Sidelink transmission method and device

Abstract

An embodiment of the present invention provides a method and apparatus for sidelink transmission, the method including: a first device determining a candidate resource set in an unlicensed frequency band, selecting a transmission resource from the candidate resource set, determining a listen-before-talk class for sidelink transmission, and transmitting sidelink information on the transmission resource if the listen-before-talk performed based on the listen-before-talk class is successful.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present invention relates to the field of communications technology. [Background technology]

[0002] 3GPP has completed the standardization of the sidelink of new radio (NR) in Rel-16, and its main application scenario is V2X (Vehicle to Everything), also called NR V2X. Compared with cellular communication using Uu link, the transmitting device directly communicates with the receiving device through the sidelink.

[0003] NR sidelink performs sidelink communication within a resource pool, and the defined physical channels include a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), and a physical sidelink feedback channel (PSFCH). The PSCCH carries 1st stage sidelink control information (SCI), and the 1st stage SCI is mainly used to reserve resources. The PSSCH carries 2nd stage SCI and data, and the 2nd stage SCI is mainly used for data demodulation. The PSFCH carries sidelink feedback information (HARQ-ACK).

[0004] NR sidelink defines two resource allocation modes: in mode 1, the resources used by the terminal device for sidelink communication are scheduled or configured by the network device (base station) over the NR Uu link, and in mode 2, the terminal device can autonomously select the time-frequency resources for sidelink communication based on its own sensing results.

[0005] To meet the increasing demand for sidelink communication, especially in commercial scenarios, the development of sidelink has become one of the projects of 3GPP in Rel-18 (also called 5G-Advanced). One of the research contents of the Rel-18 sidelink project is Sidelink Unlicensed Access (SL-U) based on sidelink, which has the main goal of supporting higher data rates using unlicensed spectrum (or shared spectrum).

[0006] The above description of the background art is merely for the purpose of more clearly and completely explaining the configurations of the present invention and for the understanding of those skilled in the art, and should not be construed as meaning that these configurations are well known to those skilled in the art just because they are described in the background art of the present invention. Summary of the Invention [Problem to be solved by the invention]

[0007] According to the findings of the inventors of the present invention, SL-U is mainly applied to commercial scenarios, but does not exclude applications such as V2X with high automation. Taking commercial scenarios as an example, high data rate is an essential and important indicator for XR technologies such as Virtual Reality (VR) and Augmented Reality (AR), and SL-U can meet the high rate requirements by using excess spectrum. In addition, industrial Internet of Things (IoT) and smart home are also suitable scenarios for the deployment and use of SL-U.

[0008] SL-U has just been proposed in Rel-18, and no concrete standardization work has been started in 3GPP. Currently, how to perform sidelink transmission based on resource allocation mode 2 (autonomous resource selection) in SL-U is still a topic under discussion.

[0009] In view of at least one of the above problems, embodiments of the present invention provide a sidelink transmission method and apparatus. [Means for solving the problem]

[0010] In one aspect of an embodiment of the present invention, a sidelink transmission method is provided, the method including: a first device determining a candidate resource set in an unlicensed frequency band; selecting transmission resources from the candidate resource set; determining a listen-before-talk class for sidelink transmission; and transmitting sidelink information on the transmission resources if listen-before-talk performed based on the listen-before-talk class is successful.

[0011] In another aspect of an embodiment of the present invention, there is provided a sidelink transmission device, comprising: a first determination unit configured to determine a candidate resource set in an unlicensed frequency band; a selection unit configured to select transmission resources from the candidate resource set; a second determination unit configured to determine a listen-before-talk class for sidelink transmission; and a transmission unit configured to transmit sidelink information on the transmission resources if the listen-before-talk performed based on the listen-before-talk class is successful.

[0012] In another aspect of an embodiment of the present invention, there is provided a communication system including a terminal device configured to determine a candidate resource set in an unlicensed frequency band, select a transmission resource from the candidate resource set, determine a listen-before-talk class for sidelink transmission, and transmit sidelink information on the transmission resource if listen-before-talk performed based on the listen-before-talk class is successful.

[0013] One of the advantageous effects of the embodiment of the present invention is as follows: determining a candidate resource set in an unlicensed frequency band, selecting a transmission resource from the candidate resource set, determining a listen-before-talk (LBT) class for sidelink transmission, and transmitting sidelink information on the transmission resource if the listen-before-talk (LBT) performed based on the LBT class is successful, thereby enabling a device that has performed sidelink communication to efficiently compete for the use of the unlicensed frequency band and to coexist fairly with other devices that use the unlicensed frequency band.

[0014] As shown in the following description and drawings, specific embodiments of the present invention are disclosed in detail to show how the principles of the present invention can be employed. However, the scope of the embodiments of the present invention is not limited to these. The embodiments of the present invention include modifications, alterations, and equivalents within the spirit and scope of the appended claims.

[0015] Features described and / or illustrated in one embodiment may be used in the same or similar manner in one or more other embodiments and may be combined with or substituted for features in the other embodiments.

[0016] It should be noted that in this text, the term "including / having" means the presence of a feature, element, step or component, and does not exclude the presence or addition of one or more other features, elements, steps or components. [Brief description of the drawings]

[0017] Elements and features depicted in one drawing and one embodiment of the present invention may be combined with elements and features shown in one or more drawings or embodiments, and in the drawings, like reference numerals may designate corresponding elements in multiple drawings and may designate corresponding elements used in more than one embodiment. [Figure 1] 1 is a schematic diagram of a communication system according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic diagram of an example of COT sharing. [Diagram 3] FIG. 2 is a schematic diagram of an example of interlace-based transmission; [Figure 4] FIG. 2 is a schematic diagram of an example of a sidelink transmission method according to an embodiment of the present invention; [Diagram 5] FIG. 2 is a schematic diagram of an example of resource selection according to an embodiment of the present invention. [Figure 6] FIG. 2 is a schematic diagram of an example of determining an LBT class according to an embodiment of the present invention. [Figure 7] FIG. 2 is a schematic diagram of an example of determining a shared COT according to an embodiment of the present invention. [Figure 8] FIG. 2 is a schematic diagram of an example of determining an LBT class based on prior transmission according to an embodiment of the present invention. [Figure 9] FIG. 13 is a schematic diagram of another example of determining an LBT class based on prior transmission according to an embodiment of the present invention. [Figure 10]FIG. 13 is a schematic diagram of another example of determining an LBT class based on prior transmission according to an embodiment of the present invention. [Figure 11] FIG. 13 is a schematic diagram of another example of determining an LBT class based on prior transmission according to an embodiment of the present invention. [Figure 12] FIG. 13 is a schematic diagram of another example of determining an LBT class based on prior transmission according to an embodiment of the present invention. [Figure 13] FIG. 13 is a schematic diagram of another example of determining an LBT class based on prior transmission according to an embodiment of the present invention. [Figure 14] FIG. 2 is a schematic diagram of an example of a sidelink transmission device according to an embodiment of the present invention. [Figure 15] FIG. 2 is a schematic diagram of an example of a network device according to an embodiment of the present invention. [Figure 16] FIG. 2 is a schematic diagram of an example of a terminal device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The above and other features of the present invention will become apparent from the following description. In the specification and drawings, specific embodiments of the present invention are disclosed in detail, and some of the embodiments in which the principles of the present invention can be adopted are shown. However, the present invention is not limited to the described embodiments. The present invention includes all modifications, variations, and equivalents within the scope of the appended claims. Each embodiment of the present invention will be described below with reference to the drawings. These embodiments are merely illustrative and do not limit the present invention.

[0019] In embodiments of the present invention, the terms "first", "second", etc. are used in the title to distinguish different elements, but do not represent the spatial arrangement or temporal order of these elements, and these elements are not limited to these terms. The term "and / or" includes any and all combinations of one or more of the terms listed in the associated list. The terms "including", "comprising", "having", etc. refer to the presence of listed features, elements, elements or components, but do not exclude the presence or addition of one or more other features, elements, elements or components.

[0020] In the embodiments of the present invention, the singular forms "a", "the", etc., include the plural forms and should be understood broadly as "one kind" or "a class", and are not limited to "one". In addition, the term "said" should be understood to include both the singular and the plural forms, unless the context clearly indicates otherwise. In addition, the term "described in" should be understood to mean "described at least in part", and the term "based on" should be understood to mean "based at least in part on", unless the context clearly indicates otherwise.

[0021] In an embodiment of the present invention, the term "communication network" or "wireless communication network" may refer to a network conforming to any communication standard, such as, for example, Long Term Evolution (LTE), Advanced Long Term Evolution (LTE-A, LTE-Advanced), Wideband Code Division Multiple Access (WCDMA), High-Speed ​​Packet Access (HSPA), etc.

[0022] Additionally, communications between devices in a communication system may occur according to any stage of communication protocols, including, but not limited to, 1G (generation), 2G, 2.5G, 2.75G, 3G, 4G, 4.5G, and 5G, New Radio (NR), and / or other currently known or future developed communication protocols.

[0023] In the embodiment of the present invention, the term "network device" refers to a device in a communication system, for example, allowing a terminal device to access the communication system and providing a service to the terminal device. The network device may include, but is not limited to, a base station (BS), an access point (AP), a transmission reception point (TRP), a broadcast transmitter, a mobility management entity (MME), a gateway, a server, a radio network controller (RNC), a base station controller (BSC), etc.

[0024] Here, the base station may include, but is not limited to, a Node B (NodeB or NB), an evolved Node B (eNodeB or eNB), and a 5G base station (gNB), etc., as well as a Remote Radio Head (RRH), a Remote Radio Unit (RRU), a relay, or a low power node (e.g., femto, pico, etc.). Also, the term "base station" may include some or all of these functions, and each base station may provide communication coverage for a particular geographic area. The term "cell" may refer to a base station and / or its coverage area depending on the context in which the term is used.

[0025] In the embodiment of the present invention, the term "User Equipment" (UE) or "Terminal Equipment" (TE) refers to an apparatus that accesses a communication network and receives a network service via, for example, a network device. The terminal apparatus may be fixed or mobile, and may be called a mobile station (MS), a terminal, a subscriber station (SS), an access terminal (AT), a station, etc.

[0026] Among them, the terminal device may include, but is not limited to, a mobile phone, a personal digital assistant (PDA), a wireless modulation / demodulation device, a wireless communication device, a handheld device, a machine-type communication device, a laptop computer, a cordless phone, a smartphone, a smart watch, a digital camera, and the like.

[0027] Also, for example, in a scenario such as the Internet of Things (IoT), the user equipment may be a monitoring or measuring device or equipment, and may include, but is not limited to, a Machine Type Communication (MTC) terminal, an in-vehicle communication terminal, a Device to Device (D2D) terminal, a Machine to Machine (M2M) terminal, and the like.

[0028] Furthermore, the term "network side" or "network device side" refers to the side of a network, which may be a base station or may include one or more of the network devices mentioned above. The term "user side" or "terminal side" or "terminal device side" refers to the side of a user or terminal, which may be a UE or may include one or more of the terminal devices mentioned above. In this specification, unless otherwise specified, "device" may refer to a network device or may refer to a terminal device.

[0029] The following describes an embodiment scenario of the present invention with reference to an example, but the present invention is not limited thereto.

[0030] 1 is a schematic diagram of a communication system according to an embodiment of the present invention, and illustrates an example of a user device and a network device. As shown in FIG. 1, a communication system 100 may include a network device 101 and terminal devices 102 and 103. For convenience of explanation, FIG. 1 illustrates two terminal devices and one network device as an example, but the embodiment of the present invention is not limited thereto.

[0031] In the embodiment of the present invention, existing services or services that can be implemented in the future can be performed between the network device 101 and the terminal devices 102 and 103. For example, these services include, but are not limited to, enhanced Mobile Broadband (eMBB), massive Machine Type Communication (mMTC), and Ultra-Reliable and Low-Latency Communication (URLLC).

[0032] 1 shows that both of the two terminal devices 102 and 103 are located within the coverage area of ​​the network device 101, but the present invention is not limited to this. Both of the two terminal devices 102 and 103 may not be located within the coverage area of ​​the network device 101, or one of the terminal devices 102 may be located within the coverage area of ​​the network device 101 and the other terminal device 103 may be located outside the coverage area of ​​the network device 101.

[0033] In an embodiment of the present invention, sidelink transmission may be performed between two terminal devices 102 and 103. For example, the two terminal devices 102 and 103 may both perform sidelink transmission within the coverage area of ​​the network device 101 to realize sidelink communication, or both perform sidelink transmission outside the coverage area of ​​the network device 101 to realize sidelink communication, or one terminal device 102 may be located within the coverage area of ​​the network device 101 and the other terminal device 103 may be located outside the coverage area of ​​the network device 101 to realize sidelink communication.

[0034] In the 5G phase, 3GPP is considering and proposing standardization for both sidelink and unlicensed frequency bands, such as NR V2X in Rel-16, sidelink enhancements in Rel-17, and NR-Unlicensed (NR-U) in Rel-16.

[0035] In NR sidelink, two resource allocation modes are defined: mode 1 and mode 2. The main steps of resource selection in mode 2 are shown in Table 1. For the complete resource selection process, one may refer to section 8.1.4 of standard TS 38.214.

[0036] [Table 1] In Rel-17, 3GPP further extends resource allocation for NR sidelink to include power saving and inter-UE coordination, and application scenarios are expanded to public safety and business-related services.

[0037] Meanwhile, in order to allow 5G technology to use unlicensed spectrum (frequency band), 3GPP completed the standardization of NR-based unlicensed access (NR-U: New Radio-Unlicensed) in Rel-16. Since the use of unlicensed frequency bands requires compliance with the regulations of various countries and regions, NR-U is based on NR and supports several new functions such as Listen Before Talk (LBT), Channel Occupancy Time (COT), COT sharing, and interlaced transmission.

[0038] To ensure fair coexistence with systems such as WiFi systems, access to unlicensed frequency bands requires using LBT to detect and evaluate the channel, and can obtain channel access opportunities for transmission only when the channel is idle (LBT is successful). In NR-U, three LBT processes are defined: Cat1 LBT (LBT class 1), Cat2 LBT (LBT class 2) and Cat4 LBT (LBT class 4). Cat1 LBT does not require channel detection. Cat2 LBT includes Cat2 16μs LBT and Cat2 25μs LBT, which require 16μs and 25μs channel detection before transmitting data. Cat4 LBT includes multiple channel detections with variable times. The higher the LBT class, the stricter the conditions for LBT success.

[0039] In order to occupy the channel more efficiently, the device (base station) can share the COT acquired by the base station (device), which is called COT sharing. The device or base station can use a low-class LBT when sharing the COT, so that the device or base station can avoid using the highest-class LBT in every transmission, and can reduce the transmission delay.

[0040] FIG. 2 is a schematic diagram of an example of COT sharing, which shows COT sharing in a simplified manner. For example, a base station occupies a channel via Cat4 LBT, transmits downlink data / information, and sends a COT indication, i.e., starts COT. The COT indication can indicate the COT period, the LBT bandwidth supported in the COT, the uplink and downlink data structures in the COT, etc.

[0041] If the time interval between the device's uplink transmission and the base station's previous downlink transmission is less than 16 μs, the base station can instruct the device to transmit data via Cat1 LBT. If the time interval between the device's uplink transmission and the base station's previous downlink transmission is equal to 16 μs or 25 μs, the base station can instruct the device to transmit data via Cat2 16 μs LBT or Cat2 25 μs LBT. If the device knows that it is within the COT initiated by the base station based on the COT instruction, the device can also adjust the LBT class of the uplink transmission based on the time interval between the uplink and downlink data, for example, change from Cat4 LBT to Cat2 LBT.

[0042] In order to meet the requirements of the regulatory rules on channel occupied bandwidth, the PUSCH and PUCCH of NR-U are transmitted according to the manner of frequency domain interlacing. Figure 3 is a schematic diagram of an example of interlace-based transmission, which shows an interlace in a schematic manner. As shown in Figure 3, an interlace includes several discrete resource blocks (RBs) in the frequency domain, and the discrete RBs are distributed at equal intervals in the frequency domain. In one transmission, one or more interlaces can be used.

[0043] For Cat4 LBT, the Channel Access Priority Class (CAPC) is used to determine the relevant parameters required for the LBT process, such as the maximum channel occupancy time, contention window length, etc. Table 2 shows the uplink channel access priority classes in a simplified manner. The smaller the CAPC value p, the higher the channel access priority class. The device needs to know which CAPC value to use when performing Cat4 LBT.

[0044] [Table 2] In the following description, unless confusion arises, the terms “sidelink” and “V2X” may be interchanged, the terms “PSFCH” and “sidelink feedback channel” may be interchanged, the terms “PSCCH” and “sidelink control channel” or “sidelink control information” may be interchanged, and the terms “PSSCH” and “sidelink data channel” or “sidelink data” may be interchanged.

[0045] Also, transmitting or receiving a PSCCH may be understood as transmitting or receiving sidelink data carried by the PSCCH. Transmitting or receiving a PSSCH may be understood as transmitting or receiving sidelink data carried by the PSSCH. Transmitting or receiving a PSFCH may be understood as transmitting or receiving sidelink feedback information carried by the PSFCH. Sidelink transmission may be understood as transmitting a PSCCH / PSSCH or transmitting sidelink data / information.

[0046] In the embodiment of the present invention, the time unit may have any time length, for example, a frame, a sub-frame, a slot, a mini-slot, etc., and the following will simply take a slot as an example. PSCCH / PSSCH may be abbreviated as PSSCH, and SCI may mean 1st stage SCI and / or 2nd stage SCI. Sidelink information includes sidelink control information and / or data information and / or feedback information.

[0047] <Example 1> An embodiment of the present invention provides a sidelink transmission method, which is described from the first device side.

[0048] 4 is a schematic diagram of an example of a sidelink transmission method according to an embodiment of the present invention. As shown in FIG. 4, the method includes the following steps:

[0049] Step 401: A first device determines a candidate resource set in an unlicensed frequency band.

[0050] Step 402: The first device selects a transmission resource from the candidate resource set.

[0051] Step 403: The first device determines a listen-before-talk (LBT) class for sidelink transmission.

[0052] Step 404: If the listen-before-talk (LBT) performed based on the LBT class is successful, the first device transmits sidelink information on the transmission resource.

[0053] It should be noted that the above FIG. 4 only shows a schematic diagram of an embodiment of the present invention, but the present invention is not limited thereto. For example, the execution order between various steps may be appropriately adjusted, some other steps may be added, and some steps may be removed. Those skilled in the art may make appropriate modifications based on the above content, and are not limited to the description of the above FIG. 4.

[0054] 5 is a schematic diagram of an example of resource selection according to an embodiment of the present invention, which illustrates a process in which a device performs transmission in an unlicensed frequency band based on autonomous resource selection (mode 2). A For example, the device may treat one or more interlaces as one candidate resource, and then reuse the resource selection method of mode 2 to determine the candidate resource set S according to section 8.1.4 of the standard TS 38.214. A Determine.

[0055] For example, as shown in FIG. A contains some candidate resources in the resource selection window. The physical layer of the device is A to the upper layer (e.g., the MAC layer), and the upper layer A The device selects one or more candidate resources from the candidate resources selected by the device according to section 5.22.1.1 of standard TS 38.321 by reusing the resource selection method of mode 2. In Fig. 5, the candidate resources selected by the device are indicated by diagonal lines, and these candidate resources are used to transmit sidelink information (PSCCH / PSSCH).

[0056] A device needs to perform an LBT before performing a transmission, and whether it can actually transmit or not depends on the result of the LBT. For each transmission, the device determines an LBT class, for example, Cat1 LBT, Cat2 LBT, or Cat4 LBT. The device performs a corresponding LBT according to the LBT class. If the LBT is successful, the device performs the transmission, and if the LBT fails, the device does not perform the transmission. For example, as shown in FIG. 5, the device does not perform the transmission in the last slot of the resource selection window because the LBT fails.

[0057] In some embodiments, the first device determines the LBT class based on whether the sidelink transmission is within a channel occupancy time (COT). The LBT class may include, for example, Cat1 LBT (LBT class 1), Cat2 LBT (LBT class 2) and Cat4 LBT (LBT class 4), or may include, for example, class 1 and class 2, or may include, for example, type A, type B, type C, type D, and the like, and embodiments of the present invention are not limited to a specific representation manner.

[0058] In some embodiments, the channel occupation time (COT) is obtained through a COT instruction received by the first device. For example, the second device (or a third device or a fourth device, which will be described later) sends a COT instruction to the first device, and the first device obtains the COT according to the COT instruction. For convenience of explanation, such a COT may be referred to as a shared COT.

[0059] In some embodiments, the channel occupancy time (COT) is obtained by the first device performing Listen Before Talk (LBT). For example, the first device may obtain the COT by the success of a Cat4 LBT (high class LBT) performed by itself. For details of LBT and COT, reference may be made to related art in NR-U. For convenience of explanation, such a COT may be referred to as an initiated COT.

[0060] In some embodiments, the first device transmits a channel occupation time (COT) indication including information of COT. For example, when the first device obtains COT through a successful Cat4 LBT performed by the first device, the first device may transmit sidelink information in the COT through a resource selection process, and the first device may transmit a COT indication including the COT information to other devices.

[0061] In some embodiments, if the sidelink transmission is within the channel occupation time (COT), the LBT class is determined to be low or high.

[0062] In some embodiments, if the sidelink transmission is outside the channel occupation time (COT), the LBT class is determined to be high class.

[0063] For example, when determining the LBT class for a transmission, the device may know whether the transmission is currently within the COT. The device may use this information to determine the LBT class. For example, the determined LBT class for a transmission that is outside the COT is Cat4 LBT, and the determined LBT class for a transmission that is within the COT is Cat1 LBT or Cat2 LBT or Cat4 LBT.

[0064] FIG. 6 is a schematic diagram of an example of LBT class determination according to an embodiment of the present invention, which shows that a device determines whether a transmission is within the COT. FIG. 6 is described from the perspective of a single device, where all transmissions belong to the same device. For ease of explanation, FIG. 6 simplifies interlacing.

[0065] As shown in FIG. 6, the COT includes a shared COT and an initiated COT. If the Cat4 LBT is successful, the first device may initiate the COT with a transmission (transmission 2) (starting at t2) and may continue transmission (transmission 3) within the COT. This COT is called the initiated COT. The first device may share the COT initiated by the second device (starting at t0), i.e., perform transmission (transmission 1) within the COT initiated by the second device. From the perspective of the first device, this COT is called the shared COT. A transmission being within the COT means that the transmission is within the shared COT or within the initiated COT.

[0066] Also, whether a transmission is in the COT or not refers to the result observed when the device determines the LBT. The device needs to determine the LBT class for a transmission before it. The device obtains the shared COT at t0, for example, by receiving a COT instruction. The device determines the LBT class for transmission 1 before t1, and before t1, the device observed that transmission 1 is in the shared COT. The device determines the LBT class for transmission 2 before t2, and after t2, transmission 2 is in the COT where it was started, but since the device did not start the COT before t2, at this time, the device observed that transmission 2 is outside the COT. If the LBT is successful, the device transmits transmission 2 at t2 and starts the COT, for example, by sending a COT instruction. The device determines the LBT class for transmission 3 before t3, and before t3, the device observed that transmission 3 is in the COT where it was started.

[0067] The above has been a brief description of a device determining an LBT class based on a COT. Below, a shared COT will be described.

[0068] In some embodiments, a first device receives one or more COT indications indicating one or more first COTs, and determines a second COT for obtaining the LBT class based on the one or more first COTs and / or a COT obtained by performing a listen-before-talk (LBT).

[0069] For example, in sidelink communication, a device may receive multiple COT indications to obtain multiple COTs, but not all COTs are suitable for COT sharing.

[0070] In some embodiments, a second channel occupation time (COT) for acquiring the LBT class is indicated by a COT indication sent by the second device. A Reference Signal Receiving Power (RSRP) between the first device and the second device is greater than a first threshold; the distance between the first device and the second device is less than a second threshold; the first device is a sender of sidelink information of the second device; the first device is a recipient of sidelink information of the second device; the first device and the second device have the same cast type; or At least one condition (first condition) is satisfied: the channel access priority class (CAPC) value of the first device is smaller than the channel access priority class (CAPC) value of the second device.

[0071] For example, if the LBT results of two devices are different, it is not appropriate to share the COT between the two devices, and therefore, whether to share the COT may be determined based on the RSRP and / or the distance between the two devices.

[0072] As another example, it is not appropriate for devices in one unicast pair to share a COT initiated by a device in another unicast pair, and therefore, whether or not to share a COT may be determined based on whether the two devices belong to a transmitting / receiving device pair.

[0073] As another example, a unicast device may not be eligible to share a COT initiated by a broadcast device, and therefore, the decision to share a COT may be based on whether the two devices have the same cast type.

[0074] As another example, a device with a low channel access priority class (CAPC) may not be suitable to share a COT initiated by a device with a high channel access priority class, and therefore, the decision as to whether to share a COT may be based on the value of the channel access priority class (CAPC).

[0075] As another example, whether to share a COT may be determined based on any combination of the above conditions.

[0076] Here, "device 1 is the sender of device 2" means that the destination ID of device 1 is an ID that device 2 is interested in. For example, device 1 is the sender of a unicast and device 2 is the receiver of the unicast. As another example, device 1 and device 2 are both members of the same group in a groupcast, and the destination ID of device 1 is the group ID. The meaning of "device 1 is the receiver of device 2" is similar.

[0077] FIG. 7 is a schematic diagram of an example of determining a shared COT according to an embodiment of the present invention, which is a schematic diagram of a device determining whether a transmission is within a shared COT. As shown in FIG. 7, device 3 receives a COT instruction sent by device 1 in slot m0 and obtains a COT period COT1. Similarly, device 3 receives a COT instruction sent by device 2 in slot m0 and obtains a COT period COT2. Among devices 1 and 2, only devices 3 and 1 The RSRP between device 3 and device 1 is greater than a threshold; The distance between device 3 and device 1 is less than a threshold value; Device 3 is the sender of device 1; Device 3 is the receiver of device 1; Device 3 and device 1 have the same cast type, or At least one of the conditions (first condition) is satisfied: the CAPC value of device 3 is smaller than the CAPC value of device 1.

[0078] Therefore, COT 1 is a shared COT, and device 3's transmission in slot m1 falls within COT 1. If device 1 and COT 1 were not present in Figure 7, it would be determined that the transmission in slot m1 does not fall within any COT, i.e., COT 2 is not a sharable COT for device 3.

[0079] The first device may obtain information required for condition judgment as follows: RSRP is equal to the RSRP of the PSCCH / PSSCH carrying the COT indication; The 2nd stage SCI may indicate a Zone ID, so that the first device can calculate the distance between the first device and the second device; The 2nd stage SCI may indicate a Source ID and a Destination ID, so that the first device can determine that the second device is its receiver or sender; The cast type indicator field of the 2nd stage SCI indicates a cast type, so that the first device can obtain the cast type of the second device; The first device may obtain the cast type of the second device based on the format (SCI format 2-A or SCI format 2-B) of the 2nd stage SCI, where SCI format 2-B represents group cast. The second device indicates the CAPC value by sending signaling, for example, conveying the CAPC value via the 1st stage SCI or the 2nd stage SCI, where a smaller CAPC value indicates a higher channel access priority class.

[0080] The following provides an overview of the situation in which an LBT class is determined based on a sidelink transmission.

[0081] In some embodiments, the sidelink transmission is a first transmission within a channel occupation time (COT), and the first device determines an LBT class for the first transmission based on a second transmission prior to the first transmission.

[0082] In some embodiments, if the time interval between the first transmission and the second transmission is less than a threshold, the LBT class is determined to be a low class.

[0083] In some embodiments, if the time interval between the first transmission and the second transmission is greater than or equal to a threshold, the LBT class is determined to be a high class.

[0084] In some embodiments, the second transmission comprises: a sidelink transmission of the first device; a sidelink transmission of a third device transmitting a Channel Occupancy Time (COT) indication to indicate a COT; or The at least one sidelink transmission of the fourth device includes not transmitting a channel occupation time (COT) indication to indicate a COT.

[0085] For example, for transmissions within the COT, the device may use a low class of LBT (Cat1 LBT, Cat2 LBT). The device determines the LBT class based on previous transmissions.

[0086] Fig. 8 is a schematic diagram of an example of LBT class determination based on prior transmission according to an embodiment of the present invention, Fig. 9 is a schematic diagram of another example of LBT class determination based on prior transmission according to an embodiment of the present invention, and Fig. 10 is a schematic diagram of another example of LBT class determination based on prior transmission according to an embodiment of the present invention. Figs. 8 to 10 show schematic diagrams of LBT class determination for transmissions in a shared COT.

[0087] As shown in Figure 8, a first device shares a COT initiated by a third device, the first device has multiple transmissions in the COT, and the first device determines an LBT class for the first transmission based on the second transmission, where the third device is the device that sends the COT indication.

[0088] For example, if the time interval between the end of the second transmission and the start of the first transmission is small enough, the first device may use Cat1 LBT or Cat2 LBT. For example, if the time interval is less than 16 μs, use Cat1 LBT. For example, if the time interval is equal to 16 μs, use Cat2 16 μs LBT. For example, if the time interval is equal to 25 μs, use Cat2 25 μs LBT.

[0089] As shown in Figure 9, the first device shares the COT initiated by the third device, and the first device determines the LBT class for the first transmission based on the transmission (second transmission) of the third device. As shown in Figure 9, the third device is the device that transmits the COT instruction, and the first device shares the COT initiated by the third device. Also, the first device can know the time domain location where the second transmission is located based on the PSCCH / PSSCH transmitted by the received third device.

[0090] For example, if the time interval between the end of the second transmission and the start of the first transmission is small enough, the first device may use Cat1 LBT or Cat2 LBT. For example, if the time interval is less than 16 μs, use Cat1 LBT. For example, if the time interval is equal to 16 μs, use Cat2 16 μs LBT. For example, if the time interval is equal to 25 μs, use Cat2 25 μs LBT.

[0091] As shown in FIG. 10, the first device shares the COT initiated by the third device, and the first device determines the LBT class for the first transmission based on the transmission (second transmission) of the fourth device. Here, the fourth device is a device that does not transmit a COT instruction. For example, as shown in FIG. 10, the third device is a device that transmits a COT instruction. Also, the first device can know the time domain location where the second transmission is located based on the PSCCH / PSSCH transmitted by the received fourth device.

[0092] For example, if the time interval between the end of the second transmission and the start of the first transmission is small enough, the first device may use Cat1 LBT or Cat2 LBT. For example, if the time interval is less than 16 μs, use Cat1 LBT. For example, if the time interval is equal to 16 μs, use Cat2 16 μs LBT. For example, if the time interval is equal to 25 μs, use Cat2 25 μs LBT.

[0093] Fig. 11 is a schematic diagram of another example of LBT class determination based on prior transmission according to an embodiment of the present invention, Fig. 12 is a schematic diagram of another example of LBT class determination based on prior transmission according to an embodiment of the present invention, and Fig. 13 is a schematic diagram of another example of LBT class determination based on prior transmission according to an embodiment of the present invention. Figs. 11 to 13 generally illustrate the determination of an LBT class for a transmission within an initiated COT.

[0094] As shown in FIG. 11, the first device starts a COT, the first device transmits multiple transmissions within the COT, and the first device determines an LBT class for the first transmission based on the second transmission. For example, if the time interval between the end of the second transmission and the start of the first transmission is small enough, the first device may use Cat1 LBT or Cat2 LBT. For example, if the time interval is less than 16 μs, use Cat1 LBT. For example, if the time interval is equal to 16 μs, use Cat2 16 μs LBT. For example, if the time interval is equal to 25 μs, use Cat2 25 μs LBT.

[0095] As shown in Figure 12, the first device starts COT, and the first device determines the LBT class for the first transmission based on the transmission (second transmission) of the third device. As shown in Figure 12, the third device is the device that transmits the COT instruction. Also, the first device can know the time domain location where the second transmission is located based on the PSCCH / PSSCH transmitted by the received third device.

[0096] For example, if the time interval between the end of the second transmission and the start of the first transmission is small enough, the first device may use Cat1 LBT or Cat2 LBT. For example, if the time interval is less than 16 μs, use Cat1 LBT. For example, if the time interval is equal to 16 μs, use Cat2 16 μs LBT. For example, if the time interval is equal to 25 μs, use Cat2 25 μs LBT.

[0097] As shown in Figure 13, the first device starts COT, and the first device determines the LBT class for the first transmission based on the transmission (second transmission) of the fourth device. As shown in Figure 13, the fourth device is a device that does not transmit a COT indication. Also, the first device can know the time domain location where the second transmission is located based on the PSCCH / PSSCH transmitted by the received fourth device.

[0098] For example, if the time interval between the end of the second transmission and the start of the first transmission is small enough, the first device may use Cat1 LBT or Cat2 LBT. For example, if the time interval is less than 16 μs, use Cat1 LBT. For example, if the time interval is equal to 16 μs, use Cat2 16 μs LBT. For example, if the time interval is equal to 25 μs, use Cat2 25 μs LBT.

[0099] In some embodiments, the device may originally use Cat4 LBT for transmission within the COT, and may use Cat1 LBT or Cat2 LBT if the above conditions for using a lower class LBT are met. For transmission within the COT, the device may achieve switching from Cat4 LBT to Cat1 LBT or Cat2 LBT.

[0100] In some embodiments, the first device and the third device are: an RSRP between the first device and the third device is greater than a first threshold; the distance between the first device and the third device is less than a second threshold; the first device is a sender of sidelink information of a third device; the first device is a recipient of sidelink information of the third device; the first device and the third device have the same cast type; or At least one of the following conditions is satisfied: the channel access priority class (CAPC) value of the first device is less than the channel access priority class (CAPC) value of the third device.

[0101] For example, not all previous transmissions are suitable for determining the LBT class. When the first device determines the LBT class based on the previous transmissions of other devices, it may further restrict that the first device and the other devices satisfy at least one condition. For example, in FIG. 8 to FIG. 13, the first device and the third device satisfy at least one of the above conditions.

[0102] In some embodiments, the first device and the fourth device are: The RSRP between the first device and the fourth device is greater than a first threshold; the distance between the first device and the fourth device is less than a second threshold; the first device is a sender of sidelink information of the fourth device; the first device is a receiver of sidelink information of the fourth device; the first device and the fourth device have the same cast type; or At least one of the following conditions is satisfied: the channel access priority class (CAPC) value of the first device is less than the channel access priority class (CAPC) value of the fourth device.

[0103] For example, not all previous transmissions are suitable for determining the LBT class. When the first device determines the LBT class based on the previous transmissions of other devices, it may further restrict that the first device and the other devices satisfy at least one condition. For example, in FIG. 8 to FIG. 13, the first device and the fourth device satisfy at least one of the above conditions.

[0104] In some embodiments, the second transmission and the first transmission are within the same channel occupancy time (COT).

[0105] For example, as shown in Figures 8 to 13, the second transmission and the first transmission are located in the same COT (shared COT and / or initiated COT).

[0106] In some embodiments, the first device monitors the physical sidelink control channel (PSCCH) outside the channel occupation time (COT) more frequently than it monitors the physical sidelink control channel (PSCCH) within the channel occupation time (COT).

[0107] For example, a device needs to monitor the PSCCH to receive data. According to the above method, the device may determine whether a certain monitoring time point is within the COT. The device may use this information to determine the operation of monitoring the PSCCH. Due to the effect of LBT, transmission outside the COT has higher uncertainty, so the device may monitor the PSCCH more frequently outside the COT.

[0108] For example, the device periodically monitors the PSCCH, and the period during which the device monitors the PSCCH outside the COT is smaller than the period during which the device monitors the PSCCH within the COT. For example, in a unit time (one or more slots), the number of times the device monitors the PSCCH outside the COT is H1, and the number of times the device monitors the PSCCH within the COT is H2, where H1>H2.

[0109] In other words, the frequency (or frequency) at which the device monitors the PSCCH outside the COT is greater than the frequency (or frequency) at which the device monitors the PSCCH within the COT. Here, "frequency" refers to the number of times within a unit time, and is different from the "frequency" in "time-frequency resource."

[0110] Although the above describes an embodiment of the present invention from the perspective of a first device, other devices (the second device to the fourth device above) may also perform operations similar to or corresponding to those of the first device.

[0111] For example, the second device performs listen-before-talk (LBT) in the unlicensed frequency band, obtains a channel occupation time (COT) according to the listen-before-talk (LBT), and transmits a COT instruction including information of the channel occupation time (COT).

[0112] In addition, for the sake of convenience in the above description, the device that receives the COT instruction is the first device, and the devices that send the COT instruction are the second device to the fourth device, but the second device to the fourth device in the embodiment of the present invention may be the same device or may be multiple different devices, and the embodiment of the present invention is not limited to this.

[0113] The above-mentioned embodiments are merely illustrative of the present invention, and the present invention is not limited thereto, and appropriate modifications may be made based on the above-mentioned embodiments. For example, each of the above-mentioned embodiments may be used alone, or one or more of the above-mentioned embodiments may be used in combination.

[0114] According to this embodiment, a candidate resource set is determined in the unlicensed frequency band, a transmission resource is selected from the candidate resource set, a listen-before-talk (LBT) class is determined for sidelink transmission, and if the listen-before-talk (LBT) performed based on the LBT class is successful, sidelink information is transmitted in the transmission resource. This allows a device that has performed sidelink communication to efficiently compete for the use of the unlicensed frequency band and to coexist fairly with other devices that use the unlicensed frequency band.

[0115] <Example 2> An embodiment of the present invention provides a sidelink transmission device. The device may be, for example, a terminal device (for example, the above-mentioned first device), or may be one or more elements or components configured in the terminal device. Descriptions of contents similar to those in the first embodiment are omitted.

[0116] 14 is a schematic diagram of an example of a sidelink transmission device according to an embodiment of the present invention. As shown in FIG. 14, a sidelink transmission device 1400 includes the following units:

[0117] A first determining unit 1401 determines a candidate resource set in an unlicensed frequency band.

[0118] A selector 1402 selects a transmission resource from the candidate resource set.

[0119] A second determining unit 1403 determines a listen-before-talk class for the sidelink transmission.

[0120] If the listen-before-talk performed based on the listen-before-talk class is successful, the transmitting unit 1404 transmits the sidelink information using the transmission resource.

[0121] In some embodiments, the second determiner 1403 determines the listen-before-talk class based on whether the sidelink transmission is within a channel occupancy time.

[0122] In some embodiments, if the sidelink transmission is within the channel occupancy time, then it is determined that the listen-before-talk class is a low class or a high class.

[0123] In some embodiments, if the sidelink transmission is outside of the channel occupancy time, then the listen-before-talk class is determined to be a high class.

[0124] In some embodiments, the channel occupancy time is obtained via a COT indication received by the first device.

[0125] In some embodiments, the channel occupancy time is obtained by the first device performing listen-before-talk.

[0126] In some embodiments, the first device obtains the channel occupancy time by performing the listen-before-talk based on a high class of listen-before-talk.

[0127] In some embodiments, as shown in FIG. 14, the sidelink transmission device 1400 further includes the following units:

[0128] The receiver 1405 receives one or more COT indications indicating one or more first channel occupancy times.

[0129] The second determination unit 1403 determines a second channel occupancy time for acquiring the listen-before-talk class based on the one or more first channel occupancy times and / or the channel occupancy time obtained by performing listen-before-talk.

[0130] In some embodiments, the second channel occupancy time for obtaining the listen-before-talk class is indicated by a COT indication sent by the second device. The RSRP between the first device and the second device is greater than a first threshold; the distance between the first device and the second device is less than a second threshold; the first device is a sender of sidelink information of the second device; the first device is a recipient of sidelink information of the second device; the first device and the second device have the same cast type; or At least one of the following conditions is satisfied: the channel access priority class value of the first device is smaller than the channel access priority class value of the second device.

[0131] In some embodiments, the sidelink transmission is a first transmission within a channel occupancy time, and the listen-before-talk class for the first transmission is determined based on a second transmission prior to the first transmission.

[0132] In some embodiments, if the time interval between the first transmission and the second transmission is less than a threshold, the listen-before-talk class is determined to be a low class.

[0133] In some embodiments, if the time interval between the first transmission and the second transmission is greater than or equal to a threshold, the listen-before-talk class is determined to be a high class.

[0134] In some embodiments, the second transmission comprises: a sidelink transmission of the first device; a sidelink transmission of a third device transmitting a COT indication to indicate the channel occupancy time; or and at least one of the sidelink transmissions of a fourth device that does not transmit a COT indication to indicate the channel occupancy time.

[0135] In some embodiments, the first device and the third device are: The RSRP between the first device and the third device is greater than a first threshold; the distance between the first device and the third device is less than a second threshold; the first device is a sender of sidelink information of a third device; the first device is a recipient of sidelink information of the third device; the first device and the third device have the same cast type; or At least one condition is satisfied: the channel access priority class value of the first device is smaller than the channel access priority class value of the third device.

[0136] In some embodiments, the first device and the fourth device are: The RSRP between the first device and the fourth device is greater than a first threshold; the distance between the first device and the fourth device is less than a second threshold; the first device is a sender of sidelink information of the fourth device; the first device is a receiver of sidelink information of the fourth device; the first device and the fourth device have the same cast type; or At least one of the following conditions is satisfied: the channel access priority class value of the first device is smaller than the channel access priority class value of the fourth device.

[0137] In some embodiments, the second transmission and the first transmission are within the same channel occupancy period.

[0138] In some embodiments, the frequency of monitoring the physical sidelink control channel outside the channel occupancy time is greater than the frequency of monitoring the physical sidelink control channel during the channel occupancy time.

[0139] The above-mentioned embodiments are merely illustrative of the present invention, and the present invention is not limited thereto, and appropriate modifications may be made based on the above-mentioned embodiments. For example, each of the above-mentioned embodiments may be used alone, or one or more of the above-mentioned embodiments may be used in combination.

[0140] Although only components or modules related to the present invention have been described above, the present invention is not limited thereto. The sidelink transmission device 1400 may further include other components or modules. For specific contents of these components or modules, reference may be made to the related art.

[0141] Furthermore, for convenience of explanation, Fig. 14 only exemplarily illustrates the connection relationships or signal directions between various components or modules, but it is clear to those skilled in the art that various related technologies such as bus connections can be used. The above-mentioned various components or modules may be implemented by hardware devices such as a processor, a memory, a transmitter, and a receiver, and the present invention is not limited thereto.

[0142] According to this embodiment, a candidate resource set is determined in the unlicensed frequency band, a transmission resource is selected from the candidate resource set, a listen-before-talk (LBT) class is determined for sidelink transmission, and if the listen-before-talk (LBT) performed based on the LBT class is successful, sidelink information is transmitted in the transmission resource. This allows a device that has performed sidelink communication to efficiently compete for the use of the unlicensed frequency band and to coexist fairly with other devices that use the unlicensed frequency band.

[0143] <Example 3> The embodiment of the present invention further provides a communication system, and may refer to FIG. 1. Description of the same contents as those in the first and second embodiments will be omitted.

[0144] In some embodiments, the communication system 100 may include at least a terminal device.

[0145] The terminal device determines a candidate resource set in the unlicensed frequency band, selects a transmission resource from the candidate resource set, determines a listen-before-talk class for sidelink transmission, and transmits sidelink information on the transmission resource if the listen-before-talk performed based on the listen-before-talk class is successful.

[0146] An embodiment of the present invention further provides a network device, which may be, for example, a base station, but the present invention is not limited thereto and may be other network devices.

[0147] FIG. 15 is a schematic diagram of a network device according to an embodiment of the present invention. As shown in FIG. 15, the network device 1500 may include a processor 1510 (e.g., a central processing unit (CPU)) and a memory 1520, which is connected to the processor 1510. The memory 1520 may store various data, and further stores a program 1530 for information processing, and executes the program 1530 under the control of the processor 1510. For example, the processor 1510 may be configured to execute a program to send a message / configuration / information / signaling / instruction to a terminal device so that the terminal device realizes the sidelink transmission method described in the first embodiment.

[0148] Also, as shown in Fig. 15, the network device 1500 may further include a transceiver 1540 and an antenna 1550. The functions of the above members are similar to those of the prior art, and the description thereof will be omitted here. It is not necessary for the network device 1500 to include all the units shown in Fig. 15. Also, the network device 1500 may further include units not shown in Fig. 15, and may refer to the prior art.

[0149] The embodiment of the present invention further provides a terminal device, but the present invention is not limited thereto and may be other devices.

[0150] Fig. 16 is a schematic diagram of a terminal device according to an embodiment of the present invention. As shown in Fig. 16, the terminal device 1600 may include a processor 1610 and a memory 1620, which stores data and programs and is connected to the processor 1610. It should be noted that this diagram is exemplary and other types of structures may be used to supplement or replace this structure to realize communication functions or other functions.

[0151] For example, the processor 1610 may execute a program to realize the sidelink transmission method described in Example 1. For example, the processor 1610 may be configured to execute the steps of determining a candidate resource set in an unlicensed frequency band, selecting a transmission resource from the candidate resource set, determining a listen-before-talk class for sidelink transmission, and transmitting sidelink information on the transmission resource if the listen-before-talk performed based on the listen-before-talk class is successful.

[0152] Also, as shown in Fig. 16, the terminal device 1600 may further include a communication module 1630, an input unit 1640, a display 1650, and a power source 1660. Here, the functions of the above units are similar to those of the prior art, and the description thereof will be omitted here. It is not necessary for the terminal device 1600 to include all the units shown in Fig. 16. Also, the terminal device 1600 may further include units not shown in Fig. 16, and may refer to the prior art.

[0153] In an embodiment of the present invention, there is further provided a computer-readable program, which, when executed in a terminal device, causes the terminal device to execute the sidelink transmission method described in embodiment 1.

[0154] An embodiment of the present invention further provides a storage medium having a computer-readable program stored thereon, the program causing a terminal device to execute the sidelink transmission method described in embodiment 1 when the program is executed.

[0155] The above-mentioned apparatus and method of the present invention may be realized by hardware or by a combination of hardware and software.The present invention relates to a computer readable program which, when executed by a logic unit, causes the logic unit to realize the above-mentioned apparatus or components, or to realize the above-mentioned various methods or steps.The present invention relates to a storage medium for storing the above-mentioned program, such as a hard disk, a magnetic disk, an optical disk, a DVD, a flash memory, etc.

[0156] Each processing method in each device described with reference to the embodiments of the present invention may be implemented by hardware, a software module executed by a processor, or a combination of both. For example, one or more of the functional block diagrams shown in the drawings, or one or more combinations of the functional block diagrams, may correspond to each software module in a computer program flow, or each hardware module. These software modules may correspond to each step shown in the drawings. These hardware modules may be realized by implementing these software modules in hardware, for example, using a field programmable gate array (FPGA).

[0157] The software module may be located in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a mobile hard disk, a CD-ROM, or any other form of storage medium known to those skilled in the art. The storage medium may be connected to the processor so that the processor reads information from the storage medium or writes information to the storage medium, or the storage medium may be a component of the processor. The processor and the storage medium may be located in an ASIC. The software module may be stored in the memory of the mobile terminal, or in a memory card inserted in the mobile terminal. For example, if the device (e.g., a mobile terminal) uses a MEGA-SIM card or a large capacity flash memory device with a relatively large capacity, the software module may be stored in the MEGA-SIM card or the large capacity flash memory device.

[0158] One or more of the functional blocks and / or one or more combinations of functional blocks in the functional block diagrams illustrated in the drawings may be implemented with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or any suitable combination thereof to perform the functions described herein. One or more of the functional blocks and / or one or more combinations of functional blocks in the functional block diagrams illustrated in the drawings may be implemented with, for example, a combination of computing devices, such as a combination of a DSP and a microprocessor, a combination of multiple microprocessors, one or more microprocessors in combination with a DSP communication, or any other configuration.

[0159] Although the present invention has been described above with reference to specific embodiments, the above description is merely illustrative and does not limit the scope of protection of the present invention. Various modifications and changes may be made to the present invention without departing from the spirit and principles of the present invention, and these modifications and changes are also within the scope of the present invention.

[0160] Furthermore, the following supplementary notes are disclosed regarding the embodiments including the above-mentioned examples. (Appendix 1) 1. A sidelink transmission method, comprising: determining, by a first device, a candidate resource set in an unlicensed frequency band; selecting a transmission resource from the candidate resource set; determining a listen-before-talk (LBT) class for a sidelink transmission; and transmitting sidelink information on the transmission resource if the listen-before-talk (LBT) performed based on the LBT class is successful. (Appendix 2) The method of claim 1, wherein the second decision unit decides the LBT class based on whether the sidelink transmission is within a channel occupation time (COT). (Appendix 3) 3. The method of claim 2, further comprising determining that the LBT class is a low class or a high class if the sidelink transmission is within the channel occupation time (COT). (Appendix 4) 4. The method of claim 2 or 3, wherein if the sidelink transmission is outside the channel occupation time (COT), then determining that the LBT class is a high class. (Appendix 5) 5. The method of claim 2, wherein the channel occupation time (COT) is obtained via a COT indication received by the first device. (Appendix 6) 5. The method of claim 2, wherein the channel occupation time (COT) is obtained by the first device performing listen-before-talk (LBT). (Appendix 7) 7. The method of claim 6, wherein the first device obtains the channel occupation time (COT) by performing the listen-before-talk (LBT) based on a high class LBT. (Appendix 8) receiving one or more channel occupancy times (COT) indications indicative of one or more first COTs; A method according to any one of appendices 2 to 7, further comprising determining a second channel occupation time (COT) for obtaining the LBT class based on the one or more first channel occupation times (COT) and / or a channel occupation time (COT) obtained by performing a listen-before-talk (LBT). (Appendix 9) a second channel occupation time (COT) for obtaining the LBT class is indicated by a COT indication sent by the second device; The first device and the second device are an RSRP between the first device and the second device is greater than a first threshold; the distance between the first device and the second device is less than a second threshold; the first device is a sender of sidelink information of the second device; the first device is a recipient of sidelink information of the second device; the first device and the second device have the same cast type; or 9. The method of claim 8, wherein at least one condition is satisfied: the channel access priority class (CAPC) value of the first device is less than the channel access priority class (CAPC) value of the second device. (Appendix 10) the sidelink transmission being a first transmission within a channel occupation time (COT); 2. The method of claim 1, further comprising determining the LBT class for a first transmission based on a second transmission prior to the first transmission. (Appendix 11) 11. The method of claim 10, further comprising determining that the LBT class is a low class if the time interval between the first transmission and the second transmission is less than a threshold. (Appendix 12) 12. The method of claim 10 or 11, further comprising determining that the LBT class is a high class if the time interval between the first transmission and the second transmission is greater than or equal to a threshold. (Appendix 13) The second transmission comprises: a sidelink transmission of the first device; a sidelink transmission of a third device transmitting a channel occupation time (COT) indication to indicate the COT; or 13. The method of any of claims 10 to 12, comprising at least one of the sidelink transmissions of a fourth device not transmitting a channel occupation time (COT) indication to indicate the COT. (Appendix 14) The first device and the third device are an RSRP between the first device and the third device is greater than a first threshold; the distance between the first device and the third device is less than a second threshold; the first device is a sender of sidelink information of the third device; the first device is a receiver of sidelink information of the third device; the first device and the third device have the same cast type; or 14. The method of claim 13, wherein at least one condition is satisfied: the channel access priority class (CAPC) value of the first device is less than the channel access priority class (CAPC) value of the third device. (Appendix 15) The first device and the fourth device are an RSRP between the first device and the fourth device is greater than a first threshold; the distance between the first device and the fourth device is less than a second threshold; the first device is a sender of sidelink information of the fourth device; the first device is a recipient of sidelink information of the fourth device; the first device and the fourth device have the same cast type; or 14. The method of claim 13, wherein at least one condition is satisfied: the channel access priority class (CAPC) value of the first device is less than the channel access priority class (CAPC) value of the fourth device. (Appendix 16) 16. The method of any of claims 10 to 15, wherein the second transmission and the first transmission are within the same channel occupancy time (COT). (Appendix 17) 17. The method of claim 1, wherein the frequency of monitoring the physical sidelink control channel (PSCCH) outside the channel occupation time (COT) is greater than the frequency of monitoring the physical sidelink control channel (PSCCH) within the channel occupation time (COT). (Appendix 18) 1. A sidelink transmission method, comprising: A first device acquiring a channel occupancy time (COT) in an unlicensed frequency band; and the first device monitoring a physical sidelink control channel (PSCCH); A method of claim 1, wherein a frequency of monitoring a physical sidelink control channel (PSCCH) outside the channel occupation time (COT) is greater than a frequency of monitoring a physical sidelink control channel (PSCCH) within the channel occupation time (COT). (Appendix 19) 20. The method of claim 18, wherein the channel occupation time (COT) is obtained via a COT indication received by the first device. (Appendix 20) 19. The method of claim 18, wherein the channel occupation time (COT) is obtained by the first device performing listen-before-talk (LBT). (Appendix 21) A terminal device including a memory in which a computer program is stored and a processor, the processor being configured to execute the computer program to realize a sidelink transmission method according to any one of Supplementary Notes 1 to 20.

Claims

1. A sidelink transmission device, a first determiner for determining a candidate resource set in an unlicensed frequency band; a selection unit for selecting a transmission resource from the candidate resource set; a second determiner configured to determine a listen-before-talk class for a sidelink transmission; and a transmitter configured to transmit sidelink information on the transmission resource if the listen-before-talk performed based on the listen-before-talk class is successful.

2. The apparatus of claim 1 , wherein the second determiner is configured to determine the listen-before-talk class based on whether the sidelink transmission is within a channel occupancy time.

3. 3. The apparatus of claim 2, further comprising: determining, if the sidelink transmission is within the channel occupancy time, that the listen-before-talk class is a low class or a high class.

4. The apparatus of claim 2 , further comprising: determining that the listen-before-talk class is a high class if the sidelink transmission is outside the channel occupancy time.

5. The apparatus of claim 2 , wherein the channel occupancy time is obtained via a COT indication received by the first device.

6. The apparatus of claim 2 , wherein the channel occupancy time is obtained by the first device performing listen-before-talk.

7. The apparatus of claim 6 , wherein the first device obtains the channel occupancy time by performing the listen-before-talk based on a high class of listen-before-talk.

8. a receiver for receiving one or more COT indications indicative of the one or more first channel occupancy times; The device according to claim 2, wherein the second determination unit determines a second channel occupancy time for acquiring the listen-before-talk class based on the one or more first channel occupancy times and / or a channel occupancy time obtained by performing listen-before-talk.

9. a second channel occupancy time for acquiring the listen-before-talk class is indicated by a COT indication sent by a second device; The first device and the second device are a reference signal received power between the first device and the second device is greater than a first threshold; the distance between the first device and the second device is less than a second threshold; the first device is a sender of sidelink information of the second device; the first device is a recipient of sidelink information of the second device; the first device and the second device have the same cast type; or The apparatus of claim 8 , wherein at least one of the conditions is satisfied: a channel access priority class value of the first device is less than a channel access priority class value of the second device.

10. the sidelink transmission being a first transmission during a channel occupancy time; The apparatus of claim 1 , further comprising: determining the listen-before-talk class for the first transmission based on a second transmission that precedes the first transmission.

11. The apparatus of claim 10 , further comprising: determining that the listen-before-talk class is a low class if the time interval between the first transmission and the second transmission is less than a threshold.

12. The apparatus of claim 10 , further comprising: determining that the listen-before-talk class is a high class if the time interval between the first transmission and the second transmission is greater than or equal to a threshold.

13. The second transmission comprises: a sidelink transmission of the first device; a sidelink transmission of a third device transmitting a COT indication to indicate the channel occupancy time; or 11. The apparatus of claim 10, further comprising at least one of a fourth device sidelink transmission not transmitting a COT indication to indicate the channel occupancy time.

14. The first device and the third device are a reference signal received power between the first device and the third device is greater than a first threshold; the distance between the first device and the third device is less than a second threshold; the first device is a sender of sidelink information of the third device; the first device is a recipient of sidelink information of the third device; the first device and the third device have the same cast type; or The apparatus of claim 13 , wherein at least one of the conditions is satisfied: a channel access priority class value of the first device is less than a channel access priority class value of the third device.

15. The first device and the fourth device are a reference signal received power between the first device and the fourth device is greater than a first threshold; a distance between the first device and the fourth device is less than a second threshold; the first device is a sender of sidelink information of the fourth device; the first device is a recipient of sidelink information of the fourth device; the first device and the fourth device have the same cast type; or The apparatus of claim 13 , wherein at least one of the conditions is satisfied: a channel access priority class value of the first device is less than a channel access priority class value of the fourth device.

16. The apparatus of claim 10 , wherein the second transmission and the first transmission are within the same channel occupancy time.

17. 2. The apparatus of claim 1, wherein the frequency of monitoring the physical sidelink control channel outside a channel occupancy time is greater than the frequency of monitoring the physical sidelink control channel during the channel occupancy time.

18. 1. A sidelink transmission method, comprising: determining, by a first device, a candidate resource set in an unlicensed frequency band; selecting a transmission resource from the candidate resource set; determining a listen-before-talk class for a sidelink transmission; and transmitting sidelink information on the transmission resource if the listen-before-talk performed based on the listen-before-talk class is successful.

19. determining the listen-before-talk class based on whether the sidelink transmission is within a channel occupancy time; or 20. The method of claim 18, wherein the sidelink transmission is a first transmission within a channel occupancy time, and the first device determines the listen-before-talk class for the first transmission based on a second transmission that precedes the first transmission.

20. 1. A communication system comprising: a terminal device configured to determine a candidate resource set in an unlicensed frequency band, select a transmission resource from the candidate resource set, determine a listen-before-talk class for a sidelink transmission, and transmit sidelink information on the transmission resource if listen-before-talk performed based on the listen-before-talk class is successful.

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