Sidelink communication method and apparatus

Abstract

The present application provides a sidelink communication method and apparatus, including: performing, by a terminal device, channel monitoring on a shared spectrum; and, if a result of the channel monitoring is that the channel is idle, starting, by the terminal device, transmission of a first sidelink channel at a first time-domain location, the first time-domain location being one or more of a time-domain location indicated by first indication information and a time-domain location determined based on a first time unit, the first time unit being smaller than one slot.

Description

[Technical Field]

[0001] The present application relates to the technical field of communications, and more particularly to a sidelink communication method and apparatus. [Background technology]

[0002] During sidelink communication in a shared spectrum, a terminal device performs channel monitoring through a mechanism such as Listen Before Talk (LBT). If the channel monitoring is successful, the terminal device acquires channel resources and performs sidelink transmission at a channel access position. In the art, the channel access process of the terminal device causes a waste of channel resources. Summary of the Invention [Problem to be solved by the invention]

[0003] The present application provides a sidelink communication method and apparatus, thereby helping to reduce resource waste in sidelink communication. [Means for solving the problem]

[0004] According to a first aspect, there is provided a sidelink communication method, the method comprising: performing, by a terminal device, channel monitoring on a shared spectrum; and, if a result of the channel monitoring is that the channel is idle, starting, by the terminal device, transmission of a first sidelink channel at a first time-domain location, the first time-domain location being one or more of a time-domain location indicated by first indication information and a time-domain location determined based on a first time unit, the first time unit being smaller than one slot.

[0005] According to a second aspect, there is provided a sidelink communication method, the method comprising: performing, by a terminal device, channel access on first resources of a shared spectrum, the first resources being associated with second resources in a resource pool; and transmitting, by the terminal device, a first sidelink channel on the second resources.

[0006] According to a third aspect, there is provided a sidelink communications apparatus, the apparatus being a terminal device, comprising: a monitoring unit configured to perform channel monitoring on a shared spectrum; and a transmitting unit configured to start transmitting a first sidelink channel at a first time-domain location if a result of the channel monitoring is that the channel is idle, the first time-domain location being one or more of a time-domain location indicated by a first indication information and a time-domain location determined based on a first time unit, the first time unit being smaller than one slot.

[0007] According to a fourth aspect, there is provided a sidelink communications apparatus, the apparatus being a terminal device, comprising: an access unit configured to perform channel access on first resources of a shared spectrum, the first resources being associated with second resources in a resource pool; and a transmitting unit configured to transmit a first sidelink channel on the second resources.

[0008] According to a fifth aspect, there is provided a communications apparatus, the apparatus comprising a memory and a processor, the memory configured to store a program, and the processor configured to invoke the program in the memory to perform the method according to the first aspect.

[0009] According to a sixth aspect, there is provided an apparatus, the apparatus including a processor configured to invoke a program from a memory to perform a method according to the first aspect.

[0010] According to a seventh aspect, there is provided a chip, the chip including a processor configured to call a program from a memory to cause a device in which the chip is installed to perform a method according to the first aspect.

[0011] According to an eighth aspect, there is provided a computer-readable storage medium, the computer-readable storage medium storing a program for causing a computer to perform the method according to the first aspect.

[0012] According to a ninth aspect, there is provided a computer program product, the computer program product comprising a program for causing a computer to perform the method according to the first aspect.

[0013] According to a tenth aspect, there is provided a computer program causing a computer to carry out a method according to the first aspect.

[0014] In an embodiment of the present application, after the terminal device has successfully performed channel monitoring, a first time-domain location for the terminal device to perform sidelink transmission is designated, or the first time-domain location is determined based on a time unit smaller than a slot. After successful monitoring, the terminal device does not need to wait for the next slot to perform sidelink transmission, which helps reduce the waste of channel resources. [Brief explanation of the drawings]

[0015] [Figure 1] 1 illustrates a wireless communication system to which an embodiment of the present application is applied; [Figure 2] FIG. 1 is an exemplary diagram of NR-V2X communication. [Figure 3] FIG. 1 is a schematic diagram of a full-slot channel access mode. [Figure 4] 1 is a schematic diagram of three channel access modes in NR-U. [Figure 5] 1 is a schematic diagram of resource conflicts occurring in channel access; [Figure 6] 1 is a schematic flowchart of a sidelink communication method according to an embodiment of the present application; [Figure 7] 1 is a schematic diagram of a designated position channel access method according to an embodiment of the present application; [Figure 8] FIG. 2 is a schematic diagram of a half-slot channel access method according to an embodiment of the present application; [Figure 9] FIG. 2 is a schematic diagram of a more sophisticated channel access method according to an embodiment of the present application; [Figure 10] 1 is a schematic flowchart of another sidelink communication method according to an embodiment of the present application; [Figure 11] 2 is a schematic diagram of an association between a first resource and a second resource according to an embodiment of the present application; [Figure 12] FIG. 2 is a schematic diagram of another association between a first resource and a second resource according to an embodiment of the present application; [Figure 13] 1 is a schematic block diagram of a communication device according to an embodiment of the present application; [Figure 14] FIG. 2 is a schematic block diagram of another communication device according to an embodiment of the present application; [Figure 15] 1 is a schematic structural diagram of a communication device according to an embodiment of the present application; DETAILED DESCRIPTION OF THE INVENTION

[0016] The technical solutions in this application are described below with reference to the accompanying drawings. For ease of understanding, the terms and communication processes involved in this application will be first described below with reference to Figures 1 to 5.

[0017] 1 is an example diagram of a system architecture of a wireless communication system 100 to which embodiments of the present application are applicable. The wireless communication system 100 may include a network device 110 and terminal devices 121-129. The network device 110 may provide communication coverage to a particular geographic area and may communicate with terminals within the coverage area.

[0018] In some implementations, terminal devices may communicate with each other through a sidelink (SL), which may also be referred to as proximity services (ProSe) communication, unidirectional communication, side link communication, device-to-device (D2D) communication, etc.

[0019] In other words, sidelink data is transmitted between terminal devices via a sidelink. The sidelink data may include data and / or control signaling. In some implementations, the sidelink data may be, for example, a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Shared Channel (PSSCH), a PSCCH Demodulation Reference Signal (DMRS), a PSSCH DMRS, or a Physical Sidelink Feedback Channel (PSFCH).

[0020] Some common sidelink communication scenarios are described below with reference to Fig. 1. Depending on whether the terminal devices in the sidelink are within the coverage of the network device, sidelink communication can include three scenarios: In scenario 1, the terminal devices perform sidelink communication within the coverage of the network device; in scenario 2, some of the terminal devices perform sidelink communication within the coverage of the network device; and in scenario 3, the terminal devices perform sidelink communication outside the coverage of the network device.

[0021] 1, in scenario 1, terminal devices 121 and 122 can communicate with each other via a sidelink, and both terminal devices 121 and 122 are within the coverage of network device 110, or in other words, both terminal devices 121 and 122 are within the coverage of the same network device 110. In this scenario, network device 110 may send configuration signaling to terminal devices 121 and 122, and thus, terminal devices 121 and 122 communicate with each other via a sidelink based on the configuration signaling.

[0022] 1 , in scenario 2, terminal devices 123 and 124 can communicate with each other over the sidelink, where terminal device 123 is within the coverage of network device 110, but terminal device 124 is outside the coverage of network device 110. In this scenario, terminal device 123 receives configuration information from network device 110 and communicates over the sidelink based on the configuration in the configuration signaling. However, because terminal device 124 is outside the coverage of network device 110, terminal device 124 cannot receive configuration information from network device 110. In this case, terminal device 124 only needs to obtain a configuration for sidelink communication based on preconfigured configuration information and / or configuration information sent by in-coverage terminal device 123, and thereby communicates with terminal device 123 over the sidelink based on the obtained configuration.

[0023] In some cases, the terminal device 123 may send configuration information to the terminal device 124 over a physical sidelink broadcast channel (PSBCH) to configure the terminal device 124 to communicate via the sidelink.

[0024] 1, in scenario 3, all of the terminal devices 125-129 are outside the coverage of the network device 110 and cannot communicate with the network device 110. In this case, all of the terminal devices may perform sidelink communication based on pre-configured information.

[0025] In some cases, terminal devices 127-129 outside the coverage of a network device may form a communication cluster, and the terminal devices 127-129 in the communication cluster can communicate with each other. Furthermore, the terminal device 127 in the communication cluster may act as a central control node, also called a cluster header (CH). Accordingly, the other terminal devices in the communication cluster may be called "cluster members."

[0026] The terminal device 127 as a CH may have one or more of the following functions: being responsible for establishing communication clusters, joining and leaving cluster members, resource coordination, allocating sidelink transmission resources to cluster members and receiving sidelink feedback information from cluster members, resource coordination with other communication clusters, and other functions.

[0027] 1 exemplarily illustrates a network device and multiple terminal devices. Optionally, the wireless communication system 100 may include multiple network devices, and a different number of terminal devices may be included in the coverage of each network device, which is not limited in this embodiment of the present application.

[0028] Optionally, the wireless communication system 100 may further include other network entities, such as a network controller and a mobility management entity, which are not limited in this embodiment of the present application.

[0029] It should be understood that the technical solutions in the embodiments of the present application can be applied to various communication systems, such as fifth-generation (5G) systems or new radio (NR) systems, long-term evolution (LTE) systems, LTE frequency division duplex (FDD) systems, and LTE time division duplex (TDD) systems. The technical solutions provided in the present application can also be applied to future communication systems, such as sixth-generation mobile communication systems and satellite communication systems.

[0030] A terminal device in an embodiment of the present application may also be referred to as a user equipment (UE), an access terminal, a subscriber unit, a subscriber station, a mobile, a mobile station (MS), a mobile terminal (MT), a remote station, a remote terminal, a mobile device, a user terminal, a wireless communication device, a user agent, or a user equipment. A terminal device in an embodiment of the present application may be a device capable of providing voice and / or data connectivity to a user and connecting people, objects, and machines, such as handheld or in-vehicle devices, with wireless connectivity capabilities. A terminal device in an embodiment of the present application may be a mobile phone, a tablet computer (pad), a notebook computer, a palmtop computer, a mobile internet device (MID), a wearable device, a vehicle, a wireless terminal in industrial control, a wireless terminal in autonomous driving, a wireless terminal in remote surgery, a wireless terminal in smart grids, a wireless terminal in transportation safety, a wireless terminal in smart cities, a wireless terminal in smart homes, etc. Optionally, a terminal device may be used to act as a base station. For example, a terminal device may act as a scheduling entity, providing sidelink signals between terminal devices, such as in vehicle-to-everything (V2X) or vehicle-to-road (D2D) communications. For example, cellular phones and cars communicate with each other using sidelink data, and cellular phones and smart home devices communicate with each other without relaying communication signals through a base station.

[0031] A network device in an embodiment of the present application may be a device for communicating with a terminal device. The network device may also be referred to as an access network device or a wireless access network device. For example, the network device may be a base station. The network device in an embodiment of the present application may be a radio access network (RAN) node (or device) that connects a terminal device to a wireless network. A base station may broadly cover various names, such as a Node B, an evolved Node B (eNB), a next-generation Node B (gNB), a relay station, a transmit / receive point (TRP), a transmission point (TP), an access point (AP), a master eNB MeNB, a secondary eNB SeNB, a multi-standard radio (MSR) node, a home base station, a network controller, an access node, a radio node, a transmitting node, a transceiver node, a baseband unit (BBU), a remote radio unit (RRU), an active antenna unit (AAU), a remote radio head (RRH), a central unit (CU), a distributed unit (DU), and a positioning node, and may be interchangeable with these names. A base station may be a macro base station, a micro base station, a relay node, a donor node, or a combination thereof. Alternatively, the base station may be a communication module, a modem, or a chip disposed in the above-mentioned device or apparatus. Alternatively, the base station may be a mobile switching center, a device assuming the function of a base station in D2D, V2X, and machine-to-machine (M2M) communications, a network-side device in a 6G network, a device assuming the function of a base station in a future communication system, etc. The base station may support networks of the same or different access technologies. The specific technology used by the network device and the specific device type are not limited in the embodiments of the present application.

[0032] The base station may be fixed or mobile. For example, a helicopter or a drone may be configured to act as a mobile base station, and one or more cells may move according to the location of the mobile base station. In another example, a helicopter or a drone may be configured to act as a device that communicates with another base station.

[0033] In some deployments, the network device in the embodiments of the present application may be a CU or a DU, or the network device includes a CU and a DU. The gNB may further include an AAU.

[0034] The network device and the terminal device may be deployed on land, including indoors or outdoors, may be handheld or vehicle-mounted, may be deployed on water, or may be deployed on airplanes, balloons, and satellites in the sky. In the embodiment of the present application, the scenario in which the network device and the terminal device are placed is not limited.

[0035] It should be understood that all or part of the functionality of the communication device in this application may be implemented by software functions running on hardware or by virtualization functions instantiated on a platform (such as a cloud platform).

[0036] With the development of sidelink communication technology, the sidelink communication technology relates to information exchange between various terminal devices. Taking the V2X communication system 200 shown in Figure 2 as an example, vehicle-to-vehicle (V2V) communication between terminal device 201 and terminal device 202 relates to information exchange between the vehicles themselves. Vehicle-to-Infrastructure (V2I) communication, vehicle-to-network (V2N) communication, and vehicle-to-pedestrian (V2P) communication between terminal device 201 and terminal devices 203-205 respectively relate to information exchange between vehicles and external systems.

[0037] Communications spectrum for sidelink The spectrum used by communication systems includes licensed spectrum and unlicensed spectrum. An important direction for the expansion of communication systems into different fields is the use of unlicensed spectrum. For example, NR deployed on unlicensed spectrum is called NR-U.

[0038] Currently, sidelink mainly uses licensed spectrum. Sidelink may also use unlicensed spectrum. Sidelink deployed on unlicensed spectrum may be referred to as SL-U.

[0039] Compared to licensed spectrum, unlicensed spectrum is characterized by sharing without a license. Therefore, unlicensed spectrum is also called shared spectrum. For operators, spectrum sharing facilitates spectrum aggregation in a timely manner to dynamically support high-bandwidth services. Spectrum sharing can also extend the benefits of communication technologies (e.g., NR) to operating entities that may not have access to licensed spectrum.

[0040] Shared spectrum must allow for the coexistence of various radio access technology (RAT) systems, typically Wireless Fidelity (WiFi) systems and LTE-based Licensed Assisted Access (LAA) systems. The various systems use frequency bands in the unlicensed spectrum in a spectrum contention manner with principles of channel access fairness and multi-RAT coexistence.

[0041] In a shared spectrum, each RAT system must communicate under the constraints of unlicensed spectrum regulatory rules. The regulatory rules include power and power spectral density levels, maximum channel occupancy time (COT), channel occupied bandwidth, and channel monitoring mechanisms. Within the same frequency band, each system must reasonably occupy and release channels to meet the requirements of the regulatory rules and avoid causing interference with other RAT systems within the same frequency band.

[0042] For shared spectrum use, RAT systems may utilize mandatory channel monitoring techniques (e.g., LBT) to access the network. In other words, data can be transmitted only when the current channel is detected as unoccupied. For example, a sidelink terminal device may initiate LBT, which may be Category 1 (Cat 1) LBT or Category 2 (Cat 2) LBT.

[0043] After obtaining the channel resource through LBT, the terminal device transmits data according to the above-mentioned restriction rules. For example, the COT limit must be satisfied when the terminal device transmits data through the channel resource. In other words, continuous data transmission should be limited within the COT time, and if this time is exceeded, the terminal device needs to release the channel and perform LBT again.

[0044] Resource allocation method for sidelink The resource allocation method may be determined based on the service type of the terminal device. There are mainly two types of sidelink terminal device services: scheduled and non-scheduled. For scheduled services, the sidelink data of the terminal device is generally periodic. For example, in NR V2X road safety services, part of the sidelink data is periodic traffic that may arrive at predictable times. For non-scheduled services, data arrival is random, and the size of the data packets is variable.

[0045] In some communication systems (e.g., NR), two resource configuration modes for sidelink resources are defined: Mode 1 and Mode 2.

[0046] In Mode 1, the network device schedules sidelink resources for the terminal device.

[0047] Currently, Mode 1 can have two possible schemes: dynamic resource configuration and sidelink configuration grant. In dynamic resource configuration, the network device may send downlink control information (DCI) to allocate sidelink transmission resources to the terminal device. In the sidelink configuration grant scheme, after the terminal device is configured with sidelink resources, if the terminal device has data to transmit, it can use the configured sidelink resources to transmit the data and does not need to request additional sidelink resources from the network device. For scheduled services, the network device generally allocates semi-static transmission resources to the terminal device. The network device schedules transmission resources for the terminal device on the direct link, which can effectively avoid resource collisions and solve the hidden node problem.

[0048] For example, referring to FIG. 1, terminal devices 121-123 are within the coverage of network device 110, and network device 110 may allocate sidelink resources to terminal devices 121-123.

[0049] In Mode 2, the terminal device independently selects the sidelink resources in the sidelink resource pool.

[0050] A distributed resource scheduling mechanism is used in this mode. The sidelink resource pool may be configured or pre-configured by the network device. In some embodiments, the network device may configure the sidelink resource pool for the terminal devices through higher layer signaling. The terminal devices independently select time-frequency resources from the resource pool configured or pre-configured by the network device, relying on resource monitoring or random selection. For example, the terminal devices 124-129 in FIG. 1 are outside the coverage of the network device 110, and each of the terminal devices 124-129 may independently select sidelink resources from the resource pool configured by the network device.

[0051] For periodic services, the sidelink may reserve (or reserve) sidelink communication resources for a terminal device at the expected data arrival time to avoid resource contention with other terminal devices. For example, a sidelink terminal device may support resource reservation for periodic services by indicating a reservation period in the sidelink control information (SCI).

[0052] In Mode 2, for services with obvious periodic characteristics, the terminal device may implement a resource allocation mechanism that combines channel sensing and semi-persistent scheduling (SPS). This mechanism can fully utilize the periodic characteristics of the services. The transmitter side reserves periodic transmission resources for the periodic services to be transmitted, which helps the receiver side to implement resource status sensing and collision avoidance, thereby improving resource utilization and transmission reliability.

[0053] For non-scheduled services, the terminal device implements a resource allocation mechanism that combines sensing and single transmission. Since it is impossible to predict and reserve future resource occupancy, there is a relatively high probability of resource collisions.

[0054] The channel sensing process of a terminal device includes a resource sensing process and / or a resource selection process. Resource sensing may also be referred to as resource monitoring or resource probing. Terminal devices perform resource sensing and selection based on a dedicated sidelink resource pool, which can mitigate or avoid possible resource conflicts between terminal devices. For example, a terminal device may use sensing to select a sidelink transmission resource from the resource pool.

[0055] In the resource detection process, the terminal device may identify the occupancy (or reservation) of sidelink resources by demodulating the SCI, i.e., the terminal device can obtain resource reservation information of other terminal devices by demodulating the SCI. Alternatively, the terminal device may identify the occupancy of sidelink resources by measuring the received power of the sidelink.

[0056] After a transmission resource reserved by a terminal device for a periodic service is reserved, all other terminal devices that receive the reservation message avoid selecting and transmitting on the reserved resource. In some embodiments, the terminal device may select a resource from the resource pool that is not reserved by other terminal devices or that is reserved by other terminal devices but has a relatively low received power, thereby reducing the resource collision probability and improving communication reliability.

[0057] The Mode 2 resource allocation mechanism works well in licensed or dedicated spectrum (frequency ranges), however, in unlicensed spectrum the Mode 2 resource allocation mechanism has some limitations.

[0058] When the resource allocation method of Mode 2 is applied to SL-U, the uncertainty of channel monitoring needs to be taken into account. Due to the dependency on channel monitoring results, the sidelink has difficulty reserving resources at a specific time. Currently, the sidelink reserves a time window in the unlicensed channel. The time window may consist of a group of slots. These slots occur periodically. The time window starts some time before the expected data arrival time to avoid possible channel monitoring failures. The resources reserved during the time window may be a set of time- and frequency-interleaved resource blocks (RBs). These resource blocks may be used as the resources required for channel access.

[0059] Furthermore, many devices of other types of RATs, such as WiFi devices, LAA devices, enhanced license-assisted access (eLAA) devices, and NR-U devices, already exist in the unlicensed spectrum. The channel resources required for the sidelink can be occupied not only by sidelink terminal devices, but also by devices of other types of RATs. The legacy Mode 2 process cannot identify and resolve resource conflicts caused by non-sidelink terminal devices, which may cause channel monitoring failures of sidelink terminal devices.

[0060] Furthermore, resource reservation for a sidelink terminal device is invalid for devices of other types of RATs. These devices cannot monitor reservation messages sent by the sidelink terminal device, nor can they receive and understand the resource reservation information in the SCI. These devices attempt to occupy channels that overlap with the reserved resources and constantly perform clear channel assessment (CCA) on the reserved resources. For other terminal devices subject to reservation, the chance of successful CCA is lower, and the efficiency of legacy Mode 2 usage by SL-U decreases. Therefore, Mode 2 resource selection is more useful when there are no legacy devices nearby.

[0061] When a sidelink terminal device operates within the network coverage, nearby terminal devices also do not listen to reservation messages. To reduce resource reservation collisions, the sidelink terminal device may forward a reservation signal to the network device, which may avoid scheduling uplink transmissions on the reserved resources.

[0062] In Mode 2, the terminal device performs a resource selection procedure to determine the transmission resources for the corresponding PSCCH / PSSCH and PSFCH. In unlicensed spectrum, the terminal device typically initiates resource selection only after successful channel monitoring. Unlike NR-U, the sidelink terminal device must be able to perform multi-channel access independently, rather than scheduled or directed.

[0063] Channel Access for Sidelink After the terminal device detects that the channel is idle through a channel monitoring mechanism such as LBT, the terminal device performs channel access on the idle resource to transmit data. Therefore, the monitoring and avoidance mechanism such as LBT is also called a channel access mechanism.

[0064] In some protocols (R16 / R17), sidelink-capable terminal devices perform channel access on a slot-by-slot basis, which is full-slot channel access. The duration of a slot is related to the subcarrier spacing. Some communication systems (e.g., NR) can support multiple subcarrier spacings, and the structure of the radio frame varies slightly depending on the subcarrier spacing. The duration of the radio frame and the duration of the subframe do not change with the subcarrier spacing. The duration of a radio frame is always 10 ms, and the duration of a subframe is always 1 ms.

[0065] A subframe consists of one or more slots, and the duration of a slot is related to the subcarrier spacing. For example, when the subcarrier spacing is 15 kHz, the duration of one slot is 1 ms, which is the same as the duration of a subframe. When the subcarrier spacing is 30 kHz, the duration of one slot is 0.5 ms, and two slots form a subframe. However, the number of symbols in a slot does not change with the subcarrier spacing; only the configuration type of the slot changes. Typically, one slot contains 14 symbols.

[0066] In channel access based on a full slot containing 14 symbols, a terminal device uses every 14th symbol as a transmission start point based on a synchronization point. The transmission start point may also be referred to as a channel access position. Thus, regardless of when the terminal device performs channel monitoring, after successful monitoring, the terminal device needs to wait for the next transmission start point to perform channel access. In other words, after successful channel monitoring, the terminal device needs to wait for the next slot to perform data transmission.

[0067] With reference to FIG. 3, the full slotted channel access mode will be described below using an example in which a terminal device transmits a PSCCH / PSSCH through an LBT.

[0068] Referring to Figure 3, the terminal device completes the LBT in the early stage of slot 310. In full-slot channel access mode, the terminal device needs to wait for slot 320 to transmit the PSCCH / PSSCH. As shown in Figure 3, the transmission start point is at the start of slot 320. In slot 320, the first symbol is used as an automatic gain control (AGC) symbol, and data for the AGC symbol is generally not used for data demodulation. The last symbol is a guard gap (GAP) symbol. The PSCCH / PSSCH is between the AGC and GAP. In the sidelink, a slot basically carries neither uplink nor downlink symbols.

[0069] Compared with slot 320, only a few symbols in slot 310 are used for the terminal device's LBT. The terminal device cannot use the symbols between the LBT and the start of transmission in slot 310. Therefore, resources in multiple symbols in slot 310 are wasted.

[0070] 3, after completing the LBT in slot 310, the terminal device performs data transmission in slot 320. Because channel availability in a shared spectrum cannot always be guaranteed, the terminal device needs to perform CCA before data transmission, and data transmission is performed only when the channel is guaranteed to be idle. For example, the terminal device may measure channel energy in the LBT bandwidth (BW) based on a 20 MHz RB set.

[0071] In unlicensed spectrum, channel access prior to data transmission includes multiple channel access modes. The channel access process prior to data transmission is described below with reference to the three channel access modes of NR-U in Figure 4. Referring to Figure 4, both Type 2A and Type 2B channel access processes have a channel sensing gap, while Type 2C does not require channel sensing.

[0072] Taking the Type 2A channel access in FIG. 4 as an example, after the terminal device detects that the channel (medium) is idle based on an appropriate energy detection threshold, there is a delay period before SL transmission. The delay period for Type 2A in FIG. 4 is 25 μs. As shown in FIG. 4, the 25 μs delay period mainly includes a 16 μs delay time and a 9 μs contention slot. The terminal device performs explicit CCA in the contention slot. The delay period can avoid collision with the possible WiFi confirmation time (16 μs) and also allow the terminal device time to prepare.

[0073] In Type 2A channel access, the 9 μs contention slot may be called a short LBT or an additional LBT. The delay period for channel access can be adjusted by setting a specific number of additional LBTs. Therefore, the minimum duration of the delay period for Type 2A is 25 μs.

[0074] During channel access based on Type 2A, when the terminal device is ready, it can clear the additional LBT so that it starts transmission immediately. If the terminal device is still not ready after the countdown of the delay period is completed, the channel access will be declared unsuccessful, and the process should be restarted. In some cases, a device from another RAT may complete its LBT and start transmission before the next transmission start point of the SL-U terminal device. The additional LBT allows the SL-U terminal device to detect such an occurrence and delay access. For example, in FIG. 3, when the terminal device clears the additional short-term LBT, if the WiFi node has already cleared its LBT before the transmission start point, the WiFi node will occupy the channel. Therefore, a transmission resource collision occurs, and the SL-U terminal device cannot gain access.

[0075] During channel access in a shared spectrum, the sidelink needs to clear the additional LBT before data transmission, but other systems in the shared spectrum may not need to perform corresponding operations. For example, a WiFi system may start transmitting asynchronously at any time. If the sidelink coexists with WiFi-like systems, a sidelink system with a fixed and possibly sparse transmission start point will greatly waste resources or severely impact system throughput.

[0076] As mentioned above, the current channel access mode for the sidelink is full-slot channel access. During one slot, there may be multiple terminal devices performing channel monitoring. If all of the terminal devices successfully perform monitoring in this slot, they all need to wait for the next slot to perform data transmission. Therefore, multiple terminal devices may cause resource collision at the transmission start point of the next slot.

[0077] Taking the Type 2A channel access process as an example, the resource conflict occurring in channel access will be specifically described below with reference to FIG.

[0078] 5, both terminal device 1 and terminal device 2 perform LBT in slot 510. Terminal device 1 completes LBT in the early stage of slot 510 and needs to wait for slot 520 to transmit PSCCH / PSSCH. While terminal device 1 is waiting, terminal device 2 also completes LBT in the later stage of slot 510. Both terminal devices will transmit PSCCH / PSSCH in slot 520.

[0079] Before the transmission start point shown in Figure 5, both terminal devices use an additional short-term LBT to determine whether the channel is idle. Only after the channel is determined to be idle in the contention slot of the additional LBT can terminal device 1 or terminal device 2 access the channel and perform data transmission.

[0080] As shown in FIG. 5, after terminal device 1 and terminal device 2 complete countdown of the LBT in slot 510, the two terminal devices will encounter resource conflicts in additional LBTs before aligning their transmission start points.

[0081] Both the resource waste shown in Fig. 3 and the resource collision shown in Fig. 5 are caused by slot-by-slot channel access for the sidelink. After successful channel monitoring, the terminal device needs to wait for the next slot to perform channel access, and the waiting time interval is relatively long.

[0082] In view of this, embodiments of the present application provide a sidelink communication method and apparatus. The slot structure of this method provides more flexible channel access locations and shortens the time interval that a terminal device needs to wait after completing channel monitoring, thereby reducing resource waste. A sidelink communication method according to embodiments of the present application is described below with reference to FIG. 6.

[0083] Referring to FIG. 6, in step S610, the terminal device performs channel monitoring on the shared spectrum.

[0084] A terminal device is a device that performs sidelink communication and may be a device that is to transmit data in the sidelink communication.

[0085] A terminal device may perform unicast communication, multicast communication, or broadcast communication with other terminal devices. In some embodiments, a terminal device performing channel monitoring may be a cluster header that initiates multicast or broadcast communication, or may be a cluster member in multicast or broadcast communication. For example, in V2X, a terminal device performing channel monitoring may be a vehicle that performs multicast communication with other vehicles, or may be another vehicle in multicast communication.

[0086] In some embodiments, terminal devices performing channel monitoring may be within the coverage of the network or may be outside the coverage of the network, and terminal devices within the coverage of the network may perform channel monitoring in the shared spectrum based on the configuration of the network devices.

[0087] Channel monitoring may mean that a terminal device monitors multiple channel resources in a shared spectrum or monitors a target channel resource.

[0088] The channel resource may be a resource in a shared spectrum or a COT resource shared by another terminal device in a sidelink. For example, in V2X, a terminal device may perform channel monitoring for COT sharing provided by nearby vehicles.

[0089] In some embodiments, channel monitoring may mean that the terminal device monitors channel resources using an LBT mechanism, or that the terminal device performs monitoring by channel sensing or other means. For example, the terminal device may determine the occupancy of sidelink resources based on the value of the Reference Signal Received Power (RSRP) of the sidelink DMRS.

[0090] The result of the channel monitoring may be that the monitored channel resource is idle or that the monitored channel is occupied. If the result of the channel monitoring is that the channel is occupied, the terminal device may continue to perform channel monitoring until an idle channel is found.

[0091] In step S620, if the result of the channel monitoring is that the channel is idle, the terminal device starts transmitting the first sidelink channel at the first time domain position.

[0092] The first time-domain location may be a transmission start point after channel access of the terminal device, and the terminal device may perform sidelink data transmission at the first time-domain location.

[0093] In some embodiments, the first time-domain location may be a designated time-domain location. The terminal device transmits the first sidelink channel at a designated time-domain location, which is not affected by the transmission start point configuration, making access more flexible. For example, the first time-domain location may be an odd symbol in a slot after time point synchronization or an even symbol in a slot after time point synchronization. As another example, the first time-domain location may be any symbol after channel monitoring is completed.

[0094] FIG. 7 is a schematic diagram of data transmission at a designated position. Referring to FIG. 7, the ninth symbol of slot 710 is the sidelink transmission start point. After completing channel monitoring in the first through fifth symbols of slot 710, the terminal device performs channel access in the ninth symbol of slot 710. In other words, the fourth symbol after completing channel monitoring may be designated as the first time-domain position. As shown in FIG. 7, the terminal device can effectively use resources in slot 710 for data transmission without having to wait for slot 720 for access.

[0095] In some embodiments, the first time-domain location may be indicated based on first indication information. The first indication information may be carried in control signaling. For example, the first indication information may be carried in scheduling indication information of the SCI.

[0096] In some embodiments, the first time-domain location may be a time-domain location determined based on a first time unit, which may be a time unit less than one slot.

[0097] In a possible implementation, the first time unit may be a half slot. After successful channel monitoring in the early stage of the slot, the terminal device may perform sidelink transmission during the half slot, which helps reduce resource waste. This channel access mode may be called half-slot channel access. For example, when a slot includes 14 symbols, half-slot channel access means that every seventh symbol is used as a transmission starting point based on the synchronization point.

[0098] 8 is a schematic diagram of half-slot channel access. Referring to FIG. 8, the half-slot position of slot 820 is the transmission start point. After completing channel monitoring in the last three symbols of slot 810 and the first two symbols of slot 820, the terminal device performs channel access in the half-slot position of slot 820. As shown in FIG. 8, after completing channel monitoring in the second symbol of slot 820, the terminal device does not need to wait for the next slot to perform data transmission.

[0099] The duration of the first time unit in half-slot channel access is related to the subcarrier spacing. For example, when the subcarrier spacing is 30 kHz, the duration of the slot is 0.5 ms and the duration of the first time unit is 0.25 ms.

[0100] In a possible implementation, the first time unit may be one or more symbols. The number of symbols may be any integer less than the total number of symbols in a slot. When the number of symbols is less than a half slot, the time interval that the terminal device waits to transmit data after successful monitoring is relatively short. For example, every third symbol is used as the transmission start point based on the synchronization point.

[0101] When one or more symbols are used as the first time unit, the duration of the first time unit is related to the number of symbols and the duration of each symbol. The duration of each symbol is related to the subcarrier spacing. For example, when the subcarrier spacing is 15 kHz, the duration of each symbol is 66.7 μs.

[0102] In a possible implementation, the first time unit may be one or more microseconds. When the first time unit is multiple microseconds, the terminal device may perform channel access based on a finer time unit. For example, when multiple terminal devices perform data transmission at the same time-domain position, symbols near the time-domain position are divided into multiple microsecond contention slots. In other words, the first time-domain position is set with a granularity of multiple microseconds. Each terminal device may select one of the contention slots as its transmission start point according to a standard or configuration. In principle, when multiple terminal devices plan to perform data transmission at the same time-domain position, the terminal device that completes channel monitoring earlier is allowed to occupy this position. Therefore, it may be specified that the terminal device that completes channel monitoring earlier has priority in selecting the first time-domain position.

[0103] When the first time unit is multiple microseconds, the resource conflict problem can be effectively solved. For ease of understanding, the resource conflict resolution shown in Figure 5 is taken as an example, and a more elaborate channel access mode will be described in detail below with reference to Figure 9.

[0104] 9, consider that the resource collision of FIG. 5 occurs at the intersection of two slots, but the two symbols adjacent to the intersection are split. In other words, the last symbol (#13) of slot 910 and the first symbol (#0) of slot 920 are split into time units 931.

[0105] In the figure, start point 941 is the transmission start point of terminal device 1, and start point 942 is the transmission start point of terminal device 2. Terminal device 1 and terminal device 2 may synchronize the additional LBT shown in FIG. 5 to their respective transmission start points and start transmission after CCA.

[0106] If start point 941 and start point 942 occur during the last symbol of slot 910, the terminal device may begin transmission immediately. If start point 941 and start point 942 occur during the first symbol of slot 920, the terminal device may initiate transmission by masking the AGC symbol shown in FIG. 9.

[0107] It can be seen from Figure 9 that more detailed microsecond-level channel access through finer time division can maximize collision avoidance. The multi-microsecond slot-based access shown in Figure 9 can occur during any system-assigned symbol.

[0108] In some embodiments, the one or more microseconds may be determined based on a designated time unit. The designated time unit may be designated by indication information carried in control signaling. For example, the SCI may be used to specify that a contention slot when multiple terminal devices perform channel access is 20 microseconds.

[0109] In some embodiments, the one or more microseconds may alternatively be determined based on the duration of channel monitoring. The first time unit must satisfy the access requirements for channel monitoring. For example, a first time unit of 9 μs may satisfy the minimum time requirement for the additional LBT shown in FIG. 4. As another example, a first time unit of 16 μs may satisfy the Type 2B access mode shown in FIG. 4. As another example, a first time unit of 25 μs may satisfy the Type 2A access mode shown in FIG. 4.

[0110] In a possible implementation, the multiple microseconds may be a first value or an integer multiple of the first value. The first value may be a specified time unit or a time unit determined based on the duration of channel monitoring. For example, the first value may be 9 μs, 16 μs, or 25 μs.

[0111] The first sidelink channel may include one or more of channels such as, but not limited to, a PSCCH, a PSSCH, and a PSFCH.

[0112] It can be seen from the above description that the embodiments of the present application increase the number of SL-U transmission starting points based on the full-slot channel access supported by the current Third Generation Partnership Project (3GPP) protocol. The SL-U slot structure supports designated location access, half-slot access, more sophisticated access, and other access modes, which improves channel access flexibility, reduces the probability of resource collision, and reduces resource waste and access delays caused by channel access delays.

[0113] As mentioned above, in the resource scheduling scheme for sidelink mode 2, the terminal device needs to perform resource selection after successful channel monitoring. During the duration of the detection and transmission preparation process by the terminal device, another RAT may access and occupy the channel, which will invalidate the terminal device's previous channel monitoring.

[0114] In view of this, embodiments of the present application propose another sidelink communication method and apparatus. In this method, after successful channel monitoring and access, a terminal device can acquire resources required for subsequent transmissions without resource selection. The sidelink communication method will be described in detail below with reference to Figure 10. The method shown in Figure 10 is related to Figure 6. Therefore, for brevity, terms already appearing in Figure 6 will not be described in detail again in Figure 10.

[0115] Referring to FIG. 10, in step S1010, a terminal device performs channel access on a first resource of a shared spectrum.

[0116] Channel access may be an initial access of a terminal device for data transmission. In some embodiments, channel access may include only an initial access performed by the terminal device. For example, channel access may be resource sensing and access. In some embodiments, channel access may include channel monitoring and initial access performed by the terminal device.

[0117] The first resource may be a designated or reserved time-frequency resource in the shared spectrum, or may be a shared resource in a resource pool corresponding to another terminal device in the shared spectrum. The terminal device performs channel access on the first resource, which may also be referred to as an access resource.

[0118] In some embodiments, the shared resource as the first resource may be a resource in a resource pool configured by the network for another terminal device, or a resource in a resource pool obtained by another terminal device through channel monitoring. For example, the first resource may be a reserved resource in the resource pool of another terminal device.

[0119] In some embodiments, the first resource may be used by the terminal device to perform resource sensing and access. The first resource may be used by the terminal device as a resource required for initial access, or may be used by the terminal device as a resource required for channel monitoring and initial access. For example, the first resource may determine the channel monitoring and access of the terminal device.

[0120] In some embodiments, the first resource may be used by the terminal device for initial transmission. The terminal device may perform channel monitoring before the first resource, and if no available channel is found, the terminal device may wait on the first resource.

[0121] In some embodiments, the first resource may be used for retransmission resources in a dedicated frequency range, for example, the first resource may be used for retransmissions of several transport blocks (TBs).

[0122] In some embodiments, information about the first resource can be signaled in multiple ways. For example, dedicated control signaling can be used to signal the first resource to the sidelink terminal device. As another example, broadcast information can be used to signal the first resource to the sidelink terminal device.

[0123] In step S1020, the terminal device transmits the first sidelink channel on the second resource.

[0124] The second resource may be a time-frequency resource available for a channel discovered by the terminal device through channel monitoring. The terminal device transmits data on the second resource, which may also be referred to as a transmission resource. For example, the second resource may be an available resource in a shared spectrum or a shared resource in a resource pool of another terminal device.

[0125] The second resource may be a resource block in a resource pool associated with the first resource, hi some embodiments, the second resource may be a contiguous resource block, a single resource block, or a discrete resource block.

[0126] In some embodiments, when a first resource is used as a resource required for access, the first resource may be associated with a second resource in a resource pool. For example, the first resource may serve as an index for the second resource. The second resource in the resource pool may be mapped according to the index of the first resource.

[0127] The second resource may be a resource required by the terminal device for subsequent transmission after successful channel monitoring. For example, when the first resource is an index of the second resource, as long as the terminal device successfully performs channel monitoring on the first resource, the resource index can point to the resource required for subsequent transmission of the service. The terminal device does not need to perform subsequent resource selection or request resource allocation, and thus can avoid possible resource collision problems.

[0128] In some embodiments, the association relationship between the first resource and the second resource may be signaled in multiple ways. For example, dedicated control signaling may be used to signal the association relationship to the sidelink terminal devices. As another example, broadcast information may be used to signal the association relationship to the sidelink terminal devices.

[0129] The association relationship between the first resource and the second resource may be determined based on one or more types of information.

[0130] In some embodiments, the association relationship between the first resource and the second resource may be determined based on first information. The first information may be used to indicate a time-domain location of the second resource. For example, the first information may include a time-domain start location and a duration of the second resource. As another example, the first information may include a time-domain start location and an end time of the second resource.

[0131] In a possible implementation, ConfigIndex is used to represent the first information, and T is used to represent the time domain start position. initial But L is used to represent the duration. The first piece of information is ConfigIndex∈[T initial ,T initial +L] In the above equation, T initial may be determined based on the synchronization point in time as the start symbol in the time domain of the second resource, and L may be the symbol length of the persistence of the second resource.

[0132] In a possible implementation, the time-domain start position of the second resource may be the time-domain start position of the first time unit or the time-domain start position indicated by the indication information. The first time unit may be a slot, a half-slot, one or more symbols, or one or more microseconds, and is not limited herein. For example, when a slot includes 14 symbols and the first time unit is a slot, the time-domain position of every 14th symbol may be T based on the synchronization timeline. initial When the first time unit is a half slot, the time domain position of every seventh symbol is T initial As another example, the time domain position specified by the indication information is T initial is.

[0133] In some embodiments, when multiple terminal devices plan to transmit sidelink channels on the second resources, the first information may be determined based on one or more types of information. The information may be the maximum number of available time-domain resources in the resource pool, such as the maximum available number of symbols or the maximum number of symbols that can be shared by COT. The information may be the total number of second resources in the time domain of the resource pool, e.g., K, where K is a positive integer. The information may also be the number of terminal devices. For example, at a certain time, there are M actually connected terminal devices, where M may be a positive integer less than or equal to K. The information may be the number of second resources corresponding to each terminal device in the time domain, e.g., K / M.

[0134] In a possible implementation, the time domain resources in the resource pool are divided equally. max After the time domain resources are divided equally into K, the L mentioned above is L=T max / K, and the first information of each resource block is ConfigIndex∈[T initial ,T initial +(T max / K)] Satisfy.

[0135] The first information of the i-th resource block is

[0136]

number

[0137] where i is an integer between 0 and K-1;

[0138]

number

[0139] is the symbol in a particular slot during channel access for the service corresponding to the i-th resource block after successful channel monitoring.

[0140] When M terminal devices access the resource pool to which the second resource belongs, and the time domain resource is equally divided, the first information ConfigIndex corresponding to the i-th terminal device among the M terminal devices is:

[0141]

number

[0142] where i is an integer between 0 and M-1;

[0143]

number

[0144] represents the time domain start position of the second resource corresponding to the i-th terminal device, P represents the number of the second resources corresponding to the i-th terminal device in the time domain, and T max where P represents the maximum available time-domain resource in the resource pool, and K represents the total number of second resources in the time domain of the resource pool. Because the resources are evenly divided, P may be defined as K / M.

[0145] In a possible implementation, the time-domain resources in the resource pool may not be divided evenly: for example, some symbols of each resource block may be sorted according to a differential sequence, or according to an increasing or decreasing sequence.

[0146] In some embodiments, the association relationship between the first resource and the second resource may be determined based on second information. The second information may be used to indicate a frequency-domain location of the second resource. For example, the second information may include a frequency-domain start location and a frequency-domain size of the second resource. As another example, the second information may include a frequency-domain start location and a frequency-domain end location of the second resource.

[0147] In a possible implementation, the second information may be represented by a FreqIndex. The FreqIndex may indicate which physical resource block (PRB) in the frequency domain the second resource starts from, or may indicate the frequency domain size occupied by the second resource. For example, the RBs occupied by the second resource may be one or more contiguous RBs, or may be multiple non-contiguous RBs. As another example, the number of RBs among these RBs occupied by the second resource may be a fixed value or may be variously set according to the priority level of the terminal device or the transmission service.

[0148] In a possible implementation, the RBs in the resource pool are sorted based on frequency index. For example, starting from the lowest frequency in the resource pool, the RBs are numbered in ascending frequency order. n_SL_PRB may be the starting RB number in the frequency domain of the second resource in the resource pool, and RB offset may be the number of RBs offset by the second resource in the frequency domain. Thus, the second information is FreqIndex∈[n_SL_PRB,n_SL_PRB+RB offset ] where n_SL_PRB represents the frequency domain starting position, and RB offset represents the frequency domain size.

[0149] In some embodiments, when multiple terminal devices plan to transmit sidelink channels on the second resources, the second information may be determined based on one or more types of information, such as a maximum number of available resources in a bandwidth part (BWP), a maximum number of available resources in a bandwidth part (BWP), or a maximum number of available resources in a bandwidth part (BWP).

[0150]

number

[0151] The information may be a maximum number of available frequency domain resources in the resource pool, such as K. The information may be a total number of second resources in the frequency domain of the resource pool, for example, K. The information may be a number of terminal devices, for example, M. The information may be a number of second resources corresponding to each terminal device in the frequency domain, for example, K / M.

[0152] In a possible implementation, the frequency domain resources in the resource pool are divided equally. max After the frequency domain resources are divided equally into K, the RBs mentioned above are used. offset is RB offset =N max / K, and the second information of each resource block may be represented as FreqIndex∈[n_SL_PRB,n_SL_PRB+(N max / K)] Satisfy.

[0153] The second information of the i-th resource block is FreqIndex∈[n_SL_PRB i ,n_SL_PRB i +(N max / K)], and n_SL_PRB i =n_SL_PRB0+i×(N max / K) where i is an integer ranging from 0 to K-1.

[0154] When M terminal devices access the resource pool to which the second resource belongs, and the frequency domain resources are equally divided, the second information FreqIndex corresponding to the i-th terminal device among the M terminal devices is: FreqIndex∈[n_SL_PRB i ,n_SL_PRB i +P×(N max / K)], and n_SL_PRB i =n_SL_PRB0+i×P×(N max / K) where i is an integer between 0 and M-1, and n_SL_PRB i represents the frequency domain start position of the second resource corresponding to the i-th terminal device, P represents the number of second resources corresponding to the i-th terminal device in the frequency domain, and N max where P is the maximum available frequency domain resource in the resource pool, K is the total number of second resources in the frequency domain of the resource pool, and P is defined as K / M because the resources are evenly divided.

[0155] In a possible implementation, the frequency domain resources in the resource pool may not be divided evenly, for example, some RBs of each resource block may be sorted according to a differential sequence, or according to an increasing or decreasing sequence.

[0156] In some embodiments, an association relationship between a first resource and a second resource may be determined based on first information and second information. The first information is used to indicate a time-domain location of the second resource, and the second information is used to indicate a frequency-domain location of the second resource. The location of the second resource may be determined based on an index of the first resource to avoid subsequent resource collisions. For example, the index may be represented as Index(x,y), where x represents a time-domain parameter of the second resource and y represents a frequency-domain parameter of the second resource.

[0157] In a possible implementation, the index of the first resource for the terminal device to perform initial access on the shared spectrum may be Index(ConfigIndex, FreqIndex). The ConfigIndex and FreqIndex of the second resource are determined according to the above-mentioned method. After successful channel monitoring, the terminal device may determine the position for transmitting the PSCCH / PSSCH / PSFCH based on the index.

[0158] As a possible implementation, after multiple terminal devices perform channel access, the available resources in the resource pool may be divided based on the number of terminal devices to obtain the time-frequency resources (ConfigIndex, FreqIndex) allocated to each terminal device.

[0159] In a possible implementation, the available time-frequency resources in the resource pool are divided evenly. If the available time-frequency resources are divided evenly into second resources of the same size, the sidelink can obtain most of the channel resources. For example, if the time-frequency resources are N RBG When divided into N resource groups, RBG represents the number of resource block groups (RBGs). RBG , also represents the maximum allowable number of terminal devices that can be allocated resources in the resource pool.

[0160] In a possible implementation, the available resources in the resource pool are divided into resource blocks of different sizes. Each terminal device may transmit on second resources of different sizes based on service requirements. For example, the sizes of each resource block may be sorted according to a differential sequence, or according to an increasing or decreasing sequence.

[0161] For ease of understanding, taking an SL-U resource pool as an example, the mapping relationships corresponding to equal and unequal division of the second resource in the resource pool are described below with reference to Figures 11 and 12, respectively. Figure 11 is a schematic diagram of the association between the first resource and the second resource when the second resource is evenly divided. Figure 12 is a schematic diagram of the association between the first resource and the second resource when the second resource is not evenly divided.

[0162] Referring to Figure 11, in a time-frequency interleaved resource pool, each grid on the horizontal axis represents a slot, and each grid on the vertical axis represents a subchannel. Three terminal devices perform channel access in the resource pool. As shown in Figure 11, in the resource pool, first resources are used as access resources for different terminal devices, and the corresponding three resource blocks have different sizes. Second resources are used as transmission resources for different terminal devices, and the corresponding three resource blocks have the same size. In other words, regardless of the service requirements or access resource sizes of the terminal devices, all terminal devices obtain transmission resources of the same size after successful monitoring.

[0163] 11 describes various mapping relationships between first and second resources, where mapping relationship 1110 is for full-slot channel access, mapping relationship 1120 is for half-slot channel access, and mapping relationship 1130 is for designated position channel access.

[0164] Figure 12 differs from Figure 11 mainly in that the sizes of the resource blocks corresponding to the three second resources are different. In other words, the sizes of the transmission resources acquired by the three terminal devices after successful channel monitoring are different. As shown in Figure 12, the resource block for the second resource in the mapping relationship 1220 is the largest. A terminal device with a larger service requirement may perform channel access on the first resource in the mapping relationship 1220.

[0165] From the above description, it can be seen that once a terminal device performs channel access on a first resource of a shared spectrum, it can obtain a subsequent transmission resource for the terminal device based on the association relationship between the first resource and the second resource. In other words, as long as the terminal device successfully performs channel monitoring, the resource required for the subsequent transmission can be guaranteed. Therefore, the terminal device does not need to perform resource selection, thereby avoiding a situation in which another RAT occupies a successfully detected channel during resource selection.

[0166] Method embodiments of the present application have been described in detail above with reference to Figures 6 to 12. Apparatus embodiments of the present application will be described in detail below with reference to Figures 13 to 15. It will be understood that the description of the apparatus embodiments corresponds to the description of the method embodiments, and therefore, where not described in detail, reference may be made to the method embodiments above.

[0167] 13 is a schematic block diagram of a communication device according to an embodiment of the present application. The device 1300 may be any of the terminal devices mentioned above. The device 1300 shown in FIG. 13 includes a monitoring unit 1310 and a sending unit 1320.

[0168] The monitor unit 1310 may be configured to perform channel monitoring on the shared spectrum.

[0169] The transmitting unit 1320 may be configured to, when a result of the channel monitoring is that the channel is idle, start transmitting the first sidelink channel at a first time-domain location, the first time-domain location being one or more of a time-domain location indicated by the first indication and a time-domain location determined based on a first time unit, the first time unit being smaller than one slot.

[0170] Optionally, the first time unit comprises one or more of a half-slot, one or more symbols, and one or more microseconds.

[0171] Optionally, the one or more microseconds are determined based on one or more of the following information: a specified time unit, and a duration of channel monitoring.

[0172] Optionally, the one or more microseconds is a first value or an integer multiple of a first value, the first value being one of 9 microseconds, 16 microseconds, and 25 microseconds.

[0173] Optionally, the first indication information is carried in control signaling.

[0174] 14 is a schematic block diagram of a communication device according to another embodiment of the present application. The device 1400 may be any of the terminal devices described above. The device 1400 shown in FIG. 14 includes: an access unit 1410 and a sending unit 1420.

[0175] The access unit 1410 may be configured to perform channel access on a first resource of the shared spectrum, the first resource being associated with a second resource in a resource pool.

[0176] The transmitting unit 1420 may be configured to transmit the first sidelink channel on the second resources.

[0177] Optionally, the association relationship between the first resource and the second resource is determined based on one or more of the following information: first information for indicating a time domain location of the second resource; and second information for indicating a frequency domain location of the second resource.

[0178] Optionally, the first information includes one or more of the following information: a time domain start position of the second resource, a duration of the second resource, and an end time of the second resource.

[0179] Optionally, the time-domain start position of the second resource is one of a time-domain start position of a first time unit and a time-domain start position indicated by the indication information, wherein the first time unit is one of a slot, a half-slot, one or more symbols, and one or more microseconds.

[0180] Optionally, the second information includes one or more of the following information: a frequency domain start position of the second resource, a frequency domain size of the second resource, and a frequency domain end position of the second resource.

[0181] Optionally, the first information is determined based on one or more of a maximum value of available time domain resources in the resource pool, a total number of second resources in the time domain of the resource pool, a number of terminal devices, and a number of second resources corresponding to each terminal device in the time domain.

[0182] Optionally, there are M terminal devices, and the first information ConfigIndex corresponding to an i-th terminal device among the M terminal devices is:

[0183]

number

[0184] where i is an integer between 0 and M-1;

[0185]

number

[0186] represents the time domain start position of the second resource corresponding to the i-th terminal device, P represents the number of the second resources corresponding to the i-th terminal device in the time domain, and T max represents the maximum value of available time-domain resources in the resource pool, and K represents the total number of second resources in the time domain of the resource pool.

[0187] Optionally, the second information is determined based on one or more of a total number of second resources in the frequency domain of the resource pool, a number of terminal devices, a maximum value of available frequency domain resources in the resource pool, and a number of second resources in the frequency domain corresponding to each terminal device.

[0188] Optionally, the terminal device includes M terminal devices, and the second information FreqIndex corresponding to the i-th terminal device among the M terminal devices is: FreqIndex∈[n_SL_PRB i ,n_SL_PRB i +P×(N max / K)] where i is an integer between 0 and M-1, and n_SL_PRB i represents the frequency domain start position of the second resource corresponding to the i-th terminal device, P represents the number of second resources corresponding to the i-th terminal device in the frequency domain, and N max represents the maximum number of available frequency domain resources in the resource pool, and K represents the total number of second resources in the frequency domain of the resource pool.

[0189] Figure 15 is a schematic structural diagram showing a communication device according to an embodiment of the present application. The dashed lines in Figure 15 indicate that a unit or module is optional. The device 1500 may be configured to implement the methods described in the above method embodiments. The device 1500 may be a chip or a terminal device.

[0190] The device 1500 may include one or more processors 1510. The processor 1510 may enable the device 1500 to implement the methods described in the method embodiments above. The processor 1510 may be a general-purpose processor or a special-purpose processor. For example, the processor may be a central processing unit (CPU). Alternatively, the processor may be another 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, or a discrete hardware component. The general-purpose processor may be a microprocessor, or the processor may be any conventional processor, etc.

[0191] The apparatus 1500 may further include one or more memories 1520. The memories 1520 store programs that can be executed by the processor 1510 to cause the processor 1510 to perform the methods described in the above method embodiments. The memory 1520 may be separate from the processor 1510 or may be integrated into the processor 1510.

[0192] The apparatus 1500 may further include a transceiver 1530. The processor 1510 can communicate with another device or chip through the transceiver 1530. For example, the processor 1510 can send and receive data to and from another device or chip through the transceiver 1530.

[0193] The embodiments of the present application further provide a computer-readable storage medium for storing a program. The computer-readable storage medium can be applied to the terminal or network device provided in the embodiments of the present application, and the program causes a computer to perform the method to be performed by the terminal or network device in various embodiments of the present application.

[0194] The embodiments of the present application further provide a computer program product, which includes a program. The computer program product can be applied to the terminal or network device provided in the embodiments of the present application, and the program causes a computer to perform the method to be performed by the terminal or network device in various embodiments of the present application.

[0195] The embodiments of the present application further provide a computer program, which can be applied to the terminal or network device provided in the embodiments of the present application, and causes a computer to perform the method to be performed by the terminal or network device in various embodiments of the present application.

[0196] The terms "system" and "network" in this application may be used interchangeably. Furthermore, the terms used in this application are used only to describe particular embodiments of this application and are not intended to limit this application. Please note that terms such as "first," "second," "third," and "fourth" in the specification, claims, and drawings of this application are used to distinguish different items, not to describe a particular order. Furthermore, the terms "comprise" and "have," and any variations thereof, are intended to cover a non-exclusive inclusion.

[0197] In the embodiments of the present application, the term "indicate" referred to herein may refer to direct indication, or may refer to indirect indication, or may mean that there is an association relationship. For example, A indicating B may mean that A directly indicates B, e.g., B can be obtained using A, or A indirectly indicates B, e.g., A indicates C and B can be obtained using C, or may mean that there is an association relationship between A and B.

[0198] In the embodiments of the present application, the term "corresponding" may mean that there is a direct or indirect correspondence between the two, or that there is an association relationship between the two, which may be a relationship of show and show, or constitute and constitute, etc.

[0199] In the embodiments of the present application, "predefined" or "preconfigured" may be implemented by prestoring a corresponding code, table, or other form that can be used to indicate relevant information in a device (including, for example, a terminal device and a network device), and the specific implementation form is not limited in the present application. For example, predefined may refer to being defined in a protocol.

[0200] In the embodiments of the present application, "protocol" may refer to standard protocols in the communications field, and may include, for example, LTE protocols, NR protocols, and related protocols applied to future communications systems, which are not limited in the present application.

[0201] In the embodiments of the present application, determining B based on A does not mean determining B based only on A, but B may be determined based on A and / or other information.

[0202] In the embodiments of the present application, the term "and / or" is only used to describe the association relationship between associated things, and indicates that there are three possible relationships. For example, A and / or B may indicate that only A is present, that both A and B are present, and that only B is present. Furthermore, the symbol " / " in this specification generally indicates an "or" relationship between associated things.

[0203] In the embodiments of the present application, the sequence numbers of the above processes do not mean the execution order, and the execution order of the processes should be determined according to the functions and internal logic of the processes, and should not be construed as any limitation on the implementation process of the embodiments of the present application.

[0204] In some embodiments provided in the present application, it should be understood that the disclosed systems, devices, and methods may be implemented in other ways. For example, the described device embodiments are merely examples. For example, unit divisions are merely logical functional divisions, and actual implementations may be other divisions. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not implemented. Furthermore, the shown or discussed mutual or direct couplings or communication connections may be implemented using some interfaces. Indirect couplings or communication connections between devices or units may be implemented in electronic, mechanical, or other forms.

[0205] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, i.e., they may be located in one place or distributed over multiple network units. Some or all of the units may be selected according to the actual needs of achieving the objectives of the solutions of the embodiments.

[0206] Furthermore, the functional units in the embodiments of the present application may be integrated into one processing unit, each of the units may exist physically alone, or two or more units may be integrated into one unit.

[0207] All or part of the above embodiments may be implemented using software, hardware, firmware, or any combination thereof. When software is used to implement the embodiments, the above embodiments may be implemented, entirely or partially, in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the procedures or functions according to the embodiments of the present application are generated entirely or partially. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or another programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from a website, computer, server, or data center to another website, computer, server, or data center via wired (such as coaxial cable, fiber optics, and digital subscriber line (DSL)) or wireless (such as infrared, wireless, and microwave) methods. The computer-readable storage medium may be any available medium readable by a computer, or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, or a magnetic tape), an optical medium (e.g., a digital versatile disk (DVD)), a semiconductor medium (e.g., a solid-state drive (SSD)), etc.

[0208] The above description is merely a specific implementation form of the present application, and the protection scope of the present application is not limited thereto. Any changes or replacements that can be easily conceived by those skilled in the art within the technical scope disclosed in the present application shall fall within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the accompanying claims. [Explanation of symbols]

[0209] 100 Wireless Communication System 110 Network Devices 121 Terminal Devices 122 terminal devices 123 terminal devices 124 terminal devices 125 terminal devices 126 Terminal Devices 127 Terminal Devices 128 terminal devices 129 terminal devices 200 V2X communication system 201 Terminal Devices 202 Terminal Devices 203 Terminal Devices 204 Terminal Devices 205 Terminal Devices 1300 equipment 1310 Surveillance Unit 1320 Transmitting Unit 1400 equipment 1410 Access Unit 1420 Transmitting Unit 1500 equipment 1510 processor 1520 memory 1530 Transceiver

Claims

1. performing, by a terminal device, channel monitoring on the shared spectrum; determining, by the terminal device, when the result of the channel monitoring is that the channel is idle, a first time-domain location for transmitting a first sidelink signal over a first sidelink channel, the first time-domain location representing a start time position of a first time unit within a time period, the time period having a length of 2 symbols, the time period being divided into a plurality of time units including the first time unit, each of the plurality of time units having a duration of a first value, the first value being 25 microseconds; and the first time-domain location representing a start time position of a first time unit within a time period, the length of the time period being 2 symbols, the time period being divided into a plurality of time units including the first time unit, each of the plurality of time units having a duration of a first value, the first value being 25 microseconds; At a specified time, or the time of said channel monitoring; and commencing transmission, by the terminal device, of the first sidelink signal via the first sidelink channel at the first time-domain location.

2. The method of claim 1 , wherein the designated time is indicated by control signaling.

3. At least one memory; at least one processor coupled to the at least one memory, the at least one processor individually or collectively configured to perform operations, the operations including: performing, by a terminal device, channel monitoring on the shared spectrum; and when the terminal device determines that the channel monitoring result is that the channel is idle, determining, by the terminal device, a first time-domain location for transmitting a first sidelink signal over a first sidelink channel, the first time-domain location representing a start time position of a first time unit within a time period, the time period having a length of 2 symbols, the time period being divided into a plurality of time units including the first time unit, each of the plurality of time units having a duration of a first value, the first value being 25 microseconds, and the first time-domain location representing a start time position of a first time unit within a time period, the length of the time period being ... At a specified time, or determining the time of the channel monitoring; and commencing transmission, by the terminal device, of the first sidelink signal over the first sidelink channel at the first time-domain location.

4. The apparatus of claim 3 , wherein the designated time is indicated by control signaling.

5. One or more non-transitory computer-readable media storing computer instructions that, when executed by one or more processors, cause a computing device to perform operations, the operations including: performing channel monitoring on the shared spectrum; and upon determining that the channel monitoring result is that the channel is idle, determining a first time-domain location for transmitting a first sidelink signal over a first sidelink channel, the first time-domain location representing a start time position of a first time unit within a time period, the time period having a length of 2 symbols, the time period being divided into a plurality of time units that includes the first time unit, each of the plurality of time units having a duration of a first value, the first value being 25 microseconds, and the first time-domain location representing a start time position of a first time unit within a time period that includes the first time unit, ... At a specified time, or determining the time of the channel monitoring; and commencing transmission of the first sidelink signal over the first sidelink channel at the first time-domain location.

6. 6. The one or more non-transitory computer-readable media of claim 5, wherein the designated time is indicated by control signaling.

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