Terminal device and method

Abstract

[0003] Embodiments of the present disclosure relate to a method, an apparatus, and a computer-readable medium for communication. The method includes determining a reference time interval in a first terminal device. The method also includes determining a value of a contention window for a channel access procedure for a sidelink based on the reference time interval.

Description

[Technical Field]

[0001] FIELD Embodiments of the present disclosure relate generally to the field of telecommunications, and more particularly to a method, apparatus, and computer-readable medium for sidelink communications. [Background technology]

[0002] Sidelink in unlicensed spectrum or band (SL-U) is a major topic of the 3rd Generation Partnership Project (3GPP®) Release 18. SL-U should be based on New Radio (NR) sidelink and NR-U.

[0003] For sidelink terminal devices operating in unlicensed bands, a Clear Channel Assessment (CCA) procedure should be used to access the channel. Before the sidelink terminal device performs the CCA procedure, a contention window (CW) should be determined. One or more factors used to determine the CW should be evaluated or measured within a reference time interval. Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, the exemplary embodiments of the present disclosure provide a communication method, apparatus, and computer-readable medium. [Means for solving the problem]

[0005] In a first aspect, a communication method is provided, the method comprising: determining, in a first terminal device, a reference time interval; and determining, based on the reference time interval, a value of a contention window for a channel access procedure for a sidelink.

[0006] In a second aspect, there is provided a method of communication, the method comprising: determining, in a control node apparatus, a reference time interval associated with determining a contention window for a channel access procedure for a sidelink; and transmitting information relating to the reference time interval.

[0007] In a third aspect, there is provided a terminal device comprising a processor and a memory storing instructions, the memory and the instructions configured to cause the terminal device, using the processor, to perform a method according to the first aspect.

[0008] In a fourth aspect, there is provided a control node apparatus, comprising a processor and a memory storing instructions, the memory and the instructions configured to cause the control node apparatus to perform the method according to the second aspect using the processor.

[0009] In a fifth aspect, there is provided a computer readable medium storing instructions which, when executed on at least one processor of a device, cause the device to perform a method according to the first aspect.

[0010] In a sixth aspect, there is provided a computer readable medium storing instructions which, when executed on at least one processor of a device, cause the device to perform a method according to the second aspect.

[0011] It should be understood that this Summary of the Invention is not intended to identify key or essential features of the embodiments of the present disclosure, nor to limit the scope of the present disclosure. Other features of the present disclosure will be readily apparent from the following description. [Brief explanation of the drawings]

[0012] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description of several embodiments of the present disclosure in the accompanying drawings.

[0013] [Figure 1] FIG. 1 illustrates an exemplary communication network in which embodiments of the present disclosure may be implemented. [Figure 2] 1 is a diagram illustrating an example of a sub-channel according to some embodiments of the present disclosure. [Figure 3] 1 illustrates an example of Physical Sidelink Shared Channel (PSSCH) and Physical Sidelink Feedback Channel (PSFCH) resources, in accordance with some embodiments of the present disclosure. [Figure 4] 1 is a flowchart of an exemplary method according to some embodiments of the present disclosure. [Figure 5A] FIG. 2 illustrates an example of a reference time interval according to some embodiments of the present disclosure. [Figure 5B] FIG. 2 illustrates an example of a reference time interval according to some embodiments of the present disclosure. [Figure 6A] FIG. 2 illustrates an example of a reference time interval according to some embodiments of the present disclosure. [Figure 6B] FIG. 2 illustrates an example of a reference time interval according to some embodiments of the present disclosure. [Figure 6C] FIG. 2 illustrates an example of a reference time interval according to some embodiments of the present disclosure. [Figure 7A] FIG. 2 illustrates an example of a reference time interval according to some embodiments of the present disclosure. [Figure 7B] FIG. 2 illustrates an example of a reference time interval according to some embodiments of the present disclosure. [Figure 7C] FIG. 2 illustrates an example of a reference time interval according to some embodiments of the present disclosure. [Figure 7D] FIG. 2 illustrates an example of a reference time interval according to some embodiments of the present disclosure. [Figure 7E] FIG. 2 illustrates an example of a reference time interval according to some embodiments of the present disclosure. [Figure 7F] FIG. 2 illustrates an example of a reference time interval according to some embodiments of the present disclosure. [Figure 7G] FIG. 2 illustrates an example of a reference time interval according to some embodiments of the present disclosure. [Figure 7H] FIG. 2 illustrates an example of a reference time interval according to some embodiments of the present disclosure. [Figure 7I] FIG. 2 illustrates an example of a reference time interval according to some embodiments of the present disclosure. [Figure 8A] 8 is a flowchart of an example method 800 for determining a CW, according to some embodiments of the present disclosure. [Figure 8B] FIG. 10 illustrates an example of a reference time interval according to some other embodiments of the present disclosure. [Figure 8C] FIG. 10 illustrates an example of a reference time interval according to some other embodiments of the present disclosure. [Figure 8D] FIG. 10 illustrates an example of a reference time interval according to some other embodiments of the present disclosure. [Figure 8E] FIG. 10 illustrates an example of a reference time interval according to some other embodiments of the present disclosure. [Figure 8F] FIG. 10 illustrates an example of a reference time interval according to some other embodiments of the present disclosure. [Figure 8G] FIG. 10 illustrates an example of a reference time interval according to some other embodiments of the present disclosure. [Figure 9] 10 is a flowchart of an exemplary method according to some other embodiments of the present disclosure. [Figure 10]FIG. 10 illustrates an example of a reference time interval according to some other embodiments of the present disclosure. [Figure 11] FIG. 1 is a schematic block diagram of an apparatus suitable for implementing embodiments of the present disclosure.

[0014] In the drawings, the same or similar reference numbers represent the same or similar elements. DETAILED DESCRIPTION OF THE INVENTION

[0015] The principles of the present disclosure will now be described with reference to some exemplary embodiments. It should be understood that these embodiments are provided for illustrative purposes only to aid those skilled in the art in understanding and practicing the present disclosure, and do not imply any limitation on the scope of the present disclosure. The disclosure described herein can be implemented in various ways different from those described below.

[0016] 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 pertains.

[0017] As used herein, the term "terminal device" refers to any device with wireless or wired communication capabilities. Examples of terminal devices include user equipment (UE), personal computers, desktops, mobile phones, cellular phones, smartphones, personal digital assistants (PDAs), portable computers, tablets, wearable devices, Internet of Things (IoT) devices, Ultra-Reliable Low Latency Communications (URLLC) devices, Internet of Everything (IoE) devices, machine type communication (MTC) devices, vehicle-mounted devices for V2X communications where X stands for pedestrian, vehicle, or infrastructure / network, devices for integrated access and integrated access and backhaul (IAB), satellite- or airborne vehicles in a non-terrestrial network (NTN) including High Altitude Platforms (HAPs) which encompass satellites and Unmanned Aircraft Systems (UASs), extended reality (XR) devices including different types of reality such as augmented reality (AR), mixed reality (MR), and virtual reality (VR), and unmanned aerial vehicles (UAVs), which are aircraft without a human pilot and are commonly referred to as drones. This includes, but is not limited to, devices onboard vehicles, high-speed trains (HSTs), image capture devices such as digital cameras, sensor gaming devices, music storage and playback devices, or internet appliances that enable wireless or wired internet access and browsing. A "terminal device" may also have "multicast / broadcast" capabilities to support public safety and mission-critical V2X applications, transparent IPv4 / IPv6 multicast distribution, IPTV, smart TV, wireless services, over-the-air software distribution, group communication, and IoT applications. It may also incorporate one or more subscriber identity modules (SIMs), known as multi-SIMs.The term "terminal equipment" may be used interchangeably with UE, mobile station, subscriber station, mobile terminal, user terminal, or wireless device.

[0018] The term "network device" refers to a device that can provide or host a cell or coverage area within which terminal devices can communicate. Examples of network devices include, but are not limited to, a Node B (Node B or NB), an evolved Node B (eNode B or eNB), a next generation Node B (gNB), a transmit / receive point (TRP), a remote radio unit (RRU), a radio head (RH), a remote radio head (RRH), an IAB node, a femto node, a pico node, a reconfigurable intelligent surface (RIS), and other low-power nodes.

[0019] The terminal device or network device may have artificial intelligence (AI) or machine learning capabilities, which generally include a model trained from a large amount of data collected for a specific function and can be used to predict some information.

[0020] The terminal device or network device may operate over several frequency ranges, such as FR1 (410 MHz to 7125 MHz), FR2 (24.25 GHz to 71 GHz), frequency bands greater than 100 GHz, and Terahertz (THz). It can also operate over licensed, unlicensed, and shared spectrum. The terminal device may have two or more connections with the network device under a Multi-Radio Dual Connectivity (MR-DC) application scenario. The terminal device or network device can operate in full duplex, flexible duplex, and cross-division duplex modes.

[0021] Embodiments of the present disclosure may be implemented in test equipment, such as, for example, a signal generator, a signal analyzer, a spectrum analyzer, a network analyzer, a test terminal device, a test network device, a channel emulator, and the like.

[0022] As used herein, the singular forms "a," "an," and "said" include the plural forms unless the context clearly indicates otherwise. The term "comprises" and variations thereof should be understood as open-ended terms meaning "including, but not limited to." The term "based on" should be understood as "based at least in part on." The terms "some embodiments" and "embodiments" should be understood as "at least some embodiments." The term "another embodiment" should be understood as "at least one other embodiment." Terms such as "first," "second," etc. may refer to different or the same object. The following may include other explicit and implicit definitions.

[0023] In some instances, values, procedures, or devices are referred to as "best," "lowest," "highest," "minimum," "maximum," etc. It should be understood that such descriptions are intended to illustrate that choices may be made from among many functional alternatives used, and that such choices are not necessarily better, smaller, higher, or otherwise more preferred than other choices.

[0024] As mentioned above, for a sidelink terminal device operating in an unlicensed band, a CCA procedure (also called a channel access procedure) should be used to access the channel. Before the sidelink terminal device performs the CCA procedure, the CW should be determined. One or more factors used to determine the CW should be evaluated or measured within a reference time interval.

[0025] To solve the above problem and one or more other potential problems, embodiments of the present disclosure provide a solution for sidelink transmission. According to this solution, a first terminal device determines a reference time interval. Then, the first terminal device determines a contention window value for a channel access procedure for the sidelink based on this reference time interval. Thus, one or more factors used to determine the CW should be evaluated or measured within the determined reference time interval.

[0026] 1 is a schematic diagram of an exemplary communication network 100 in which embodiments of the present disclosure may be implemented. As shown in FIG. 1, communication network 100 may include a first terminal device 110, a second terminal device 120, a third terminal device 130, and network devices 140 and 150. Network devices 140 and 150 may communicate with first terminal device 110, second terminal device 120, and third terminal device 130 via respective wireless communication channels.

[0027] In some embodiments, the network device 140 may be a gNB in an NR system, and the network device 150 may be an eNB in a Long Term Evolution (LTE) system.

[0028] 1 is given for illustrative purposes only and does not imply any limitations on the present disclosure. Communications network 100 may include any suitable number of network devices and / or terminal devices suitable for implementing embodiments of the present disclosure.

[0029] Communications within communication network 100 may be performed according to any currently known or later developed generation of communication protocols, including, but not limited to, first generation (1G), second generation (2G), 2.5G, 2.75G, third generation (3G), fourth generation (4G), 4.5G, fifth generation (5G) communication protocols, 5.5G, 5G-Advanced networks, or sixth generation (6G) networks.

[0030] In some embodiments, communications in the communications network 100 may include sidelink communications. Sidelink communications are direct wireless radio communications between two or more terminal devices, e.g., a first terminal device 110, a second terminal device 120, and a third terminal device 130. In this type of communication, two or more terminal devices in close geographic proximity can communicate directly without going through a network device 140 or 150 or a core network. Thus, data transmission in sidelink communications differs from typical cellular network communications in which a terminal device transmits data to a network device 140 or 150 (i.e., uplink transmission) or receives data from a network device 140 or 150 (i.e., downlink transmission). As shown in FIG. 1, in sidelink communications, data is transmitted directly from a source terminal device (e.g., the first terminal device 110) to a target terminal device (e.g., the second terminal device 120) over a unified air interface, e.g., a PC5 interface.

[0031] Sidelink communication can provide several advantages, including reducing data transmission load on the core network, system resource consumption, transmission power consumption and network operation costs, conserving radio spectrum resources and improving the spectral efficiency of cellular wireless communication systems.

[0032] In a sidelink communication system, sidelink resources are used to transmit information between terminal devices. Depending on application scenarios, service types, etc., sidelink communication methods include, but are not limited to, device-to-device (D2D) communication, vehicle-to-everything (V2X) communication, etc.

[0033] V2X communication enables vehicles to communicate with other vehicles (i.e., vehicle-to-vehicle (V2V) communication), infrastructure (i.e., vehicle-to-infrastructure (V2I) communication), wireless networks (i.e., vehicle-to-network (V2N) communication), pedestrians (i.e., vehicle-to-pedestrian (V2P) communication), and even with the owner's home (i.e., vehicle-to-home (V2H) communication). Examples of infrastructure include roadside devices such as traffic lights and toll booths. V2X communication can be used in a wide range of scenarios, including accident prevention, safety, convenience, traffic efficiency, and accident-free driving, ultimately leading to autonomous and self-driving vehicles.

[0034] The first terminal device 110, the second terminal device 120, and the third terminal device 130 may transmit sidelink signaling or information using sidelink channels, including at least one of: physical sidelink control channel (PSCCH) resources used to carry sidelink control information (SCI), physical sidelink shared channel (PSSCH) resources used to carry sidelink data service information, physical sidelink feedback channel (PSFCH) resources used to carry sidelink ACK / NACK (A / N) feedback information, physical sidelink broadcast channel (PSBCH) resources for carrying sidelink broadcast information, and physical sidelink discovery channel (PSDCH) resources used to carry sidelink discovery signals.

[0035] In a resource pool, PSSCH resources include all symbols in a slot configured as sidelink available symbols and one or more subchannels in the frequency domain, where each subchannel includes an integer number of consecutive RBs. The number m of RBs included in one subchannel is also referred to as the subchannel size. Each slot included in the resource pool includes multiple available sidelink symbols, and PSSCH resources are located in the time domain from the first available sidelink symbol to all available symbols in the slot. In the frequency domain, the resource pool includes multiple RBs, and according to the subchannel size m, each m RBs is divided into one subchannel, starting from the first RB in the resource pool, and each PSSCH channel resource is located on one or more subchannels. When one of the first terminal device 110, the second terminal device 120, and the third terminal device 130 transmits sidelink information using a PSSCH resource, it may use one or more subchannels to carry corresponding data information. A PSCCH resource includes t symbols in the time domain and k RBs in the frequency domain. As shown in Figure 2, each PSCCH channel resource is located at t consecutive symbols starting from the first symbol of the available symbols in the time domain, and at k consecutive RBs starting from the first RB of the corresponding subchannel in the frequency domain.

[0036] In the resource pool, it is necessary to configure or pre-configure whether a PSFCH resource is available. According to the resource pool configuration or pre-configuration, one slot out of every N slots in the resource pool includes a PSFCH resource, where N = [1, 2, 4]. In the sidelink resource pool, a PSCCH / PSSCH resource exists in each slot and is used to transmit sidelink data packets. On the other hand, the PSFCH is used to carry a sidelink ACK / NACK (A / N) for the corresponding sidelink data packet in the allocated slot. Based on this, the time interval between the A / N on the PSFCH and the corresponding sidelink data packet on the PSSCH varies.

[0037] 3 illustrates an example of PSSCH and PSFCH resources according to some embodiments of the present disclosure. In this example, N=2, i.e., one slot out of every two slots in the resource pool includes a PSFCH resource. Therefore, an A / N associated with the PSSCH in slot #n should be reported on the PSFCH in slot #n+2. That is, the time interval between the data and the A / N is two slots. For data transmission on the PSSCH in slot #n+1, the corresponding A / N should be reported in slot #n+4. That is, the time interval between the data and the A / N is three slots.

[0038] 4 is a flowchart of an example method 400 according to some embodiments of the present disclosure. In some embodiments, method 400 may be implemented in a terminal device, such as one of first terminal device 110, second terminal device 120, and third terminal device 130 as shown in FIG. 1. For illustrative purposes, and without loss of generality, method 400 will be described as being performed by first terminal device 110 with reference to FIG. 1.

[0039] In block 410, first terminal device 110 determines a reference time interval. In block 420, first terminal device 110 determines a value of CW for a channel access procedure for the sidelink based on the reference time interval.

[0040] In some embodiments, the first terminal device 110 may determine the reference time interval by determining at least one of the start of the reference time interval, the end of the reference time interval, or the length of the reference time interval.

[0041] In some embodiments, the first terminal device 110 determines the start or end of the reference time interval as: Timing, e.g. t0s, t0ms or t0μs, the boundaries of the slots or slots of the first type, Sidelink Channel Occupancy (CO) boundaries, Burst boundaries within sidelink COs, the boundaries of the first type of sidelink channels, the timing involved in determining the value of the contention window; Timing related to channel access procedures for sidelink; or Timing related to sidelink authorization; The determination may be based on at least one of the following:

[0042] In some embodiments, a slot boundary may be the start or end of a slot, a first type slot boundary may be the start or end of a slot of the first type, a sidelink CO boundary may be the start or end of a sidelink CO, a burst boundary within a sidelink CO may be the start or end of a burst, or a first type sidelink channel boundary may be the start or end of a sidelink channel of the first type.

[0043] In embodiments where the start or end of the reference time interval is determined based on a timing relative to determining the value of the CW, the start or end of the reference time interval may be determined as the timing to start determining the value of the CW, or alternatively, the start or end of the reference time interval may be determined to be prior to the timing to start determining the value of the CW.

[0044] In embodiments where the start or end of the reference time interval is determined based on a timing related to a channel access procedure for the sidelink, the start or end of the reference time interval may be determined as the timing for initiating the channel access procedure for the sidelink. Alternatively, the start or end of the reference time interval may be determined to be prior to the timing for initiating the channel access procedure for the sidelink.

[0045] In embodiments where the start or end of the reference time interval is determined based on a timing related to a sidelink grant, the start or end of the reference time interval may be determined as the timing of receiving the sidelink grant. Alternatively, the start or end of the reference time interval may be determined as being prior to the timing of receiving the sidelink grant.

[0046] In some embodiments, the first terminal device 110 determines the length of the reference time interval as: a time interval, e.g. ts, tms or tμs, a time interval comprising a first number of slots or frames; a time interval including a second set of number of sidelink channels of the first type; a time interval including a third number of sidelink COs; a time interval containing the fourth number of bursts in a sidelink CO, or a fifth number of slots of the first type; and a time interval comprising the fifth number of slots of the first type.

[0047] In some embodiments, the sidelink control unit (CO) may be at least one of a sidelink terminal device initiated CO, a CO containing sidelink transmissions, and a CO containing a sidelink channel. In some embodiments, the sidelink transmissions may include at least one of a sidelink transmission in a CO and a Uu transmission.

[0048] In some embodiments, the sidelink control order may be a control order initiated by a control node device specifically for the sidelink. In some embodiments, the control node device may be a network device, a road side unit (RSU), or a header terminal device in a group for sidelink communication.

[0049] In some embodiments, the first type of sidelink channel may include at least one of a PSSCH, a PSCCH, a PSFCH, a PSBCH, or a PSDCH.

[0050] In some embodiments, the first type of slots may comprise at least one of: slots comprised in a sidelink resource pool, slots comprising a sidelink transmission, or slots comprising a sidelink channel.

[0051] In some embodiments, the first terminal device 110 may determine the length of the reference time interval based on a time interval including a second number of sets of sidelink channels of the first type, each set including the sidelink channels of the first type contained within one slot.

[0052] In some embodiments, the first number, the second number, the third number, the fourth number, or the fifth number may be determined according to at least one of predefinition, preconfiguration, configuration from a network device, or configuration from a sidelink terminal device.

[0053] Examples of reference time intervals will be described below with reference to FIGS. 5A to 7I and 8B to 8G.

[0054] In each of the examples shown in Figures 5A and 5B, the length of the reference time interval is preset as M = 3 slots. In the example shown in Figure 5A, the M slots are physically consecutive slots. In the example shown in Figure 5B, the M slots are slots of the first type contained in the sidelink control units (COs). Therefore, M logically consecutive slots in two or more sidelink control units (COs) are used as the reference time interval.

[0055] In the example shown in Figure 6A, the length of the reference time interval is determined as the time interval of N sets of PSSCH resources, where a set of PSSCH resources includes one or more PSSCH resources in the same slot. Therefore, the length of the reference time interval is determined according to the sidelink resource scheme. That is, the time window includes N slots, each of which may include a set of PSSCH resources.

[0056] The example shown in FIG. 6B differs from the example shown in FIG. 6A in that the N=3 sets of PSSCH resources are located within N logically consecutive slots.

[0057] In the example shown in FIG. 6C, the length of the reference time interval is determined as the time interval of k1=2 sidelink COs.

[0058] In some embodiments, the first terminal device 110 may determine the length of the reference time interval as a timing interval having a predefined fixed value. The fixed value may be Mms. In such embodiments, the first terminal device 110 may determine the end of the reference time interval as a timing before starting a channel access procedure for the sidelink. This timing is a multiple of the length of the reference time interval from the start of the system frame (SFN) or the start of the direct frame (DFN). In this way, the reference time interval can be easily determined according to the SFN or DFN and the fixed length. Using such a common definition of the reference time interval allows it to be used for any terminal device and factor for determining the CW without introducing additional overhead or complexity. This will be described with reference to FIG. 7A.

[0059] FIG. 7A illustrates an example of a reference time interval according to some embodiments of the present disclosure. As illustrated, M=10, i.e., the length of the reference time interval is equal to 10 ms. The reference time intervals are periodically consecutive and start from the start of SFN#0 or DFN#0. For the first terminal device 110 or the second terminal device 120, the associated reference time interval may be determined according to the start of the channel access procedure for the sidelink, respectively. The last aggregated reference time interval before the terminal device starts the channel access procedure for its sidelink procedure may be used as the associated reference time interval and may also be used for CW determination.

[0060] In some embodiments, the first terminal device 110 may determine the length of the reference time interval as a time interval including the sixth number of slots. The first terminal device 110 may determine the end of the reference time interval as one of the timings for initiating a channel access procedure, receiving a sidelink grant, or starting to determine a value for the CW. In such embodiments, the reference time interval may be determined based on the associated timing of the CW determination or the start of the channel access procedure, providing up-to-date information or status within the reference time interval that is useful for the procedure, as will be described with reference to FIG. 7B.

[0061] 7B is a diagram illustrating an example of a reference time interval according to some embodiments of the present disclosure. As shown, the reference time interval for the first terminal device 110 is determined based on the start of the channel access procedure of the first terminal device 110, and the reference time interval for the second terminal device 120 is determined based on the associated timing of the CW determination of the second terminal device 120. The length of the reference time interval is 10 slots, i.e., the sixth number is equal to 10, which is preset in the system.

[0062] In some embodiments, the first terminal device 110 may determine the length of the reference time interval as a time interval including one sidelink control frame. In such embodiments, the first terminal device 110 may determine the end of the reference time interval as the end of this sidelink control frame, which is earlier than the timing to start determining the value of the CW. In this way, the reference time interval is determined based on this sidelink control frame, which may provide more effective information and context for sidelink transmissions and may be combined with a scheme in which the CW should be determined based on related sidelink channels or information. This will be described with reference to FIG. 7C.

[0063] 7C, the first terminal device 110 determines the length of the reference time interval as the time interval including the sidelink CO 710. The end of the sidelink CO 710 occurs before the first terminal device 110 starts to determine the value of CW.

[0064] In some embodiments, the first terminal device 110 may determine the length of the reference time interval as a time interval including the second number of sidelink channels of the first type in the sidelink CO. In such embodiments, the first terminal device 110 may determine the end of the reference time interval as the end of the sidelink channels of the first type, which is earlier than the timing to start determining the value of CW.

[0065] 7D, the first terminal device 110 determines the reference time interval as the time interval of the last PSFCH, i.e., the PSFCH is defined as a first type of sidelink channel included in the sidelink CO for the first terminal device 110.

[0066] In some embodiments, the first terminal device 110 may determine the start of the reference time interval as the start of a sidelink CO whose end precedes the timing at which the first terminal device 110 starts determining the value of the CW. In such embodiments, the first terminal device 110 may determine the end of the reference time interval as occurring earlier than the end of an initiating slot in the sidelink CO, the end of an initiating burst in the sidelink CO, or the end of a first type of sidelink channel in the sidelink CO. This provides greater flexibility in determining the reference time interval, since the end of the reference time interval may be earlier than one that satisfies predefined rules. In such embodiments, a shorter reference time interval is obtained, which is beneficial for the CW determination and channel access procedures. This will be described with reference to Figures 7E and 7F.

[0067] 7E, the start of the reference time interval 720 for the first terminal device 110 is determined as the start of the last sidelink CO for the first terminal device 110, and the end of the reference time interval 720 is determined as the end of the starting burst (i.e., the first burst in the order) in the last sidelink CO. The start of the reference time interval 730 for the second terminal device 120 is determined as the start of the last sidelink CO for the second terminal device 120, and the end of the reference time interval 730 is determined as the end of the starting PSSCH (i.e., the first PSSCH in the order) in the last sidelink CO for the second terminal device 120.

[0068] In some embodiments, if two or more potential ends of a reference time interval exist within the same sidelink CO, the earlier one may be used as the end of the associated reference time interval. As shown in FIG. 7F, the PSFCH is a first type of sidelink channel. For the first terminal device 110, in the last sidelink CO 740, the PSFCH exists in the second slot within the CO 740. The start of the reference time interval for the first terminal device 110 is determined as the start of the CO 740, and the end of the reference time interval for the first terminal device 110 is determined as the end of the starting slot (i.e., the first slot in sequence) within the CO 740. In other words, the end of the reference time interval for the first terminal device 110 is determined as the end of slot #1 within the CO 740.

[0069] Meanwhile, for the second terminal device 120, in the last sidelink CO 750, the PSFCH is present at the start of the CO 750, and the first aggregated slot is slot #5 in the CO 750. The start of the reference time interval for the second terminal device 120 may be determined as the start of the CO 750, and the end of the reference time interval for the second terminal device 120 may be determined as the end of the PSFCH.

[0070] In some embodiments, the first terminal device 110 may determine the start of the reference time interval as the start of a starting slot in the sidelink CO. The end of the sidelink CO precedes the timing for starting the channel access procedure for the sidelink. In such embodiments, the first terminal device 110 may determine the length of the reference time interval as a number of slots. In such embodiments, the start of the reference time interval is from the actual start of the sidelink transmission, which may not be aligned with the start of the sidelink CO. Based on this, the associated CW can be determined more accurately. This will be described with reference to FIG. 7G.

[0071] In the example shown in Figure 7G, in the last sidelink CO received by the first terminal device 110, a cyclic prefix extension (CPE) signal is transmitted at the beginning of the CO and the actual sidelink information is transmitted starting from slot #1. Based on the rules for determining the reference time interval, the first terminal device 110 determines the start of the reference time interval as the start of the starting slot in the CO (i.e., slot #1) and the end of the reference time interval as the end of slot #5.

[0072] In some embodiments, the first terminal device 110 may determine the start of the reference time interval as the start of the last PSSCH in a sidelink control unit (CO) that contains sidelink data for unicast. The first terminal device 110 may also determine the end of the reference time interval as the end of this sidelink control unit. Such an embodiment may be used for CW determination based on factors related to the designated sidelink channel, providing an available and efficient reference time interval. This will be described with reference to FIG. 7H.

[0073] In the example shown in Fig. 7H, according to the CW decision rule, the reference time interval is determined based on certain sidelink information or transmissions on certain sidelink channels, i.e. sidelink channels of the first type. For this case, the PSSCH used for unicast is pre-configured as a sidelink channel of the first type, and the reference time interval for the sidelink CO is determined according to the last PSSCH in the CO.

[0074] The first terminal device 110 receives a sidelink signal in a control area (CO) including multiple sidelink data packets. For each packet, there is an SCI on the PSCCH indicating whether the associated sidelink data packet on the PSSCH is for unicast, groupcast, or broadcast. The first terminal device 110 may then determine a reference time interval for this CO. As shown in FIG. 7H, the start of the reference time interval is determined as the start of the last PSSCH used for unicast, and the end of the reference time interval is determined as the end of the CO.

[0075] In some embodiments, the use of a last sidelink burst having a certain length does not require the short sidelink channels included in the last sidelink burst. In such embodiments, the first terminal device 110 may determine the start of the reference time interval as the start of the last burst in the sidelink CO that does not include a sidelink channel of the second type. The first terminal device 110 may determine the end of the reference time interval as the end of the last burst. In some embodiments, the sidelink channel of the second type includes at least one of the PSFCH, PSDCH, or PSBCH. Based on the reference time interval according to the burst, further CW determination may become more accurate. This will be described with reference to FIG. 7I.

[0076] In the example shown in Fig. 7I, two or more transmission bursts are included in the sidelink CO. The last burst in the CO contains the PSFCH and therefore should not be used as the reference time interval. Therefore, the burst before the last burst in the CO may be used as the reference time interval for the current sidelink CO.

[0077] In some embodiments, the first terminal device 110 may determine one or more reference time intervals, each of which may be related to at least one of factors such as sidelink Hybrid Automatic Repeat Request (HARQ) feedback, SCI, a sidelink Channel Busy Ratio (CBR), or a sidelink Channel Occupancy Ratio (CR). The first terminal device 110 may determine a value for CW according to at least one of the factors within one of the reference time intervals.

[0078] In some embodiments, two factors may be used in different steps of the CW adjustment procedure, and two reference time intervals associated with each factor may be determined and used. For example, the first terminal device 110 may determine a first reference time interval associated with sidelink HARQ feedback and a second reference time interval associated with SCI. The first terminal device 110 may determine the value of CW according to the sidelink HARQ feedback received within the first reference time interval and the SCI received within the second reference time interval. This will be described with reference to FIG. 8A.

[0079] 8A is a flowchart of an example method 800 for determining a CW according to some embodiments of the present disclosure. In some embodiments, method 800 may be implemented in a terminal device, such as first terminal device 110 or second terminal device 120 as shown in FIG. 1. For purposes of explanation, and without loss of generality, method 800 will be described as being performed by first terminal device 110 with reference to FIG. 1.

[0080] In the example method 800, the value of CW is determined based on two factors related to the sidelink, which may include a first factor related to the sidelink and a second factor related to the sidelink.

[0081] As shown in FIG. 8, in block 810, the first terminal device 110 transmits a CW p The CW min,p That is, CW p =CW min,p Set it to be.

[0082] At block 820, CW p According to the decision rule, the first terminal device 110 determines whether the first factor satisfies a first threshold. The first factor is determined within a first reference time interval. For example, the first factor may be sidelink HARQ feedback. If the first factor satisfies the first threshold, method 800 proceeds to block 810. Otherwise, method 800 proceeds to block 830.

[0083] At block 830, CW pAccording to the decision rule, the first terminal device 110 determines whether the second factor satisfies a second threshold. The second factor is different from the first factor. For example, the second factor may be SCI. The second factor is determined within a second reference time interval. The second threshold may be the same as or different from the first threshold. The first threshold and the second threshold may be independently set, preset, or defined. If the second factor satisfies the second threshold, the method 800 proceeds to block 850. Otherwise, the method 800 proceeds to block 880.

[0084] In block 880, the first terminal device 110 transmits a CW p Increase.

[0085] In block 850, the first terminal device 110 selects a CW for priority p. p Keep it as it is.

[0086] The situation of sidelink communication is different from that of cellular communication, and more options may be applied. Therefore, determining the reference time interval based on the factor provides a more appropriate CW and is beneficial to the channel access procedure for the sidelink.

[0087] In some embodiments, the first terminal device 110 may determine a first reference time interval within the reference time interval. Then, the first terminal device 110 may determine the value of CW according to the first reference time interval. For example, the first reference time interval may be: the reference time interval with the longest or shortest length of the reference time intervals, the reference time interval that starts earliest among the reference time intervals, The earliest ending reference time interval of the reference time intervals, the reference time interval with the latest start of the reference time interval, or The latest ending reference time interval may include one of the following:

[0088] In some embodiments, the first terminal device 110 may determine the reference time interval as the time interval of the PSSCH associated with the sidelink HARQ feedback detected by the first terminal device 110. If the sidelink CW is to be determined according to the A / N feedback of the sidelink transmission, the time interval of the transmission, i.e., the time window of the corresponding PSSCH resource, may be used as the associated reference time interval. Based on the reference time interval, the A / N should be detected and used for CW determination, which can provide an accurate assessment of the channel state. This will be described with reference to FIG. 8B.

[0089] In the example shown in FIG. 8B , in the case of sidelink unicast communication in an unlicensed band, the first terminal device 110 transmits sidelink data to the second terminal device 120 on a PSSCH resource, and the second terminal device 120 then notifies the first terminal device 110 of an ACK or NACK depending on the reception result of the data. The first terminal device 110 may then detect an A / N corresponding to the PSSCH within a reference time interval. The reference time interval is determined as the time interval of the PSSCH in which the associated A / N should be used for CW determination. Furthermore, the first terminal device 110 may determine a CW for following the channel access procedure.

[0090] In some embodiments, the first terminal device 110 may determine the reference time interval as at least one of the slots including the PSFCH detected by the first terminal device 110. If the CW is determined according to the status of the detected sidelink A / N on the PSFCH, the reference time interval may be determined as a time window including all potential associated PSFCH resources. Based on this, the reference time interval should focus on the time interval of the associated PSFCH resources and avoid introducing additional overhead for the terminal device. This will be described with reference to FIG. 8C.

[0091] 8C, in the case of sidelink groupcast communication in an unlicensed band, the first terminal device 110 transmits sidelink data to two or more terminal devices in the group, and the receiving terminal devices may then notify the first terminal device 110 of an ACK or NACK according to the reception result of the data. Then, the first terminal device 110 may detect A / Ns from the different receiving terminal devices and further determine a CW to follow the channel access procedure.

[0092] 8C, multiple receiving terminal devices may each report an A / N to the first terminal device 110, for example, by using a different PSFCH for each receiving terminal device, so that the first terminal device 110 may detect an A / N on multiple PSFCH resources that may involve the same slot or different slots. Therefore, the time interval of the PSFCH resources that may be used to feedback A / N for the sidelink transmission of the first terminal device 110 should be used as a reference time interval for the first terminal device 110.

[0093] As shown in Figure 8C, according to the sidelink resource configuration, the PSFCH resources carrying A / N for the associated PSSCH are in slot #3 and slot #5. The reference time interval is determined as the time interval between slot #3 and slot #5 which includes two fragments in the time domain, i.e. the reference time interval is not a physically consecutive time interval.

[0094] In some embodiments, the first terminal device 110 may determine the reference time interval as the time interval of the PSSCH in a slot. The slot does not include a PSFCH and is the last slot before the timing at which the first terminal device 110 starts the channel access procedure. If the sidelink A / N is used for CW determination, the corresponding PSSCH resource in the slot used for sidelink information transmission may be different. That is, if other sidelink channels, such as a PSFCH, are also included in the same slot, the actual resources used for the PSSCH should be less than the resources without a PSFCH. A reference time interval determined as the time interval of the PSSCH without a PSFCH in the same slot with more resources for data transmission can more accurately represent the channel conditions and data transmission results, making CW adjustment more reasonable. This will be described with reference to FIG. 8D.

[0095] In the example shown in Figure 8D, in the sidelink CO, the starting slot 821 (i.e., the first slot in the order) includes both PSSCH and PSFCH resources, while the slot 822 following the starting slot 821 (i.e., the second slot in the order) includes only PSSCH and no PSFCH. According to the rule for determining the reference time interval, the time interval of the PSSCH in the second slot 822 in the CO is determined as the reference time interval. In other words, the time interval of the PSSCH in the starting slot (i.e., the first slot in the order) in the sidelink CO that does not include a PSFCH is determined as the reference time interval.

[0096] In the example shown in Fig. 8E, the first terminal device 110 may determine the CW by detecting all potential sidelink A / Ns on the PSFCH within the reference time interval, and the PSFCH resource allocation should be determined based on the sidelink channel structure and configuration. As shown, as a system pre-definition, the reference time interval is determined as the time interval including the last M = 3 slots including candidate PSFCH resources. That is, the reference time interval is determined as the time interval including slots #1, #3, and #5 including candidate PSFCH resources.

[0097] In some embodiments, the first terminal device 110 may determine the start of the sidelink CO as the start of the reference time interval and the end of the PSCCH containing the SCI as the end of the reference time interval. The PSCCH is included in this sidelink CO, and the SCI indicates information about this sidelink CO. In such embodiments, the reference time interval is determined according to the sidelink channel scheme or configuration. This is therefore a general definition of the reference time interval that may be used by all sidelink terminal devices and has no bearing on the actual sidelink transmission or sidelink channel access. In this way, other terminal devices receiving the SCI can accurately and timely determine the CW. This is described with reference to FIG. 8F.

[0098] In the example shown in Fig. 8F, a sidelink CO is initiated by the sidelink terminal device, and an SCI may be indicated by the sidelink terminal device on PSCCH resources within this CO to allocate information related to this CO, such as the length, priority, usage, resource allocation, etc. Upon receiving this SCI, the first terminal device 110 may determine the start of this sidelink CO as the start of a reference time interval and the end of the PSCCH containing this SCI as the end of the reference time interval.

[0099] In some embodiments, the first terminal device 110 may determine the reference time interval as the last sidelink CO that ends before the first terminal device 110 receives a sidelink grant. The time interval of the last sidelink CO exceeds a threshold. Since the sidelink CR and CBR are dedicated parameters indicating the sidelink channel conditions and are used for sidelink resource selection, a CW determined based on the sidelink CR or CBR is a general solution for sidelink terminal devices and introduces less overhead. Therefore, the sidelink CR or CBR requires a certain sidelink CO time interval to obtain a usable evaluation, and the corresponding reference time interval should be determined to meet the requirements of the sidelink CR / CBR evaluation. This will be described with reference to FIG. 8G.

[0100] In the example shown in FIG. 8G, when the first terminal device 110 receives a sidelink grant, it may determine a CW. The first terminal device 110 may listen to the channel and evaluate the sidelink CR / CBR within a reference time interval, and further determine a CW according to the CR / CBR. To obtain a reasonable evaluation of the CR / CBR, the reference time interval is determined as the time interval of the last sidelink CO having a length of K=5 ms or longer.

[0101] For some scenarios, such as a network device scheduling a sidelink terminal device in a sidelink unicast, groupcast or unlicensed band, the sidelink CW should be determined based on a reference time interval associated with the controlling node device of the sidelink communication, as will be explained with reference to Fig. 9.

[0102] 9 is a flowchart of an example method 900 according to some embodiments of the present disclosure. In some embodiments, the method 900 may be implemented in a control node device. In some embodiments, the control node device may include a network device (e.g., one of the network devices 140 and 150 shown in FIG. 1), a roadside unit, a header terminal device in a sidelink communication group, or a terminal device paired for sidelink unicast communication (e.g., one of the second terminal device 120 and the third terminal device 130).

[0103] In block 910, the control node device determines a reference time interval. The reference time interval is related to determining a CW for a channel access procedure for the sidelink. In block 920, the control node device transmits information about the reference time interval.

[0104] The method 900 may be advantageous for sidelink resource coordination and management.

[0105] In some embodiments, the information about the reference time interval may include at least one of the start of the reference time interval, the end of the reference time interval, or the length of the reference time interval.

[0106] In embodiments in which first terminal device 110 receives information regarding a reference time interval, first terminal device 110 may determine a reference time interval for first terminal device 110 based on the received information.

[0107] In an embodiment in which the first terminal device 110 receives information about a reference time interval, the first terminal device 110 may determine the reference time interval as one of the last CO initiated by the control node device or a time interval within a CO initiated by the control node device, as will be described with reference to FIG.

[0108] 10 is a diagram illustrating an example of a reference time interval according to some embodiments of the present disclosure. In the example shown in FIG. 10, a sidelink communication group includes multiple sidelink terminal devices. A header terminal device (also referred to as a header in FIG. 10) in the group initiates a sidelink communication control unit (CO) and transmits information to the member terminal devices. The member terminal devices (also referred to as members in FIG. 10) detect and receive signals in the sidelink CO from the header terminal device and other member terminal devices, and the member terminal devices determine the reference time interval as the time interval in the last CO initiated by the header terminal device.

[0109] In some embodiments, two terminal devices performing sidelink unicast may be paired with each other, and the reference time interval may be indicated by the paired terminal device in the sidelink unicast. This provides greater flexibility in determining the reference time interval and may be used for some specific scenarios, e.g., sidelink unicast, groupcast with a control node in the group, etc.

[0110] For example, the first terminal device 110 and the second terminal device 120 perform sidelink unicast with each other and maintain a PC5 RRC connection, in which case the first terminal device 110 may be referred to as a paired terminal device with respect to the second terminal device 120, and vice versa.

[0111] Between a pair of terminals, the first terminal 110 may share a self-initiated sidelink with the second terminal 120 and indicate a reference time interval having a fixed 5 ms starting from the start of the CO. Based on this indication, the second terminal 120 may further determine its CW based on the allocated reference time interval.

[0112] 11 is a schematic block diagram of an apparatus 1100 suitable for implementing some embodiments of the present disclosure. The apparatus 1100 can be considered as another exemplary embodiment of one of the terminal devices 110, 120, and 130 or one of the network devices 140 and 150 shown in FIG. 1. Thus, the apparatus 1100 may be implemented in, or as at least a part of, one of the terminal devices 110, 120, and 130 or one of the network devices 140 and 150.

[0113] As shown, the apparatus 1100 comprises a processor 1110, a memory 1120 coupled to the processor 1110, a suitable transmitter (TX) and receiver (RX) 1140 coupled to the processor 1110, and a communication interface coupled to the TX / RX 1140. The memory 1120 stores at least a portion of a program 1130. The TX / RX 1140 is used for bidirectional communication. The TX / RX 1140 has at least one antenna to facilitate communication, although the access nodes referred to herein may actually have multiple antennas. The communication interface may represent any interface required for communication with other network elements, such as an X2 interface for bidirectional communication between gNBs or eNBs, an S1 interface for communication between a Mobility Management Entity (MME) / Serving Gateway (S-GW) and an eNB, an Un interface for communication between a gNB or eNB and a Relay Node (RN), or a Uu interface for communication between a gNB or eNB and a terminal device.

[0114] The program 1130 is assumed to include program instructions that, when executed by the associated processor 1110, enable the device 1100 to operate according to embodiments of the present disclosure, as described herein with reference to Figures 1-10. The embodiments herein may be implemented by computer software executable by the processor 1110 of the device 1100, by hardware, or by a combination of software and hardware. The processor 1110 may be configured to implement various embodiments of the present disclosure. Furthermore, the combination of the processor 1110 and the memory 1120 may form a processing means 1150 suitable for implementing various embodiments of the present disclosure.

[0115] Memory 1120 may be of any type suitable for a local technology network and may be implemented using any suitable data storage technology, including, by way of non-limiting example, non-transitory computer-readable storage media, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, and removable memory. While only one memory 1120 is shown in device 1100, several physically distinct memory modules may be present within device 1100. Processor 1110 may be of any type suitable for a local technology network and may include, by way of non-limiting example, one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. Device 1100 may have multiple processors, for example, application-specific integrated circuit chips time-slaved to a clock that synchronizes the main processor.

[0116] Components included in the devices and / or apparatus of the present disclosure may be implemented in various ways, including software, hardware, firmware, or any combination thereof. In one embodiment, one or more units may be implemented using software and / or firmware, such as machine-executable instructions stored on a storage medium. In addition to, or instead of, machine-executable instructions, some or all of the units in the devices and / or apparatus may be implemented, at least in part, by one or more hardware logic components. By way of example and not limitation, exemplary types of hardware logic components that may be used include field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific general purpose products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), etc.

[0117] Overall, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic, or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software executable by a controller, microprocessor, or other computing device. While various aspects of embodiments of the present disclosure have been illustrated and described using block diagrams, flowcharts, or other pictorial representations, it should be understood that the blocks, devices, systems, techniques, or methods described herein may be implemented, by way of non-limiting example, in hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing device, or any combination thereof.

[0118] 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 instructions included in program modules, that execute in a device on a target real or virtual processor to perform a process or method described above with reference to any one of FIGS. 1 through 10. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, etc. that perform particular tasks or implement particular abstract data types. In various embodiments, the functionality of the program modules may be combined or split between program modules as desired. The machine-executable instructions of the program modules may be executed in local or distributed devices. In a distributed device, program modules may be located in both local and remote storage media.

[0119] Program code for carrying out the methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, and when executed by the processor or controller, cause the program code to implement the functions / acts specified in the flowcharts and / or block diagrams. The program code may run entirely on the machine, partially on the machine, as a separate software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0120] The above-described program code may be embodied on a machine-readable medium, which may be any tangible medium that can contain or store a program used by or associated with an instruction execution system, apparatus, or device. The machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. The machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the aforementioned media. More specific examples of a machine-readable storage medium may include an electrical connection having 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 above.

[0121] Although operations have been described in a particular order, it should not be understood that performing these operations in the particular order shown, or in any sequential order, or performing all of the operations described, is required to achieve desirable results. In some cases, multitasking or parallel processing may be advantageous. Similarly, although details of several specific embodiments are included in the above discussion, these should not be construed as limitations on the scope of the disclosure, but rather as descriptions of features that may be unique to particular embodiments. Some features that are described in the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable subcombination.

[0122] 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, as defined in the appended claims, is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

1. means for determining a contention window value for a channel access procedure for a sidelink according to a decision based on Hybrid Automatic Repeat Request (HARQ) feedback corresponding to a Physical Sidelink Shared Channel (PSSCH) within a reference time interval and whether the PSSCH is for a unicast or groupcast sidelink transmission, wherein the reference time interval is a time interval during which at least one PSSCH with the HARQ feedback comprising an ACK or NACK is transmitted; means for transmitting a sidelink transmission using the channel access procedure; and Including, Whether the PSSCH is for the unicast sidelink transmission or the groupcast sidelink transmission is indicated by sidelink control information (SCI). Terminal device.

2. the reference time interval starts from a start of channel occupation initiated by the terminal device, including sidelink transmission, and ends at the end of a start slot in which the at least one PSSCH is transmitted. The terminal device according to claim 1 .

3. 1. A method performed by a terminal device, comprising: determining a contention window value for a channel access procedure for a sidelink according to a determination based on Hybrid Automatic Repeat Request (HARQ) feedback corresponding to a Physical Sidelink Shared Channel (PSSCH) within a reference time interval, whether the PSSCH is for a unicast sidelink transmission or a groupcast sidelink transmission, wherein the reference time interval is a time interval during which at least one PSSCH is transmitted with the HARQ feedback including an ACK or a NACK; transmitting a sidelink transmission using the channel access procedure; and Including, Whether the PSSCH is for the unicast sidelink transmission or the groupcast sidelink transmission is indicated by sidelink control information (SCI). method.

4. the reference time interval starts from a start of channel occupation initiated by the terminal device, including sidelink transmission, and ends at the end of a start slot in which the at least one PSSCH is transmitted. The method of claim 3.

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