CN118923087A - Communication method and terminal device - Google Patents

Abstract

A communication method and a terminal device are provided. The communication method comprises: on an unlicensed spectrum, a first terminal device sends a first positioning reference signal PRS through a sidelink. Through the first PRS, a positioning technology for sidelink communication on an unlicensed spectrum can be implemented. That is, through the first PRS, the positioning of a first terminal device and/or a second terminal device performing sidelink communication on an unlicensed spectrum can be implemented.

Description

Communication method and terminal device Technical Field

The present application relates to the field of communication technology, and more specifically, to a communication method and a terminal device.

Background Art

Through positioning technology, the location of a communication device in a communication network can be determined. For example, in some communication systems (such as NR systems), positioning can be achieved through a positioning reference signal (PRS).

In sideline communication technology, how to implement positioning technology on unlicensed spectrum is an urgent problem to be solved.

Summary of the invention

The present application provides a communication method and a terminal device. The following introduces various aspects involved in the present application.

In a first aspect, a communication method is provided, the method comprising: on an unlicensed spectrum, a first terminal device sends a first positioning reference signal PRS via a sidelink.

According to a second aspect, a communication method is provided, the method comprising: receiving, by a second terminal device, a first positioning reference signal PRS via a sidelink on an unlicensed spectrum.

According to a third aspect, a terminal device is provided. The terminal device is a first terminal device, and the terminal device includes: a first sending unit, configured to send a first positioning reference signal PRS via a side link on an unlicensed spectrum.

In a fourth aspect, a terminal device is provided, where the terminal device is a second terminal device, and the terminal device includes: a first receiving unit, configured to receive a first positioning reference signal PRS via a side link on an unlicensed spectrum.

In a fifth aspect, a terminal is provided, comprising a processor, a memory and a transceiver, wherein the memory is used to store one or more computer programs, and the processor is used to call the computer program in the memory so that the terminal device executes part or all of the steps in the method of the first aspect and/or the second aspect.

In a sixth aspect, an embodiment of the present application provides a communication system, which includes the above-mentioned terminal device. In another possible design, the system may also include other devices that interact with the terminal device in the solution provided by the embodiment of the present application.

In a seventh aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program enables a terminal to execute part or all of the steps in the methods of the above aspects.

In an eighth aspect, an embodiment of the present application provides a computer program product, wherein the computer program product includes a non-transitory computer-readable storage medium storing a computer program, and the computer program is operable to cause a terminal to execute some or all of the steps in the above-mentioned various aspects of the method. In some implementations, the computer program product can be a software installation package.

In a ninth aspect, an embodiment of the present application provides a chip comprising a memory and a processor, wherein the processor can call and run a computer program from the memory to implement some or all of the steps described in the methods of the above aspects.

It is understandable that the positioning technology of the sideline communication on the unlicensed spectrum can be implemented through the first PRS. That is, the positioning of the first terminal device and/or the second terminal device performing the sideline communication on the unlicensed spectrum can be implemented through the first PRS.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a diagram showing an example of a system architecture of a wireless communication system to which an embodiment of the present application may be applied.

FIG. 2 is a diagram showing an example scenario of sideline communication within network coverage.

FIG3 is an example diagram of a side communication scenario with partial network coverage.

FIG. 4 is a diagram showing an example scenario of sideline communication outside network coverage.

FIG. 5 is a diagram showing an example of a side communication scenario with a central control node.

FIG. 6 is an exemplary diagram of a sideline communication method based on broadcasting.

FIG. 7 is an example diagram of a unicast-based sideline communication method.

FIG. 8 is an example diagram of a side communication method based on multicast.

FIG9 is a diagram showing an example of a time slot structure of certain side-by-side communication systems (e.g., an NR-V2X system).

FIG. 10 is an example diagram showing changes in available OFDM symbols for PSSCH in different time slots.

FIG11 is an exemplary diagram showing time-frequency resources occupied by the second-order SCI in a time slot.

FIG. 12 is a schematic diagram of a DMRS pattern of a PSCCH.

FIG13 is a schematic diagram of the time domain position of 4 DMRS symbols when the number of PSSCH symbols is 14.

FIG14 is an example diagram of a single-symbol DMRS frequency domain type 1.

FIG15 is a diagram showing an example of the time-frequency position of an SL CSI-RS.

FIG16 is an example diagram showing a channel occupancy time obtained by a communication device after successful LBT on a channel of an unlicensed spectrum, and signal transmission using resources within the channel occupancy time.

FIG. 17 is an example diagram of a scenario in which a terminal device performs channel access.

FIG18 is a schematic flowchart of a communication method provided in an embodiment of the present application.

FIG. 19 is an example diagram of a communication method provided in an embodiment of the present application.

FIG. 20 is an example diagram of a communication method provided in an embodiment of the present application.

FIG. 21 is an example diagram of a communication method provided in an embodiment of the present application.

FIG. 22 is an example diagram of a communication method provided in an embodiment of the present application.

Figure 23 is a schematic structural diagram of a terminal device provided in an embodiment of the present application.

Figure 24 is a schematic structural diagram of a terminal device provided in an embodiment of the present application.

FIG. 25 is a schematic structural diagram of a device provided in an embodiment of the present application.

DETAILED DESCRIPTION

The technical solution in this application will be described below in conjunction with the accompanying drawings.

Communication System

FIG1 is a diagram showing an example of the system architecture of a wireless communication system 100 used in an embodiment of the present application. The wireless communication system 100 may include a network device 110 and a terminal device 120. The network device 110 may be a device that communicates with the terminal device 120. The network device 110 may provide communication coverage for a specific geographical area, and may communicate with the terminal device 120 located in the coverage area.

Optionally, the wireless communication system 100 may include multiple network devices and the coverage area of each network device may include other number of terminal devices, which is not limited in the embodiments of the present application.

Optionally, the wireless communication system 100 may further include other network entities such as a network controller and a mobility management entity, which is not limited in the embodiments of the present application.

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

The terminal device in the embodiment of the present application may also be referred to as user equipment (UE), access terminal, user unit, user station, mobile station, mobile station (MS), mobile terminal (MT), remote station, remote terminal, mobile device, user terminal, terminal, wireless communication device, user agent or user device. The terminal device in the embodiment of the present application may be a device that provides voice and/or data connectivity to a user, and may be used to connect people, objects and machines, such as a handheld device with wireless connection function, a vehicle-mounted device, etc. The terminal device in the embodiment of the present application can be a mobile phone, a tablet computer, a laptop, a PDA, a mobile internet device (MID), a wearable device, a virtual reality (VR) device, an augmented reality (AR) device, a wireless terminal in industrial control, a wireless terminal in self-driving, a wireless terminal in remote medical surgery, a wireless terminal in smart grid, a wireless terminal in transportation safety, a wireless terminal in smart city, a wireless terminal in smart home, etc. Optionally, the terminal device can be used to act as a base station. For example, the terminal device can act as a dispatching entity, which provides sidelink signals between terminal devices in vehicle-to-everything (V2X) or device-to-device communication (D2D), etc. For example, a cellular phone and a car communicate with each other using sidelink signals. Cell phones and smart home devices communicate with each other without relaying communication signals through a base station. Optionally, the terminal device can be used to act as a base station.

The network device in the embodiment of the present application may be a device for communicating with a terminal device, and the network device may also be referred to as an access network device or a wireless access network device, such as a base station. The network device in the embodiment of the present application may refer to a wireless access network (RAN) node (or device) that connects a terminal device to a wireless network. Base station can broadly cover various names as follows, or replace with the following names, such as: NodeB, evolved NodeB (eNB), next generation NodeB (gNB), relay station, access point, transmission point (TRP), transmission point (TP), master station MeNB, auxiliary station SeNB, multi-standard radio (MSR) node, home base station, network controller, access node, wireless node, access point (AP), transmission node, transceiver node, base band unit (BBU), remote radio unit (RRU), active antenna unit (AAU), remote radio head (RRH), central unit (CU), distributed unit (DU), positioning node, etc. The base station can be a macro base station, a micro base station, a relay node, a donor node or the like, or a combination thereof. The base station can also refer to a communication module, a modem or a chip used to be set in the aforementioned device or apparatus. The base station can also be a mobile switching center and a device to device (D2D), vehicle to vehicle (V2V), vehicle-to-everything (V2X), machine-to-machine (M2M) communication device that performs the base station function, a network side device in a 6G network, and a device that performs the base station function in a future communication system. The base station can support networks with the same or different access technologies. The embodiments of the present application do not limit the specific technology and specific device form adopted by the network equipment.

Base stations can be fixed or mobile. For example, a helicopter or drone can be configured to act as a mobile base station, and one or more cells can move based on the location of the mobile base station. In other examples, a helicopter or drone can be configured to act as a device that communicates with another base station.

In some deployments, the network device in the embodiments of the present application may refer to a CU or a DU, or the network device includes a CU and a DU. The gNB may also include an AAU.

The network equipment and terminal equipment can be deployed on land, including indoors or outdoors, handheld or vehicle-mounted; they can also be deployed on the water surface; they can also be deployed on aircraft, balloons and satellites in the air. The embodiments of the present application do not limit the scenarios in which the network equipment and terminal equipment are located.

It should be understood that all or part of the functions of the communication device in the present application may also be implemented by software functions running on hardware, or by virtualization functions instantiated on a platform (eg, a cloud platform).

Sideline communication under different network coverage conditions

Sidelink communication (or sidelink transmission) refers to a communication technology based on a sidelink (SL). Sidelink communication can be, for example, D2D or V2X. Sidelink communication supports direct communication data transmission between terminal devices. Direct communication data transmission between terminal devices can have higher spectrum efficiency and lower transmission latency. For example, the Internet of Vehicles system uses sidelink communication technology.

In side communication, according to the network coverage of the terminal device, the side communication can be divided into side communication within the network coverage, side communication with partial network coverage, side communication outside the network coverage and side communication controlled by the central node.

FIG2 is a diagram showing an example of a sideline communication scenario within network coverage. In the scenario shown in FIG2, both terminal devices 120a are within the coverage of the network device 110. Therefore, both terminal devices 120a can receive the configuration signaling of the network device 110 (the configuration signaling in this application can also be replaced by configuration information), and determine the sideline configuration according to the configuration signaling of the network device 110. After both terminal devices 120a perform the sideline configuration, sideline communication can be performed on the sideline link.

FIG3 is a diagram showing an example of a sidelink communication scenario with partial network coverage. In the scenario shown in FIG3, terminal device 120a performs sidelink communication with terminal device 120b. Terminal device 120a is located within the coverage of network device 110, so terminal device 120a can receive the configuration signaling of network device 110 and determine the sidelink configuration according to the configuration signaling of network device 110. Terminal device 120b is located outside the network coverage and cannot receive the configuration signaling of network device 110. In this case, terminal device 120b can determine the sidelink configuration according to the pre-configuration information and/or the information carried in the physical sidelink broadcast channel (PSBCH) sent by terminal device 120a located within the network coverage. After both terminal device 120a and terminal device 120b perform sidelink configuration, sidelink communication can be performed on the sidelink.

FIG4 is a diagram showing an example of a sideline communication scenario outside network coverage. In the scenario shown in FIG4, both terminal devices 120b are outside network coverage. In this case, both terminal devices 120b can determine the sideline configuration according to the preconfiguration information. After both terminal devices 120b perform the sideline configuration, sideline communication can be performed on the sideline link.

FIG5 is an example diagram of a side communication scenario with a central control node. In the scenario shown in FIG5, multiple terminal devices 120b may constitute a communication group. The communication group may have a central control node. In some cases, the central control node may become a cluster header (CH) terminal device. The central control node may have one or more of the following functions: responsible for establishing a communication group, joining and leaving group members, coordinating resources, allocating side transmission resources to other terminal devices, receiving side feedback information from other terminal devices, and coordinating resources with other communication groups.

Sideline communication mode

Some standards or protocols (such as the 3rd generation partnership project (3GPP)) define two modes (or transmission modes) of sideline communication: a first mode and a second mode.

In the first mode, the resources of the terminal device (the resources mentioned in this application may also be referred to as transmission resources, such as time-frequency resources) are allocated by the network device. The terminal device can send data on the sidelink according to the resources allocated by the network device. The network device can allocate resources for a single transmission to the terminal device, or it can allocate resources for semi-static transmission to the terminal device. This first mode can be applied to scenarios covered by network devices, such as the scenario shown in Figure 2 above. In the scenario shown in Figure 2, the terminal device 120a is within the network coverage of the network device 110, so the network device 110 can allocate resources used in the sidelink transmission process to the terminal device 120a.

In the second mode, the terminal device can autonomously select one or more resources in a resource pool (RP). Then, the terminal device can perform side transmission according to the selected resources. For example, in the scenario shown in FIG4, the terminal device 120b is located outside the cell coverage. Therefore, the terminal device 120b can autonomously select resources from the preconfigured resource pool for side transmission. Alternatively, in the scenario shown in FIG2, the terminal device 120a can also autonomously select one or more resources from the resource pool configured by the network device 110 for side transmission.

Data transmission method of sideline communication

Some sidewalk communication systems (such as LTE-V2X) support broadcast-based data transmission (hereinafter referred to as broadcast transmission). For broadcast transmission, the receiving terminal device can be any terminal device around the transmitting terminal device. Taking Figure 6 as an example, terminal device 1 is a transmitting terminal device, and the receiving terminal device corresponding to the transmitting terminal device is any terminal device around terminal device 1, for example, terminal device 2-terminal device 6 in Figure 6.

In addition to broadcast transmission, some communication systems also support unicast-based data transmission (hereinafter referred to as unicast transmission) and/or multicast-based data transmission (hereinafter referred to as multicast transmission). For example, NR-V2X hopes to support autonomous driving. Autonomous driving places higher requirements on data interaction between vehicles. For example, data interaction between vehicles requires higher throughput, lower latency, higher reliability, larger coverage, more flexible resource allocation methods, etc. Therefore, in order to improve the data interaction performance between vehicles, NR-V2X introduces unicast transmission and multicast transmission.

For unicast transmission, there is generally only one receiving terminal device. Taking FIG. 7 as an example, unicast transmission is performed between terminal device 1 and terminal device 2. Terminal device 1 may be a transmitting terminal device, and terminal device 2 may be a receiving terminal device, or terminal device 1 may be a receiving terminal device, and terminal device 2 may be a transmitting terminal device.

For multicast transmission, the receiving terminal device can be a terminal device in a communication group, or the receiving terminal device can be a terminal device within a certain transmission distance. Taking Figure 7 as an example, terminal device 1, terminal device 2, terminal device 3 and terminal device 4 constitute a communication group. If terminal device 1 sends data, the other terminal devices in the group (terminal device 2 to terminal device 4) can all be receiving terminal devices.

Sideline communication system frame structure

A time slot may include channels such as a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), and a physical sidelink feedback channel (PSFCH). The above channels will be described in detail below and will not be described here.

FIG9 is an example diagram of a time slot structure of some sidelink communication systems (e.g., NR-V2X systems). FIG9(a) is an example diagram of a time slot structure in which a physical sidelink feedback channel (PSFCH) is not included in the time slot. FIG9(b) is an example diagram of a time slot structure in which a PSFCH channel is included in the time slot.

As shown in Figure 9, in the time domain, PSCCH can start from the second sideline symbol of the time slot, occupy 2 or 3 orthogonal frequency division multiplexing (OFDM) symbols, and can occupy {10, 12 15, 20, 25} physical resource blocks (PRBs) in the frequency domain. In order to reduce the complexity of blind detection of PSCCH by terminal equipment, only one number of PSCCH symbols and PRBs can be configured in a resource pool. In addition, the subchannel is the minimum granularity of PSSCH resource allocation in some sideline communication systems (such as NR-V2X systems). Therefore, the number of PRBs occupied by PSCCH must be less than or equal to the number of PRBs contained in a subchannel in the resource pool, so as to avoid additional restrictions on PSSCH resource selection or allocation.

In the time domain, PSSCH can start from the second sideline symbol of the time slot. The last time domain symbol in the time slot is the guard period (GP) symbol (also called the gap (GAP) symbol), and the remaining symbols can be mapped to PSSCH. The first sideline symbol in the time slot can be a repetition of the second sideline symbol. The receiving terminal device can use the first sideline symbol as an automatic gain control (AGC) symbol, and the data on this symbol is generally not used for data demodulation. As shown in Figure 9(a), PSSCH can occupy K subchannels in the frequency domain, and each subchannel can include N consecutive PRBs. Among them, K can be an integer greater than 0, and N can be an integer greater than 0.

As shown in FIG9( b ), when a PSFCH channel is included in a time slot, the second to last and third to last symbols in the time slot can be used for PSFCH channel transmission, and a time domain symbol before the PSFCH channel can be used as a GP symbol.

PSSCH

In some sidelink communication systems (such as NR-V2X systems), PSSCH can be used to carry second-order sidelink control information (SCI). The second-order SCI may include SCI 2-A or SCI 2-B. The second-order SCI may use Polar coding. The second-order SCI may be fixedly modulated with QPSK. The data portion of PSSCH may use a low-density parity check code (LDPC). The highest modulation order that the data portion of PSSCH can support is 256QAM.

In some sideline communication systems (such as NR-V2X systems), PSSCH supports up to two stream transmissions, and uses a unit precoding matrix to map the data on the two layers to two antenna ports. At most, one TB can be sent in one PSSCH. However, unlike the transmission method of the PSSCH data part, when PSSCH adopts a dual-stream transmission method, the modulation symbols sent by the second-order SCI on the two streams are exactly the same. This design can ensure the reception performance of the second-order SCI under highly correlated channels.

In some side-by-side communication systems (such as NR-V2X systems), the maximum number of retransmissions of a PSSCH is 32 times. If there are PSFCH resources in the resource pool and the configuration period of the PSFCH resources is 2 or 4, the OFDM symbols available in the time slots where different transmissions of a PSSCH are located may change. Figure 10 is an example diagram of the change in the available OFDM symbols for PSSCH in different time slots. As shown in Figure 10, due to the existence of PSFCH resources, the number of OFDM symbols available for the nth transmission and the n+1th transmission of PSSCH is different. If the number of symbols for PSSCH transmission is calculated according to the actual number of OFDM symbols in a time slot The Q′ _SCI2 may be different due to the different number of symbols available for PSSCH transmission in a time slot, and the change of Q′ _SCI2 will cause the size of the TB carried by PSSCH to change, as described below. In order to ensure that the transmission block size (TBS) remains unchanged during multiple PSSCH transmissions, The actual number of PSFCH symbols is not used. The number of resource elements (REs) occupied by the PSSCH demodulation reference signal (DMRS) and the number of REs occupied by the phase-tracking reference signals (PT-RS), which may change during the retransmission process, are not taken into account.

The code rate of the second-order SCI can be dynamically adjusted within a certain range, and the specific code rate used can be indicated by the first-order SCI. Therefore, the receiving end does not need to perform blind detection on the second-order SCI even after the code rate changes. Figure 11 is an example diagram of the time-frequency resources occupied by the second-order SCI in a time slot. As shown in Figure 11, the modulation symbol of the second-order SCI can be mapped from the symbol where the first PSSCH DMRS is located in the frequency domain first and then the time domain. On the OFDM symbol where the DMRS is located, the second-order SCI can be mapped to the RE not occupied by the DMRS.

In a resource pool, the data part of PSSCH can adopt multiple different modulation and coding scheme (MCS) tables. For example, one or more of the following tables can be used: conventional 64QAM MCS table, 256QAM MCS table, and low spectrum efficiency 64QAM MCS table. In a transmission, the specific MCS table used in the data part of PSSCH can be indicated by the "MCS table indication" field in the first-order SCI. In order to control PAPR, PSSCH must be sent using continuous PRBs. Since the subchannel is the minimum frequency domain resource granularity of PSSCH, PSSCH must occupy continuous subchannels.

Sidelink TBS

PSSCH follows the TBS determination mechanism of PDSCH and PUSCH, that is, the TBS can be determined according to the reference value of the number of REs used for PSSCH in the time slot where PSSCH is located, so that the actual code rate is as close to the target code rate as possible. It should be noted that the purpose of using the reference value of the number of REs instead of the actual number of REs is to ensure that the number of REs used to determine the TBS remains unchanged during the PSSCH retransmission process, so that the determined TBS size is the same. To achieve this purpose, the reference value N _RE of the number of REs occupied by PSSCH in the TBS determination process can be determined according to the following formula:

Among them, _nPRB is the number of PRBs occupied by PSSCH, is the number of REs occupied by the first-order SCI (including the REs occupied by the DMRS of the PSCCH), is the number of REs occupied by the second-order SCI (as described above), and _N′RE represents the number of reference REs that can be used for PSSCH in a PRB. _N′RE can be determined by the following formula:

in, It can represent the number of subcarriers in a PRB, for example, Indicates the number of symbols available for sidelink in a time slot, which may not include the last GP symbol and the first symbol used for AGC. A reference value indicating the number of symbols occupied by PSFCH, for example, Or 3, the specific value can be indicated by the "PSFCH symbol number" field in the first-order SCI. It can represent the reference value of the number of REs occupied by PT-RS and channel state information-reference signal (CSI-RS), and can be configured by radio resource control (RRC) layer parameters. It can represent the average number of DMRS REs in a time slot, which is related to the DMRS pattern allowed in the resource pool. Table 1 shows the DMRS pattern allowed in the resource pool and The corresponding relationship.

Table 1

Sidelink DMRS

In some sideline communication systems (such as NR-V2X systems), the DMRS pattern of PSCCH can be the same as that of the physical downlink control channel (PDCCH). That is, DMRS can exist on each OFDM symbol of PSCCH and can be located in {#1, #5, #9} REs of a PRB in the frequency domain. Figure 12 is a schematic diagram of a DMRS pattern of PSCCH. The DMRS sequence of PSCCH is generated by the following formula:

Among them, the pseudo-random sequence c(m) can be obtained by Initialize. Wherein, l can represent the index of the OFDM symbol where the DMRS is located in the time slot, It can represent the index of the time slot where the DMRS is located in the system frame. It can represent the number of OFDM symbols in a time slot, N _ID ∈{0,1,…,65535}. The specific value of N _ID in a resource pool is configured or pre-configured by the network.

Some sideline communication systems (such as NR-V2X systems) use multiple time domain PSSCH DMRS patterns, which refers to the design in the Uu interface of the NR system. In a resource pool, the number of DMRS patterns that can be used may be related to the number of PSSCH symbols in the resource pool. For a specific number of PSSCH symbols (including the first AGC symbol) and PSCCH symbols, the available DMRS patterns and the position of each DMRS symbol in the pattern are shown in Table 2. Figure 13 is a schematic diagram of the time domain position of 4 DMRS symbols when the PSSCH has 14 symbols.

Table 2

If multiple time-domain DMRS patterns are configured in the resource pool, the specific time-domain DMRS pattern to be used is selected by the transmitting terminal device and indicated in the first-order SCI. This design allows high-speed moving terminal devices to select high-density DMRS patterns to ensure the accuracy of channel estimation, while for low-speed moving terminal devices, low-density DMRS patterns can be used to improve spectrum efficiency.

The generation method of the PSSCH DMRS sequence is almost identical to that of the PSCCH DMRS sequence. The only difference is in the initialization formula c _init of the pseudo-random sequence c(m). Wherein, _pi is the i-th CRC bit of the PSCCH that schedules the PSSCH. L may be the number of bits of the PSCCH CRC, for example, L=24.

In the NR communication system, two frequency domain DMRS patterns are supported in PDSCH and PUSCH, namely DMRS frequency domain type 1 and DMRS frequency domain type 2. For each frequency domain type, there are two different types: single DMRS symbols and double DMRS symbols. Single-symbol DMRS frequency domain type 1 supports 4 DMRS ports, and single-symbol DMRS frequency domain type 2 can support 6 DMRS ports. In the case of double DMRS symbols, the number of supported ports is doubled. However, in sideline communication systems (such as NR-V2X), since PSSCH only needs to support two DMRS ports at most, only single-symbol DMRS frequency domain type 1 can be supported. Figure 14 is an example diagram of a single-symbol DMRS frequency domain type 1.

Sidelink CSI-RS

The sidelink communication system can support sidelink CSI-RS (SL CSI-RS) to better support unicast communication. SL CSI-RS can be sent when the following three conditions are met: the terminal device sends the corresponding PSSCH, that is, the terminal device cannot only send SL CSI-RS; high-level signaling activates SL CSI-RS reporting; when high-level signaling activates SL CSI-RS reporting, the corresponding bit in the second-order SCI sent by the terminal device triggers SL CSI-RS reporting.

The maximum number of ports supported by SL CSI-RS is 2. Two ports are SL CSI-RS of different ports multiplexed by code division on two adjacent REs of the same OFDM symbol. The number of SL CSI-RS of each port in a PRB is 1, that is, the density is 1. Therefore, SL CSI-RS will appear in at most one OFDM symbol in a PRB. The specific position of this OFDM symbol can be determined by the transmitting terminal device. In order to avoid affecting the resource mapping of PSCCH and second-order SCI, SL CSI-RS cannot be located in the same OFDM symbol as PSCCH and second-order SCI. Since the channel estimation accuracy of the OFDM symbol where the PSSCH DMRS is located is high, and the SL CSI-RS of the two ports will occupy two consecutive REs in the frequency domain, the SL-CSI-RS cannot be sent on the same OFDM symbol as the PSSCH DMRS. The position of the OFDM symbol where the SL CSI-RS is located is indicated by the sl-CSI-RS-FirstSymbol parameter in PC5RRC.

The position of the first RE occupied by the SL CSI-RS in a PRB can be indicated by the sl-CSI-RS-FreqAllocation parameter in PC5RRC. If the SL CSI-RS is one port, the parameter can be a bitmap with a length of 12, corresponding to 12 REs in a PRB. If the SL CSI-RS is two ports, the parameter is a bitmap with a length of 6. In this case, the SL CSI-RS can occupy two REs, 2f(1) and 2f(1)+1. Among them, f(1) can represent the index of the bit with a value of 1 in the above bitmap. The frequency domain position of the SL CSI-RS can also be determined by the transmitting terminal device. The determined frequency domain position of the SL CSI-RS cannot conflict with the PT-RS. Figure 15 is an example diagram of the time-frequency position of the SL CSI-RS. In FIG15 , the number of SL CSI-RS ports is 2, sl-CSI-RS-FirstSymbol is 8, and sl-CSI-RS-FreqAllocation is [b ₅ ,b ₄ ,b ₃ ,b ₂ ,b ₁ ,b ₀ ]=[0,0,0,1,0,0].

Unlicensed spectrum communications

Unlicensed spectrum is a spectrum that can be used for radio equipment communications, which is divided by countries and regions. This spectrum is usually considered a shared spectrum, that is, as long as the communication equipment meets the regulatory requirements set by the country or region on the spectrum, it can use the spectrum without applying for exclusive spectrum authorization from the country or region's exclusive spectrum management agency. Unlicensed spectrum can also be called shared spectrum, unlicensed spectrum, unlicensed frequency band or unlicensed frequency band, etc.

In the LTE system, unlicensed spectrum has been used as a supplementary frequency band for licensed spectrum in cellular networks. For the NR system, the NR system can achieve seamless coverage, high spectrum efficiency, high peak rate and high reliability of the cellular network. The NR system can also use unlicensed spectrum as part of 5G cellular network technology to provide services to users. In the 3GPP R16 standard, the NR system used on unlicensed spectrum is discussed, which is called the NR unlicensed (NR-unlicensed, NR-U) system.

The NR-U system supports two networking modes: licensed spectrum assisted access and unlicensed spectrum independent access. Licensed spectrum assisted access requires the use of licensed spectrum to access the network, and unlicensed spectrum is used as a secondary carrier. Unlicensed spectrum independent access can be independently networked through unlicensed spectrum, and terminal devices can directly access the network through unlicensed spectrum. The range of unlicensed spectrum used by the NR-U system introduced in 3GPP R16 is concentrated in the 5GHz and 6GHz frequency bands. For example, in the United States, the range of unlicensed spectrum is 5925–7125MHz; in Europe, the range of unlicensed spectrum is 5925–6425MHz. In the R16 standard, band 46 (5150MHz-5925MHz) is newly defined for use as unlicensed spectrum.

The use of unlicensed spectrum needs to meet the requirements of specific regulations in various countries and regions. For example, communication equipment can use unlicensed spectrum to achieve channel access on unlicensed spectrum through channel monitoring to avoid conflicts with other communication equipment or other communication systems (such as WiFi systems). As an implementation method, communication equipment can use unlicensed spectrum in accordance with the principle of "listen-before-talk" (LBT). Therefore, for NR-U, NR technology needs to be enhanced accordingly to adapt to the regulatory requirements of unlicensed frequency bands, while efficiently utilizing unlicensed spectrum to provide services. In the 3GPP R16 standard, the standardization of NR-U technology in the following aspects is mainly completed: channel monitoring process; initial access process; control channel design; HARQ and scheduling; scheduling-free authorized transmission, etc.

LBT

The LBT principle may include: before a communication device uses a channel on an unlicensed spectrum to send a signal, it is necessary to perform LBT first. When LBT is successful, the result of the channel monitoring is that the channel is idle. Only when the channel is idle can the communication device send a signal through the channel. If the channel monitoring result of the communication device on the channel is that the channel is busy or LBT fails, then the communication device cannot send a signal through the channel. In addition, in order to ensure the fairness of the use of spectrum resources in the shared spectrum, if a communication device succeeds in LBT on a channel in the unlicensed spectrum, the duration that the communication device can use the channel for communication transmission cannot exceed a certain duration. This mechanism limits the maximum duration that communication can be carried out after a successful LBT, so that different communication devices have the opportunity to access the shared channel, thereby allowing different communication systems to coexist in a friendly manner on the shared spectrum.

Signal transmission on unlicensed spectrum involves concepts related to channel occupancy, such as channel occupancy time (COT), maximum channel occupancy time (MCOT), COT of network devices (such as base stations), and COT of terminal devices.

MCOT may refer to the maximum length of time that a communication device is allowed to use a channel of unlicensed spectrum for signal transmission when LBT is successful. It should be understood that MCOT refers to the time occupied by signal transmission. The MCOT corresponding to a communication device may be different if the channel access priority of the communication device is different. The maximum value of MCOT may be set to 10ms, for example.

FIG16 is an example diagram showing a channel occupancy time obtained by a communication device after successful LBT on a channel of an unlicensed spectrum, and signal transmission using resources within the channel occupancy time.

Although channel sensing is not a global regulatory requirement, it can bring interference avoidance and friendly coexistence benefits to communication transmissions between communication systems on shared spectrum. Therefore, in the design process of NR systems on unlicensed spectrum, channel sensing is a feature that communication devices in the system need to support.

Channel access methods for unlicensed spectrum or shared spectrum

Some communication systems (such as NR-U system) introduce a channel access method for channel access through LBT. Some communication systems may also support channel access through short control signaling transmission (SCSt). The above two channel access methods are introduced below.

From the perspective of system layout, the channel access method through LBT can include two mechanisms, one is LBT based on load equipment (LBE), also known as dynamic channel monitoring or dynamic channel occupancy; the other is LBT based on frame structure equipment (FBE), also known as semi-static channel monitoring or semi-static channel occupancy. Among them, the LBT principle of dynamic channel monitoring is: the communication equipment performs LBT on the carrier of the unlicensed spectrum after the service arrives, and starts sending signals on the carrier after the LBT is successful.

The LBT mode of dynamic channel monitoring may include a Type 1 channel access mode and a Type 2 channel access mode.

The following describes in detail the type 1 channel access method and the type 2 channel access method using a network device as an example. It is understandable that the process of other communication devices such as terminal devices performing channel monitoring through the type 1 channel access method or the type 2 channel access method is similar.

Type 1 channel access method can also be called multi-slot channel detection with random backoff based on contention window size adjustment. In type 1 channel access method, the communication device can initiate channel occupation with a length of Tmcot according to the channel access priority p. If the network device uses type 1 channel access method, the network device can not only send its own data during the channel occupation period, but also share the COT with the terminal device. The so-called sharing of COT with the terminal device means: allowing the terminal device to send data within the time length corresponding to the COT (that is, the COT obtained by the network device through channel access). Correspondingly, if the terminal device uses type 1 channel access method, the terminal device can not only send its own data during the channel occupation period, but also share the COT with the network device.

Table 3 gives the channel access priority and its corresponding parameters when the terminal device performs type 1 channel access.

Table 3

The default channel access mode on the network device side is type 1 channel access mode. The channel access parameters corresponding to the channel access priority p are shown in Table 3. In Table 3, m _p may refer to the number of backoff slots corresponding to the channel access priority p, CW _p may refer to the contention window (CW) size corresponding to the channel access priority p, CW _min,p may refer to the minimum value of CW _p corresponding to the channel access priority p, CW _max,p may refer to the maximum value of CW _p corresponding to the channel access priority p, and T _mcot,p refers to the maximum occupancy time length of the channel corresponding to the channel access priority p.

The channel access method of type 2 (channel access method of Type 2) may also be referred to as a channel access method based on a fixed-length channel monitoring time slot. The channel access method of type 2 includes the channel access method of type 2A (channel access method of Type 2A), the channel access method of type 2B (channel access method of Type 2B), and the channel access method of type 2C (channel access method of Type 2C). When resources within the COT are shared with other communication devices, other communication devices may use the channel access method of type 2.

In the channel access mode of type 2A, the communication device can use a single time slot detection of the channel of 25us. That is, the communication device can start channel detection 25us before data starts to be sent. The 25us channel detection can include a 16us channel detection and a 9us channel detection. If both detection results indicate that the channel is idle, it can be considered that the channel is idle and channel access can be performed.

In the channel access mode of type 2B, the communication device may use a 16us single-slot channel detection. During the channel detection process, if the communication device detects that the channel is idle for more than 4us in the last 9us, the channel may be considered idle.

In the channel access method of type 2C, the communication device can directly transmit data through the channel without channel detection. In the channel access method of type 2C, the time difference between the current transmission and the previous transmission is less than or equal to 16us. In other words, if the time difference between two transmissions is less than or equal to 16us, they can be considered to be the same transmission and channel detection is not required. It should be noted that in the channel access method of type 2C, the transmission time of the communication device is limited and usually cannot exceed 584us.

The above introduces the channel access method based on LBT, and the following introduces SCSt. In the unlicensed spectrum, in order to improve the success rate of communication equipment accessing the channel when transmitting control signaling, SCSt is introduced. SCSt is a transmission in which the communication device does not sense whether there are other signals on the channel. For example, SCSt is a communication device used to send management and control frames without sensing whether there are other signals on the channel. In other words, when a communication device adopts SCSt, the communication device does not need to listen to the channel to access the channel for transmission. However, the use of SCSt needs to meet certain conditions. For example, if a communication device hopes to use SCSt for channel access, the communication device needs to meet one or more of the following conditions: within an observation period of 50ms, the number of times SCSt is used is less than or equal to 50; and within an observation period of 50ms, the duration occupied by SCSt does not exceed 2.5ms.

From the above content, it can be seen that the channel access mechanism of type 1 requires a relatively long channel monitoring process. In the case of successful channel access, it is necessary to perform another short LBT (i.e., LBT with a shorter duration) before sending to ensure that the resources are not snatched away by users of different systems (such as WiFi users). In addition, the sending resources after successful access through type 1 can be shared with other communication devices. For example, in a possible design of sidelink unlicensed (SL-U), the terminal device can share the sending resources after successful type 1 access with other terminal devices, while other terminal devices need to perform Type-2A/B/C LBT before sending in shared resources (such as COT resources) according to specific conditions to ensure that the resources are still valid and have not been snatched away before sending.

The following uses Figure 17 as an example to illustrate the process in which a terminal device can access a channel as type 1 or type 2. Figure 17 is an example diagram of a terminal device accessing a channel on an unlicensed spectrum. Terminal device 1 (represented by UE1 in Figure 17) performs type 1 channel access in time slot (slot) n. In time slot n+1, terminal device 1 sends data. Before time slot n+1, terminal device 1 performs a short LBT, and then transmits data after the short LBT is successful. Terminal device 1 shares time slot n+2 in the resources within the COT with other communication devices. Terminal device 2 (represented by UE2 in Figure 17) performs type 2A channel access before time slot n+2. After the channel access is successful, terminal device 2 transmits data in time slot n+2.

Positioning Technology

In communication technology, positioning technology can be a technology that determines the geographical location of a communication device in a communication network by some method.

In some communication systems (such as NR systems), positioning can be achieved through positioning reference signals (PRS). For example, the observed time difference of arrival (OTDOA) positioning method is a positioning method based on positioning reference signals defined in the 3GPP protocol.

Side-traffic based positioning is one of the enhancement schemes of R18 positioning technology. In this topic, the scenarios and requirements of NR positioning use cases within, partially and outside the coverage of cellular networks will be considered. The positioning requirements of V2X use cases, public safety use cases, commercial use cases and industrial internet of things (IIOT) use cases will be considered, and the following functions will be considered to support: absolute positioning, ranging/direction finding and relative positioning; the positioning method combining side-traffic measurement quantities and Uu interface measurement quantities will be studied; the side-traffic positioning reference signal will be studied, including signal design, physical layer control signaling, resource allocation, physical layer measurement quantities, and related physical layer processes, etc.; the positioning system architecture and signaling process, such as configuration, measurement reporting, etc. will be studied.

In the related sideline communication technologies, positioning technology on unlicensed spectrum has not yet been implemented.

Fig. 18 is a schematic flow chart of a communication method provided in an embodiment of the present application. The method shown in Fig. 18 may be performed by the first terminal device and/or the second terminal device. The method shown in Fig. 18 may include step S1810.

Step S1810: In an unlicensed spectrum, a first terminal device sends a first PRS via a sidelink. Correspondingly, a second terminal device receives the first PRS via a sidelink.

The first PRS may be a PRS for sidelink positioning, that is, the first PRS may be a sidelink PRS (SL-PRS). As an implementation, based on the first PRS, one or more positioning technologies of sidelink communication within network coverage, sidelink communication with partial network coverage, sidelink communication outside network coverage, and sidelink communication by a central control node may be implemented.

It can be understood that, through the first PRS, the positioning technology of sideline communication on the unlicensed spectrum can be implemented. That is, through the first PRS, the positioning of the first terminal device and/or the second terminal device performing sideline communication on the unlicensed spectrum can be implemented. Among them, positioning can include one or more of absolute positioning, ranging/direction finding, and relative positioning.

It should be noted that the first PRS may not need to be sent periodically. Alternatively, the first PRS may also be sent periodically.

The sending of the first PRS may be implemented based on the first channel access. That is, the first terminal device may perform the first channel access to transmit the first PRS in the unlicensed spectrum.

The first channel access may be a channel access method for performing channel monitoring, that is, the first channel access may include a channel monitoring process. The channel monitoring process may be, for example, the LBT process described above. It is understood that if the channel monitoring process is successful, the first channel access process may also be successful. If the channel monitoring process fails, the first channel access process may fail.

The present application does not limit the result of the first channel access. For example, the result of the first channel access may be successful or failed. That is, in the case where the first channel access is successful, the first terminal device may send the first PRS. In the case where the first channel access fails, the first terminal device may also send the first PRS. In some embodiments, in the case where the first channel access fails, the first terminal device may repeatedly send the first PRS. The repeatedly transmitted PRS may be combined to achieve positioning.

The first channel access and the transmission of the first PRS may be performed in the same time slot. For example, the first terminal device may perform the first channel access in the first time slot, and the first terminal device may transmit the first PRS in the first time slot. It is understood that in the first time slot, the first PRS may be transmitted quickly, thereby achieving more efficient transmission of the SL-PRS.

The first time slot may include one or more symbols (e.g., OFDM symbols) for sideline communication. One or more symbols for sideline communication may include resources for SL-U communication. In other words, the first time slot may include resources for SL-U communication and may also include resources for non-SL-U communication. For example, all symbols in the first time slot may be used for sideline communication. Alternatively, some symbols in the first time slot may be used for sideline communication. Among them, the symbols used for sideline communication may be used to transmit sideline signals or sideline channels. For example, the symbols used for sideline communication may be used to transmit one or more of PSCCH, PSSCH, and sidelink synchronization signal block (S-SSB). Among them, the symbols used for sideline communication in a time slot may be continuous.

The first channel access may start at the third symbol, and the third symbol may be, for example, one of the one or more symbols used for sideline communication in the first time slot. It is understandable that the third symbol may be any one of the one or more symbols used for sideline communication in the first time slot. The third symbol may be a preset value, a predefined protocol, a high-level signaling configuration, or determined by the terminal device itself.

As an implementation, in the first time slot, starting from symbol k, n consecutive OFDM symbols can be used for sideline communication. At symbol m, the first channel access can be started. Wherein, k can be an integer greater than or equal to 0, n can be an integer greater than 0, and m can be an integer greater than or equal to k.

The third symbol may be the first symbol of one or more symbols used for sideline communication in the first time slot. That is, in the case where the symbol in the first time slot can be used for sideline communication, the first channel access may be performed immediately. It is understood that in this case, the first channel access may be performed as early as possible, thereby transmitting the first PRS as early as possible.

FIG. 19 is an example diagram of a communication method provided by an embodiment of the present application. In FIG. 19 , the first time slot may be time slot t. The number of symbols n that can be used for sideline communication in time slot t is 12 (i.e., symbol 3 to symbol 13). Symbol 2 is the first of the 12 symbols used for sideline communication. The first channel access may start at symbol 2. That is, the third symbol may be symbol 2.

FIG. 20 is an example diagram of another communication method provided by an embodiment of the present application. In FIG. 20 , the first time slot may be time slot t. The number of symbols n that can be used for sideline communication in time slot t is 12. Time slot t includes 12 symbols for sideline communication, namely symbols 3 to 13. Symbol 4 is one of the 12 symbols for sideline communication. The first channel access may start at symbol 4. That is, the third symbol may be symbol 4.

The first PRS may occupy one or more symbols. In some embodiments, the number of symbols occupied by the first PRS may be less than or equal to the total number of symbols in the first time slot. That is, the resources occupied by the SL-PRS transmission may be less than or equal to one time slot. In some embodiments, the number of symbols occupied by the first PRS may be less than or equal to the number of symbols available for sideline communication in the first time slot.

As an implementation, the first symbol occupied by the first PRS may be the first symbol, the symbol before the first symbol may be the second symbol, and the first channel access may end at the second symbol. Both the first symbol and the second symbol may be symbols used for sideline communication. For example, the first symbol may be the second symbol (i.e., symbol 1) in the first time slot, and the second symbol may be the first symbol (i.e., symbol 0) in the first time slot. That is, the first PRS may be transmitted at the next symbol of the symbol at which the first channel access ends.

Continuing to use FIG. 19 as an example for description, as shown in FIG. 19 , the first channel access ends at symbol 2. That is, symbol 2 is the second symbol. Symbol 3, the next symbol of symbol 2, may be the first symbol. The first PRS may start to be transmitted at symbol 3.

In one implementation, the first channel access process may end at the end time of the second symbol. That is, at the end time of the second symbol, the first channel access process ends. In other words, at the start time of the first channel, the first channel access process ends. For example, the first channel access process may end at the last microsecond of the second symbol. The first PRS may start transmission immediately after the first symbol (the next symbol of the second symbol).

It can be understood that, in the case where the first channel access ends at the end time of the second symbol, there is almost no gap between the first channel access process and the time when the first PRS starts to be transmitted. That is, after the first channel access process ends, usually no other communication device will seize the channel, so that the transmission resources of the first PRS in the unlicensed spectrum will not conflict with the transmission resources of other communication devices.

The start time of the first channel access can be determined according to the end time of the first channel access, so that when the first channel access is completed, the first PRS can be immediately sent in the first symbol. For example, the start time of the first channel access can be determined according to the end time of the first channel access and the duration of the first channel access. As an implementation method, when the first channel access ends at the end time of the second symbol, the start time of the first channel access can be the first moment before the end time of the second symbol, and the time length between the first moment and the end time of the second symbol can be the duration of the first channel access.

Continuing with FIG. 19 as an example, the time C at which the first channel access ends may be the end time of symbol 2 or the start time of symbol 3, and the first PRS may start transmission immediately at symbol 3.

In another implementation, a first time gap may be included between the end time of the first channel access and the start time of the first PRS transmission. That is, after the first channel access ends, the first PRS may not be sent immediately. For example, the first channel access may start at the start time (or start position, start point) of the second symbol in the first time slot. In this case, the end time of the first channel access may be earlier than the end time of the second symbol.

It can be understood that, on the one hand, the first time gap can make the start or end of the first channel access more flexible, that is, the start time or end time of the first channel access may not need to be determined according to the first PRS transmission start time. On the one hand, the first time gap can make the transmission start time of the first PRS more flexible, that is, the transmission start time of the first PRS may not need to be determined according to the end time of the first channel access. As an implementation method, the first channel access can end in the middle of the second symbol (any time between the start time and the end time of the second symbol).

In the first time interval, the first terminal device can send a placeholder, and the second terminal device can receive the placeholder. The placeholder can be used for the first terminal device to occupy the channel accessed by the first channel access process, thereby preventing other communication devices from occupying the channel.

As an implementation method, the placeholder may be a cyclic prefix extension (CPE). Taking the first symbol occupied by the first PRS as the first symbol as an example, if there is still a period of time between the end of the first channel access process and the first symbol, that is, the first time interval is not 0, the first terminal device may send CPE in the first time interval.

FIG21 is an example diagram of a communication method provided by an embodiment of the present application. In FIG21 , the first channel access process ends in the middle of symbol 4, that is, the moment C at which the first channel access ends is not the end moment of symbol 4. The transmission of the first PRS starts at symbol 5. Between the end moment of the first channel access (the middle of symbol 4) and the start moment of the first PRS transmission (the starting point of symbol 5), the first terminal device can send CPE.

The first channel access may not occur on a GAP symbol. For example, the previous time slot of the first time slot is the second time slot. In the second time slot, the last one or more symbols may be a GAP symbol, that is, the GAP symbol is connected to the first time slot. The first channel access may not occur on a GAP symbol in the second time slot. Alternatively, the first time slot may include a GAP symbol, and the first channel access does not occur on a GAP symbol in the first time slot.

Optionally, the previous time slot of the first time slot may be the second time slot. In the case where the second time slot can be used for sideline communication, if the first terminal device or other terminal devices (terminal devices different from the first terminal device) perform sideline communication in the second time slot, the first channel access may not occur on the GAP symbol of the second time slot.

The duration of the first channel access may be shorter. For example, the duration of the first channel access may be less than or equal to the length of one symbol.

In some implementations, the type of the first channel access may be type 2A or type 2B. It is understandable that, compared with most cases of type 1, the channel access duration of type 2A or type 2B (in the case of type 2A or type 2B, the channel access duration may be the channel monitoring duration) is shorter. In some cases, the channel access duration of type 2A and type 2B may be less than the length of one symbol. As described above, the channel access duration of type 2A is 25 microseconds, and the channel access duration of type 2B is 16 microseconds. Taking the sub-carrier spacing (SCS) of 15KHz as an example, the length of one symbol is approximately 71.4 microseconds. The channel access duration of type 2A or type 2B is much less than the length of one symbol, that is, the first channel access process can be completed within one symbol.

It should be noted that the present application does not limit the length of the symbol in the first time slot. Therefore, in some cases, the channel access duration of type 2A or type 2B may also be greater than the length of one symbol. It is understandable that even in this case, the channel access duration of type 2A or type 2B is still shorter than that of most type 1 channels.

It should be noted that, when the type of the first channel access is non-type 1, such as type 2A or type 2B, the first channel access may not be implemented based on the COT sharing scenario. In other words, the default channel access type for the first terminal device to send the first PRS may be non-type 1 (e.g., type 2).

In some implementations, the type of the first channel access may also be type 1. As described above, the CW size of type 1 may be larger or smaller. When the CW is larger (e.g., greater than or equal to the first CW threshold), the duration of the first channel access is longer; when the CW is smaller (e.g., less than or equal to the second CW threshold), the duration of the first channel access is longer. When the type of the first channel access is type 1, the method with a shorter duration in type 1 may be selected for the first channel access.

It can be understood that a shorter channel access duration can save channel access time and resources, and the first PRS can be sent as early as possible to improve positioning efficiency.

In some implementations, the first channel access method may be a channel access method that does not require channel monitoring. That is, the first terminal device may not perform the LBT process and directly send the first PRS. It is understandable that this can greatly simplify the first channel access process.

As an implementation method, the first channel access may be based on the first condition. The first condition may be related to the second time interval, for example. The second time interval may be, for example, the interval between the start time of sending the first PRS and the end time of the last side communication. The end time of the last side communication may be the end time of the transmission of the side communication by the first terminal device or other terminal devices (not the first terminal device). The first condition may include, for example, that when the second time interval is less than the first threshold, the first channel access method may be an access method that does not require channel monitoring. The first threshold may be, for example, X microseconds. X may be an integer greater than 0. X may be preset, specified by the protocol, or configured through high-level signaling.

It is understandable that the first channel access mode may be type 2C. When the first condition is consistent with the channel access condition of type 2C, it can be considered that the first channel access mode is type 2C.

In some embodiments, the transmission mode of the first PRS may be a short control signaling transmission (SCSt) mode. It is understandable that when the transmission mode of the first PRS is the SCSt mode, the channel monitoring process may not be performed, that is, the transmission process of the first PRS may be simplified. It should be noted that when the first PRS is sent in the SCSt mode, the channel monitoring process may also be performed. For example, a first channel access of type 2A or type 2B may be performed and the first PRS may be sent in the SCSt mode.

The first PRS may be carried on a first sidelink resource, and the first sidelink resource is configured in a resource pool by preconfiguration or by high-level signaling. The first sidelink resource may include a time domain resource. For example, a time slot for transmitting the first PRS may be configured in a resource pool by preconfiguration or by high-level signaling.

The first terminal device may acquire the first sidelink resource to transmit the first PRS through sidelink sensing and resource selection mechanism. Alternatively, the first terminal device may directly select the first sidelink resource to transmit the first PRS without sidelink sensing or resource selection mechanism.

Based on the above content, combinations of possible implementation methods of the method provided in the present application may include but are not limited to: 1) The first terminal device does not obtain the sideline transmission resources for transmitting the first PRS through sideline sensing, the first channel access method is type 2A or type 2B, and the first PRS is sent through the SCSt method; 2) The first terminal device obtains the sideline transmission resources for transmitting the first PRS through sideline sensing, the first channel access method is type 2A or type 2B, and the first PRS is sent through the SCSt method; 3) The first terminal device does not obtain the sideline transmission resources for transmitting the first PRS through sideline sensing, the first channel access method is a channel access method that does not require channel monitoring, and the first PRS is sent through the SCSt method.

The communication method provided by the present application is described in detail below through embodiments 1 to 5. It is understandable that embodiments 1 to 5 can be implemented separately or in combination.

Example 1

The method disclosed in Example 1 may include steps S1910 to S1920. The method provided in Example 1 may be implemented by the first terminal device and/or the second terminal device.

Step S1910: The first terminal device accesses the first channel at symbol k.

Symbol k is a symbol in the first time slot. In the first time slot, n consecutive OFDM symbols starting from the kth symbol can be used for sideline communication. That is, symbol k can be used as the first symbol of multiple symbols used for sideline communication in the first time slot. Wherein, k can be an integer greater than or equal to 0, and n can be an integer greater than 0.

The first channel access mode is type 2A or type 2B.

The following is a detailed description in conjunction with FIG19. As shown in FIG19, time slot t may be the first time slot. Symbol 0 and symbol 1 in time slot t are not used for sideline communication. The resources used for sideline communication are n symbols starting from symbol 2 of time slot t (i.e., the resources in the dashed rectangular box). It can be understood that in FIG19, n=12, k=2.

The length of the symbol k may satisfy the second condition. The second condition may include that the length of the symbol k is greater than or equal to the channel monitoring (eg, LBT process) duration L of the channel access process.

Taking Figure 19 as an example, when the subcarrier spacing is 15KHz, the length of one symbol is approximately 71.4μs. Taking the first channel access mode as type 2A as an example, the channel monitoring time length L can be 25μs. Taking the first channel access mode as type 2B as an example, the channel monitoring time length L can be 16μs. It can be understood that the first channel access mode is type 2A or type 2B, both of which can meet the second condition.

Step S1920: When the first channel access is successful, the first terminal device may start to send the first PRS from symbol k+1. The second terminal device may start to receive the first PRS from symbol k+1.

It should be noted that, at the start time of the channel monitoring process of the first channel access, it is necessary to ensure that the first PRS can be sent immediately at symbol k+1 after the channel monitoring is completed and the channel access is successful.

Continuing with FIG. 19 as an example, within symbol 2 and before symbol 3, the first terminal device must complete the first channel access process (including the channel monitoring process). In FIG. 19, the channel monitoring process is completed in the last microsecond of symbol 2, and the first channel access process is successfully completed. The first terminal device then starts sending the first PRS (i.e., SL-PRS) in symbol 3.

In FIG. 19 , the transmission of the first PRS occupies seven symbols, namely, symbol 3 to symbol 9 .

In some implementations, the resources used for the sidewalk communication may be acquired through sidewalk sensing. For example, if the first terminal device performs sidewalk sensing, the resources used for the sidewalk communication may be acquired through a sidewalk sensing and resource selection process.

In some implementations, the resources for the sidewalk communication may be obtained from a resource pool. For example, the first terminal device may not perform sidewalk perception, and the first terminal device may obtain the resources for the sidewalk communication through high-level signaling configuration or pre-configuration.

Example 2

The method disclosed in Embodiment 2 may include steps S2010 to S2020. The method provided in Embodiment 3 may be implemented by the first terminal device and/or the second terminal device.

Step S2010: The first terminal device performs a first channel access at symbol m of the first time slot.

Symbol k is a symbol in the first time slot. In the first time slot, n consecutive OFDM symbols starting from the kth symbol can be used for sideline communication. That is, symbol k can be used as the first symbol of multiple symbols used for sideline communication in the first time slot. Wherein, k can be an integer greater than or equal to 0, and n can be an integer greater than 0.

The symbol m may be an integer greater than or equal to k. That is, the symbol m is any one of the n OFDM symbols.

The first channel access mode is type 2A or type 2B.

The following is a detailed description in conjunction with FIG20. As shown in FIG20, time slot t may be the first time slot. Symbol 0 and symbol 1 in time slot t are not used for sideline communication. The resources used for sideline communication are n symbols starting from symbol 2 of time slot t (i.e., the resources in the dotted rectangular box). The first terminal device performs the first channel access at symbol 4. It can be understood that in FIG20, n=12, k=2, and m=4.

Step S2020: When the first channel access is successful, the first terminal device may start to send the first PRS from symbol m+1. The second terminal device may start to receive the first PRS from symbol m+1.

It can be understood that embodiment 1 can be a special case of embodiment 2 where m=k.

Example 3

The method disclosed in Embodiment 3 may include steps S2110 to S2130. The method provided in Embodiment 3 may be implemented by the first terminal device and/or the second terminal device.

Step S2110: The first terminal device performs a first channel access at symbol m of the first time slot.

The first channel access starts at the starting point of symbol m. As shown in FIG21, m=4, and the first channel access process starts from the starting point of symbol 4.

Step S2120: the first terminal device sends a placeholder after the first channel access process is completed, and the second terminal device receives the placeholder after the first channel access process is completed.

As shown in FIG21 , if the moment when the first channel access is successful (also the moment when the channel monitoring is successful) has not yet reached the start moment (i.e., the starting point or the start boundary) of symbol 5, the first terminal device may start sending the placeholder at the moment when the first channel access is successful, and end the sending of the placeholder at the start moment of symbol 5. The placeholder may be a CPE.

It is understandable that, in Embodiment 3, the first terminal device may not be required to start accessing the first channel at the position of symbol 4. In other words, the start time of accessing the first channel may be flexibly determined.

Step S2130: The first terminal device starts to send the first PRS at symbol m+1. The second terminal device starts to receive the first PRS at symbol m+1.

Example 4

Fig. 22 is an example diagram of a communication method provided in Embodiment 4. The method shown in Fig. 22 may include steps S2210 to S2220. The method provided in Embodiment 4 may be executed by the first terminal device and/or the second terminal device.

Step S2210: The first terminal device performs a first channel access at symbol m of the first time slot.

All symbols in the first time slot can be used for side communication. As shown in Figure 22, time slot t can be the first time slot, and symbols 0 to 13 in the first time slot can all be used for side communication. All symbols in time slot t-1 can also be used for side communication (the resources that can be used for side communication in time slot t and time slot t-1 are framed by a rectangular dotted box). Symbol m can be any symbol in the first time slot. In Figure 22, symbol m can be symbol 0, and symbol 0 is the first symbol of the first time slot. That is to say, the first terminal device can perform first channel access at the first symbol of the first time slot.

The access mode of the first channel access is type 2A or type 2B. The length of the symbol m may satisfy the second condition. The second condition includes that the length of the symbol m is greater than or equal to the channel monitoring (e.g., LBT process) duration L of the channel access process. Taking the first channel access mode as type 2A as an example, the channel monitoring duration L may be 25μs, then the second condition includes that the length of the symbol m is greater than or equal to 25μs. Taking the first channel access mode as type 2B as an example, the channel monitoring duration L may be 16μs, then the second condition may include that the length of the symbol m is greater than or equal to 16μs.

Embodiment 4 does not limit the start time and end time of the first channel access process. For example, the start time of the first channel access process can ensure that the first PRS can be sent immediately on symbol m+1 when the first channel access process ends (similar to embodiment 1 or embodiment 2). Alternatively, the end time of the first channel access process can be a time interval (i.e., a first time interval) from the symbol m+1, during which a placeholder CPE can be sent to ensure that resources are not preempted by other devices (similar to embodiment 3).

Step S2220: The first terminal device sends a first PRS at symbol m+1 of the first time slot. The second terminal device receives the first PRS at the second symbol of the first time slot.

In FIG. 22 , at the second symbol (symbol 1) of time slot t, the first PRS is transmitted or received.

Optionally, the previous time slot of time slot t, that is, time slot t-1, may also be a time slot for sideline communication. In time slot t-1, there is a first terminal device or a terminal device different from the first terminal device performing sideline transmission. In this case, the first terminal device does not perform a channel monitoring process for first channel access in the GAP symbol of time slot t-1.

Example 5

In Embodiment 5, the first channel access may be a channel access mode that does not require channel monitoring. That is, the first terminal device may directly transmit the first PRS without performing LBT.

In one implementation, when the interval between the start time of sending the first PRS and the end time of the previous sideline communication is the second time interval, if the second time interval is less than or equal to Xμs, the first terminal device may directly send the first PRS without channel monitoring. Wherein, X is greater than or equal to 0. It can be understood that in this implementation, the type of the first channel access may be type 2C.

In one implementation, the first terminal device may directly send the first PRS in any symbol on the resource used for sideline communication without performing LBT. The first PRS may be sent in a SCSt sending manner.

The method embodiment of the present application is described in detail above in conjunction with Figures 1 to 22, and the device embodiment of the present application is described in detail below in conjunction with Figures 23 to 25. It should be understood that the description of the method embodiment corresponds to the description of the device embodiment, so the part not described in detail can refer to the previous method embodiment.

23 is a schematic structural diagram of a terminal device 2300 provided in an embodiment of the present application. The terminal device 2300 is a first terminal device, and the terminal device 2300 includes a first sending unit 2310 .

The first sending unit 2310 may be configured to send a first positioning reference signal PRS via a sidelink in an unlicensed spectrum.

Optionally, the terminal device 2300 may further include an access unit 2320. The access unit 2320 is configured to perform a first channel access in a first time slot, wherein the first channel access is used to send the first PRS in the first time slot.

Optionally, the first symbol occupied by the first PRS is a first symbol, the symbol before the first symbol is a second symbol, and the first channel access ends at the second symbol.

Optionally, the first channel access ends at an end time of the second symbol.

Optionally, a first time gap is included between the end time of the first channel access and the start time of the first PRS transmission, and the terminal device 2300 further includes: a second sending unit, configured to send a placeholder in the first time gap.

Optionally, the first channel access starts at a third symbol, and the third symbol is one of one or more symbols in the first time slot that can be used for sideline communication.

Optionally, the third symbol is the first symbol of one or more symbols that can be used for sideline communication in the first time slot.

Optionally, the first channel access does not occur on a gap GAP symbol.

Optionally, the type of the first channel access is type 2A or type 2B.

Optionally, the first channel access method is a channel access method that does not require channel monitoring.

Optionally, the first channel access is performed based on a first condition.

Optionally, the interval between the start time of sending the first PRS and the end time of the previous sideline communication is a second time interval, and the first condition is related to the second time interval.

Optionally, the type of the first channel access is type 2C.

Optionally, the first PRS is sent in a short control signaling SCSt manner.

Optionally, the first PRS is carried on a first sidelink resource, and the first sidelink resource is configured in a resource pool by pre-configuration or by high-layer signaling.

FIG24 is a schematic structural diagram of a terminal device 2400 provided in an embodiment of the present application. The terminal device 2400 may be a second terminal device. The terminal device 2400 may include a first receiving unit 2410 .

The first receiving unit 2410 is configured to receive a first positioning reference signal PRS via a sidelink in an unlicensed spectrum.

Optionally, the transmission of the first PRS is performed based on a first channel access on a first time slot, and the first channel access is used to send the first PRS in the first time slot.

Optionally, the first symbol occupied by the first PRS is a first symbol, the symbol before the first symbol is a second symbol, and the first channel access ends at the second symbol.

Optionally, the first channel access ends at an end time of the second symbol.

Optionally, a first time gap is included between the end time of the first channel access and the start time of the first PRS transmission, and the terminal device 2400 may further include a second receiving unit 2420. The second receiving unit 2420 may be configured to receive a placeholder in the first time gap.

Optionally, the first channel access starts at a third symbol, and the third symbol is one of one or more symbols in the first time slot that can be used for sideline communication.

Optionally, the third symbol is the first symbol of one or more symbols that can be used for sideline communication in the first time slot.

Optionally, the first channel access does not occur on a gap GAP symbol.

Optionally, the type of the first channel access is type 2A or type 2B.

Optionally, the first channel access method is a channel access method that does not require channel monitoring.

Optionally, the first channel access is performed based on a first condition.

Optionally, the interval between the start time of sending the first PRS and the end time of the previous sideline communication is a second time interval, and the first condition is related to the second time interval.

Optionally, the type of the first channel access is type 2C.

Optionally, the first PRS is sent in a short control signaling SCSt manner.

Optionally, the first PRS is carried on a first sidelink resource, and the first sidelink resource is configured in a resource pool by pre-configuration or by high-layer signaling.

In an optional embodiment, the first sending unit 2310, the first receiving unit 2410 or the second receiving unit may be a transceiver 2540, and the access unit 2320 may be a processor 2510. The terminal device 2300 or the terminal device 2400 may further include a memory 2520, as specifically shown in FIG.

FIG25 is a schematic structural diagram of a communication device according to an embodiment of the present application. The dotted lines in FIG25 indicate that the unit or module is optional. The device 2500 may be used to implement the method described in the above method embodiment. The device 2500 may be a chip, a terminal device, or a network device.

The device 2500 may include one or more processors 2510. The processor 2510 may support the device 2500 to implement the method described in the method embodiment above. The processor 2510 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 also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

The apparatus 2500 may further include one or more memories 2520. The memory 2520 stores a program, which can be executed by the processor 2510, so that the processor 2510 executes the method described in the above method embodiment. The memory 2520 may be independent of the processor 2510 or integrated in the processor 2510.

The apparatus 2500 may further include a transceiver 2530. The processor 2510 may communicate with other devices or chips through the transceiver 2530. For example, the processor 2510 may transmit and receive data with other devices or chips through the transceiver 2530.

The present application also provides a computer-readable storage medium for storing a program. The computer-readable storage medium can be applied to a terminal or network device provided in the present application, and the program enables a computer to execute the method performed by the terminal or network device in each embodiment of the present application.

The embodiment of the present application also provides a computer program product. The computer program product includes a program. The computer program product can be applied to the terminal or network device provided in the embodiment of the present application, and the program enables the computer to execute the method performed by the terminal or network device in each embodiment of the present application.

The embodiment of the present application also provides a computer program. The computer program can be applied to the terminal or network device provided in the embodiment of the present application, and the computer program enables a computer to execute the method executed by the terminal or network device in each embodiment of the present application.

It should be understood that the terms "system" and "network" in this application can be used interchangeably. In addition, the terms used in this application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application. The terms "first", "second", "third" and "fourth" in the specification and claims of this application and the accompanying drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions.

In the embodiments of the present application, the "indication" mentioned can be a direct indication, an indirect indication, or an indication of an association relationship. For example, A indicates B, which can mean that A directly indicates B, for example, B can be obtained through A; it can also mean that A indirectly indicates B, for example, A indicates C, and B can be obtained through C; it can also mean that there is an association relationship between A and B.

In the embodiment of the present application, "B corresponding to A" means that B is associated with A, and B can be determined according to A. However, it should be understood that determining B according to A does not mean determining B only according to A, and B can also be determined according to A and/or other information.

In the embodiments of the present application, the term "corresponding" may indicate that there is a direct or indirect correspondence between the two, or an association relationship between the two, or a relationship of indication and being indicated, configuration and being configured, etc.

In the embodiments of the present application, "pre-definition" or "pre-configuration" can be implemented by pre-saving corresponding codes, tables or other methods that can be used to indicate relevant information in a device (for example, including a terminal device and a network device), and the present application does not limit the specific implementation method. For example, pre-definition can refer to what is defined in the protocol.

In the embodiments of the present application, the “protocol” may refer to a standard protocol in the communication field, for example, it may include an LTE protocol, an NR protocol, and related protocols used in future communication systems, and the present application does not limit this.

In the embodiments of the present application, the term "and/or" is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and/or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character "/" in this article generally indicates that the associated objects before and after are in an "or" relationship.

In various embodiments of the present application, the size of the above-mentioned serial numbers does not mean the order of execution. The order of execution should be determined by its function and internal logic, and should not constitute any limitation on the implementation of the embodiments of the present application.

In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part 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 process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium may be any available medium that can be read by a computer or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital video disc (DVD)), or a semiconductor medium (eg, a solid state disk (SSD)).

The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims (66)

A communication method, characterized in that the method comprises: In the unlicensed spectrum, the first terminal device sends a first positioning reference signal PRS via a sidelink. The method according to claim 1, characterized in that the method further comprises: The first terminal device performs first channel access in a first time slot; The first channel access is used to send the first PRS in the first time slot. The method according to claim 2 is characterized in that the first symbol occupied by the first PRS is the first symbol, the previous symbol of the first symbol is the second symbol, and the first channel access ends at the second symbol. The method according to claim 3 is characterized in that the first channel access ends at an end time of the second symbol. The method according to claim 2 or 3, characterized in that the end time of the first channel access and the start time of the first PRS transmission include a first time gap, and the method further comprises: In the first time interval, the first terminal device sends a placeholder. The method according to any one of claims 2-5 is characterized in that the first channel access starts at a third symbol, and the third symbol is one of one or more symbols in the first time slot that can be used for sideline communication. The method according to claim 6 is characterized in that the third symbol is the first symbol of one or more symbols that can be used for sideline communication in the first time slot. The method according to any one of claims 2-7 is characterized in that the first channel access does not occur on a gap GAP symbol. The method according to any one of claims 2-8 is characterized in that the type of the first channel access is type 2A or type 2B. The method according to any one of claims 2-8 is characterized in that the first channel access method is a channel access method that does not require channel monitoring. The method according to claim 10 is characterized in that the first channel access is performed based on a first condition. The method according to claim 11 is characterized in that the interval between the start time of sending the first PRS and the end time of the previous sideline communication is a second time interval, and the first condition is related to the second time interval. The method according to any one of claims 10-12 is characterized in that the type of the first channel access is type 2C. The method according to any one of claims 1-13 is characterized in that the sending method of the first PRS is a short control signaling SCSt sending method. The method according to any one of claims 1-14 is characterized in that the first PRS is carried on a first sidelink resource, and the first sidelink resource is configured in a resource pool by pre-configuration or by high-layer signaling. A communication method, characterized in that the method comprises: In the unlicensed spectrum, the second terminal device receives the first positioning reference signal PRS through the side link. The method according to claim 16 is characterized in that the transmission of the first PRS is performed based on a first channel access on a first time slot, and the first channel access is used to send the first PRS in the first time slot. The method according to claim 17 is characterized in that the first symbol occupied by the first PRS is a first symbol, the previous symbol of the first symbol is a second symbol, and the first channel access ends at the second symbol. The method according to claim 18 is characterized in that the first channel access ends at an end time of the second symbol. The method according to claim 17 or 18, characterized in that the end time of the first channel access and the start time of the first PRS transmission include a first time gap, and the method further comprises: In the first time interval, the second terminal device receives a placeholder. The method according to any one of claims 17-20 is characterized in that the first channel access starts at a third symbol, and the third symbol is one of one or more symbols in the first time slot that can be used for sideline communication. The method according to claim 21 is characterized in that the third symbol is the first symbol of one or more symbols that can be used for sideline communication in the first time slot. The method according to any one of claims 17-22 is characterized in that the first channel access does not occur on a gap GAP symbol. The method according to any one of claims 17-23 is characterized in that the type of the first channel access is type 2A or type 2B. The method according to any one of claims 17-23 is characterized in that the first channel access method is a channel access method that does not require channel monitoring. The method according to claim 25 is characterized in that the first channel access is performed based on a first condition. The method according to claim 26 is characterized in that the interval between the start time of sending the first PRS and the end time of the previous side communication is a second time interval, and the first condition is related to the second time interval. The method according to any one of claims 25-27 is characterized in that the type of the first channel access is type 2C. The method according to any one of claims 16-28 is characterized in that the first PRS is sent in a short control signaling SCSt manner. The method according to any one of claims 16-29 is characterized in that the first PRS is carried on a first sidelink resource, and the first sidelink resource is configured in a resource pool by pre-configuration or by high-layer signaling. A terminal device, characterized in that the terminal device is a first terminal device, and the terminal device comprises: The first sending unit is used to send a first positioning reference signal PRS through a side link on an unlicensed spectrum. The terminal device according to claim 31, characterized in that the terminal device further comprises: An access unit, configured to access a first channel in a first time slot; The first channel access is used to send the first PRS in the first time slot. The terminal device according to claim 32 is characterized in that the first symbol occupied by the first PRS is the first symbol, the previous symbol of the first symbol is the second symbol, and the first channel access ends at the second symbol. The terminal device according to claim 33 is characterized in that the first channel access ends at the end time of the second symbol. The terminal device according to claim 32 or 33, characterized in that the end time of the first channel access and the start time of the first PRS transmission include a first time gap, and the terminal device further includes: The second sending unit is used to send a placeholder in the first time interval. The terminal device according to any one of claims 32-35 is characterized in that the first channel access starts at a third symbol, and the third symbol is one of one or more symbols in the first time slot that can be used for side communication. The terminal device according to claim 36 is characterized in that the third symbol is the first symbol of one or more symbols in the first time slot that can be used for sideline communication. The terminal device according to any one of claims 32-37 is characterized in that the first channel access does not occur on the gap GAP symbol. The terminal device according to any one of claims 32-38 is characterized in that the type of the first channel access is type 2A or type 2B. The terminal device according to any one of claims 32-38 is characterized in that the first channel access method is a channel access method that does not require channel monitoring. The terminal device according to claim 40 is characterized in that the first channel access is performed based on a first condition. The terminal device according to claim 41 is characterized in that the interval between the start time of sending the first PRS and the end time of the previous side communication is a second time interval, and the first condition is related to the second time interval. The terminal device according to any one of claims 40-42 is characterized in that the type of the first channel access is type 2C. The terminal device according to any one of claims 31-43 is characterized in that the sending method of the first PRS is a short control signaling SCSt sending method. The terminal device according to any one of claims 31-44 is characterized in that the first PRS is carried on a first sideline resource, and the first sideline resource is configured in a resource pool by pre-configuration or by high-layer signaling. A terminal device, characterized in that the terminal device is a second terminal device, and the terminal device comprises: The first receiving unit is configured to receive a first positioning reference signal PRS via a sidelink in an unlicensed spectrum. The terminal device according to claim 46 is characterized in that the transmission of the first PRS is performed based on a first channel access on a first time slot, and the first channel access is used to send the first PRS in the first time slot. The terminal device according to claim 47 is characterized in that the first symbol occupied by the first PRS is the first symbol, the previous symbol of the first symbol is the second symbol, and the first channel access ends at the second symbol. The terminal device according to claim 48 is characterized in that the first channel access ends at the end time of the second symbol. The terminal device according to claim 47 or 48, characterized in that a first time gap is included between the end time of the first channel access and the start time of the first PRS transmission, and the terminal device further comprises: The second receiving unit is used to receive a placeholder in the first time interval. The terminal device according to any one of claims 47-50 is characterized in that the first channel access starts at a third symbol, and the third symbol is one of one or more symbols in the first time slot that can be used for side communication. The terminal device according to claim 51 is characterized in that the third symbol is the first symbol of one or more symbols that can be used for sideline communication in the first time slot. The terminal device according to any one of claims 47-52 is characterized in that the first channel access does not occur on the gap GAP symbol. The terminal device according to any one of claims 47-53 is characterized in that the type of the first channel access is type 2A or type 2B. The terminal device according to any one of claims 47-53 is characterized in that the first channel access method is a channel access method that does not require channel monitoring. The terminal device according to claim 55 is characterized in that the first channel access is performed based on a first condition. The terminal device according to claim 56 is characterized in that the interval between the start time of sending the first PRS and the end time of the previous side communication is a second time interval, and the first condition is related to the second time interval. The terminal device according to any one of claims 55-57 is characterized in that the type of first channel access is type 2C. The terminal device according to any one of claims 46-58 is characterized in that the sending method of the first PRS is a short control signaling SCSt sending method. The terminal device according to any one of claims 46-59 is characterized in that the first PRS is carried on a first sidelink resource, and the first sidelink resource is configured in a resource pool by preconfiguration or by high-layer signaling. A terminal device, characterized in that it includes a transceiver, a memory and a processor, the memory is used to store programs, and the processor is used to call the program in the memory so that the terminal executes the method as described in any one of claims 1-30. A device, characterized in that it comprises a processor, which is used to call a program from a memory so that the device executes the method as described in any one of claims 1-30. A chip, characterized in that it comprises a processor for calling a program from a memory so that a device equipped with the chip executes a method as described in any one of claims 1 to 30. A computer-readable storage medium, characterized in that a program is stored thereon, wherein the program enables a computer to execute the method according to any one of claims 1 to 30. A computer program product, characterized in that it comprises a program, wherein the program enables a computer to execute the method according to any one of claims 1 to 30. A computer program, characterized in that the computer program enables a computer to execute the method according to any one of claims 1 to 30.