio of the number of ACKs to the total number of feedbacks indicated by the HARQ feedback information exceeds a threshold value of the ACK ratio, the number of terminal devices sending SCI exceeds a threshold value of the number of devices, or the ratio of the number of terminal devices sending SCI to the number of multiple terminal devices exceeds a threshold value of the device ratio.

[0133] In some examples, the threshold of the number of ACKs is expressed as N0 (an integer, such as 1), and the threshold of the ACK ratio is expressed as x% (e.g., 10%). Thus, if at least N0 HARQ feedbacks or x% of the HARQ feedbacks are "ACKs" for PSSCH transmissions within the COT, the first terminal device 110 may reset the size of the CW.

[0134] In some examples, the first terminal device 110 may determine a change in channel energy detected before and after a predefined time within the COT, and if the change exceeds a threshold for energy detection, determine that the feedback information indicates ACK. In some examples, if no NACK is detected when only NACK is fed back, the first terminal device 110 may determine that "ACK" is detected.

[0135] In some examples, the threshold value of the number of devices is represented as M0 (an integer, such as 1), and the threshold value of the device ratio is represented as y% (e.g., 10%). In this way, if at least M0 expected devices or y% of the expected devices among the plurality of terminal devices 120 are detected to send SCI within the COT, the first terminal device 110 can reset the size of the CW. In some examples, for a specific terminal device (e.g., terminal device 120-2), the first terminal device 110 can determine whether the terminal device 120-2 is the expected device based on the monitored SCI of the terminal device 120-2 and / or the BSR from the terminal device 120-2.

[0136] In some embodiments, the first terminal device 110 may increase the size of the CW based on one or more of the following: no SCI is detected, no HARQ feedback is detected, the number of detected SCIs is lower than a threshold for SCI, the number of detected HARQ feedbacks is lower than a threshold for feedback, or the ratio of a time period during which the channel energy level is higher than a threshold to the COT exceeds a threshold for a time ratio. For example, the threshold for SCI may be represented as N1, the threshold for feedback may be represented as N2, and the threshold for the time ratio may be represented as z%. In some examples, no SCI is detected may indicate that SL transmission is not performed.

[0137] In other words, the first terminal device 110 may increase the CW if at least one of the following conditions is met: there is no HARQ feedback for SL transmission of multiple terminal devices 120 during the COT; no SL transmission is detected through the SCI during the COT; the number of detected SCIs is less than N1; the number of detected HARQ feedbacks is less than N2; or the time period during which the energy sensing at the first terminal device 110 is above the threshold is more than z% of the COT.

[0138] In some embodiments, the above thresholds, such as N0, M0, N1, N2, x, y, z, may be predetermined or preconfigured by the network device 130 .

[0139] In this way, the first terminal device 110 may perform CW adjustment based on input information associated with the detection result within the COT shared by the plurality of terminal devices 120 .

[0140] It should be understood that the first terminal device 110 (CH device) can obtain the COT, but it is not related to the SL transmission with any of the multiple terminal devices 120 (CM devices). In other words, there is no logical channel associated with the expected transmission for the first terminal device 110 within the COT. The present disclosure provides a CW adjustment mechanism for a type 1 LBT process so that the first terminal device 110 (CH) shares the initiated COT with multiple terminal devices 120 for (multiple) SL transmissions. According to the present disclosure, even if there is no logical channel associated with the expected transmission within the COT, the first terminal device 110 can adjust the CW based on the input information. In some embodiments, the first terminal device 110 and the multiple terminal devices 120 are within the coverage of the network device 130.

[0141] Figure 4B Another example of a process flow 405 according to some example embodiments of the present disclosure is shown. The process flow 405 involves a CH device 401, a first CM device 402, and a second CM device 403. In some embodiments, the process flow 405 may be a specific implementation of the process flow 400 described above. For example, the CH device 401 may be the first terminal device 110, the first CM device 402 may be the terminal device 120-1, and the second CM device 120-2 may be the terminal device 120-2.

[0142] In process flow 405, CH device 401 determines 4051 a CAPC for a COT shared with its CM devices, including first CM device 402 and second CM device 403. In some examples, the determination depends at least on whether traffic information of CM devices 402-403 is available at CH device 401 during the expected COT.

[0143] The CH device 401 obtains 4052 the COT having the CW associated with the determined CAPC. The CH device 401 then indicates 4053 the COT information to its CM devices. In some embodiments, the COT information may be sent via (eg, SCI or sequence-based) control signaling.

[0144] In some embodiments, the COT information may indicate the acquired COT. In some other embodiments, the COT information may indicate the acquired COT and the determined CAPC. In some embodiments, the COT information may be shared with the first CM device 402. In some other embodiments, the COT information may be shared with the first CM device 402 and the second CM device 403.

[0145] The first CM device 402 determines 4054 a traffic type for SL transmission. In some examples, the determination is based at least on whether CAPC is indicated in the COT information.

[0146] In some embodiments, if the COT information indicates the acquired COT and the determined CAPC, the service type can be determined based on the indicated CAPC. In some other embodiments, if the acquired COT (without CAPC) is indicated in the COT information, the service type can be determined based on the default CAPC.

[0147] The first CM device 402 and the second CM device 403 perform SL transmission within the COT (eg Figure 4B PSCCH / PSSCH 4055 and PSFCH 4056 shown). In some embodiments, SL transmission can be performed based on resource selection and COT indication. In some embodiments, SL transmission within the COT can be limited to multicast and / or unicast transmission.

[0148] In process flow 405, CH device 401 monitors 4057 SL transmissions (PSCCH / PSFCH) and / or channel energy levels of SL transmissions. In some embodiments, CH device 401 may monitor SL transmission(s) between its CM devices and determine input information for CW adjustment.

[0149] In some alternative embodiments, when the CH device 401 and the CM devices 402-403 are within the coverage of a network device (e.g., a gNB) and the SL HARQ feedback is reported to the gNB, the gNB may monitor the results of the HARQ feedback from the CM devices 402-403 and indicate the results to the CH device 401 as part of the input information for CW adjustment.

[0150] The CH device 401 further adjusts 4058 the CW based on predefined rules and input information.

[0151] It should be understood that Figure 4B The process 405 shown in FIG. 4 is for illustration purposes only and does not imply any limitation.

[0152] Figure 5 An example of a process flow 500 according to some example embodiments of the present disclosure is shown. For discussion purposes, reference will be made to Figure 1A Describes process flow 500. It should be understood that although Figure 1A The processing flow 500 is described in the network environment 100, but the processing flow can also be applied to other communication scenarios.

[0153] Processing flow 500 involves first terminal device 110, terminal device 120-1, terminal device 120-2, and network device 130. In some embodiments, first terminal device 110 may be a CH device, terminal device 120-1 and terminal device 120-2 may be CM devices in the same cluster. In some embodiments, terminal device 120-1 may be an initiator of SL transmission, and terminal device 120-2 may be a responder of SL transmission.

[0154] In the process flow 500 , the first terminal device 110 determines 510 a CAPC. Alternatively or additionally, operation 501 or 505 may be performed before determining 510 .

[0155] like Figure 5 As shown, the terminal device 120-1 sends 502 service information 503 to the first terminal device 110, and the first terminal device 110 receives 504 the service information 503. Therefore, the first terminal device 110 can determine the CAPC based on the service information from the terminal device 120-1.

[0156] like Figure 5 As shown, the network device 130 sends 508 an initiation command 509 to the first terminal device 110. Alternatively or additionally, the terminal device 120-1 may send 506 service information 503 to the network device 130, and the network device 130 receives 507 the service information 503.

[0157] In some embodiments, the initiation command 509 may be carried in an RRC message or RRC signaling. In some other embodiments, the initiation command 509 may be carried in another message, which is not limited by the present disclosure.

[0158] In some example embodiments, the initiation command 509 is used to instruct the first terminal device 110 to initiate a COT. In some example embodiments, the initiation command may include one or more of the following: a CAPC, multiple identifiers of multiple terminal devices, service information, or timing information for initiating a COT.

[0159] In some examples, network device 130 may determine the CAPC based on the cluster configuration. In some examples, network device 130 may determine the CAPC based on traffic information from terminal device 120-1.

[0160] In some examples, multiple terminal devices may be grouped into one or more clusters. Figure 1B As shown, the terminal devices 120 - 1 and 120 - 2 belong to the same cluster, and the terminal devices 120 - 3 , 120 - 4 , and 120 - 5 belong to another cluster.

[0161] In some embodiments, assuming that there is a SL transmission from terminal device 120-1 to terminal device 120-2, the initiation command 509 may include an identifier of terminal device 120-1 and an identifier of terminal device 120-2. In some examples, the initiation command 509 may also indicate that terminal device 120-1 is the initiator of the SL transmission, and terminal device 120-2 is the responder of the SL transmission.

[0162] It should be understood that in some other embodiments, if there is a first SL transmission from terminal device 120-1 to terminal device 120-2 and a second SL transmission from terminal device 120-3 to terminal device 120-4 (eg Figure 1C As shown), the initiation command 509 may also indicate that the terminal devices 120-1 and 120-2 belong to the same cluster, and the terminal devices 120-3, 120-4, and 120-5 belong to another cluster.

[0163] In some examples, the initiation command 509 may include service information associated with the terminal device 120-1 and / or the terminal device 120-2. It should be understood that in some other embodiments, the initiation command 509 may also include another service information associated with the terminal device 120-3 and / or the terminal device 120-4.

[0164] In some examples, the initiation command 509 may include timing information for initiating the COT. For example, the timing information may indicate the initiation time, so that the first terminal device 110 may initiate the COT at the initiation time. For example, the timing information may indicate the initiation period, so that the first terminal device 110 may re-initiate the COT based on the time period of expiration of the initiation period after the previous initiation of the COT.

[0165] At the other end of the communication, the first terminal device 110 receives 5091 the launch command 509. In some examples, if the launch command 509 includes a CAPC, the first terminal device 110 can determine 510 the CAPC by obtaining the CAPC from the launch command 509. In some other examples, if the launch command 509 does not include a CAPC but includes business information, the first terminal device 110 can determine 510 the CAPC based on the business information. In some other examples, if the launch command 509 does not include a CAPC or business information, the first terminal device 110 can determine 510 the CAPC itself, such as a predefined CAPC (which can be the lowest or highest CAPC among multiple preconfigured CAPCs), or a CAPC based on the business information 503 received at 504.

[0166] The first terminal device 110 initiates 520 COT by executing an LBT process associated with the CAPC. In some embodiments, the LBT process may be a type 1 LBT process, or also referred to as type 1 LBT. In some embodiments, the first terminal device 100 may initiate COT based on an initiation command 509 from the network device 130.

[0167] In some embodiments, the initiation command 509 includes timing information for initiating the COT, and the first terminal device 110 may initiate 520 the COT based on the timing information. For example, the first terminal device 110 may initiate the COT at the initiation time indicated by the timing information. For example, the timing information may indicate an initiation period, and the first terminal device 110 may re-initiate the COT based on a time period after the previous initiation when the initiation period expires.

[0168] The first terminal device 110 includes Figure 5 The multiple terminal devices 120 shown as terminal device 120-1 and terminal device 120-2 send 530 indications of COT 531. In this way, terminal device 120-1 can receive 532 indications of COT 531, and terminal device 120-2 can receive 534 indications of COT 531. Alternatively or additionally, the first terminal device 110 can send indications of CAPC to multiple terminal devices 120.

[0169] In some examples, the first terminal device 110 may determine that the target terminal devices indicated by the COT include the terminal device 120-1 and the terminal device 120-2 based on the launch command 509. For example, the launch command 509 may include an identifier of the terminal device 120-1 and an identifier of the terminal device 120-2.

[0170] Terminal device 120-1 determines 536 the traffic type of the SL transmission based on the CAPC. Terminal device 120-1 sends 540 the SL transmission 542 to terminal device 120-2 during the COT. At the other end of the communication, terminal device 120-2 receives 544 the SL transmission 542. Terminal device 120-2 sends 550 feedback information 552 of the SL transmission to terminal device 120-1. Thus, terminal device 120-1 receives 554 the feedback information 552.

[0171] It should be understood that processing 520-554 can refer to Figure 4A Those processes described above are therefore not repeated here.

[0172] like Figure 5As shown, the network device 130 monitors 560 the feedback information sent by the terminal device 120 - 2 , and the network device 130 sends 570 the feedback information 572 to the first terminal device 110 , so the first terminal device 110 receives the feedback information 572 .

[0173] The first terminal device 110 detects 580 a SL transmission during the COT. In some example embodiments, the first terminal device 110 may detect the SL transmission and determine a detection result. In some example embodiments, the detection result may include one or more of the following: an SCI associated with the SL transmission, or a channel energy level of the SL transmission.

[0174] Alternatively or additionally, the first terminal device 110 may determine input information based at least on the feedback information 572 or the detection result from the network device 130 , wherein the input information may be used for CW adjustment.

[0175] The first terminal device 110 performs 590 CW adjustment based on the input information.In some embodiments, the first terminal device 110 may adjust the CW associated with the CAPC according to at least one predefined rule.

[0176] It should be understood that Figure 5 Similar operations can be found in Figure 4A Although reference is made to Figure 4A-Figure 5 Embodiments are described, but it should be understood that some operations may be combined in some other embodiments. Figure 4A In the example, the first terminal device 110 may initiate a COT based on an initiation command from the network device 130. Figure 5 In the embodiment, the first terminal device 110 may receive timing information from the network device 130 and receive service information from the terminal device 120 - 1 , but the present disclosure is not limited in this regard.

[0177] In a specific example, refer to Figure 1C , assuming that the network device 130 can configure the first terminal device 110 as a CH device, and configure multiple terminal devices 120-1 to 120-5 as CM devices. The first terminal device 110 can be responsible for COT initiation and share it with multiple terminal devices 120-1 to 120-5. In some examples, multiple terminal devices 120-1 to 120-5 are within the coverage of the first terminal device 110, so that the first terminal device 110 can successfully share its initiated COT with multiple terminal devices 120-1 to 120-5, and the first terminal device 110 is able to detect SL transmission between multiple terminal devices 120-1 to 120-5 based on the identifiers of the multiple terminal devices 120-1 to 120-5.

[0178] It is assumed that there is SL transmission between the terminal device 120 - 1 and the terminal device 120 - 2 , and there is another SL transmission between the terminal device 120 - 3 and the terminal device 120 - 4 . Figure 6 An example frame structure 600 is shown according to some example embodiments of the present disclosure.

[0179] In some embodiments, the first terminal device 110 may determine the expected terminal device based on the BSR, for example, the expected terminal device includes the terminal devices 120 - 1 to 120 - 4 .

[0180] The first terminal device 110 will perform a Type 1 LBT process 60 at time slot #n. If the first terminal device 110 successfully acquires the channel, it will initiate a COT 62 with a duration of 30 OFDM symbols and share the COT 61 to the terminal devices 120-1 to 120-4 for SL transmission. For example, the first terminal device 110 sends control signaling (e.g., via a sequence) to indicate the COT on two OFDM symbols 61 within the COT 52 (i.e., OFDMA symbols #11 / 12 in time slot #n). In some examples, the indication of the COT may at least be able to inform the terminal devices 120-1 to 120-4 whether the COT has been acquired in subsequent (multiple) time slots.

[0181] The terminal device 120-1 and the terminal device 120-3 are intended to perform SL transmission. Therefore, the terminal device 120-1 and the terminal device 120-3 can respectively transmit the second protection symbol (such as Figure 6 611 and 613 in the COT) to access the channel. Therefore, terminal device 120-1 can send PSCCH / PSSCH 621 to terminal device 120-2 in time slot #(n+1) within the COT. Terminal device 120-3 can send PSCCH / PSSCH 623 to terminal device 120-4 in time slot #(n+2) within the COT.

[0182] Terminal device 120-2 and terminal device 120-4 may respectively use the first protection symbol (e.g. Figure 6 612 and 614 in the COT) to access the channel. Therefore, terminal device 120-2 sends PSFCH 622 for HARQ feedback to terminal device 120-1 in time slot #(n+1) within the COT. Terminal device 120-4 sends PSFCH 624 for HARQ feedback to terminal device 120-3 in time slot #(n+2) within the COT.

[0183] It should be understood that simplified LBT can be implemented in the protection symbol by CP extension like in NR-U, and the present disclosure is not limited in this regard. In addition, SL transmission during COT can be multicast or unicast SL transmission, so multicast or unicast SL transmission is allowed in different subbands.

[0184] In this example, the CH may decide how to adjust the CW size based on, for example, the SCI on the PSCCH or the HARQ feedback on the PSFCH (i.e., the PSSCH or PSFCH is a reference resource for CW adjustment). Alternatively, the CH may detect the channel energy only during, for example, the AGC symbol DMRS or PSFCH. Another option is that the CH performs detection of the DMRS sequence sent by the CM.

[0185] Figure 7 700 shows a method implemented at a first terminal device according to some example embodiments of the present disclosure. For the purpose of discussion, reference will be made to Figure 1A The method 700 is described from the perspective of the first terminal device 110 .

[0186] At block 710, the first terminal device 110 initiates a channel occupation time (COT) by performing a listen-before-talk (LBT) procedure associated with a channel access priority class (CAPC). At block 720, the first terminal device 110 sends an indication of the COT for sidelink (SL) transmissions between the plurality of terminal devices 120 to the plurality of terminal devices 120. At block 730, the first terminal device 110 detects SL transmissions during the COT.

[0187] In some example embodiments, the first terminal device 110 receives an initiation command from the network device 130 instructing the first terminal device to initiate a COT, the initiation command including at least one of the following items: a CAPC, multiple identifiers of multiple terminal devices, service information transmitted by the SL, or timing information for initiating the COT.

[0188] In some example embodiments, the first terminal device 110 receives service information of the SL transmission from one of the plurality of terminal devices 120; and determines the CAPC based on the service information.

[0189] In some example embodiments, the service information indicates service types associated with categories of the plurality of terminal devices 120 .

[0190] In some example embodiments, the first terminal device 110 determines the CAPC to be a predefined CAPC, which is a lowest CAPC or a highest CAPC from a plurality of preconfigured CAPCs.

[0191] In some example embodiments, the first terminal device 110 determines the CAPC to be the highest CAPC from among a plurality of pre-configured CAPCs.

[0192] In some example embodiments, the first terminal device 110 sends an indication of the CAPC to the plurality of terminal devices 120 .

[0193] In some example embodiments, the first terminal device 110 determines input information based at least on a detection result of a SL transmission during a COT; and performs a contention window (CW) adjustment based at least in part on the input information.

[0194] In some example embodiments, the detection result of the SL transmission includes at least one of the following items: sidelink control information (SCI) associated with the SL transmission, HARQ feedback information of the SL transmission, or a channel energy level of the SL transmission.

[0195] In some example embodiments, the first terminal device 110 detects resource allocation for SL transmission within the COT; and monitors HARQ feedback information based on the resource allocation.

[0196] In some example embodiments, the first terminal device 110 detects the channel energy level by sensing the channel at a predetermined time.

[0197] In some example embodiments, the first terminal device 110 receives HARQ feedback information from the network device 130 , and the first terminal device 110 and the plurality of terminal devices 120 are within the coverage of the network device 130 .

[0198] In some example embodiments, the first terminal device 110 resets the size of the CW to an initial value based on at least one of the following items: the number of acknowledgments (ACKs) indicated by the HARQ feedback information exceeds a threshold value of the number of ACKs, the ratio of the number of ACKs to the total number of feedbacks indicated by the HARQ feedback information exceeds a threshold value of the ACK ratio, the number of terminal devices sending SCI exceeds a threshold value of the number of devices, or the ratio of the number of terminal devices sending SCI to the number of multiple terminal devices exceeds a threshold value of the device ratio.

[0199] In some example embodiments, the HARQ feedback is determined based on a change in channel energy detected before and after a predefined time within the COT exceeding a threshold for energy detection.

[0200] In some example embodiments, the first terminal device 110 increases the size of the CW based on at least one of the following items: no SCI is detected, no HARQ feedback is detected, the number of detected SCIs is lower than a threshold for SCI, the number of detected HARQ feedbacks is lower than a threshold for feedback, or the ratio of the time period during which the channel energy level is higher than a threshold to the COT exceeds a threshold for the time ratio.

[0201] Figure 8 800 of a method implemented at a second terminal device according to some example embodiments of the present disclosure is shown. For discussion purposes, reference will be made to Figure 1A The method 800 is described from the perspective of one terminal device (eg, the second terminal device 120 - 1 ) among the plurality of terminal devices 120 .

[0202] At block 810, the second terminal device 120-1 sends traffic information to at least one of the first terminal device 110 or the network device 130. At block 820, the second terminal device 120-1 receives an indication of a channel occupancy time (COT) initiated by the first terminal device 110 from the first terminal device 110. At block 830, the second terminal device 120-1 sends a sidelink (SL) transmission to the third terminal device 120-2 during the COT.

[0203] In some example embodiments, the service information indicates service types associated with categories of the plurality of terminal devices 120, the plurality of terminal devices 120 including the second terminal device 120-1 and the third terminal device 120-2.

[0204] In some example embodiments, the second terminal device 120 - 1 receives an indication of a channel access priority class (CAPC) from the first terminal device 110 .

[0205] In some example embodiments, if no indication of a CAPC is received from first terminal device 110 , second terminal device 120 - 1 determines a default CAPC configured by network device 130 .

[0206] In some example embodiments, the second terminal device 120 - 1 determines SL transmission with a traffic type based on the CAPC.

[0207] In some example embodiments, the second terminal device 120-1 receives hybrid automatic repeat request (HARQ) feedback information of the SL transmission within the COT from the third terminal device 120-2.

[0208] Fig. 9 900 is a flowchart of a method implemented at a network device according to some other embodiments of the present disclosure. For discussion purposes, reference will be made to Figure 1AMethod 900 is described from the perspective of network device 130 .

[0209] In box 910, the network device 130 sends an initiation command to the first terminal device 110, instructing the first terminal device to initiate COT, and the initiation command includes at least one of the following items: CAPC, multiple identifiers of multiple terminal devices, service information of SL transmission between multiple terminal devices, or timing information for initiating COT.

[0210] In some example embodiments, network device 130 receives, from second terminal device 120 - 1 , service information of a SL transmission between the second terminal device and a third terminal device, the plurality of terminal devices including the second terminal device and the third terminal device.

[0211] In some example embodiments, the service information indicates service types associated with categories of the second terminal device and the third terminal device.

[0212] In some example embodiments, network device 130 monitors feedback information sent by third terminal device 120-2 to second terminal device 120-1, the feedback information being provided for SL transmission from second terminal device 120-1 to third terminal device 120-2, the SL transmission being sent during a COT initiated by first terminal device 110, the plurality of terminal devices including the second terminal device and the third terminal device. Network device 130 then sends the feedback information to first terminal device 110.

[0213] In some example embodiments, the feedback information comprises hybrid automatic repeat request (HARQ) feedback information.

[0214] In some example embodiments, an apparatus capable of executing method 700 (eg, first terminal device 110) may include a component for executing each step of method 700. The component may be implemented in any appropriate form. For example, the component may be implemented in a circuit or a software module.

[0215] In some example embodiments, the apparatus includes: a component for initiating a channel occupancy time (COT) at a first terminal device by performing a listen-before-talk (LBT) process associated with a channel access priority category (CAPC); a component for sending an indication of the COT for sidelink (SL) transmissions between the multiple terminal devices to a plurality of terminal devices; and a component for detecting SL transmissions during the COT.

[0216] In some example embodiments, the apparatus includes: a component for receiving an initiation command from a network device instructing a first terminal device to initiate a COT, the initiation command including at least one of the following items: a CAPC, multiple identifiers of multiple terminal devices, service information transmitted by an SL, or timing information for initiating a COT.

[0217] In some example embodiments, the apparatus includes: means for receiving service information of a SL transmission from a terminal device among a plurality of terminal devices; and means for determining a CAPC based on the service information.

[0218] In some example embodiments, the service information indicates service types associated with categories of the plurality of terminal devices.

[0219] In some example embodiments, the apparatus comprises means for determining the CAPC to be a predefined CAPC, the predefined CAPC being a lowest CAPC or a highest CAPC from a plurality of preconfigured CAPCs.

[0220] In some example embodiments, the apparatus comprises means for determining the CAPC as a highest CAPC from a plurality of pre-configured CAPCs.

[0221] In some example embodiments, the apparatus comprises means for sending an indication of the CAPC to a plurality of terminal devices.

[0222] In some example embodiments, the apparatus includes: means for determining input information based at least on detection of SL transmissions during a COT; and means for performing a contention window (CW) adjustment based at least in part on the input information.

[0223] In some example embodiments, the detection result of the SL transmission includes at least one of the following items: sidelink control information (SCI) associated with the SL transmission, hybrid automatic repeat request (HARQ) feedback information of the SL transmission, or a channel energy level of the SL transmission.

[0224] In some example embodiments, the apparatus includes: means for detecting resource allocation for SL transmission within the COT; and means for monitoring HARQ feedback information based on the resource allocation.

[0225] In some example embodiments, the apparatus comprises means for detecting a channel energy level by sensing the channel at a predetermined time.

[0226] In some example embodiments, the apparatus comprises: means for receiving HARQ feedback information from a network device, the first terminal device and the plurality of terminal devices being within coverage of the network device.

[0227] In some example embodiments, the apparatus includes: a component for resetting the size of the CW to an initial value based on at least one of the following items: the number of acknowledgments (ACKs) indicated by the HARQ feedback information exceeds a threshold value of the number of ACKs, the ratio of the number of ACKs to the total number of feedbacks indicated by the HARQ feedback information exceeds a threshold value of the ACK ratio, the number of terminal devices sending SCI exceeds a threshold value of the number of devices, or the ratio of the number of terminal devices sending SCI to the number of multiple terminal devices exceeds a threshold value of the device ratio.

[0228] In some example embodiments, the HARQ feedback is determined based on a change in channel energy detected before and after a predefined time within the COT exceeding a threshold for energy detection.

[0229] In some example embodiments, the apparatus includes: means for increasing the size of the CW based on at least one of: no SCI is detected, no HARQ feedback is detected, the number of detected SCIs is below a threshold for SCI, the number of detected HARQ feedbacks is below a threshold for feedback, or a ratio of a time period during which a channel energy level is above a threshold to the COT exceeds a threshold for a time ratio.

[0230] In some example embodiments, the apparatus further comprises: means for performing other steps in some example embodiments of method 700. In some example embodiments, the means comprises at least one processor and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to cause execution of the apparatus together with the at least one processor.

[0231] In some example embodiments, an apparatus capable of executing method 800 (eg, second terminal device 120-1) may include a component for executing each step of method 800. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit or a software module.

[0232] In some example embodiments, the apparatus includes: a component for sending service information to a first terminal device or at least one of a network device at a second terminal device; a component for receiving an indication of a channel occupancy time (COT) initiated by the first terminal device from the first terminal device; and a component for sending a sidelink (SL) transmission to a third terminal device during the COT.

[0233] In some example embodiments, the service information indicates service types associated with categories of the plurality of terminal devices, the plurality of terminal devices including the second terminal device and the third terminal device.

[0234] In some example embodiments, the apparatus comprises means for receiving an indication of a channel access priority class (CAPC) from the first terminal device.

[0235] In some example embodiments, the apparatus comprises means for determining a default CAPC configured by the network device if no indication of a CAPC is received from the first terminal device.

[0236] In some example embodiments, the apparatus comprises means for determining a SL transmission having a traffic type based on the CAPC.

[0237] In some example embodiments, the apparatus comprises means for receiving hybrid automatic repeat request (HARQ) feedback information for SL transmissions within the COT from a third terminal device.

[0238] In some example embodiments, the apparatus further comprises: means for performing other steps in some example embodiments of method 800. In some example embodiments, the means comprises at least one processor and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to cause execution of the apparatus together with the at least one processor.

[0239] In some example embodiments, an apparatus capable of performing method 900 (e.g., network device 130) may include a component for performing each step of method 900. The component may be implemented in any suitable form. For example, the component may be implemented in a circuit or a software module.

[0240] In some example embodiments, the apparatus includes: a component for sending an initiation command to a first terminal device instructing the first terminal device to initiate a COT, the initiation command including at least one of the following items: a CAPC, multiple identifiers of multiple terminal devices, service information of SL transmission between multiple terminal devices, or timing information for initiating a COT.

[0241] In some example embodiments, the apparatus includes: a component for receiving, from a second terminal device, service information of a SL transmission between the second terminal device and a third terminal device, the plurality of terminal devices including the second terminal device and the third terminal device.

[0242] In some example embodiments, the service information indicates service types associated with categories of the second terminal device and the third terminal device.

[0243] In some example embodiments, the apparatus includes: a component for monitoring, at a network device, feedback information sent by a third terminal device to a second terminal device, the feedback information being provided for a SL transmission from the second terminal device to the third terminal device, the SL transmission being sent during a COT initiated by a first terminal device, the plurality of terminal devices including the second terminal device and the third terminal device; and a component for sending the feedback information to the first terminal device.

[0244] In some example embodiments, the feedback information comprises hybrid automatic repeat request (HARQ) feedback information.

[0245] In some example embodiments, the apparatus further comprises: means for performing other steps in some example embodiments of method 900. In some example embodiments, the means comprises at least one processor and at least one memory comprising computer program code, the at least one memory and the computer program code being configured to cause execution of the apparatus together with the at least one processor.

[0246] Fig.10 1 is a simplified block diagram of a device 1000 suitable for implementing some example embodiments of the present disclosure. The device 1000 may be provided to implement a communication device such as Figure 1A The first terminal device 110, any terminal device in the terminal devices 120, or the network device 130 are shown. As shown in the figure, the device 1000 includes one or more processors 1010, one or more memories 1020 coupled to the processors 1010, and one or more communication modules 1040 coupled to the processors 1010.

[0247] The communication module 1040 is used for two-way communication. The communication module 1040 has at least one antenna to facilitate communication. The communication interface may represent any interface required to communicate with other network elements.

[0248] Processor 1010 may be of any type suitable for the local technology network and may include one or more of the following: a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture, as non-limiting examples. Device 1000 may have multiple processors, such as application specific integrated circuit chips that are time slaved to a clock of a synchronized main processor.

[0249] The memory 1020 may include one or more non-volatile memories and one or more volatile memories. Examples of non-volatile memories include, but are not limited to, read-only memory (ROM) 1024, electrically programmable read-only memory (EPROM), flash memory, hard disk, compact disk (CD), digital video disk (DVD), and other magnetic and / or optical memories. Examples of volatile memories include, but are not limited to, random access memory (RAM) 1022 and other volatile memories that do not persist during the duration of a power outage.

[0250] Computer program 1030 includes computer executable instructions that are executed by associated processor 1010. Program 1030 may be stored in ROM 1024. Processor 1010 may perform any appropriate actions and processes by loading program 1030 into RAM 1022.

[0251] The embodiments of the present disclosure can be implemented by means of program 1030, so that device 1000 can execute the following steps: FIG. 4A to FIG. 9 The embodiments of the present disclosure may also be implemented by hardware or a combination of software and hardware.

[0252] In some example embodiments, program 1030 may be tangibly embodied in a computer-readable medium that may be included in device 1000 (e.g., in memory 1020) or in other storage devices accessible by device 1000. Device 1000 may load program 1030 from the computer-readable medium to RAM 1022 for execution. The computer-readable medium may include any type of tangible non-volatile memory, such as ROM, EPROM, flash memory, hard disk, CD, DVD, etc.

[0253] Fig.11 1 shows a block diagram of an example of a computer readable medium 1100 according to some example embodiments of the present disclosure. The computer readable medium 1100 has a program 1030 stored thereon. Fig.11 The computer-readable medium 1100 is shown in the form of a CD or a DVD, but the computer-readable medium 1100 may be in any other form suitable for carrying or storing the program 1030.

[0254] Generally, various embodiments of the present disclosure may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software, which may be executed by a controller, microprocessor, or other computing device. Although various aspects of the embodiments of the present disclosure are shown and described as block diagrams, flow charts, or using some other graphical representations, it should be understood that the boxes, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general hardware or controllers or other computing devices, or some combination thereof, as non-limiting examples.

[0255] The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer executable instructions, such as those included in a program module, executed in a device on a target real or virtual processor to perform the above-referenced Figure 7-Figure 9 In any of the methods described in. Typically, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The functions of program modules can be combined or separated between program modules as needed in various embodiments. Machine executable instructions for program modules can be executed in local or distributed devices. In distributed devices, program modules can be located in local and remote storage media.

[0256] The program code for executing the method of the present disclosure can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device, so that when the program code is executed by the processor or controller, the program code causes the functions / operations specified in the flow chart and / or block diagram to be executed. The program code can be executed entirely on the machine, partially on the machine, as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0257] In the context of the present disclosure, computer program codes or related data may be carried by any appropriate carrier to enable a device, apparatus or processor to perform the above-mentioned various processes and operations. Examples of carriers include signals, computer-readable media, etc.

[0258] 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 electrical, magnetic, optical, electromagnetic, infrared or semiconductor system, apparatus or device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media would include an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The term "non-transitory" as used herein is a limitation on the medium itself (i.e., tangible, not a signal), not a limitation on the persistence of data storage (e.g., RAM versus ROM).

[0259] In addition, although operations are described in a particular order, this should not be understood as requiring that the operations be performed in the particular order shown or in sequence, or requiring that all operations shown be performed to achieve the desired results. In some cases, multitasking and parallel processing may be advantageous. Similarly, although several specific implementation details are included in the above discussion, these should not be interpreted as limitations on the scope of the present disclosure, but rather as descriptions of the unique features of a particular embodiment. Certain features described in the context of a separate embodiment may also be implemented in a single embodiment in combination. On the contrary, the various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments.

[0260] Although the present disclosure has been described in language specific to structural features and / or methodological acts, it should be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Instead, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. A first terminal device, comprising: at least one processor; as well as at least one memory storing instructions, which, when executed by the at least one processor, cause the first terminal device to at least: Initiating Channel Occupancy Time (COT) by performing a Listen Before Talk (LBT) procedure associated with a Channel Access Priority Class (CAPC); sending an indication of the COT for sidelink (SL) transmissions between the plurality of terminal devices to a plurality of terminal devices; and The SL transmission is detected during the COT.

2. The first terminal device according to claim 1, wherein the first terminal device is further configured to: Receiving, from a network device, an initiation command instructing the first terminal device to initiate the COT, the initiation command comprising at least one of the following items: The CAPC, a plurality of identifiers of the plurality of terminal devices, The service information transmitted by the SL, or Timing information for initiating the COT.

3. The first terminal device according to claim 1, wherein the first terminal device is further configured to: Receiving the service information transmitted by the SL from one of the plurality of terminal devices; and The CAPC is determined based on the service information. 4 . The first terminal device according to claim 2 , wherein the service information indicates service types associated with categories of the plurality of terminal devices.

5. The first terminal device according to claim 1, wherein the first terminal device is further configured to: The CAPC is determined to be a predefined CAPC, the predefined CAPC being a lowest CAPC or a highest CAPC from a plurality of preconfigured CAPCs.

6. The first terminal device according to any one of claims 1 to 5, wherein the first terminal device is further configured to: An indication of the CAPC is sent to the plurality of terminal devices.

7. The first terminal device according to any one of claims 1 to 6, wherein the first terminal device is further configured to: determining input information based at least on a detection result of the SL transmission during the COT; and Based at least in part on the input information, a contention window (CW) adjustment is performed.

8. The first terminal device according to claim 7, wherein the detection result transmitted by the SL includes at least one of the following items: Sidelink Control Information (SCI) associated with said SL transmission, Hybrid Automatic Repeat Request (HARQ) feedback information transmitted by the SL, or The channel energy level of the SL transmission.

9. The first terminal device according to claim 8, wherein the first terminal device is further configured to: detecting resource allocation of the SL transmission within the COT; and The HARQ feedback information is monitored based on the resource allocation.

10. The first terminal device according to claim 8 or 9, wherein the first terminal device is further configured to: The channel energy level is detected by sensing the channel at a predetermined time.

11. The first terminal device according to claim 8, wherein the first terminal device is further configured to: The HARQ feedback information is received from a network device, and the first terminal device and the multiple terminal devices are within the coverage of the network device.

12. The first terminal device according to any one of claims 7 to 11, wherein the first terminal device performs the CW adjustment by: The size of the CW is reset to an initial value based on at least one of the following: The number of acknowledgments (ACKs) indicated by the HARQ feedback information exceeds a threshold value of the number of ACKs, a ratio of the number of ACKs to the total number of feedbacks indicated by the HARQ feedback information exceeds a threshold of an ACK ratio, The number of terminal devices sending the SCI exceeds the threshold of the number of devices, or A ratio of the number of terminal devices that transmit the SCI to the number of the plurality of terminal devices exceeds a threshold value of a device ratio.

13. The method of claim 12, wherein the HARQ feedback is determined based on a change in channel energy detected before and after a predefined time within the COT exceeding a threshold for energy detection.

14. The first terminal device according to any one of claims 7 to 11, wherein the first terminal device performs the CW adjustment by: Increasing the size of the CW based on at least one of the following: No SCI detected, No HARQ feedback detected, The number of detected SCIs is below the SCI threshold, The number of detected HARQ feedbacks is below the feedback threshold, or The ratio of the time period during which the channel energy level is higher than the threshold to the COT exceeds a threshold of the time ratio.

15. A second terminal device, comprising: at least one processor; as well as at least one memory storing instructions, which, when executed by the at least one processor, cause the first terminal device to at least: Sending service information to at least one of the first terminal device or the network device; receiving, from the first terminal device, an indication of a channel occupancy time (COT) initiated by the first terminal device; and A sidelink (SL) transmission is sent to a third terminal device during the COT. 16 . The second terminal device according to claim 15 , wherein the service information indicates service types associated with categories of a plurality of terminal devices, the plurality of terminal devices including the second terminal device and the third terminal device.

17. The second terminal device according to claim 15 or 16, wherein the second terminal device is further configured to: An indication of a channel access priority class (CAPC) is received from the first terminal device.

18. The second terminal device according to claim 15 or 16, wherein the second terminal device is further configured to: Based on determining that an indication of a CAPC was not received from the first terminal device, a default CAPC configured by the network device is determined.

19. The second terminal device according to claim 17 or 18, wherein the second terminal device is further configured to: The SL transmission having a traffic type is determined based on the CAPC.

20. The second terminal device according to any one of claims 15 to 19, wherein the second terminal device is further configured to: Receive hybrid automatic repeat request (HARQ) feedback information of the SL transmission within the COT from the third terminal device.

21. A network device comprising: at least one processor; as well as at least one memory storing instructions, which, when executed by the at least one processor, cause the first terminal device to at least: Sending an initiation command to a first terminal device, instructing the first terminal device to initiate a channel occupancy time (COT), the initiation command including at least one of the following items: Channel Access Priority Class (CAPC), multiple identifiers for multiple terminal devices, service information transmitted by the sidelink (SL) between the plurality of terminal devices, or Timing information for initiating the COT.

22. The network device of claim 21, wherein the network device is further configured to: The service information of the SL transmission between the second terminal device and a third terminal device is received from a second terminal device, and the plurality of terminal devices include the second terminal device and the third terminal device.

23. The network device according to claim 22, wherein the service information indicates a service type associated with categories of the second terminal device and the third terminal device.

24. The network device according to any one of claims 21 to 23, wherein the network terminal device is further configured to: monitoring feedback information sent by a third terminal device to a second terminal device, the feedback information being provided for the SL transmission from the second terminal device to the third terminal device, the SL transmission being sent during the COT initiated by the first terminal device, the plurality of terminal devices including the second terminal device and the third terminal device; and Sending the feedback information to the first terminal device.

25. The network device of claim 24, wherein the feedback information comprises hybrid automatic repeat request (HARQ) feedback information.

26. A method comprising: At a first terminal device, initiating a channel occupation time (COT) by performing a listen before talk (LBT) procedure associated with a channel access priority class (CAPC); sending, to a plurality of terminal devices, an indication of a COT for sidelink (SL) transmissions between the plurality of terminal devices; and The SL transmission is detected during the COT.

27. A method comprising: At the second terminal device, sending service information to at least one of the first terminal device or the network device; receiving, from the first terminal device, an indication of a channel occupancy time (COT) initiated by the first terminal device; and A sidelink (SL) transmission is sent to a third terminal device during the COT.

28. A method comprising: Sending an initiation command to a first terminal device, instructing the first terminal device to initiate a channel occupancy time (COT), the initiation command including at least one of the following items: Channel Access Priority Class (CAPC), multiple identifiers for multiple terminal devices, service information transmitted by the sidelink (SL) between the plurality of terminal devices, or Timing information for initiating the COT.

29. An apparatus, comprising: means for initiating a channel occupancy time (COT) at a first terminal device by performing a listen-before-talk (LBT) procedure associated with a channel access priority class (CAPC); means for sending to a plurality of terminal devices an indication of a COT for sidelink (SL) transmissions between the plurality of terminal devices; as well as Means for detecting said SL transmission during said COT.

30. An apparatus comprising: A component for sending service information to at least one of the first terminal device or the network device at the second terminal device; means for receiving from said first terminal device an indication of a channel occupancy time (COT) initiated by said first terminal device; as well as Means for sending a sidelink (SL) transmission to a third terminal device during said COT.

31. An apparatus comprising: A component configured to send an initiation command to a first terminal device, instructing the first terminal device to initiate a channel occupancy time (COT), wherein the initiation command includes at least one of the following items: Channel Access Priority Class (CAPC), multiple identifiers for multiple terminal devices, service information transmitted by the sidelink (SL) between the plurality of terminal devices, or Timing information for initiating the COT.

32. A non-transitory computer-readable medium comprising program instructions, wherein the program instructions are used to cause an apparatus to at least perform the method according to any one of claims 26-28.

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