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 technologies, and more particularly, to a communication method and a terminal device.

Background

The location of the communication device in the communication network can be determined by means of positioning techniques. For example, in some communication systems (e.g., NR systems), positioning may be achieved by Positioning Reference Signals (PRS) REFERENCE SIGNAL.

In the sidestream communication technology, how to implement the positioning technology on the unlicensed spectrum is a problem to be solved.

Disclosure of Invention

The application provides a communication method and terminal equipment. Various aspects of the application are described below.

In a first aspect, a communication method is provided, the method comprising: on the unlicensed spectrum, the first terminal device transmits a first positioning reference signal PRS over a side uplink.

In a second aspect, there is provided a communication method, the method comprising: on the unlicensed spectrum, the second terminal device receives the first positioning reference signal PRS over the side uplink.

In a third aspect, a terminal device is provided, where the terminal device is a first terminal device, and the terminal device includes: and a first transmitting unit for transmitting the first positioning reference signal PRS over the side uplink over an unlicensed spectrum.

In a fourth aspect, there is provided a terminal device, the terminal device being a second terminal device, the terminal device comprising: a first receiving unit for receiving a first positioning reference signal PRS over a side uplink over an unlicensed spectrum.

In a fifth aspect, there is provided a terminal comprising a processor, a memory for storing one or more computer programs, and a transceiver, the processor being for invoking the computer programs in the memory to cause the terminal device to perform some or all of the steps of the methods of the first and/or second aspects.

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

In a seventh aspect, embodiments of the present application provide a computer-readable storage medium storing a computer program that causes a terminal to execute some or all of the steps of the methods of the above aspects.

In an eighth aspect, embodiments of the present application provide a computer program product, wherein the computer program product comprises a non-transitory computer readable storage medium storing a computer program operable to cause a terminal to perform some or all of the steps of the methods of the above aspects. In some implementations, the computer program product can be a software installation package.

In a ninth aspect, embodiments of the present application provide a chip comprising a memory and a processor, the processor being operable to invoke 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 appreciated that with the first PRS, a positioning technique for upstream communication over unlicensed spectrum may be implemented. That is, through the first PRS, positioning of the first terminal device and/or the second terminal device for sidelink communication over an unlicensed spectrum may be achieved.

Drawings

Fig. 1 is a diagram illustrating an example of a system architecture of a wireless communication system to which embodiments of the present application may be applied.

FIG. 2 is an exemplary diagram of a scenario for sidestream communications within a network overlay.

Fig. 3 is an exemplary diagram of a scenario for partial network coverage sidestream communication.

Fig. 4 is an exemplary diagram of a scenario for sidestream communications outside of a network coverage.

FIG. 5 is an exemplary diagram of a scenario for side-row communication with a central control node.

Fig. 6 is an example diagram of a broadcast-based side-row communication scheme.

Fig. 7 is an example diagram of a unicast-based sidestream communication scheme.

Fig. 8 is an example diagram of a side-row communication scheme based on multicast.

Fig. 9 is an exemplary diagram of a time slot structure for some sidestream communication systems (e.g., NR-V2X systems).

Fig. 10 is an exemplary diagram of a change in the available OFDM symbols of the PSSCH in different slots.

Fig. 11 is an exemplary diagram of time-frequency resources occupied by a second order SCI in one slot.

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

Fig. 13 is a schematic diagram of time domain positions of 4 DMRS symbols when PSSCH is 14 symbols.

Fig. 14 is a diagram illustrating an example of a single symbol DMRS frequency domain type 1.

Fig. 15 is a diagram illustrating an example of a time-frequency location of a SL CSI-RS.

Fig. 16 is an exemplary diagram of a primary channel occupation time obtained by a communication device after LBT is successful on a channel of an unlicensed spectrum, and signaling using resources within the channel occupation time.

Fig. 17 is a diagram illustrating a scenario in which a terminal device performs channel access.

Fig. 18 is a schematic flow chart of a communication method according to an embodiment of the present application.

Fig. 19 is an exemplary diagram of a communication method according to an embodiment of the present application.

Fig. 20 is an exemplary diagram of a communication method according to an embodiment of the present application.

Fig. 21 is an exemplary diagram of a communication method according to an embodiment of the present application.

Fig. 22 is an exemplary diagram of a communication method according to an embodiment of the present application.

Fig. 23 is a schematic block diagram of a terminal device according to an embodiment of the present application.

Fig. 24 is a schematic block diagram of a terminal device according to an embodiment of the present application.

Fig. 25 is a schematic structural diagram of an apparatus according to an embodiment of the present application.

Detailed Description

The technical scheme of the application will be described below with reference to the accompanying drawings.

Communication system

Fig. 1 is a diagram illustrating an example of a system architecture of a wireless communication system 100 to which embodiments of the present application are applied. The wireless communication system 100 may include a network device 110 and a terminal device 120. Network device 110 may be a device that communicates with terminal device 120. Network device 110 may provide communication coverage for a particular geographic area and may communicate with terminal devices 120 located within the coverage area.

Alternatively, the wireless communication system 100 may include a plurality of network devices and each network device may include other numbers of terminal devices within a coverage area of the network device, which is not limited by the embodiments of the present application.

Optionally, the wireless communication system 100 may further include a network controller, a mobility management entity, and other network entities, which are not limited by the embodiment of the present application.

It should be understood that the technical solution of the embodiment of the present application may be applied to various communication systems, for example: fifth generation (5th generation,5G) systems or New Radio (NR), long term evolution (long term evolution, LTE) systems, LTE frequency division duplex (frequency division duplex, FDD) systems, LTE time division duplex (time division duplex, TDD), and the like. The technical scheme provided by the application can also be applied to future communication systems, such as a sixth generation mobile communication system, a satellite communication system and the like.

The terminal device in the embodiments of the present application may also be referred to as a User Equipment (UE), an access terminal, a subscriber unit, a subscriber station, a Mobile Station (MS), a Mobile Terminal (MT), a remote station, a remote terminal, a mobile device, a user terminal, a wireless communication device, a user agent, or a user equipment. The terminal device in the embodiment of the application can be a device for providing voice and/or data connectivity for a user, and can be used for connecting people, things and machines, such as a handheld device with a wireless connection function, a vehicle-mounted device and the like. The terminal device in the embodiments of the present application may be a mobile phone (mobile phone), a tablet (Pad), a notebook, a palm, a Mobile Internet Device (MID), a wearable device, a Virtual Reality (VR) device, an augmented reality (augmented reality, AR) device, a wireless terminal in industrial control (industrial control), a wireless terminal in unmanned (SELF DRIVING), a wireless terminal in teleoperation (remote medical surgery), a wireless terminal in smart grid (SMART GRID), a wireless terminal in transportation security (transportation safety), a wireless terminal in smart city (SMART CITY), a wireless terminal in smart home (smart home), and the like. Alternatively, the terminal device may be used to act as a base station. For example, the terminal devices may act as scheduling entities that provide side-uplink signals between terminal devices in vehicle-to-everything, V2X, or device-to-device (D2D), etc. For example, a cellular telephone and a car communicate with each other using side-link signals. Communication between the cellular telephone and the smart home device is accomplished without relaying communication signals through the base station. Alternatively, the terminal device may 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 radio access network device, for example, the network device may be a base station. The network device in the embodiments of the present application may refer to a radio access network (radio access network, RAN) node (or device) that accesses the terminal device to the wireless network. The base station may broadly cover or replace various names in the following, such as: a node B (NodeB), an evolved NodeB (eNB), a next generation NodeB (gNB), a relay station, an access point, a transmission point (TRANSMITTING AND RECEIVING point, TRP), a transmission point (TRANSMITTING POINT, TP), a master MeNB, a secondary SeNB, a multi-mode wireless (MSR) node, a home base station, a network controller, an access node, a radio node, an Access Point (AP), a transmission node, a transceiver node, a baseband unit (BBU), a radio remote unit (Remote Radio Unit, RRU), an active antenna unit (ACTIVE ANTENNA unit, AAU), a radio head (remote radio head, RRH), a Central Unit (CU), a Distributed Unit (DU), a positioning node, and the like. The base station may be a macro base station, a micro base station, a relay node, a donor node, or the like, or a combination thereof. A base station may also refer to a communication module, modem, or chip for placement within the aforementioned device or apparatus. The base station may also be a mobile switching center and a device-to-device (D2D), a vehicle-to-vehicle (vehicle to vehicle, V2V), a vehicle-to-everything, V2X, a device that assumes a base station function in machine-to-machine (M2M) communication, a network-side device in a 6G network, a device that assumes a base station function in a future communication system, or the like. The base stations may support networks of the same or different access technologies. The embodiment of the application does not limit the specific technology and the specific equipment form adopted by the network equipment.

The base station may be fixed or mobile. For example, a helicopter or drone may be configured to act as a mobile base station, and one or more cells may move according to the location of the mobile base station. In other examples, a helicopter or drone may be configured to function as a device to communicate with another base station.

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

Network devices and terminal devices may be deployed on land, including indoors or outdoors, hand-held or vehicle-mounted; the device can be deployed on the water surface; but also on aerial planes, balloons and satellites. In the embodiment of the application, the scene where the network equipment and the terminal equipment are located is not limited.

It should be understood that all or part of the functionality of the communication device in the present application may also be implemented by software functions running on hardware or by virtualized functions instantiated on a platform, such as a cloud platform.

Sidestream communication under different network coverage conditions

Side-link communication (or side-transmission) refers to a side-link (SL) based communication technology. The sidestream communication may be, for example, D2D or V2X. The side communication supports the direct communication data transmission between the terminal devices. The transmission of communication data between the terminal device and the terminal device directly can have higher spectral efficiency and lower transmission delay. For example, internet of vehicles systems employ sidestream communication techniques.

In the sidestream communication, the sidestream communication can be divided into sidestream communication in the network coverage, sidestream communication in part of the network coverage, sidestream communication outside the network coverage and sidestream communication by the central control node according to the condition of the network coverage where the terminal device is located.

FIG. 2 is an exemplary diagram of a scenario for sidestream communications within a network overlay. In the scenario shown in fig. 2, both terminal devices 120a are within the coverage of the network device 110. Thus, both terminal devices 120a may receive configuration signaling (configuration signaling in the present application may be replaced by configuration information) of the network device 110, and determine the sidestream configuration according to the configuration signaling of the network device 110. After both terminal devices 120a are sidelink configured, sidelink communication may be performed on the sidelink.

Fig. 3 is an exemplary diagram of a scenario for partial network coverage sidestream communication. In the scenario illustrated in fig. 3, terminal device 120a is in sidestream communication with terminal device 120 b. The terminal device 120a is located within the coverage area of the network device 110, so that the terminal device 120a can receive the configuration signaling of the network device 110 and determine the sidestream configuration according to the configuration signaling of the network device 110. The terminal device 120b is located outside the network coverage area and cannot receive the configuration signaling of the network device 110. In this case, the terminal device 120b may determine the sidestream configuration according to pre-configuration information and/or information carried in a physical sidestream broadcast channel (PHYSICAL SIDELINK broadcast channel, PSBCH) transmitted by the terminal device 120a located in the network coverage area. After both terminal device 120a and terminal device 120b are sidestream configured, sidestream communications may be conducted on the sidestream link.

Fig. 4 is an exemplary diagram of a scenario for sidestream communications outside of a network coverage. In the scenario shown in fig. 4, both terminal devices 120b are located outside the network coverage. In this case, both terminal apparatuses 120b may determine the sidestream configuration according to the preconfiguration information. After both terminal devices 120b are sidelink configured, sidelink communication may be performed on the sidelink.

FIG. 5 is an exemplary diagram of a scenario for side-row communication with a central control node. In the scenario shown in fig. 5, a plurality of terminal apparatuses 120b may constitute one communication group. There may be a central control node within the communication group. In some cases, the central control node may become a Cluster Head (CH) terminal device. The central control node may have one or more of the following functions: and the communication group is established, the joining and leaving of group members are performed, the resource coordination is performed, the sidestream transmission resources are allocated for other terminal equipment, the sidestream feedback information of other terminal equipment is received, and the resource coordination and other functions are performed with other communication groups.

Modes of sidestream communication

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

In the first mode, the resources of the terminal device (the resources referred to in the present application may also be referred to as transmission resources, such as time-frequency resources) are allocated by the network device. The terminal device may transmit data on the sidelink according to the resources allocated by the network device. The network device may allocate resources for single transmission to the terminal device, or may allocate resources for semi-static transmission to the terminal device. This first mode may be applied to a scenario with network device coverage, such as the scenario shown in fig. 2. In the scenario shown in fig. 2, the terminal device 120a is located within the network coverage of the network device 110, so the network device 110 may allocate resources for use in the sidelink transmission procedure to the terminal device 120 a.

In the second mode, the terminal device may autonomously select one or more resources in a Resource Pool (RP). And then, the terminal equipment can carry out sidestream transmission according to the selected resources. For example, in the scenario shown in fig. 4, the terminal device 120b is located outside the cell coverage. Therefore, the terminal device 120b may autonomously select resources from the preconfigured resource pool to perform sidelink transmission. Or in the scenario shown in fig. 2, the terminal device 120a may also autonomously select one or more resources from the resource pool configured by the network device 110 for sidelink transmission.

Data transmission mode of sidestream communication

Some sidestream communication systems (e.g., LTE-V2X) support broadcast-based data transmission modes (hereinafter referred to as broadcast transmissions). For broadcast transmission, the receiving end terminal device may be any one of the end terminal devices around the transmitting end terminal device. Taking fig. 6 as an example, the terminal device 1 is a transmitting terminal device, and the receiving terminal device corresponding to the transmitting terminal device is any terminal device around the terminal device 1, for example, may be the terminal device 2-terminal device 6 in fig. 6.

In addition to broadcast transmissions, some communication systems also support unicast-based data transmission modes (hereinafter referred to as unicast transmissions) and/or multicast-based data transmission modes (hereinafter referred to as multicast transmissions). For example, NR-V2X is intended to support autopilot. Autopilot places higher demands on data interaction between vehicles. For example, data interaction between vehicles requires higher throughput, lower latency, higher reliability, greater coverage, more flexible resource allocation, etc. Therefore, in order to improve the data interaction performance between vehicles, the NR-V2X introduces unicast transmission and multicast transmission.

For unicast transmissions, the receiving end terminal typically has only one terminal. Taking fig. 7 as an example, unicast transmission is performed between the terminal device 1 and the terminal device 2. The terminal device 1 may be a transmitting terminal device, the terminal device 2 may be a receiving terminal device, or the terminal device 1 may be a receiving terminal device, and the terminal device 2 may be a transmitting terminal device.

For multicast transmission, the receiving end terminal device may be a terminal device within a communication group (group), or the receiving end terminal device may be a terminal device within a certain transmission distance. Taking fig. 7 as an example, terminal device 1, terminal device 2, terminal device 3, and terminal device 4 constitute one communication group. If terminal device 1 transmits data, the other terminal devices in the group (terminal device 2 to terminal device 4) may each be a receiving end terminal device.

Frame structure of sidestream communication system

One slot may include a Physical Sidelink Control Channel (PSCCH), a physical sidelink shared channel (PHYSICAL SIDELINK SHARED CHANNEL, PSSCH), a physical sidelink feedback channel (PHYSICAL SIDELINK feedback channel, PSFCH), and the like. The above-mentioned channels will be described in detail hereinafter and will not be described in detail here.

Fig. 9 is an exemplary diagram of a time slot structure for some sidestream communication systems (e.g., NR-V2X systems). Fig. 9 (a) is a diagram illustrating an example of a slot structure in which a physical sidelink feedback channel (PHYSICAL SIDELINK feedback channel, PSFCH) is not included in a slot. Fig. 9 (b) is a diagram illustrating an example of a slot structure including PSFCH channels in a slot.

As shown in fig. 9, in the time domain, PSCCH may occupy 2 or 3 orthogonal frequency division multiplexing (orthogonal frequency division multiplexing, OFDM) symbols from the second side row symbol of the slot, and in the frequency domain {10,12, 15,20,25} physical resource blocks (physical resource block, PRBs) may be occupied. In order to reduce the complexity of blind detection of PSCCH by a terminal device, only one PSCCH symbol number and PRB number may be allowed to be configured in one resource pool. In addition, the sub-channels are the smallest granularity of PSSCH resource allocation in some sidelink communication systems (such as NR-V2X systems), and therefore, the number of PRBs occupied by the PSCCH must be less than or equal to the number of PRBs contained in one sub-channel in the resource pool, so as not to impose additional restrictions on PSSCH resource selection or allocation.

In the time domain, the PSSCH may start with the second sidelink symbol of the slot. The last time domain symbol in the slot is a Guard Period (GP) symbol (which may also be referred to as a GAP (GAP) symbol), and the remaining symbols may be mapped to the PSSCH. The first side symbol in the slot may be a repetition of the second side symbol. The receiving end terminal device may use the first sidestream symbol as an automatic gain control (automatic gain control, AGC) symbol, the data on which is not typically used for data demodulation. As shown in fig. 9 (a), the PSSCH may occupy K subchannels in the frequency domain, and each subchannel may include N consecutive PRBs. Where K may be an integer greater than 0 and N may be an integer greater than 0.

As shown in fig. 9 (b), when PSFCH channels are included in the slot, the penultimate and penultimate symbols in the slot may be used as PSFCH channel transmission, and one time domain symbol before PSFCH channel may be used as GP symbol.

PSSCH

In some sidestream communication systems (e.g., NR-V2X systems), PSSCH may be used to carry second order sidestream control information (sidelink control information, SCI). The second order SCI may include SCI 2-A or SCI 2-B. The second order SCI may be Polar encoded. The second order SCI may be fixed with QPSK modulation. The data portion of the PSSCH may employ a low density parity check code (low DENSITY PARITY CHECK, LDPC). The highest modulation order that can be supported by the data portion of the PSSCH is 256QAM.

In some sidestream communication systems (e.g., NR-V2X systems), the PSSCH supports at most two streams and the data on two layers is mapped to two antenna ports using a unit precoding matrix, and at most one TB can be transmitted in one PSSCH. However, unlike the transmission mode of the PSSCH data portion, when the PSSCH adopts the dual-stream transmission mode, modulation symbols transmitted by the second-stage SCI on the two streams are identical, and thus the design can ensure the reception performance of the second-stage SCI under the high correlation channel.

The maximum number of retransmissions of one PSSCH in some sidestream communication systems (e.g., NR-V2X systems) is 32. If PSFCH resources are present in the resource pool and the allocation period of PSFCH resources is 2 or 4, the available OFDM symbols in the slot where different transmissions of one PSSCH are located may change. Fig. 10 is an exemplary diagram of a change in the available OFDM symbols of the PSSCH in different slots. As shown in fig. 10, the number of OFDM symbols available for the nth transmission and the n+1th transmission of the PSSCH is different due to the existence of PSFCH resources. If the number of symbols of PSSCH transmission is calculated according to the actual number of OFDM symbols in one slotQ '_SCI2 may be different due to the different number of symbols available for PSSCH transmission in one slot, while a change in Q' _SCI2 may result in a change in the size of the TB carried by the PSSCH, as described below. In order to ensure that the transport block size (transmission block size, TBS) remains unchanged during multiple PSSCH transmissions, the method is performedThe actual PSFCH symbols are not used, and are calculatedThe number of Resource Elements (REs) occupied by the PSSCH demodulation reference signal (demodulation reference symbol, DMRS) that may be changed during retransmission and the number of REs occupied by the tracking reference signal (phase-TRACKING REFERENCE SIGNALS, PT-RS) are not taken into consideration.

The code rate of the second-order SCI can be dynamically adjusted within a certain range, and the specifically adopted code rate 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 is changed. Fig. 11 is an exemplary diagram of time-frequency resources occupied by a second order SCI in one slot. As shown in fig. 11, the modulation symbol of the second-order SCI may be mapped from the symbol where the first PSSCH DMRS is located in a frequency-domain-first-time-domain manner, and on the OFDM symbol where the DMRS is located, the second-order SCI may be mapped to REs not occupied by the DMRS.

Within a resource pool, the data portion of the PSSCH can employ multiple different modulation coding scheme (modulation and coding scheme, MCS) tables. For example, one or more of the following tables may be employed: a conventional 64QAM MCS table, a 256QAM MCS table, and a low spectral efficiency 64QAM MCS table. In one transmission, the MCS table specifically employed for the data portion of the PSSCH may be indicated by an "MCS table indication" field in the first order SCI. In order to control the PAPR, the PSSCH must be transmitted using consecutive PRBs. Since the sub-channel is the minimum frequency domain resource granularity of the PSSCH, the PSSCH must occupy consecutive sub-channels.

Side-link TBS

The PSSCH uses a TBS determining mechanism of the PDSCH and the PUSCH, namely the TBS can be determined according to the reference value of the RE number used for the PSSCH in the time slot where the PSSCH is positioned, so that the actual code rate is as close to the target code rate as possible. It should be noted that the purpose of adopting the reference value of the number of REs instead of the actual number of REs is to ensure that the number of REs used for determining the TBS remains unchanged during the PSSCH retransmission process, so that the determined TBS size is the same. To achieve this, the reference value N _RE of the number of occupied REs of the PSSCH in the TBS determination procedure may be determined according to the following formula:

Wherein n _PRB is the number of PRBs occupied by PSSCH, For the number of REs occupied by the first order SCI (including REs occupied by the DMRS of the PSCCH),For the number of REs occupied by the second order SCI (as described above), N' _RE represents the number of reference REs available for PSSCH within one PRB. N' _RE can be determined by the following formula:

wherein, May represent the number of subcarriers within a PRB, e.g.,The number of symbols representing the side row available in a slot may not include the last GP symbol and the first symbol for AGC.A reference value representing the number of symbols occupied by PSFCH, e.g.,Or 3, the specific value may be indicated by the "PSFCH symbols number" field in the first-order SCI.The reference value, which may represent the number of occupied REs of the PT-RS and the channel state information reference signal (CHANNEL STATE information-REFERENCE SIGNAL, CSI-RS), may be configured by radio resource control (radio resource control, RRC) layer parameters.The average DMRS RE number in one slot may be represented, in relation to the allowed DMRS pattern in the resource pool. Table 1 shows allowed DMRS patterns and within the resource poolCorresponding relation of (3).

TABLE 1

Side-link DMRS

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

wherein the pseudo-random sequence c (m) may be defined by Initialization is performed. Where l may represent an index of an OFDM symbol in which the DMRS is located within a slot,May represent the index of the slot in which the DMRS is located within the system frame,The number of OFDM symbols in a slot, N _ID e {0,1, …,65535}, the specific value of N _ID in a resource pool being configured or preconfigured by the network can be represented.

Some sidestream communication systems (e.g., NR-V2X systems) employ multiple time domain PSSCH DMRS patterns, i.e., reference is made to the design in the Uu interface of the NR system. The number of DMRS patterns that can be employed in a resource pool can be related to the number of symbols of the PSSCH in the resource pool. The available DMRS patterns and the location of each DMRS symbol within the pattern for a particular PSSCH symbol number (including the first AGC symbol) and PSCCH symbol number are shown in table 2. Fig. 13 is a schematic diagram of time domain positions of 4 DMRS symbols when PSSCH is 14 symbols.

TABLE 2

If multiple time domain DMRS patterns are configured in the resource pool, the specifically adopted time domain DMRS pattern is selected by the transmitting terminal device and indicated in the first-order SCI. The design allows the terminal equipment moving at high speed to select the DMRS pattern with high density, thereby ensuring the accuracy of channel estimation, and for the terminal equipment moving at low speed, the DMRS pattern with low density can be adopted, thereby improving the frequency spectrum efficiency.

The generation mode of PSSCH DMRS sequences is almost identical to that of PSCCH DMRS sequences, and the only difference is that in the initialization formula c _init of the pseudo random sequence c (m),Where p _i is the ith bit CRC of the PSCCH that schedules the PSSCH. L may be the number of bits of the PSCCH CRC, e.g. l=24.

In an NR communication system, two frequency domain DMRS patterns, i.e., DMRS frequency domain type 1 and DMRS frequency domain type 2, are supported in PDSCH and PUSCH. For each frequency domain type, there are two different types of single DMRS symbols and dual DMRS symbols. The single-symbol DMRS frequency domain type 1 supports 4 DMRS ports, and the single-symbol DMRS frequency domain type 2 can support 6 DMRS ports. In the case of dual DMRS symbols, the number of ports supported is doubled. However, in a sidestream communication system (e.g., NR-V2X), since the PSSCH may only need to support at most two DMRS ports, only a single symbol DMRS frequency domain type 1 may be supported. Fig. 14 is a diagram illustrating an example of a single symbol DMRS frequency domain type 1.

Side-link CSI-RS

The sidelink communication system may support sidelink CSI-RS (SL CSI-RS) to better support unicast communications. SL CSI-RS may be sent when the following 3 conditions are met: the terminal device transmits the corresponding PSSCH, that is, the terminal device cannot transmit only the SL CSI-RS; the high-layer signaling activates SL CSI-RS reporting; under the condition that the high-layer signaling activates the SL CSI-RS reporting, the corresponding bit in the second-order SCI sent by the terminal equipment triggers the SL CSI-RS reporting.

The maximum port number supported by the SL CSI-RS is 2. The two ports are SL CSI-RS of different ports multiplexed by means of code division on two adjacent REs of the same OFDM symbol. The number of SL CSI-RS per port within one PRB is 1, i.e., the density is 1. Thus, the SL CSI-RS will only appear on one OFDM symbol at most within one PRB. The specific position of this OFDM symbol may be determined by the transmitting terminal device. To avoid affecting the resource mapping of the PSCCH and second order SCI, the SL CSI-RS cannot be located in the same OFDM symbol as the PSCCH and second order SCI. Because PSSCH DMRS is in the OFDM symbol with higher channel estimation precision, and the SL CSI-RS of the two ports occupies two continuous REs on the frequency domain, the SL-CSI-RS and the DMRS of the PSSCH cannot be transmitted on the same OFDM symbol. The position of the OFDM symbol where the SL CSI-RS is located is indicated by the SL-CSI-RS-FirstSymbol parameter in PC5 RRC.

The position of the first RE occupied by the SL CSI-RS within one PRB may be indicated by the SL-CSI-RS-FreqAllocation parameter in the PC5 RRC. If the SL CSI-RS is a port, the parameter may be a bit map with a length of 12, corresponding to 12 REs in one PRB. If the SL CSI-RS is two ports, the parameter is a bit map that may be 6 in length, in which case the SL CSI-RS may occupy two REs of 2f (1) and 2f (1) +1. Where f (1) may represent an index of a bit having a value of 1 in the bit map described above. The frequency domain position of the SL CSI-RS may also be determined by the transmitting terminal device. The determined frequency domain position of the SL CSI-RS cannot collide with the PT-RS. Fig. 15 is a diagram illustrating an example of a time-frequency location of a SL CSI-RS. In fig. 15, the SL CSI-RS port number 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 communication

Unlicensed spectrum is a nationally and regionally divided spectrum that is available for radio communications and is generally considered to be a shared spectrum, i.e., a spectrum that can be used by a communication device as long as the regulatory requirements set by the country or region on that spectrum are met, without requiring a proprietary spectrum authority of the country or region to be filed with the proprietary spectrum authority. Unlicensed spectrum may also be referred to as shared spectrum, unlicensed band, or the like.

In LTE systems, unlicensed spectrum has been implemented as a supplemental band of licensed spectrum for cellular networks. For NR systems, NR systems can achieve seamless coverage, high spectral efficiency, high peak rates, and high reliability of cellular networks. The NR system may also use unlicensed spectrum as part of 5G cellular network technology to provide services to users. In the 3GPP R16 standard, NR systems for unlicensed spectrum are discussed, referred to as NR unlicensed (NR-unlicensed, NR-U) systems.

NR-U system support can be achieved in two networking modes: licensed spectrum assisted access and unlicensed spectrum independent access. Licensed spectrum assisted access requires access to the network by means of licensed spectrum, unlicensed spectrum being used as a secondary carrier. Unlicensed spectrum independent access can be achieved through unlicensed spectrum independent networking, and terminal equipment can be directly accessed to a network through unlicensed spectrum. The range of unlicensed spectrum used by the NR-U system introduced in 3GPP R16 is concentrated with the 5GHz and 6GHz bands. For example, in the united states, the unlicensed spectrum ranges from 5925-7125MHz; in europe, the unlicensed spectrum ranges from 5925-6425MHz. In the standard of R16, band 46 (5150 MHz-5925 MHz) is newly defined for use as unlicensed spectrum.

The use of unlicensed spectrum is required to meet the requirements of various country and region specific regulations, for example, a communication device may use unlicensed spectrum by implementing channel access over unlicensed spectrum through channel listening to avoid collisions with other communication devices or other communication systems (e.g., wiFi systems). As one implementation, a communication device may use unlicensed spectrum following the principle of listen-before-talk (LBT). Therefore, for NR-U, the NR technology needs to be correspondingly enhanced to meet the regulatory requirements of unlicensed bands, while efficiently providing services using unlicensed spectrum. In the 3GPP R16 standard, standardization of NR-U technology is mainly accomplished in the following aspects: a channel monitoring process; an initial access process; control channel design; HARQ and scheduling; scheduling-free grant transmission, etc.

LBT

LBT principles may include: the communication device needs to perform LBT before signaling using channels on unlicensed spectrum. In case of successful LBT, the result of channel listening is that the channel is idle. Only when the channel is idle, the communication device can signal over the channel. If the channel listening result of the communication device on the channel is that the channel is busy or LBT fails, the communication device cannot signal over the channel. In addition, in order to ensure fairness of spectrum resource usage of the shared spectrum, if LBT of the communication device on a channel of the unlicensed spectrum is successful, a duration in which the communication device can use the channel for communication transmission cannot exceed a certain duration. By limiting the maximum duration that can be communicated after LBT is successful once, different communication devices can have opportunities to access the shared channel, so that different communication systems can coexist on the shared frequency spectrum in a friendly way.

Signal transmission over unlicensed spectrum involves the concept of channel occupancy correlation. Such as channel occupancy time (channel occupancy time, COT), maximum channel occupancy time (maximum channel occupancy time, MCOT), COT of a network device (e.g., base station), and COT of a terminal device.

MCOT may refer to the maximum length of time that a communication device is allowed to signal using a channel of unlicensed spectrum in case LBT is successful. It should be understood that MCOT refers to the time taken for signal transmission. The channel access priorities of the communication devices are different, and the MCOTs corresponding to the communication devices may be different. The maximum value of MCOT can be set to 10ms, for example.

Fig. 16 is an exemplary diagram of a primary channel occupation time obtained by a communication device after LBT is successful on a channel of an unlicensed spectrum, and signaling using resources within the channel occupation time.

Although channel listening is not a global regulation, it can bring the benefits of interference avoidance and friendly coexistence to communication transmissions between communication systems on a shared spectrum. Thus, during the design of an NR system over unlicensed spectrum, channel listening is a feature that communication devices in the system need to support.

Channel access mode of unlicensed spectrum or shared spectrum

Some communication systems, such as NR-U systems, introduce a channel access scheme for channel access via LBT. Some communication systems may also support channel access by way of short control signaling transmissions (short control signaling transmission, SCSt). The two channel access modes are respectively described below.

From the network deployment perspective of the system, the channel access manner of channel access by LBT may include two mechanisms, one is LBT of load-based devices (load based equipment, LBE), also referred to as dynamic channel listening or dynamic channel occupancy; another is LBT of the frame structure based device (frame based equipment, FBE), also known as semi-static channel listening or semi-static channel occupancy. The LBT principle of dynamic channel listening is: the communication device performs LBT on a carrier of unlicensed spectrum after service arrives and starts transmission of signals on the carrier after LBT is successful.

The LBT mode of dynamic channel listening may include a Type1 (Type 1) channel access mode and a Type2 (Type 2) channel access mode.

The type 1 channel access mode and the type 2 channel access mode will be described in detail below by taking a network device as an example. It will be appreciated that the process of channel listening by other communication devices such as terminal devices via type 1 or type 2 channel access is similar.

The type 1 channel access manner may also be referred to as a random back-off multi-slot channel detection based on contention window size adjustment. In the channel access manner of type 1, the communication device may initiate a channel occupation with a length Tmcot according to the channel access priority p. If the network device uses the channel access mode of type 1, the network device may share the COT to the terminal device in addition to transmitting its own data during the channel occupation period. The sharing of the COT to the terminal device means that: and allowing the terminal equipment to send data in the duration corresponding to the COT (i.e. the COT obtained by the network equipment through channel access). Accordingly, if the terminal device uses the channel access mode of type 1, the terminal device may share the COT to the network device in addition to transmitting its own data during the channel occupation period.

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

TABLE 3 Table 3

The default channel access mode of the network equipment side is a 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 size of a contention window (contention window, CW) corresponding to the channel access priority p, CW _min,p may refer to the minimum value of the value of CW _p corresponding to the channel access priority p, CW _max,p may refer to the maximum value of the value of CW _p corresponding to the channel access priority p, and T _mcot,p refers to the maximum occupied time length of the channel corresponding to the channel access priority p.

The Type2 channel access method (Type 2 channel access method) may also be referred to as a channel access method based on a fixed-length channel listening slot. The Type2 channel access method includes a Type2A channel access method (Type 2A channel access method), a Type2B channel access method (Type 2B channel access method), and a Type2C channel access method (Type 2C channel access method). In the case of sharing resources in the COT to other communication devices, the other communication devices may use a type2 channel access scheme.

In the type 2A channel access mode, the communication device may employ single slot detection of a 25us channel. That is, the communication device may start channel detection 25us before data starts to be transmitted. The 25us channel detection may include 1 16us channel detection and 19 us channel detection. If the two detection results indicate that the channel is idle, the channel can be considered to be idle and channel access can be performed.

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

In the type 2C channel access mode, the communication device may directly transmit data through the channel without performing channel detection. In the channel access mode of type 2C, the time difference between the current transmission distance and the last transmission is less than or equal to 16us. That is, if the time difference between the two transmissions is less than or equal to 16us, it can be considered as the same transmission, and channel detection is not required. In the channel access mode of type 2C, the transmission duration of the communication device is limited, and typically cannot exceed 584us.

The LBT-based channel access scheme is described above and SCSt is described below. In unlicensed spectrum, SCSt is introduced to improve the success rate of a communication device accessing a channel when transmitting control signaling. SCSt is that the communication device does not sense whether the channel has transmissions of other signals. For example, SCSt is a communication device for transmitting management and control frames without sensing whether there is transmission of other signals on the channel. In other words, when SCSt is employed by a communication device, the communication device may access the channel for transmission without listening to the channel. However, SCSt needs to satisfy certain conditions. For example, if a communication device wishes to employ SCSt for channel access, the communication device needs to satisfy one or more of the following conditions: the number of times SCSt is taken during an observation period of 50ms is less than or equal to 50; and a SCSt occupies a period of no more than 2.5ms during a 50ms observation period.

As can be seen from the above, the type 1 channel access mechanism requires a long channel listening procedure. In case of successful channel access, a short LBT (i.e. one with a short duration) needs to be performed again immediately before transmission to ensure that the resources are not robbed by the users of the different system (e.g. WiFi users). In addition, the transmission resources after the successful access through the type 1 can be shared for other communication devices to use. For example, in a possible design of side-link unlicensed (sidelink unlicensed, SL-U), a terminal device may share a transmission resource after Type 1 access is successful for other terminal devices to use, and the other terminal devices need to first perform LBT of Type-2A/B/C according to specific conditions before transmitting in the shared resource (e.g., COT resource) to ensure that the resource is still valid, not robbed, and then can transmit.

The procedure by which the terminal device can perform channel access in type 1 or type 2 will be described below by taking fig. 17 as an example. Fig. 17 is an exemplary diagram of a terminal device performing channel access over unlicensed spectrum. The terminal device 1 (denoted by UE1 in fig. 17) performs type 1 channel access in slot (slot) n. In the time slot n+1, the terminal device 1 performs transmission of data. Before time slot n+1, terminal device 1 performs a short LBT, and after the short LBT is successful, the data is retransmitted. The terminal device 1 shares the time slot n+2 in the resource within the COT to the other communication device. Terminal device 2 (denoted by UE2 in fig. 17) performs channel access of type 2A before time slot n+2, and after the channel access is successful, terminal device 2 transmits data in time slot n+2.

Positioning technology

In the communication technology, the positioning technology may be a technology of determining by some method the geographical location of the communication device located in the communication network.

In some communication systems, such as NR systems, positioning may be achieved by Positioning Reference Signals (PRS) REFERENCE SIGNAL. For example, an Observed Time Difference (OTDOA) positioning method is a positioning method defined in the 3GPP protocol based on positioning reference signals.

Sideways based positioning is one of the enhancements to R18 positioning technology, in this topic will be considered to support the scenarios and requirements of the intra-, partially-, and out-of-cellular network coverage NR positioning use cases, V2X use cases, public safety use cases, commercial and industrial internet (industrial internet of things, IIOT) use cases positioning requirements, and support the following functions: absolute positioning, ranging/direction finding and relative positioning; a positioning method combining the sidestream measurement quantity and the Uu interface measurement quantity is researched; study the side-going positioning reference signals, including signal design, physical layer control signaling, resource allocation, physical layer measurement quantity, and related physical layer processes, etc.; the positioning system architecture and signaling procedures, such as configuration, measurement reporting, etc., are studied.

In related sidestream communication techniques, positioning techniques on unlicensed spectrum have not been implemented.

Fig. 18 is a schematic flow chart of a communication method according to 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.

In step S1810, the first terminal device transmits a first PRS over a side uplink on an unlicensed spectrum. Accordingly, the second terminal device receives the first PRS over the side uplink.

The first PRS may be a PRS for sidelink positioning, i.e., the first PRS may be a sidelink PRS (SIDELINK PRS, SL-PRS). As an implementation, based on the first PRS, one or more positioning techniques may be implemented in a sidelink communication within a network overlay, a sidelink communication of a partial network overlay, a sidelink communication outside of a network overlay, a sidelink communication by a central control node.

It is appreciated that with the first PRS, a positioning technique for upstream communication over unlicensed spectrum may be implemented. That is, through the first PRS, positioning of the first terminal device and/or the second terminal device for sidelink communication over an unlicensed spectrum may be achieved. The positioning may include one or more of absolute positioning, ranging/direction finding, relative positioning, among others.

It should be noted that the first PRS may not need to implement periodic transmission. Or the first PRS may be sent periodically.

The transmission of the first PRS may be based on a first channel access implementation. That is, the first terminal device may make a first channel access to transmit the first PRS over the unlicensed spectrum.

The first channel access may be a channel access manner in which channel monitoring is performed, i.e. the first channel access may include a channel monitoring procedure. The channel listening procedure may be, for example, the LBT procedure described above. It will be appreciated that the first channel access procedure may also be successful in the case that the channel listening procedure is successful. In case the channel listening procedure fails, the first channel access procedure may fail.

The application does not limit the result of the first channel access, for example, the result of the first channel access may be successful or may fail. That is, the first terminal device may transmit the first PRS in case the first channel access is successful. The first terminal device may also transmit the first PRS in case of a first channel access failure. In some implementations, the first terminal number device can repeatedly transmit the first PRS in the event of a first channel access failure. The PRS of the repeated transmissions 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, a first terminal device may make a first channel access on a first time slot, and the first terminal device may transmit a first PRS on the first time slot. It can be appreciated that the first PRS can be quickly transmitted in the first time slot, thereby enabling more efficient transmission of the SL-PRS.

The first slot may include one or more symbols (e.g., OFDM symbols) for sidelink communication. The one or more symbols for sidestream communications may include the resources of the SL-U communications. 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 slot may be used for sidestream communications. Or a portion of the symbols in the first slot may be used for sidestream communications. Wherein the symbols used for sidestream communications may be used to transmit sidestream signals or sidestream channels. For example, symbols used for sidelink communications may be used to transmit one or more of the PSCCH, PSSCH, sidelink synchronization signal blocks (sidelink synchronization signal block, S-SSB). Wherein symbols for sidestream communication in one slot may be consecutive.

The first channel access may begin with a third symbol, which may be, for example, one of one or more symbols in the first slot for sidestream communication. It will be appreciated that the third symbol may be any one of one or more symbols used for sidestream communication in the first slot. The third symbol may be a preset value, a protocol pre-definition, a higher layer signaling configuration or a terminal device self-determination.

As one implementation, in the first slot, starting from symbol k, n consecutive OFDM symbols may be used for sidelink communications. At symbol m, a first channel access may begin. Where k may be an integer greater than or equal to 0, n may be an integer greater than 0, and m may be an integer greater than or equal to k.

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

Fig. 19 is an exemplary diagram of a communication method according to an embodiment of the present application. In fig. 19, the first slot may be slot t. The number of symbols n=12 (i.e., symbols 3 to 13) available for side-row communication in slot t. Symbol 2 is the first of 12 symbols for sidestream communication. The first channel access may begin with symbol 2. That is, the third symbol may be symbol 2.

Fig. 20 is an exemplary diagram of another communication method according to an embodiment of the present application. In fig. 20, the first slot may be slot t. The number of symbols n=12 available for sidestream communication in time slot t. The slot t includes 12 symbols 3 to 13 for sidelink communication. Symbol 4 is one of 12 symbols for sidestream communication. The first channel access may begin with 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 SL-PRS transmissions may be less than or equal to one 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 sidelink communications in the first slot.

As an implementation, the first symbol occupied by the first PRS may be a first symbol, a previous symbol of the first symbol may be a second symbol, and the first channel access may end at the second symbol. The first symbol and the second symbol may each be a symbol for sidestream communication. For example, the first symbol may be the second symbol in the first slot (i.e., symbol 1) and the second symbol may be the first symbol in the first slot (i.e., symbol 0). That is, the first PRS may be transmitted on the next symbol of the symbol where the first channel access is ended.

The description will be continued with reference to fig. 19. As shown in fig. 19, the first channel access ends at symbol 2. I.e. symbol 2 is the second symbol. The next symbol 3 of symbol 2 may be the first symbol. The first PRS may begin transmission at symbol 3.

In one implementation, the first channel access procedure may end at an end time that is the second symbol. That is, at the end time of the second symbol, the first channel access procedure ends. In other words, at the start time of the first channel, the first channel access procedure ends. For example, the first channel access procedure may end at the last microsecond of the second symbol. The first PRS may begin transmitting immediately following the first symbol (next symbol to the second symbol).

It can be appreciated that in the case where the first channel access ends at the end of the second symbol, there is little gap between the first channel access procedure and the time when the first PRS starts to transmit. That is, after the first channel access procedure is completed, no other communication device will typically preempt the channel, thereby enabling that the transmission resources of the first PRS in the unlicensed spectrum will not collide with the transmission resources of other communication devices.

The starting time of the first channel access may be determined according to the ending time of the first channel access, so as to realize that when the first channel access is completed, the first PRS can be immediately started to be transmitted in the first symbol. For example, the starting time of the first channel access may be determined according to the ending time of the first channel access and the duration of the first channel access. As an implementation, in the case where the first channel access ends at the end time of the second symbol, the start time of the first channel access may be a first time before the end time of the second symbol, and the length of time between the first time and the end time of the second symbol may be a duration of the first channel access.

Continuing with the example of fig. 19, 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 begin transmitting immediately after symbol 3.

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

It is to be appreciated that, on the one hand, the first time gap may make the start or end of the first channel access more flexible, i.e., the start or end time of the first channel access may not need to be determined from the first PRS transmission start time. In one aspect, the first time slot may make the transmission start time of the first PRS more flexible, i.e., 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, the first channel access may end in the middle of the second symbol (any time between the start time and the end time of the second symbol).

In a first time interval, a first terminal device may transmit a placeholder and a second terminal device may receive the placeholder. The placeholder may be used for the first terminal device to occupy the channel accessed by the first channel access procedure, thereby avoiding other communication devices from occupying the channel.

As one implementation, the placeholder may be a cyclic prefix extension (cyclic prefix extension, CPE). Taking the first symbol occupied by the first PRS as an example of the first symbol, if the first channel access procedure ends at a time point still longer than the first symbol, that is, the first time interval is not 0, in the first time interval, the first terminal device may send the CPE.

Fig. 21 is an exemplary diagram of a communication method according to an embodiment of the present application. In fig. 21, the first channel access procedure ends in the middle of symbol 4, i.e. the instant C at which the first channel access ends is not the end instant of symbol 4. The transmission of the first PRS begins with symbol 5. The first terminal device may send CPE between a first channel access end time (middle of symbol 4) to a first PRS transmission start time (starting point of symbol 5).

The first channel access may not occur on the GAP symbols. For example, the previous slot of the first slot is the second slot. In the second slot, the last symbol or symbols may be GAP symbols, that is, the GAP symbols are concatenated with the first slot. The first channel access may not occur with GAP symbols in the second slot. Or the first slot may include GAP symbols, the first channel access not occurring in the GAP symbols in the first slot.

Alternatively, the last slot of the first slot may be the second slot. In the case where the second time slot is available for sidestream communication, the first channel access may not occur on the GAP symbols of the second time slot if the first terminal device or other terminal device (a terminal device different from the first terminal device) is conducting sidestream communication in 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 first channel access may be type 2A or type 2B. It will be appreciated that 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 a channel listening duration) is shorter than in most cases of type 1. 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 (sub-CARRIER SPACING, SCS) as an example of 15KHz, one symbol is about 71.4 microseconds in length. The channel access of type 2A or type 2B is much smaller than the length of one symbol, i.e. the first channel access procedure 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 slot. Thus, in some cases, the channel access duration of type 2A or type 2B may also be greater than the length of one symbol. It will be appreciated that even in this case, type 2A or type 2B is short compared to most of the type 1 channel access durations.

It should be noted that, in the case that the type of the first channel access is non-type 1, for example, type 2A or type 2B, the first channel access may not be implemented based on the COT sharing scenario. That is, the default channel access type for the first terminal device to transmit the first PRS may be non-type 1 (e.g., type 2).

In some implementations, the type of first channel access may also be type 1. As described above, the CW size of type 1 may be larger or smaller. In the case where the CW is large (e.g., greater than or equal to the first CW threshold), the duration of the first channel access is long; in the case where the CW is small (e.g., less than or equal to the second CW threshold), the duration of the first channel access is long. In the case that the type of the first channel access is type 1, the first channel access may be performed by selecting a mode with a shorter duration in type 1.

It can be understood that the channel access duration is shorter, so that the channel access time and resources can be saved, the first PRS can be sent as early as possible, and the positioning efficiency is improved.

In some implementations, the first channel access mode may be a channel access mode that does not require channel listening. That is, the first terminal device may directly transmit the first PRS without performing an LBT procedure. It will be appreciated that this may greatly simplify the procedure of the first channel access.

As one implementation, the first channel access may be based on a first condition. The first condition may for example relate to the second time interval. The second time interval may be, for example, an interval between a start time of transmitting the first PRS and an end time of a previous sidelink communication. The last end time of the sidestream communication may be a transmission end time of the sidestream communication performed by the first terminal device or other terminal devices (not the first terminal device). The first condition may include, for example: and when the second time interval is smaller than the first threshold value, the first channel access mode can be an access mode which does not need channel monitoring. The first threshold may be, for example, X microseconds. Wherein X may be an integer greater than 0. X may be preset, protocol-specified, or configured through higher layer signaling.

It is understood that the manner in which the first channel is accessed may be type 2C. In the case where the first condition is consistent with the channel access condition of type 2C, the first channel access may be considered to be type 2C.

In some embodiments, the first PRS may be sent in a short control signaling (short control signaling transmission, SCSt) manner. It can be appreciated that, in the case that the transmission manner of the first PRS is SCSt, the channel listening procedure may not be performed, and the transmission procedure of the first PRS may be simplified. It should be noted that, in the case where the first PRS is sent by means of SCSt, a channel listening procedure may also be performed. For example, a first channel access of type 2A or type 2B may be performed and the first PRS transmitted by SCSt.

The first PRS may be carried on a first sidelink resource that is configured in a resource pool through pre-configuration or through higher layer signaling. Wherein the first side row resource may comprise a time domain resource. For example, the time slot in which the first PRS is transmitted may be configured in a resource pool through pre-configuration or higher layer signaling.

The first terminal device may obtain a first sidelink resource transfer first PRS through a sidelink awareness (SIDELINK SENSING) and a resource selection mechanism. Or the first terminal device may directly select the first sidelink resource to transmit the first PRS without a sidelink awareness or a resource selection mechanism.

Based on the foregoing, possible combinations of implementation of the method provided by the present application may include, but are not limited to: 1) The first terminal equipment does not acquire a sidestream transmission resource for transmitting the first PRS through sidestream awareness, the first channel is accessed in a mode of type 2A or type 2B, and the first PRS is transmitted in a SCSt mode; 2) The first terminal equipment acquires a sidestream transmission resource for transmitting a first PRS through sidestream sensing, the first channel is accessed in a mode of type 2A or type 2B, and the first PRS is transmitted in a SCSt mode; 3) The first terminal equipment does not acquire side line transmission resources for transmitting the first PRS through side line perception, the first channel access mode is a channel access mode which does not need channel monitoring, and the first PRS is transmitted through SCSt mode.

The communication method provided by the present application is described in detail below by way of examples 1-5. It will be appreciated that embodiments 1-5 may be implemented alone or in combination.

Example 1

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

In step S1910, the first terminal device performs the first channel access at symbol k.

Symbol k is a symbol in the first slot. In the first slot, n OFDM symbols, where the kth symbol starts to be consecutive, may be used for sidelink communication. That is, symbol k may be the first symbol of the plurality of symbols for sidelink communication in the first slot. Where k may be an integer greater than or equal to 0 and n may be an integer greater than 0.

The first channel is accessed in a mode of type 2A or type 2B.

This is described in detail below with reference to fig. 19. As shown in fig. 19, the time slot t may be a first time slot. Symbol 0 and symbol 1 in slot t are not used for sidestream communications. The resources for sidelink communication are n symbols (i.e., the resources in the dashed rectangular box) from symbol 2 of slot t. It will be appreciated that in fig. 19, n=12, k=2.

Wherein 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 listening (e.g., LBT procedure) duration L of the channel access procedure.

Taking fig. 19 as an example, in the case where the subcarrier spacing is 15KHz, the length of one symbol is about 71.4 μs. Taking the first channel access mode as type 2A as an example, the channel listening duration L may be 25 μs. Taking the first channel access mode as the type 2B as an example, the channel listening duration L may be 16 μs. It can be understood that the first channel access manner is type 2A or type 2B, and the second condition may be satisfied.

In step S1920, the first terminal device may send the first PRS from the symbol k+1 if the first channel access is successful. The second terminal device may receive the first PRS starting from symbol k+1.

It should be noted that, when the channel monitoring process of the first channel access starts, it needs to be ensured that the first PRS can be sent at symbol k+1 immediately when the channel monitoring is completed and the channel access is successful.

Continuing with the example of fig. 19, the first terminal device completes the first channel access procedure (including the channel listening procedure) within symbol 2 and prior to symbol 3. In fig. 19, the channel listening procedure is completed in the last microsecond of symbol 2, and the first channel access procedure is successfully completed. The first terminal device then starts transmitting the first PRS (i.e., SL-PRS) at symbol 3.

In fig. 19, the transmission of the first PRS occupies 7 symbols, symbol 3 through symbol 9.

In some implementations, resources for sidestream communications may be acquired through sidestream awareness. For example, if the first terminal device performs sidestream awareness, resources for sidestream communications may be obtained through sidestream awareness and resource selection procedures.

In some implementations, resources for sidestream communications may be obtained from a pool of resources. For example, the first terminal device may not perform sidestream awareness, and the first terminal device may acquire resources for sidestream communication through higher layer 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.

In step S2010, the first terminal device performs the first channel access in symbol m of the first slot.

Symbol k is a symbol in the first slot. In the first slot, n OFDM symbols, where the kth symbol starts to be consecutive, may be used for sidelink communication. That is, symbol k may be the first symbol of the plurality of symbols for sidelink communication in the first slot. Where k may be an integer greater than or equal to 0 and n may be an integer greater than 0.

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

The first channel is accessed in a mode of type 2A or type 2B.

This is described in detail below with reference to fig. 20. As shown in fig. 20, the time slot t may be a first time slot. Symbol 0 and symbol 1 in slot t are not used for sidestream communications. The resources for sidelink communication are n symbols (i.e., the resources in the dashed rectangular box) from symbol 2 of slot t. The first terminal device performs a first channel access at symbol 4. It will be appreciated that in fig. 20, n=12, k=2, m=4.

In step S2020, in case the first channel access is successful, the first terminal device may send the first PRS starting from symbol m+1. The second terminal device may receive the first PRS starting from symbol m+1.

It will be appreciated that embodiment 1 may be a special case of m=k in embodiment 2.

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.

In step S2110, the first terminal device performs the first channel access in symbol m of the first slot.

The first channel access starts at the beginning of symbol m. As shown in fig. 21, m=4, and the first channel access procedure starts from the start point of symbol 4.

In step S2120, the first terminal device transmits the placeholder after the first channel access procedure is ended. The second terminal device receives the placeholder after the end of the first channel access procedure.

As shown in fig. 21, when the time when the first channel access is successful (also the time when the channel listening is successful) has not reached the start time (i.e., the start point or the start boundary) of the symbol 5, the first terminal device may start transmitting the placeholder at the time when the first channel access is successful until the start time of the symbol 5 ends the transmission of the placeholder. The placeholder may be a CPE.

It will be appreciated that in embodiment 3, the first terminal device may not be required to start the first channel access at the position of symbol 4. That is, the start time of the first channel access can be flexibly determined.

In step S2130, the first terminal device starts transmitting the first PRS at symbol m+1. The second terminal device starts receiving the first PRS at symbol m+1.

Example 4

Fig. 22 is an exemplary 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 performed by the first terminal device and/or the second terminal device.

In step S2210, the first terminal device performs the first channel access in symbol m of the first slot.

All symbols in the first slot may be used for sidestream communications. As shown in fig. 22, the time slot t may be a first time slot, and all of symbols 0 to 13 in the first time slot may be used for sidestream communication. All symbols in slot t-1 may also be used for sidestream communications (the resources available for sidestream communications in slot t and slot t-1 are outlined by the rectangular dashed box). Symbol m may be any one symbol in the first slot. In fig. 22, symbol m may be symbol 0, and symbol 0 is the first symbol of the first slot. That is, the first terminal device may perform the first channel access in the first symbol of the first 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 listening (e.g., LBT procedure) duration L of the channel access procedure. Taking the first channel access mode as type 2A as an example, the channel listening duration L may be 25 μs, and the second condition includes that the length of the symbol m is greater than or equal to 25 μs. Taking the first channel access mode as the type 2B as an example, the channel listening duration L may be 16 μs, and the second condition may include that the length of the symbol m is greater than or equal to 16 μs.

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

In step S2220, the first terminal device sends the first PRS in symbol m+1 of the first slot. The second terminal device receives the first PRS in a second symbol of the first slot.

In fig. 22, a first PRS is transmitted or received in a second symbol (symbol 1) of a slot t.

Alternatively, the last time slot of the time slot t, namely the time slot t-1, can be the time slot for side communication. And at time slot t-1 there is a first terminal device or a terminal device different from the first terminal device to perform sidestream transmission. In this case, the first terminal device does not perform the channel listening procedure for the 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 LBT.

In one implementation, in a case where the interval between the start time of transmitting the first PRS and the end time of the last sidestream communication is a second time interval, if the second time interval is less than or equal to X μs, the first terminal device may directly transmit the first PRS without performing channel listening. Wherein X is greater than or equal to 0. It will be appreciated that in such an implementation, the type of first channel access may be type 2C.

In one implementation, the first terminal device may directly send the first PRS on any symbol on the resource used for sidelink communications without performing LBT. The manner of transmitting the first PRS may be a transmission manner using SCSt.

The method embodiment of the present application is described above in detail with reference to fig. 1 to 22, and the apparatus embodiment of the present application is described below in detail with reference to fig. 23 to 25. It is to be understood that the description of the method embodiments corresponds to the description of the device embodiments, and that parts not described in detail can therefore be seen in the preceding method embodiments.

Fig. 23 is a schematic block diagram of a terminal device 2300 according to an embodiment of the present application. The terminal device 2300 is a first terminal device, and the terminal device 2300 includes a first transmitting unit 2310.

The first transmission unit 2310 may be used to transmit the first positioning reference signal PRS over the side uplink on an unlicensed spectrum.

Optionally, the terminal device 2300 may further include an access unit 2320. An access unit 2320 is configured to perform a first channel access on a first timeslot; wherein the first channel access is configured to transmit the first PRS in the first time slot.

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

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

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

Optionally, the first channel access starts with a third symbol, the third symbol being one of one or more symbols available for sidestream communication in the first slot.

Optionally, the third symbol is a first symbol of one or more symbols available for sidestream communication in the first slot.

Optionally, the first channel access does not occur over the GAP symbols.

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

Optionally, the first channel access mode is a channel access mode that does not need channel monitoring.

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

Optionally, an interval between a start time of transmitting the first PRS and an end time of a last sidestream 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 sending mode of the first PRS is a short control signaling sending SCSt mode.

Optionally, the first PRS is carried on a first sidelink resource, the first sidelink resource being configured in a resource pool through pre-configuration or through higher layer signaling.

Fig. 24 is a schematic block diagram of a terminal device 2400 according to 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.

A first receiving unit 2410 for receiving a first positioning reference signal PRS over an unlicensed spectrum over a side uplink.

Optionally, the transmission of the first PRS is based on a first channel access on a first time slot, the first channel access being used to transmit the first PRS within the first time slot.

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

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

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

Optionally, the first channel access starts with a third symbol, the third symbol being one of one or more symbols available for sidestream communication in the first slot.

Optionally, the third symbol is a first symbol of one or more symbols available for sidestream communication in the first slot.

Optionally, the first channel access does not occur over the GAP symbols.

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

Optionally, the first channel access mode is a channel access mode that does not need channel monitoring.

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

Optionally, an interval between a start time of transmitting the first PRS and an end time of a last sidestream 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 sending mode of the first PRS is a short control signaling sending SCSt mode.

Optionally, the first PRS is carried on a first sidelink resource, the first sidelink resource being configured in a resource pool through pre-configuration or through higher layer signaling.

In an alternative embodiment, the first transmitting 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. Terminal device 2300 or terminal device 2400 can also include memory 2520, as shown in particular in fig. 25.

Fig. 25 is a schematic structural diagram of a communication apparatus of an embodiment of the present application. The dashed lines in fig. 25 indicate that the unit or module is optional. The apparatus 2500 may be used to implement the methods described in the method embodiments above. The apparatus 2500 may be a chip, a terminal device or a network device.

The apparatus 2500 may include one or more processors 2510. The processor 2510 may support the apparatus 2500 in performing the methods described in the method embodiments 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 (central processing unit, CPU). Or the processor may be another general purpose processor, a digital signal processor (DIGITAL SIGNAL processor), an Application SPECIFIC INTEGRATED Circuit (ASIC), an off-the-shelf programmable gate array (field programmable GATE ARRAY, FPGA) or other programmable logic device, a discrete gate or transistor logic device, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

The apparatus 2500 may also include one or more memories 2520. The memory 2520 has stored thereon a program that can be executed by the processor 2510 to cause the processor 2510 to perform the methods described in the method embodiments above. Memory 2520 may be separate from processor 2510 or may be integrated within processor 2510.

The device 2500 may also 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 to and from other devices or chips through the transceiver 2530.

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

The embodiment of the application also provides a computer program product. The computer program product includes a program. The computer program product may be applied to a terminal or a network device provided in an embodiment of the present application, and the program causes a computer to execute the method executed by the terminal or the network device in the respective embodiments of the present application.

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

It should be understood that the terms "system" and "network" may be used interchangeably herein. In addition, the terminology used herein is for the purpose of describing particular embodiments of the application only and is not intended to be limiting of the application. The terms "first," "second," "third," and "fourth" and the like in the description and in the claims and drawings are used for distinguishing between different objects and not necessarily for describing a particular sequential or chronological order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion.

In the embodiment of the present application, the "indication" may be a direct indication, an indirect indication, or an indication having an association relationship. For example, a indicates B, which may mean that a indicates B directly, e.g., B may be obtained by a; it may also indicate that a indicates B indirectly, e.g. a indicates C, B may be obtained by C; it may also be indicated that there is an association between a and B.

In the embodiment of the application, "B corresponding to A" means that B is associated with A, from which B can be determined. It should also be understood that determining B from a does not mean determining B from a alone, but may also determine B from a and/or other information.

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

In the embodiment of the present application, the "pre-defining" or "pre-configuring" may be implemented by pre-storing corresponding codes, tables or other manners that may be used to indicate relevant information in devices (including, for example, terminal devices and network devices), and the present application is not limited to the specific implementation manner thereof. Such as predefined may refer to what is defined in the protocol.

In the embodiment of the present application, the "protocol" may refer to a standard protocol in the communication field, for example, may include an LTE protocol, an NR protocol, and related protocols applied in a future communication system, which is not limited in the present application.

In the embodiment of the present application, the term "and/or" is merely an association relationship describing the association object, which indicates that three relationships may exist, for example, a and/or B may indicate: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

In various embodiments of the present application, the sequence numbers described above do not mean the order of execution, and each order of execution should be determined by its functions and internal logic, and should not constitute any limitation on the implementation of the embodiments of the present application.

In the several embodiments provided by the present application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of 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 the embodiments of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may 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 loaded and executed on a computer, produces a flow or function in accordance with embodiments of the present application, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. 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 one website, computer, server, or data center to another website, computer, server, or data center by a wired (e.g., coaxial cable, fiber optic, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). 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, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., digital versatile disk (digital video disc, DVD)), or a semiconductor medium (e.g., solid State Disk (SSD)), etc.

The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (66)

1. A method of communication, the method comprising:

   on the unlicensed spectrum, the first terminal device transmits a first positioning reference signal PRS over a side uplink.
2. The method according to claim 1, wherein the method further comprises:

   the first terminal equipment performs first channel access on a first time slot;

   Wherein the first channel access is configured to transmit the first PRS in the first time slot.
3. The method of claim 2, wherein a first symbol occupied by the first PRS is a first symbol, a previous symbol of the first symbol is a second symbol, and the first channel access ends at the second symbol.
4. A method according to claim 3, characterized in that the first channel access ends at the end time of the second symbol.
5. A method according to claim 2 or 3, wherein a first time gap is included between an end time of the first channel access and the first PRS transmission start time, the method further comprising:

   And in the first time interval, the first terminal equipment transmits a placeholder.
6. The method of any of claims 2-5, wherein the first channel access starts with a third symbol, the third symbol being one of one or more symbols available for sidestream communication in the first slot.
7. The method of claim 6, wherein the third symbol is a first symbol of one or more symbols available for sidestream communication in the first slot.
8. The method according to any of claims 2-7, wherein the first channel access does not occur on GAP symbols.
9. The method according to any of claims 2-8, wherein the type of first channel access is type 2A or type 2B.
10. The method according to any of claims 2-8, wherein the first channel access mode is a channel access mode that does not require channel listening.
11. The method of claim 10, wherein the first channel access is based on a first condition.
12. The method of claim 11, wherein a start time of transmitting the first PRS is spaced from an end time of a last sidelink communication by a second time interval, and wherein the first condition is related to the second time interval.
13. The method according to any of claims 10-12, wherein the type of first channel access is type 2C.
14. The method according to any of claims 1-13, wherein the transmission mode of the first PRS is a short control signaling transmission SCSt mode.
15. The method of any of claims 1-14, wherein the first PRS is carried on a first side row resource that is configured in a resource pool by pre-configuration or by higher layer signaling.
16. A method of communication, the method comprising:

    on the unlicensed spectrum, the second terminal device receives the first positioning reference signal PRS over the side uplink.
17. The method of claim 16, in which the transmission of the first PRS is based on a first channel access on a first time slot, the first channel access being used to transmit the first PRS within the first time slot.
18. The method of claim 17, wherein a first symbol occupied by the first PRS is a first symbol, a previous symbol of the first symbol is a second symbol, and the first channel access ends at the second symbol.
19. The method of claim 18, wherein the first channel access ends at an end time of the second symbol.
20. The method of claim 17 or 18, wherein a first time gap is included between an end time of the first channel access and the first PRS transmission start time, the method further comprising:

    in the first time interval, the second terminal device receives a placeholder.
21. The method of any of claims 17-20, wherein the first channel access starts with a third symbol, the third symbol being one of one or more symbols available for sidestream communication in the first slot.
22. The method of claim 21, wherein the third symbol is a first symbol of one or more symbols available for sidestream communication in the first slot.
23. The method according to any of claims 17-22, wherein the first channel access does not occur on GAP symbols.
24. The method according to any of claims 17-23, wherein the type of first channel access is type 2A or type 2B.
25. The method according to any of claims 17-23, wherein the first channel access is a channel access that does not require channel listening.
26. The method of claim 25, wherein the first channel access is based on a first condition.
27. The method of claim 26, wherein a start time of transmitting the first PRS is spaced from an end time of a last sidelink communication by a second time interval, and wherein the first condition is related to the second time interval.
28. The method according to any of claims 25-27, wherein the type of first channel access is type 2C.
29. The method of any of claims 16-28, wherein the first PRS is sent in a manner of a short control signaling transmission SCSt.
30. The method of any of claims 16-29, wherein the first PRS is carried on a first side row resource that is configured in a resource pool by pre-configuration or by higher layer signaling.
31. A terminal device, wherein the terminal device is a first terminal device, the terminal device comprising:

    And a first transmitting unit for transmitting the first positioning reference signal PRS over the side uplink over an unlicensed spectrum.
32. The terminal device of claim 31, wherein the terminal device further comprises:

    an access unit, configured to perform a first channel access on a first timeslot;

    Wherein the first channel access is configured to transmit the first PRS in the first time slot.
33. The terminal device of claim 32, wherein a first symbol occupied by the first PRS is a first symbol, a preceding symbol of the first symbol is a second symbol, and the first channel access ends at the second symbol.
34. The terminal device of claim 33, wherein the first channel access ends at an end time of the second symbol.
35. The terminal device of claim 32 or 33, wherein a first time gap is included between an end time of the first channel access and the first PRS transmission start time, the terminal device further comprising:

    And the second sending unit is used for sending the placeholder in the first time interval.
36. The terminal device of any of claims 32-35, wherein the first channel access starts with a third symbol, the third symbol being one of one or more symbols available for sidestream communication in the first slot.
37. The terminal device of claim 36, wherein the third symbol is a first symbol of one or more symbols available for sidestream communication in the first slot.
38. The terminal device according to any of claims 32-37, wherein the first channel access does not occur on GAP symbols.
39. The terminal device according to any of the claims 32-38, wherein the type of the first channel access is type 2A or type 2B.
40. The terminal device according to any of the claims 32-38, wherein the first channel access is a channel access without channel listening.
41. The terminal device of claim 40, wherein the first channel access is based on a first condition.
42. The terminal device of claim 41, wherein a start time of transmitting the first PRS is spaced from an end time of a last sidestream communication by a second time interval, and wherein the first condition is related to the second time interval.
43. The terminal device according to any of claims 40-42, wherein the type of first channel access is type 2C.
44. The terminal device according to any of claims 31-43, wherein the transmission manner of the first PRS is a short control signaling transmission SCSt manner.
45. The terminal device of any of claims 31-44, wherein the first PRS is carried on a first side-row resource that is configured in a resource pool by pre-configuration or by higher layer signaling.
46. A terminal device, wherein the terminal device is a second terminal device, the terminal device comprising:

    a first receiving unit for receiving a first positioning reference signal PRS over a side uplink over an unlicensed spectrum.
47. The terminal device of claim 46, wherein the transmission of the first PRS is based on a first channel access on a first time slot, the first channel access being used to transmit the first PRS within the first time slot.
48. The terminal device of claim 47, wherein a first symbol occupied by the first PRS is a first symbol, a preceding symbol of the first symbol is a second symbol, and the first channel access ends at the second symbol.
49. The terminal device of claim 48, wherein the first channel access ends at an end time of the second symbol.
50. The terminal device of claim 47 or 48, wherein a first time gap is included between an end time of the first channel access and the first PRS transmission start time, the terminal device further comprising:

    and the second receiving unit is used for receiving the placeholder in the first time interval.
51. The terminal device of any of claims 47-50, wherein the first channel access starts with a third symbol, the third symbol being one of one or more symbols available for sidestream communication in the first slot.
52. The terminal device of claim 51, wherein the third symbol is a first symbol of one or more symbols available for sidestream communication in the first slot.
53. The terminal device according to any of claims 47-52, wherein the first channel access does not occur on GAP symbols.
54. The terminal device of any of claims 47-53, wherein the type of first channel access is type 2A or type 2B.
55. The terminal device of any of claims 47-53, wherein the first channel access is a channel access that does not require channel listening.
56. The terminal device of claim 55, wherein the first channel access is based on a first condition.
57. The terminal device of claim 56, wherein a start time of transmitting the first PRS is spaced from an end time of a last sidestream communication by a second time interval, the first condition being related to the second time interval.
58. The terminal device of any of claims 55-57, wherein the type of first channel access is type 2C.
59. The terminal device of any of claims 46-58, wherein the first PRS is sent in a manner of a short control signaling transmission SCSt.
60. The terminal device of any of claims 46-59, wherein the first PRS is carried on a first side-row resource that is configured in a resource pool by pre-configuration or by higher layer signaling.
61. A terminal device comprising a transceiver, a memory for storing a program, and a processor for invoking the program in the memory to cause the terminal to perform the method of any of claims 1-30.
62. An apparatus comprising a processor to invoke a program from a memory to cause the apparatus to perform the method of any of claims 1-30.
63. A chip comprising a processor for calling a program from a memory, causing a device on which the chip is mounted to perform the method of any one of claims 1-30.
64. A computer-readable storage medium, having stored thereon a program that causes a computer to perform the method of any of claims 1-30.
65. A computer program product comprising a program for causing a computer to perform the method of any one of claims 1-30.
66. A computer program, characterized in that the computer program causes a computer to perform the method according to any one of claims 1-30.