Sidelink communication method, communication apparatus, and communication system

Abstract

Provided in the present application are a sidelink communication method, a communication apparatus, and a communication system. The method comprises: a first terminal device sending a first message to a second terminal device, wherein the first message comprises first indication information and an identifier of a third terminal device, the first indication information is used for indicating an end-to-end QoS flow between the first terminal device and the second terminal device, and the first indication information comprises a QFI; and sending a first correspondence to the second terminal device, wherein the first correspondence is the correspondence between the first indication information and a PC5 configuration index, and the PC5 configuration index is used for identifying an SLRB configuration between the first terminal device and the third terminal device. By means of the first indication information and the first correspondence, the second terminal device can associate the SLRB configuration with the corresponding third terminal device, such that the third terminal device corresponding to the configuration can be determined when the SLRB configuration is acquired subsequently, thereby ensuring the normal execution of a control-plane process.

Description

Sidelink communication method, communication device and communication system

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on December 29, 2023, with application number 202311866954.6 and invention name “Method, communication device and communication system for side link communication”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of communications, and more specifically, to a sidelink communication method, a communication device, and a communication system. Background Art

[0003] With the development of technology, device-to-device (D2D) communication and relay communication of user equipment (UE) have begun to be discussed in standards (for example, the 3rd Generation Partnership Project (3GPP)). D2D communication and relay communication between UEs can be used for public safety and improve the system performance of the network and users, for example, to enhance coverage and increase system capacity.

[0004] To this end, the standard proposes deploying one or more relay terminals (UEs) between devices based on D2D communication. These terminals have stronger capabilities, such as more receive and transmit antennas. They can assist the source UE in relaying data to the target UE, thereby improving coverage and increasing communication range. Communication between the source UE and the relay UE, as well as between the relay UE and the target UE, is carried out via sidelinks.

[0005] When there is a relay UE, the link configuration between the source UE and the relay UE, and the link configuration between the relay UE and the target UE are both crucial to the normal communication of the sidelink. If the source UE, relay UE and target UE still obtain the link configuration according to the mechanism of direct sidelink communication, the relay UE will not be able to associate the configuration with the corresponding source UE and target UE, thereby affecting the normal communication between the source UE and the target UE. Summary of the Invention

[0006] The present application provides a sidelink communication method, communication device and communication system to ensure normal communication between the source UE and the target UE. It can be applied to UE to UE relay (UE to UE relay, U2U relay) scenarios, and can also be applied to other scenarios where the technical problems described in the background technology exist.

[0007] In a first aspect, a sidelink communication method is provided. The method may be executed by a first terminal device, or may be executed by a chip or circuit used for the first terminal device, and this application does not limit this.

[0008] The method includes: sending a first message to a second terminal device, the first message including first indication information and an identifier of a third terminal device, the first indication information being used to indicate a first quality of service (QoS) flow between the first terminal device and the second terminal device, the first QoS flow being a QoS flow between the first terminal device and the third terminal device, the first terminal device communicating with the third terminal device through the second terminal device, the first indication information including a QoS flow identifier QFI; sending a first correspondence to the second terminal device, the first correspondence being a correspondence between the first indication information and a PC5 configuration index, the PC5 configuration index being used to identify a sidelink radio bearer (SLRB) configuration between the first terminal device and the third terminal device.

[0009] Based on the above technical solution, through the first indication information and the first correspondence, the second terminal device can associate the SLRB configuration between the first terminal device and the third terminal device with the corresponding third terminal device, so that when the SLRB configuration is subsequently obtained, the third terminal device corresponding to the configuration can be determined, ensuring the normal execution of the control plane process, thereby ensuring normal communication between the first terminal device and the third terminal device.

[0010] In one possible implementation, the first message also includes QoS parameters corresponding to the first QoS flow, and the method also includes: receiving a second message from a second terminal device, the second message including a first packet delay budget and first indication information, the first packet delay budget is determined according to the QoS parameters, the first packet delay budget is used to indicate the packet delay budget corresponding to the first QoS flow on the first link, and the first link is a link between the first terminal device and the second terminal device.

[0011] In a possible implementation manner, the method further includes: determining a correspondence between the first packet delay budget and the first QoS flow according to the first indication information.

[0012] In a possible implementation, the identifier of the third terminal device is a layer 2 identifier.

[0013] In a possible implementation, the correspondence between the first packet delay budget and the first QoS flow is used to determine the PC5 configuration index.

[0014] Optionally, one first terminal device communicates with N third terminal devices through the second terminal device, where N is a positive integer; the first message includes N first information, and each first information includes first indication information and an identifier of the third terminal device.

[0015] In a second aspect, a sidelink communication method is provided. The method can be executed by a second terminal device, or can also be executed by a chip or circuit used for the second terminal device, which is not limited in this application.

[0016] The method includes: receiving a first message from a first terminal device, the first message including first indication information and an identifier of a third terminal device, the first indication information being used to indicate a first quality of service (QoS) flow between the first terminal device and the second terminal device, the first QoS flow being a QoS flow between the first terminal device and the third terminal device, the first terminal device communicating with the third terminal device via the second terminal device, the first indication information including a QFI; receiving a first correspondence from the first terminal device, the first correspondence being a correspondence between the first indication information and a PC5 configuration index, the PC5 configuration index being used to identify an SLRB configuration between the first terminal device and the third terminal device; and determining a correspondence between the PC5 configuration index and the third terminal device based on the first message and the first correspondence.

[0017] Based on the above technical solution, through the first indication information and the first correspondence, the second terminal device can associate the SLRB configuration between the first terminal device and the third terminal device with the corresponding third terminal device, so that when the SLRB configuration is subsequently obtained, the third terminal device corresponding to the configuration can be determined, ensuring the normal execution of the control plane process, thereby ensuring normal communication between the first terminal device and the third terminal device.

[0018] In a possible implementation, determining the correspondence between the PC5 configuration index and the third terminal device according to the first message and the first correspondence includes associating the third terminal device with the PC5 configuration index one-to-one according to the first indication information.

[0019] In one possible implementation, the first message also includes QoS parameters corresponding to the first QoS flow, and the method also includes: determining a first packet delay budget based on the QoS parameters, the first packet delay budget being used to indicate the packet delay budget corresponding to the first QoS flow on the first link, the first link being the link between the first terminal device and the second terminal device; sending a second message to the first terminal device, the second message including the first packet delay budget and the first indication information.

[0020] In a third aspect, a sidelink communication method is provided. The method can be executed by a first terminal device, or can also be executed by a chip or circuit used for the first terminal device, which is not limited in this application.

[0021] The method includes: sending a first message to a second terminal device, the first message including second indication information and an identifier of a third terminal device, the second indication information being used to indicate a first QoS flow within the range of the third terminal device, the first QoS flow being a QoS flow between the first terminal device and the third terminal device, the first terminal device communicating with the third terminal device through the second terminal device, the second indication information including a PC5 QoS flow identifier PFI; sending a third message to the second terminal device, the third message including an identifier of the third terminal device and a second corresponding relationship, the second corresponding relationship being a corresponding relationship between the second indication information and a PC5 configuration index, the PC5 configuration index being used to identify an SLRB configuration between the first terminal device and the third terminal device.

[0022] Based on the above scheme, through the second indication information and the second correspondence, the second terminal device can associate the SLRB configuration between the first terminal device and the third terminal device with the corresponding third terminal device, so that when the SLRB configuration is subsequently obtained, the third terminal device corresponding to the configuration can be determined, ensuring the correct execution of the control plane process, thereby ensuring normal communication between the first terminal device and the third terminal device.

[0023] In one possible implementation, the first message also includes QoS parameters corresponding to the first QoS flow, and the method also includes: receiving a second message from a second terminal device, the second message including a first packet delay budget, an identifier of a third terminal device and second indication information, the first packet delay budget is determined based on the QoS parameters, the first packet delay budget is used to indicate the packet delay budget corresponding to the first QoS flow on the first link, and the first link is a link between the first terminal device and the second terminal device.

[0024] In a possible implementation, the method further includes: determining a relationship between the first packet delay budget and the first QoS flow according to an identifier of the third terminal device and the second indication information.

[0025] Optionally, the correspondence between the first packet delay budget and the first QoS flow is used to determine a PC5 configuration index.

[0026] Exemplarily, the identifier of the third terminal device is a layer 2 identifier.

[0027] Optionally, one first terminal device communicates with N third terminal devices through a second terminal device, where N is a positive integer; the first message includes N second information, each second information includes second indication information and an identifier of a third terminal device; the third message includes N third information, each third information includes an identifier of a third terminal device and a second correspondence.

[0028] Exemplarily, the second message includes N pieces of fourth information, and each piece of fourth information includes an identifier of the third terminal device and the second indication information.

[0029] In a fourth aspect, a sidelink communication method is provided. The method can be executed by a second terminal device, or can also be executed by a chip or circuit used for the second terminal device. This application does not limit this.

[0030] The method includes: receiving a first message from a first terminal device, the first message including second indication information and an identifier of a third terminal device, the second indication information being used to indicate a first QoS flow within the range of the third terminal device, the first QoS flow being a QoS flow between the first terminal device and the third terminal device, the first terminal device communicating with the third terminal device through the second terminal device, the second indication information including PFI; receiving a third message from the first terminal device, the third message including an identifier of the third terminal device and a second corresponding relationship, the second corresponding relationship being a corresponding relationship between the second indication information and a PC5 configuration index, the PC5 configuration index being used to identify an SLRB configuration between the first terminal device and the third terminal device; and determining a corresponding relationship between the PC5 configuration index and the third terminal device based on the first message and the third message.

[0031] Based on the above scheme, through the second indication information and the second correspondence, the second terminal device can associate the SLRB configuration between the first terminal device and the third terminal device with the corresponding third terminal device, so that when the SLRB configuration is subsequently obtained, the third terminal device corresponding to the configuration can be determined, ensuring the correct execution of the control plane process, thereby ensuring normal communication between the first terminal device and the third terminal device.

[0032] In a possible implementation, determining the correspondence between the PC5 configuration index and the third terminal device according to the first message and the third message includes associating the third terminal device with the PC5 configuration index one by one according to the identifier of the third terminal device and the second indication information.

[0033] In one possible implementation, the first message also includes QoS parameters corresponding to the QoS flow, and the method also includes: determining a first packet delay budget based on the QoS parameters, the first packet delay budget being used to indicate the packet delay budget corresponding to the first QoS flow on the first link, the first link being the link between the first terminal device and the second terminal device; sending a second message to the first terminal device, the second message including an identifier of the third terminal device, second indication information and the first packet delay budget.

[0034] In a fifth aspect, a sidelink communication method is provided. The method can be executed by a second terminal device, or can also be executed by a chip or circuit used for the second terminal device. This application does not limit this.

[0035] The method includes: sending third indication information to the access network device, the third indication information is used to identify the first SLRB between the second terminal device and the access network device, the first SLRB is the SLRB between the first terminal device and the third terminal device, and the first terminal device communicates with the third terminal device through the second terminal device; receiving a third correspondence from the access network device, the third correspondence is the correspondence between the third indication information and the radio link control RLC channel; determining the correspondence between the RLC channel and the third terminal device based on the third indication information and the third correspondence.

[0036] Based on the above scheme, through the third indication information and the third corresponding relationship, the second terminal device can associate the RLC channel with the corresponding first terminal device, so that in subsequent data transmission, the RLC channel corresponding to the data packet can be determined to ensure the normal execution of the data plane process, thereby ensuring normal communication between the first terminal device and the third terminal device.

[0037] In a possible implementation, determining the correspondence between the RLC channel and the third terminal device according to the third indication information and the third correspondence includes associating the RLC channel and the third terminal device one-to-one according to the third indication information.

[0038] In a possible implementation, the method further includes: mapping a PC5 configuration index to third indication information, where the PC5 configuration index is used to identify the SLRB configuration between the first terminal device and the third terminal device.

[0039] In the sixth aspect, a method for sidelink communication is provided. The method can be executed by an access network device, or can also be executed by a chip or circuit used for the access network device. This application does not limit this.

[0040] The method includes: receiving third indication information from the second terminal device, the third indication information identifies a first SLRB between the second terminal device and the access network device, the first SLRB is the SLRB between the first terminal device and the third terminal device, and the first terminal device communicates with the third terminal device through the second terminal device; sending a third correspondence to the second terminal device, the third correspondence is a correspondence between the third indication information and the RLC channel.

[0041] Based on the above scheme, through the third indication information and the third corresponding relationship, the second terminal device can associate the RLC channel with the corresponding first terminal device, so that in subsequent data transmission, the RLC channel corresponding to the data packet can be determined to ensure the normal execution of the data plane process, thereby ensuring normal communication between the first terminal device and the third terminal device.

[0042] In the seventh aspect, a method for sidelink communication is provided. The method can be executed by a second terminal device, or can also be executed by a chip or circuit used for the second terminal device. This application is not limited to this.

[0043] The method includes: sending a fourth message to an access network device, the fourth message including fourth indication information and an identifier of a first terminal device, the fourth indication information being used to identify a first SLRB on a first unicast connection, the first unicast connection being a unicast connection between a first terminal device and a third terminal device, the first SLRB being an SLRB between the first terminal device and the third terminal device, and the first terminal device communicating with the third terminal device through a second terminal device; receiving a fifth message from the access network device, the fifth message including an identifier of the first terminal device and a fourth correspondence, the fourth correspondence being a correspondence between the fourth indication information and an RLC channel; and determining a correspondence between the first terminal device and the RLC channel based on the fourth message and the fifth message.

[0044] Based on the above scheme, through the fourth indication information and the fourth corresponding relationship, the second terminal device can associate the RLC channel with the corresponding first terminal device, so that in subsequent data transmission, the RLC channel corresponding to the data packet can be determined to ensure the normal execution of the data plane process, thereby ensuring normal communication between the first terminal device and the third terminal device.

[0045] In one possible implementation, determining the correspondence between the first terminal device and the RLC channel according to the fourth message and the fifth message includes associating the first terminal device and the RLC channel one-to-one according to the fourth indication information and the identifier of the first terminal device.

[0046] Exemplarily, the identifier of the first terminal device is a layer 2 identifier.

[0047] Optionally, M first terminal devices communicate with 1 third terminal device through the second terminal device, where M is a positive integer; the fourth message includes the identifier of the third terminal device and M fifth information, each fifth information includes the identifier of the first terminal device and the fourth indication information; the fifth message includes the identifier of the third terminal device and M sixth information, each sixth information includes the identifier of the first terminal device and the fourth correspondence.

[0048] In an eighth aspect, a method for sidelink communication is provided. The method can be executed by an access network device, or can also be executed by a chip or circuit used for the access network device. This application does not limit this.

[0049] The method includes: receiving a fourth message from a second terminal device, the fourth message including fourth indication information and an identifier of the first terminal device, the fourth indication information being used to identify a first SLRB on a first unicast connection, the first unicast connection being a unicast connection between the first terminal device and a third terminal device, the first SLRB being an SLRB between the first terminal device and the third terminal device, and the first terminal device communicating with the third terminal device through the second terminal device; and sending a fifth message to the second terminal device, the fifth message including an identifier of the first terminal device and a fourth correspondence, the fourth correspondence being a correspondence between the fourth indication information and an RLC channel.

[0050] Based on the above scheme, through the fourth indication information and the fourth corresponding relationship, the second terminal device can associate the RLC channel with the corresponding first terminal device, so that in subsequent data transmission, the RLC channel corresponding to the data packet can be determined to ensure the normal execution of the data plane process, thereby ensuring normal communication between the first terminal device and the third terminal device.

[0051] In the ninth aspect, a sidelink communication method is provided, which can be executed by a second terminal device, or can also be executed by a chip or circuit used for the second terminal device, and this application does not limit this.

[0052] The method includes: determining a sixth message, the sixth message includes fifth indication information, the fifth indication information is used to indicate the RLC mode of the RLC channel between the first terminal device and the second terminal device, the sixth message does not include information about the first QoS flow, the first QoS flow is the QoS flow between the first terminal device and the third terminal device, and the first terminal device communicates with the third terminal device through the second terminal device; sending the sixth message to the access network device.

[0053] Based on the above solution, the second terminal device can correctly report the RLC mode when acting as an RX UE, which facilitates the normal operation of the control plane process, thereby ensuring normal communication between the source UE and the target UE.

[0054] In the tenth aspect, a communication device is provided, which may be a first terminal device, or a chip or circuit used for the first terminal device, which is not limited in this application.

[0055] The device includes: a transceiver unit, used to send a first message to the second terminal device, the first message includes first indication information and an identifier of the third terminal device, the first indication information is used to indicate a first quality of service QoS flow between the first terminal device and the second terminal device, the first QoS flow is a QoS flow between the first terminal device and the third terminal device, the first terminal device communicates with the third terminal device through the second terminal device, and the first indication information includes a QoS flow identifier QFI; the transceiver unit is also used to: send a first correspondence to the second terminal device, the first correspondence is a correspondence between the first indication information and a PC5 configuration index, and the PC5 configuration index is used to identify the side link radio bearer SLRB configuration between the first terminal device and the third terminal device.

[0056] In one possible implementation, the first message also includes QoS parameters corresponding to the first QoS flow, and the transceiver unit is also used to: receive a second message from the second terminal device, the second message includes a first packet delay budget and first indication information, the first packet delay budget is determined according to the QoS parameters, the first packet delay budget is used to indicate the packet delay budget corresponding to the first QoS flow on the first link, and the first link is the link between the first terminal device and the second terminal device.

[0057] In a possible implementation manner, the apparatus further includes: a processing unit, configured to determine a correspondence between the first packet delay budget and the first QoS flow according to the first indication information.

[0058] In a possible implementation, the identifier of the third terminal device is a layer 2 identifier.

[0059] In a possible implementation, the correspondence between the first packet delay budget and the first QoS flow is used to determine the PC5 configuration index.

[0060] In the eleventh aspect, a communication device is provided, which may be a second terminal device, or a chip or circuit for a second terminal device, which is not limited in this application.

[0061] The device includes: a transceiver unit for receiving a first message from a first terminal device, the first message including first indication information and an identifier of a third terminal device, the first indication information being used to indicate a first quality of service QoS flow between the first terminal device and the second terminal device, the first QoS flow being a QoS flow between the first terminal device and the third terminal device, the first terminal device communicating with the third terminal device through the second terminal device, the first indication information including QFI; the transceiver unit is also used to: receive a first correspondence from the first terminal device, the first correspondence being a correspondence between the first indication information and a PC5 configuration index, the PC5 configuration index being used to identify the SLRB configuration between the first terminal device and the third terminal device; a processing unit for determining a correspondence between the PC5 configuration index and the third terminal device based on the first message and the first correspondence.

[0062] In a possible implementation, the processing unit is specifically configured to associate the third terminal device with the PC5 configuration index one by one according to the first indication information.

[0063] In one possible implementation, the first message also includes QoS parameters corresponding to the first QoS flow, and the processing unit is further used to: determine a first packet delay budget based on the QoS parameters, the first packet delay budget is used to indicate the packet delay budget corresponding to the first QoS flow on the first link, and the first link is the link between the first terminal device and the second terminal device; the transceiver unit is also used to: send a second message to the first terminal device, the second message includes the first packet delay budget and the first indication information.

[0064] In the twelfth aspect, a communication device is provided, which may be a first terminal device, or a chip or circuit used for the first terminal device, which is not limited in this application.

[0065] The device includes: a transceiver unit, used to send a first message to the second terminal device, the first message includes second indication information and an identifier of the third terminal device, the second indication information is used to indicate a first QoS flow within the range of the third terminal device, the first QoS flow is a QoS flow between the first terminal device and the third terminal device, the first terminal device communicates with the third terminal device through the second terminal device, and the second indication information includes a PC5QoS flow identifier PFI; the transceiver unit is also used to: send a third message to the second terminal device, the third message includes the identifier of the third terminal device and a second corresponding relationship, the second corresponding relationship is the corresponding relationship between the second indication information and the PC5 configuration index, and the PC5 configuration index is used to identify the SLRB configuration between the first terminal device and the third terminal device.

[0066] In one possible implementation, the first message also includes QoS parameters corresponding to the first QoS flow, and the transceiver unit is also used to: receive a second message from the second terminal device, the second message includes a first packet delay budget, an identifier of a third terminal device and second indication information, the first packet delay budget is determined according to the QoS parameters, and the first packet delay budget is used to indicate the packet delay budget corresponding to the first QoS flow on the first link, the link between the first terminal device and the second terminal device.

[0067] In a possible implementation, the apparatus further includes: a processing unit configured to determine a relationship between the first packet delay budget and the first QoS flow according to an identifier of the third terminal device and the second indication information.

[0068] Optionally, the correspondence between the first packet delay budget and the first QoS flow is used to determine a PC5 configuration index.

[0069] Exemplarily, the identifier of the third terminal device is a layer 2 identifier.

[0070] In the thirteenth aspect, a communication device is provided, which may be a second terminal device, or a chip or circuit for a second terminal device, which is not limited in this application.

[0071] The device includes: a transceiver unit, used to receive a first message from a first terminal device, the first message includes second indication information and an identifier of a third terminal device, the second indication information is used to indicate a first QoS flow within the range of the third terminal device, the first QoS flow is a QoS flow between the first terminal device and the third terminal device, the first terminal device communicates with the third terminal device through the second terminal device, and the second indication information includes PFI; the transceiver unit is also used to: receive a third message from the first terminal device, the third message includes an identifier of the third terminal device and a second corresponding relationship, the second corresponding relationship is a corresponding relationship between the second indication information and a PC5 configuration index, and the PC5 configuration index is used to identify the SLRB configuration between the first terminal device and the third terminal device; a processing unit, used to determine the corresponding relationship between the PC5 configuration index and the third terminal device based on the first message and the third message.

[0072] In a possible implementation, the processing unit is specifically configured to associate the third terminal device with the PC5 configuration index one by one according to the identifier of the third terminal device and the second indication information.

[0073] In one possible implementation, the first message also includes QoS parameters corresponding to the QoS flow, and the processing unit is further used to: determine a first packet delay budget based on the QoS parameters, the first packet delay budget is used to indicate the packet delay budget corresponding to the first QoS flow on the first link, and the first link is the link between the first terminal device and the second terminal device; the transceiver unit is also used to: send a second message to the first terminal device, the second message includes an identifier of the third terminal device, second indication information and the first packet delay budget.

[0074] In the fourteenth aspect, a communication device is provided, which may be a first terminal device, or a chip or circuit used for the first terminal device, which is not limited in this application.

[0075] The device includes: a transceiver unit, used to send third indication information to the access network device, the third indication information is used to identify the first SLRB between the second terminal device and the access network device, the first SLRB is the SLRB between the first terminal device and the third terminal device, and the first terminal device communicates with the third terminal device through the second terminal device; the transceiver unit is also used to: receive a third correspondence from the access network device, the third correspondence is the correspondence between the third indication information and the radio link control RLC channel; the processing unit is used to: determine the correspondence between the RLC channel and the third terminal device based on the third indication information and the third correspondence.

[0076] In a possible implementation, the processing unit is specifically configured to associate the RLC channel and the third terminal device one-to-one according to the third indication information.

[0077] In a possible implementation, the processing unit is further configured to: map a PC5 configuration index to third indication information, where the PC5 configuration index is used to identify the SLRB configuration between the first terminal device and the third terminal device.

[0078] In the fifteenth aspect, a communication device is provided, which may be an access network device, or a chip or circuit used for an access network device, which is not limited in this application.

[0079] The device includes: a transceiver unit, used to receive third indication information from the second terminal device, the third indication information identifies a first SLRB between the second terminal device and the access network device, the first SLRB is the SLRB between the first terminal device and the third terminal device, and the first terminal device communicates with the third terminal device through the second terminal device; the transceiver unit is also used to: send a third correspondence to the second terminal device, the third correspondence is a correspondence between the third indication information and the RLC channel.

[0080] In the sixteenth aspect, a communication device is provided, which may be a second terminal device, or a chip or circuit for a second terminal device, which is not limited in this application.

[0081] The device includes: a transceiver unit, used to send a fourth message to the access network device, the fourth message includes fourth indication information and an identifier of the first terminal device, the fourth indication information is used to identify the first SLRB on the first unicast connection, the first unicast connection is a unicast connection between the first terminal device and the third terminal device, the first SLRB is the SLRB between the first terminal device and the third terminal device, and the first terminal device communicates with the third terminal device through the second terminal device; the transceiver unit is also used to: receive a fifth message from the access network device, the fifth message includes the identifier of the first terminal device and a fourth correspondence, the fourth correspondence is the correspondence between the fourth indication information and the RLC channel; a processing unit, used to determine the correspondence between the first terminal device and the RLC channel based on the fourth message and the fifth message.

[0082] In a possible implementation, the processing unit is specifically configured to associate the first terminal device and the RLC channel one-to-one according to the fourth indication information and the identifier of the first terminal device.

[0083] Exemplarily, the identifier of the first terminal device is a layer 2 identifier.

[0084] In the seventeenth aspect, a communication device is provided, which may be an access network device, or a chip or circuit used for an access network device, which is not limited in this application.

[0085] The device includes: a transceiver unit, used to receive a fourth message from the second terminal device, the fourth message includes fourth indication information and an identifier of the first terminal device, the fourth indication information is used to identify the first SLRB on the first unicast connection, the first unicast connection is a unicast connection between the first terminal device and the third terminal device, the first SLRB is the SLRB between the first terminal device and the third terminal device, and the first terminal device communicates with the third terminal device through the second terminal device; the transceiver unit is also used to: send a fifth message to the second terminal device, the fifth message includes the identifier of the first terminal device and a fourth correspondence, and the fourth correspondence is a correspondence between the fourth indication information and the RLC channel.

[0086] In the eighteenth aspect, a communication device is provided, which may be a second terminal device, or a chip or circuit used for the second terminal device, which is not limited in this application.

[0087] The device includes: a processing unit, used to determine a sixth message, the sixth message includes fifth indication information, the fifth indication information is used to indicate the RLC mode of the RLC channel between the first terminal device and the second terminal device, the sixth message does not include information about the first QoS flow, the first QoS flow is a QoS flow between the first terminal device and the third terminal device, and the first terminal device communicates with the third terminal device through the second terminal device; a transceiver unit, used to send the sixth message to the access network device.

[0088] The technical effects of the tenth to eighteenth aspects and any possible implementation methods thereof can refer to the technical effects of the corresponding first to ninth aspects and any possible implementation methods thereof, and will not be repeated here.

[0089] In the nineteenth aspect, a communication device is provided, comprising: at least one processor, the at least one processor being coupled to at least one memory, the at least one processor being used to execute a computer program or instruction stored in the at least one memory, so that the communication device executes the communication method in any possible implementation of the above-mentioned first to seventh aspects.

[0090] In the twentieth aspect, a processor is provided for executing the communication method in any possible implementation of the first to seventh aspects above.

[0091] For the operations such as sending and acquiring / receiving involved in the processor, unless otherwise specified, or if they do not conflict with their actual functions or internal logic in the relevant descriptions, they can be understood as processor output, reception, input and other operations, and can also be understood as sending and receiving operations performed by the radio frequency circuit and antenna. This application does not limit this.

[0092] In the twenty-first aspect, a chip system is provided, comprising: a processor for calling and running a computer program from a memory, so that a communication device equipped with the chip system executes a communication method in any possible implementation of the first to seventh aspects above.

[0093] Optionally, as an implementation method, the chip also includes a memory, in which a computer program or instruction is stored, and the processor is used to execute the computer program or instruction stored in the memory. When the computer program or instruction is executed, the processor is used to execute the communication method in any possible implementation of the first to seventh aspects above.

[0094] In aspect twenty-second, a computer program product comprising instructions is provided, which, when run on a communication device, enables the communication device to execute a communication method in any possible implementation of aspect one to aspect seven.

[0095] In the twenty-third aspect, a computer-readable storage medium is provided, which stores a program code for execution by a device, wherein the program code includes instructions for executing the communication method provided by any possible implementation of the first to seventh aspects.

[0096] In the twenty-fourth aspect, a chip is provided, comprising at least one processor and a communication interface, wherein the communication interface is used to receive data and / or information and transmit the received data and / or information to the processor, and the processor processes the data and / or information to execute the communication method in any possible implementation of the first to seventh aspects above.

[0097] In a twenty-fifth aspect, a communication system is provided, comprising a first terminal device and a second terminal device. The first terminal device is configured to execute the communication method of the first or third aspect, and any possible implementation thereof; and the second terminal device is configured to execute the communication method of the second or fourth aspect, and any possible implementation thereof.

[0098] In a twenty-sixth aspect, a communication system is provided, comprising a second terminal device and an access network terminal device. The second terminal device is configured to execute the communication method of the fifth or seventh aspect, and any possible implementation thereof; and the access network device is configured to execute the communication method of the sixth or eighth aspect, and any possible implementation thereof.

[0099] In a twenty-seventh aspect, a communication system is provided, comprising a second terminal device and an access network device, wherein the second terminal device is configured to execute the communication method in any possible implementation of the ninth aspect.

[0100] Optionally, any of the above communication systems may further include a third terminal device. BRIEF DESCRIPTION OF THE DRAWINGS

[0101] FIG1 is a schematic diagram of the architecture of a communication system 100 used in an embodiment of the present application.

[0102] FIG2 shows a schematic diagram of a protocol stack architecture applicable to an embodiment of the present application.

[0103] FIG3 is a schematic diagram showing a TX UE acquiring SLRB configuration.

[0104] Figure 4 shows the control plane process in the L2 U2U relay scenario.

[0105] FIG5 is a schematic diagram of a scenario in which a relay UE provides relay services for multiple remote UEs.

[0106] FIG6 is a schematic flowchart of a sidelink communication method provided by the present application.

[0107] FIG7 is a schematic flowchart of a sidelink communication method 400 provided in the present application.

[0108] FIG8 is a schematic flowchart of a sidelink communication method 500 provided in the present application.

[0109] FIG9 is a schematic flowchart of a sidelink communication method 600 provided in the present application.

[0110] FIG10 is a schematic flowchart of a sidelink communication method 700 provided in the present application.

[0111] FIG11 is a schematic flowchart of a sidelink communication method 800 provided in the present application.

[0112] FIG12 is a schematic block diagram of a communication device according to an embodiment of the present application.

[0113] FIG13 is a schematic block diagram of another communication device 1300 provided in an embodiment of the present application.

[0114] FIG14 is a schematic block diagram of a chip system 1400 provided in an embodiment of the present application. DETAILED DESCRIPTION

[0115] The technical solution in this application will be described below with reference to the accompanying drawings.

[0116] In a wireless communication system, terminal devices can communicate data with each other through access network devices, or they can communicate directly with each other without the help of access network devices, which can effectively reduce communication delays.

[0117] The interface between terminal devices is called the Proximity Communication (PC5) interface, which is similar to the Uu interface between terminal devices and access network equipment. The link between terminal devices is called the Sidelink (SL). A typical application scenario for SL communication is the vehicle-to-everything (V2X) network. In the V2X network, each vehicle can be considered a terminal device.

[0118] SL supports broadcast, unicast, and multicast communications. The following describes each of these.

[0119] (1) Broadcast communications

[0120] Similar to the access network device broadcast system information, that is, the terminal device sends the broadcast service data to the outside without encryption. Any other terminal device within the effective receiving range can receive the broadcast service data if it is interested in the broadcast service.

[0121] (2) Unicast communication

[0122] This is similar to data communication between a terminal device and an access network device after establishing a radio resource control (RRC) connection. In unicast communication, two terminal devices first need to establish a unicast connection. After the unicast connection is established, the two terminal devices communicate data based on negotiated identifiers (such as the source L2ID and destination L2ID described below).

[0123] A unicast communication on the SL corresponds to a pair of IDs: a source layer 2 identifier (L2ID) and a destination layer 2 identifier (Destination L2ID). The subheader of each SL media access control protocol data unit (MAC PDU) contains partial bytes of the source L2ID and the destination L2ID to ensure that the data is transmitted to the correct receiving end.

[0124] The data transmitted between two terminal devices can be encrypted or unencrypted. Compared with broadcast communication, unicast communication can only be carried out between two terminal devices that have established a unicast connection.

[0125] (3)Multicast communication

[0126] Refers to the communication between all terminal devices in a communication group. Any terminal device in the group can send and receive data of the multicast service.

[0127] In SL communication, a terminal device can provide relay services for communications between other terminal devices. This scenario can be called a UE to UE relay (UE to UE relay, U2U relay) scenario. In this scenario, there is an initiating UE (also called a source UE), one or more target UEs and one or more relay UEs, wherein there is a need for unicast communication between the source UE and the target UE, and the coverage can be enhanced through the relay UE (for example, the coverage signal between the source UE and the target UE is poor or is out of coverage) or the capacity can be increased (for example, the relay UE is a very capable device). The source UE and the target UE can transmit data and signaling through the relay UE. It should be understood that the relay UE has stronger capabilities, such as having more receiving and transmitting antennas. The terminal can assist the source UE in relaying data to the target UE, thereby improving coverage and increasing communication distance.

[0128] Among them, in the U2U relay scenario, the source UE and the target UE can both be called remote UE (remote UE) or end UE (end UE), the source UE can also be called transmitting remote UE (TX remote UE), and the target UE can also be called receiving remote UE (RX remote UE).

[0129] The U2U relay communication system provided in the embodiment of the present application is introduced below with reference to FIG1 and FIG2.

[0130] FIG1 is a schematic diagram of the architecture of an example of a communication system applicable to an embodiment of the present application.

[0131] For example, as shown in Figure 1, a U2U relay communication system 100 includes: a first terminal device (also referred to as a remote UE or source UE), at least one second terminal device (also referred to as a relay UE), and a third terminal device (also referred to as a remote UE or target UE). The second terminal device is configured to provide a relay service for communication between the first terminal device and the third terminal device.

[0132] In the communication system 100 , the second terminal device communicates with the first terminal device via a sidelink (SL) (eg, a PC5 interface), and the second terminal device communicates with the third terminal device via the SL (eg, a PC5 interface).

[0133] It should be understood that the second terminal device, the first terminal device and the third terminal device (hereinafter collectively referred to as terminal devices) are a type of device with wireless transceiver functions, which may refer to user equipment (UE), access terminal, subscriber unit, user station, mobile station, remote station, remote terminal, mobile device, user terminal, wireless communication device, user agent or user device. The terminal device 120 may also be a satellite phone, a cellular phone, a smart phone, a wireless data card, a wireless modem, a machine type communication device, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a customer-premises equipment (CPE), a smart point of sale (POS), a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a communication device carried on a high-altitude aircraft, a wearable device, a drone, a robot, a terminal in device-to-device (D2D) communication, a terminal in vehicle-to-everything (V2X), a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control, a wireless terminal in self-driving, a remote medical device, or a similar device. This application does not limit the wireless terminals in medical, smart grid, transportation safety, smart city, smart home, or terminal devices in communication networks evolved after 5G.

[0134] The communication device used to implement the functions of the terminal device can be the terminal device, or it can be a device that can support the terminal device to implement the functions, such as a chip system. The device can be installed in the terminal device or used in conjunction with the terminal device. In this application, the chip system can be composed of a chip or include a chip and other discrete devices.

[0135] Optionally, the communication system 100 may further include an access network device. The access network device and the terminal device may communicate via an air interface (e.g., a Uu interface), and the access network device may provide network services to the terminal device. For example, as shown in FIG1 , a first terminal device and the access network device may communicate via a Uu interface, and the access network device may provide network services to the first terminal device.

[0136] It should be understood that the access network device is a device with wireless transceiver functions, which is used to communicate with the terminal device. The access network device can be a node in the radio access network (RAN), which can be called a base station or a RAN node. It can be an evolved Node B (eNB or eNodeB) of long term evolution (LTE); or a base station of a 5G network such as gNodeB (gNB) or a base station in a public land mobile network (PLMN) evolved after 5G, a broadband network gateway (BNG), an aggregation switch or a third generation partnership project (3GPP) access device, etc.

[0137] The RAN can be configured as a RAN defined by the 3GPP protocol, an open radio access network (O-RAN), or a cloud radio access network (C-RAN). The access network device 110 can also include various forms of base stations, such as macro base stations, micro base stations (also known as small stations), relay stations, transmission points (transmitting and receiving points, TRP), transmission points (transmitting points, TP), mobile switching centers, and devices that perform base station functions in device-to-device (D2D), vehicle-to-everything (V2X), and machine-to-machine (M2M) communications, access network devices in non-terrestrial networks (NTN), etc., without specific limitation.

[0138] The access network equipment may also include network elements or modules that implement some functions of the base station, such as one or more of the following: a centralized unit (CU), a distributed unit (DU), or a radio unit (RU). Optionally, the CU can be further separated into a CU-control plane (CP) and a CU-user plane (UP). The functions of the CU and DU can be implemented by different network elements, or simultaneously by the baseband unit (BBU) of the base station. The functions of the RU can be implemented by the radio frequency equipment of the base station. For example, the radio frequency equipment of the base station may be a remote radio unit (RRU), a pico remote radio unit (pRRU), an active antenna unit (AAU), or other units, modules or devices with radio frequency processing functions. The communication interface protocol between the BBU and the radio frequency equipment can be a common public radio interface (CPRI) interface protocol, an enhanced common public radio interface (eCPRI) interface protocol, or a fronthaul interface protocol between the DU and RU in the O-RAN system, etc., without limitation.

[0139] In different systems, CU (or CU-CP and CU-UP), DU or RU may also have different names, but those skilled in the art can understand their meanings. For example, in the ORAN system, CU may also be called O-CU (Open CU), DU may also be called O-DU, CU-CP may also be called O-CU-CP, CU-UP may also be called O-CU-UP, and RU may also be called O-RU. For the convenience of description, this application uses CU, CU-CP, CU-UP, DU and RU as examples for description. Any unit of CU (or CU-CP, CU-UP), DU and RU in this application can be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0140] The communication device used to implement the functions of the access network device can be the access network device, or it can be a device that can support the access network device to implement the functions, such as a chip system. The device can be installed in the access network device or used in conjunction with the access network device. The chip system in the embodiments of the present application can be composed of a chip, or it can include a chip and other discrete devices.

[0141] The communication system 100 may also be the following systems: long term evolution (LTE) system, LTE frequency division duplex (FDD) system, LTE time division duplex (TDD) system, universal mobile telecommunication system (UMTS), 5G system, 6G system, inter-satellite communication, satellite communication and other NTN systems. Among them, the satellite communication system includes a satellite base station and terminal equipment. The satellite base station provides communication services for the terminal equipment. The satellite base station can also communicate with the ground base station. The satellite can be used as a base station or as a terminal device. Among them, the satellite can refer to non-ground base stations or non-ground equipment such as drones, hot air balloons, low-orbit satellites, medium-orbit satellites, and high-orbit satellites.

[0142] The communication system 100 may also be a terrestrial cellular communication system, a high altitude platform station (HAPS) communication system, a V2X system, an integrated access and backhaul (IAB) system, and a reconfigurable intelligent surface (RIS) communication system, etc., without limitation.

[0143] It should be understood that FIG1 is only a simplified schematic diagram for ease of understanding, and the communication system may also include other devices that are not shown in FIG1 .

[0144] Figure 2 shows a schematic diagram of a protocol stack architecture applicable to an embodiment of the present application, which is a user plane protocol architecture in an L2-based U2U scenario. As shown in Figure 2, the protocol architecture includes: Internet Protocol (IP), Non-IP layer, Service Data Adaptation Protocol (SDAP) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) protocol layer, Medium Access Control (MAC) protocol layer, and Physical Layer (PHY) protocol layer.

[0145] In addition, the protocol architecture adds an adaptation layer between the RLC layer and the PDCP layer. The main function of the adaptation layer is to multiplex and demultiplex bearers. This means that data from different target UEs can be multiplexed into a unicast connection between the source UE and the relay UE, or data from a unicast connection can be split into different unicast connections. It also supports data from different radio bearers being multiplexed into a single RLC bearer, or data from a single RLC bearer being split into different radio bearers.

[0146] It should be understood that in an L2-based relay scenario, user plane data is relayed and forwarded below the PDCP layer on the relay user equipment side.

[0147] In addition, to distinguish data belonging to different target UEs multiplexed on the same unicast connection, and to distinguish data belonging to different radio bearers multiplexed on the same RLC bearer, the source UE will carry its own local ID and the local ID of the target UE and the bearer ID in the adaptation layer header of the data packet to indicate which target UE and which radio bearer the data belongs to. The local IDs of the source UE and target UE are allocated by the relay UE.

[0148] In NR Single-Link (SL) communication, when two UEs perform unicast communication, the transmitting UE (TX UE) and the receiving UE (RX UE) must have consistent sidelink radio bearer (SLRB) configurations to control data transmission or signaling. The following, combined with Figure 3, illustrates the process of a UE acquiring the SLRB configuration in a direct SL communication mechanism.

[0149] Figure 3 shows a schematic diagram of the TX UE obtaining the SLRB configuration. According to the R16 direct SL communication mechanism, when the transmitting UE (TX UE) is in the connected state, the TX UE will report the L2ID of the receiving UE (RX UE) and the corresponding quality of service (QoS) information to its serving base station through the sidelink communication terminal information (SidelinkUEInformationNR, SUI) message, as shown in step 1 of Figure 3. When there are multiple RX UEs, the TX UE reports a list, in which each entry includes the L2ID of an RX UE and the corresponding QoS information, so that the serving base station can distinguish the QoS information corresponding to different RX UEs. The QoS information includes the QoS flow identifier (QFI) and the corresponding QoS parameters of each QoS flow. The QFI uniquely identifies an SL QoS flow between the UE and the network. The QFI value is unique within the UE range and is unique for different destinations (Destination) and communication types (broadcast, multicast, unicast).

[0150] Among them, the QoS flow of communication between TX UE and RX UE is generated by the upper layer (such as the application layer, V2X layer, ProSe layer, etc.), and the upper layer will indicate the PC5QoS flow identifier (PC5QoS identifier, abbreviated as PFI or PQFI, for the sake of convenience, it will be referred to as PFI in the following text) to the access (AS) layer. The PFI is unique within per Destination, that is, the PFIs corresponding to the QoS flows between the TX UE and the same RX UE are different, but the PFIs corresponding to the QoS flows between different RX UEs can be the same. The TX UE maps the PFIs one by one to the unique QFI within the UE, that is, the QFIs corresponding to the QoS flows between the TX UE and different RX UEs are different. How to map is implemented by the TX UE, and the TX UE will save the mapping relationship, which is recorded as mapping relationship #a.

[0151] Based on the QoS information reported by the TX UE, the base station provides the TX UE with an SLRB configuration list, where each entry includes SDAP configuration, PDCP configuration, RLC configuration, MAC configuration, and PHY configuration. The base station can send the SLRB configuration list to the TX UE via an RRC reconfiguration message, as shown in step 2 of Figure 3.

[0152] After the TX UE receives the SLRB configuration sent by the base station, it determines the RX UE corresponding to each entry in the SLRB configuration list based on the QFI in the SDAP configuration and the above mapping relationship #a. The TX UE will send configuration parameters related to both transmission and reception (such as the mapping relationship between QoS flow and SLRB, PDCP sequence number (SN) length, RLC mode (mode), logical channel identity (LCID), etc.) to the RX UE through the RRC reconfiguration (RRCReconfigurationSidelink) message between the sidelinks, as shown in step 3 of Figure 3, where the mapping relationship between QoS flow and SLRB is indicated by PFI and PC5 configuration indication (Config Index).

[0153] SL communication is usually bidirectional. According to the R16 direct SL communication mechanism, the RX UE can also report the RLC mode of the SLRB indicated by the TX UE and the QoS information associated with the SLRB to its serving base station through the SUI message. In this way, when the base station provides SLRB configuration for the RX UE, it can comprehensively consider the RLC channel (channel) that the RX UE has established. For example, if the RX UE has established an Acknowledged Mode (AM) RLC channel #1 with the TX UE, when the base station needs to configure the AM RLC channel for the RX UE, the base station can consider reusing the RLC channel #1. It should be understood that the RX UE can determine the QoS information associated with the SLRB based on the mapping relationship between the QoS flow from the TX UE and the SLRB.

[0154] It should be understood that in the U2U relay scenario, the process of UE obtaining SLRB configuration is still under discussion. The above describes the basic process of TX UE and RX UE obtaining SLRB configuration in the direct SL communication mechanism. The control plane process of L2 U2U relay is explained in conjunction with Figure 4.

[0155] Figure 4 shows the control plane process in the L2 U2U relay scenario. As shown in Figure 4, the process includes the following steps.

[0156] S201: The TX remote UE, the relay UE, and the RX remote UE discover each other.

[0157] It should be understood that in the L2 U2U relay scenario, the TX remote UE may also be referred to as the U2U remote UE, the relay UE may be referred to as the U2U relay UE, and the RX remote UE may also be referred to as the peer U2U remote UE.

[0158] S202a: A PC5 connection is established between the TX remote UE and the relay UE.

[0159] S202b: A PC5 connection is established between the relay UE and the RX remote UE.

[0160] S203: The relay UE allocates local IDs to the TX remote UE and the RX remote UE.

[0161] The relay UE may send the allocated local ID to the TX remote UE and the RX remote UE respectively through RRC reconfiguration between sidelinks (RRCReconfigurationSidelink).

[0162] S204: The TX remote UE and the RX remote UE establish an end-to-end (E2E) PC5 connection.

[0163] S205 , the TX remote UE sends the E2E QoS information to the relay UE.

[0164] S206: The relay UE splits the QoS parameters in the QoS information.

[0165] S207, the relay UE sends the split QoS information to the TX remote UE.

[0166] S208 , an E2E RRC reconfiguration (E2E RRCReconfigurationSidelink) message is transmitted between the TX remote UE and the RX remote UE.

[0167] S209a, an RRC reconfiguration (E2E RRCReconfigurationSidelink) message is transmitted between the TX remote UE and the relay UE.

[0168] S209b, an RRC reconfiguration (E2E RRCReconfigurationSidelink) message is transmitted between the relay UE and the RX remote UE.

[0169] At this point, the configuration of the control plane is completed. After this, the TX remote UE and the RX remote UE can perform data transmission through the relay UE.

[0170] In the above process, after the TX remote UE and the RX remote UE establish an E2E PC5 connection (as shown in S204), the TX remote UE will send the E2E QoS information to the relay UE (as shown in S205). The relay UE splits the packet delay budget (PDB) in the E2E QoS information (as shown in S206) and sends the split first-hop PDB to the TX remote UE (as shown in S207).

[0171] It should be understood that in this application, end-to-end refers to the concept between remote UEs. For example, the E2E QoS information mentioned above refers to QoS information between remote UEs. The first hop refers to the link between the TX remote UE and the relay UE. For example, the first hop PDB mentioned above refers to the PDB parameters that the E2E QoS flow must meet on the link between the TX remote UE and the relay UE. Similarly, the second hop refers to the link between the relay UE and the RX remote UE.

[0172] When the TX remote UE is in a connected state, it can report E2E QoS information and first-hop QoS information to its serving base station through a SUI message. The base station provides the UE with SLRB configuration based on the QoS information reported by the TX remote UE, including SDAP configuration, PDCP configuration, SRAP configuration (including the mapping relationship between SLRB and RLC channel), and RLC channel configuration (including RLC and MAC configuration), and sends it to the TX remote UE through an RRC reconfiguration message. The process between the TX remote UE and its serving base station can be seen in Figure 3.

[0173] After the TX remote UE obtains the SL configuration from the base station, it sends the E2E SDAP configuration and PDCP configuration parameters related to both sending and receiving (such as the mapping relationship between QoS flow and SLRB, PDCP SN length, and other parameters) to the RX remote UE through the E2E RRCReconfigurationSidelink message (as shown in S208), and sends the first-hop configuration parameters related to both sending and receiving (such as RLC mode, LCID, and other parameters) to the relay UE through the first-hop RRCReconfigurationSidelink message (as shown in S209a). In addition, in S209a, the TX remote UE also sends the mapping relationship between QoS flow and SLRB to the relay UE.

[0174] The relay UE will aggregate the QoS parameters of the second hop into QoS parameters of SLRB granularity according to the mapping relationship between QoS flow and SLRB, that is, the QoS parameters that the E2E SLRB needs to meet on the second hop, and report the QoS information of SLRB granularity to its serving base station through SUI message. The serving base station provides the UE with SRAP configuration (including the mapping relationship between SLRB and RLC channel) and RLC channel configuration (including RLC / MAC configuration) according to the QoS information reported by the relay UE, and sends it to the relay UE through RRC reconfiguration message.

[0175] After the relay UE obtains the SL configuration from the base station, it sends the second-hop configuration parameters related to both sending and receiving (such as RLC mode, LCID and other parameters) to the RX remote UE through the second-hop RRC reconfiguration message (RRCReconfigurationSidelink) message (as shown in S209b).

[0176] However, the above solution has the following problems:

[0177] Since end-to-end QoS flows and SLRBs are established between remote UEs, the upper layer of the relay UE does not generate QoS flows. The relay UE obtains QoS flow and SLRB information from the remote UE. When the relay UE provides relay services for multiple remote UEs (for example, as shown in Figure 5, in a 2:1:3 network topology scenario, there are two TX remote UEs, namely UE1 and UE2, and three RX remote UEs, namely UE3, UE4, and UE5. The relay UE provides relay services for communications between UE1 and UE3, between UE1 and UE4, between UE1 and UE5, and between UE2 and UE3, respectively), the TX remote UE sends the mapping relationship between QoS flows and SLRBs to the relay UE. The QoS flow can be a QoS flow for communication between the TX remote UE and multiple RX remote UEs. So how does the relay UE associate the QoS flows and SLRBs with the corresponding RX remote UEs?

[0178] In addition, in the U2U relay scenario, the relay UE is not only the TX UE between the relay UE and the RX remote UE, but also the RX UE between the TX remote UE and the relay UE.

[0179] First of all, when acting as a TX UE, the difference from the direct SL communication mechanism is that the relay UE reports QoS information at the SLRB granularity in the SUI, but does not report the QFI. After the relay UE obtains the SLRB configuration from its serving base station, how does it associate the SLRB configuration with the corresponding RX remote UE?

[0180] Secondly, in U2U relay, the remote UE is the data generator, and the relay UE only forwards the data. Therefore, when the relay UE reports SUI as the RX UE, the relay UE does not need to report the QoS information corresponding to the SLRB, but only needs to report the RLC mode. However, according to the direct SL communication mechanism, when the UE reports SUI as the RX UE, the QoS information corresponding to the SLRB is mandatory, as shown below:

[0181] In other words, the relay UE will report redundant information. Furthermore, bearer multiplexing occurs in the U2U relay, meaning multiple SLRBs can be transmitted over the same RLC channel. However, the mapping between SLRBs and RLC channels is a configuration on the TX remote UE side. The relay UE, acting as the RX UE, is unaware of this mapping and therefore cannot determine the QoS information associated with the RLC channel, preventing it from correctly reporting the SUI.

[0182] In summary, the link configuration between the source UE and the relay UE, and the link configuration between the relay UE and the target UE are crucial to the normal communication of the side link. If the source UE, relay UE and target UE still obtain the link configuration according to the direct SL communication mechanism, the relay UE will not be able to associate the configuration with the corresponding source UE and target UE, thereby affecting the normal communication between the source UE and the target UE.

[0183] In view of this, the present application provides a sidelink communication method, a communication device and a communication system, which can associate the configuration with the corresponding source UE and target UE to ensure normal communication between the source UE and the target UE.

[0184] It should be understood that the embodiments shown below do not particularly limit the specific structure of the execution subject of the method provided in the embodiments of the present application. As long as it is possible to communicate according to the method provided in the embodiments of the present application by running a program that records the code of the method provided in the embodiments of the present application. For example, the execution subject of the method provided in the embodiments of the present application can be a terminal device, or a functional module in the terminal device that can call and execute the program.

[0185] FIG6 is a schematic flow chart of a sidelink communication method 300 provided by the present application. The method 300 may include the following steps:

[0186] S310, the first terminal device sends a first message to the second terminal device, and accordingly, the second terminal device receives the first message.

[0187] The first message includes first indication information and an identifier of the third terminal device.

[0188] It should be understood that in the present application, the first terminal device communicates with the third terminal device through the second terminal device, or in other words, the second terminal device is used to provide a relay service for the communication between the first terminal device and the third terminal device. The first terminal device can be understood as the source UE or TX remote UE, the second terminal device can be understood as the relay UE, and the third terminal device can be understood as the target UE or RX remote UE.

[0189] The first indication information is used to indicate a first QoS flow between the first terminal device and the second terminal device, and the first QoS flow is a QoS flow between the first terminal device and the third terminal device.

[0190] Specifically, the first QoS flow can be understood as an end-to-end (E2E) QoS flow, and the first QoS flow can be called an SL QoS flow or a PC5 QoS flow.

[0191] The first indication information can be understood as: used to uniquely indicate the E2E QoS flow between the first terminal device and the second terminal device, or in other words, used to uniquely indicate the E2E QoS flow within the scope of the first terminal device.

[0192] For example, the first terminal device includes UE1 and UE2, then UE1 and UE2 can respectively determine the first indication information, the first indication information determined by UE1 is unique within the scope of UE1 and does not conflict with each other; the first indication information determined by UE2 is unique within the scope of UE2 and does not conflict with each other.

[0193] As an example, the first indication information is QFI.

[0194] It should be understood that, generally speaking, the identifier of a QoS flow on the Uu port is QFI, and the identifier of a QoS flow on the PC5 port is PFI. In this application, the first terminal device can map the PFI to a QFI (i.e., an example of the first indication information) and send the QFI to the second terminal device via the PC5 interface. Through the QFI, the E2E QoS flow can be uniquely identified between the first terminal device and the second terminal device.

[0195] For example (recorded as Example 1), the first terminal device includes UE1 (i.e., the remote UE ID is 1), the third terminal device includes UE3 and UE4 (i.e., the remote UE IDs are 3 and 4), there are three QoS flows between UE1 and UE3, whose PFIs are PFI#1, PFI#2, and PFI#3 respectively, and there are two QoS flows between UE1 and UE4, whose PFIs are PFI#1 and PFI#2 respectively. Then UE1 can map the PFIs of these five QoS flows to QFIs one by one. The PFIs of the three QoS flows between UE1 and UE3 are mapped to QFI#1, QFI#2, and QFI#3 respectively, and the PFIs of the two QoS flows between UE1 and UE4 are mapped to QFI#4 and QFI#5 respectively. The values ​​of the first indication information are QFI#1, QFI#2, QFI#3, QFI#4, and QFI#5 respectively.

[0196] As another example, the first indication information is bit information.

[0197] For example, the first terminal device includes UE1 and UE2, and the third terminal device includes UE3 and UE4. There are three QoS flows between UE1 and UE3, whose PFIs are PFI#1, PFI#2, and PFI#3 respectively. There are two QoS flows between UE1 and UE4, whose PFIs are PFI#1 and PFI#2 respectively. There is one QoS flow between UE2 and UE3, whose PFI is PFI#1. There is one QoS flow between UE2 and UE4, whose PFI is PFI#1. UE1 can map the PFIs of the five QoS flows related to it to bit information (for example, 11 bits). The PFIs of the three QoS flows between UE1 and UE3 are mapped to 00000000000, 00000000001, and 000000000010 respectively, and the PFIs of the two QoS flows between UE1 and UE4 are mapped to 00000000011 and 00000000100 respectively. Similarly, UE2 can map the PFIs of its two related QoS flows into bit information (e.g., 11 bits) one by one. PFI#1 between UE2 and UE3 is mapped to 00000000000, and PFI#1 between UE2 and UE4 is mapped to 00000000001.

[0198] It should be understood that as long as the first indication information can uniquely indicate the E2E QoS flow within the range of the first terminal device, this application does not limit the form of the first indication information.

[0199] The identifier of the third terminal device may be a layer 2 identifier (L2ID).

[0200] It should be understood that the layer 2 identifier is a UE identifier commonly used in SL unicast communication. Using the layer 2 identifier can reuse the current protocol, which is simple and efficient.

[0201] Optionally, the identifier of the third terminal device may also be a local ID, which is determined by the second terminal device.

[0202] Optionally, the "first indication information and the identifier of the third terminal device" in the first message can be understood as a group of information, for example, recorded as first information, and the quantity of the first information in the first message is determined according to the number of third terminal devices.

[0203] For example, there may be N third terminal devices (N is a positive integer). In other words, the first terminal device can communicate with N third terminal devices through the second terminal device. In this case, the first message may include N first information, each of which includes first indication information and an identifier of a third terminal device. In other words, the first message carries a list, the number of entries in the list being determined by the number of third terminal devices, and each entry includes an identifier of a third terminal device and the first indication information corresponding to the third terminal device.

[0204] After receiving the first message, the second terminal device may determine the correspondence between the identifier of the third terminal device and the first indication information, and save the correspondence.

[0205] Let's continue with the scenario in Example 1. In this scenario, the third terminal device includes UE3 and UE4, that is, N=2. Therefore, the list in the first message can include two entries, one of which is {UE3's L2ID, {QFI#1, QoS parameters}, {QFI#2, QoS parameters}, {QFI#3, QoS parameters}}; and the other is {UE4's L2ID, {QFI#4, QoS parameters}, {QFI#5, QoS parameters}}. Each of the above entries is an example of the first information. Based on the first message, the second terminal device can determine that UE3 corresponds to QFI#1-3 and UE4 corresponds to QFI#4-5. The corresponding relationship stored by the second terminal device can be shown in Table 1.

[0206] Table 1

[0207] Exemplarily, the first message is a user information request (UEInformationRequestSidelink) message in a sidelink, or a PC5 RRC message.

[0208] S320, the first terminal device sends the first corresponding relationship to the second terminal device, and correspondingly, the second terminal device receives the first corresponding relationship.

[0209] The first corresponding relationship is the corresponding relationship between the first indication information and the PC5 configuration index (PC5config index).

[0210] In this application, the PC5 configuration index is used to identify the SLRB configuration between the first terminal device and the third terminal device (recorded as the first SLRB configuration). The first SLRB configuration can be used to determine the first SLRB, or in other words, according to the first SLRB configuration, a first SLRB can be established between the first terminal device and the third terminal device. The first SLRB is the SLRB between the first terminal device and the third terminal device, that is, E2ESLRB.

[0211] It should be understood that in the L2 U2U relay scenario, the PC5 Config Index is unique within each Destination, which can be understood as the PC5 Config Index uniquely indicating an SLRB configuration between the first terminal device and the third terminal device.

[0212] It should be understood that the first QoS flow can be mapped to the first SLRB, that is, there is a mapping relationship between the first QoS flow and the first SLRB, and the first SLRB configuration can be used to determine the first SLRB. Therefore, the first terminal device can determine the mapping relationship between the first QoS flow and the first SLRB configuration, and indicate the mapping relationship through the first corresponding relationship.

[0213] For example, let's continue with the scenario in Example 1. In this scenario, if there are two SLRB configurations between UE1 and UE3, their PC5 configuration indexes are Index#1 and Index#2 respectively, and PFI#1 between UE1 and UE3 is mapped to Index#1, and PFI#2 and PFI#3 are mapped to Index#2. There is one SLRB configuration between UE1 and UE4, whose PC5 configuration index is Index#1, and PFI#1 and PFI#2 between UE1 and UE4 are both mapped to Index#1. Then, the first correspondence can be: {Index#1, {QFI#1}}, {Index#2, {QFI#2, QFI#3}}, {Index#1, {QFI#4, QFI#5}}. The first correspondence can be understood as a mapping list of the first indication information and the PC5 configuration index. For example, as shown in Table 2.

[0214] Table 2

[0215] Exemplarily, the first corresponding relationship is carried in a third message, and the third message is an RRC reconfiguration message.

[0216] S330: The second terminal device determines the correspondence between the PC5 configuration index and the third terminal device according to the first message and the first correspondence.

[0217] Specifically, the second terminal device may associate the third terminal device with the PC5 configuration index one by one according to the first indication information.

[0218] For example, according to Table 1 and Table 2 above, the second terminal device can determine that Index#1 corresponding to QFI#1, and Index#2 corresponding to QFI#2 and QFI#3 represent the SLRB configuration between UE1 and UE3, while Index#1 corresponding to QFI#4 and QFI#5 represents the SLRB configuration between UE1 and UE4.

[0219] Based on the above scheme, through the first indication information and the first correspondence, the second terminal device can associate the SLRB configuration between the first terminal device and the third terminal device with the corresponding third terminal device, so that when the SLRB configuration is subsequently obtained, the third terminal device corresponding to the configuration can be determined, ensuring the normal execution of the control plane process, thereby ensuring normal communication between the first terminal device and the third terminal device.

[0220] On the other hand, in the above scheme, there is also a corresponding relationship between the first indication information and the third terminal device. Through the first indication information, the second terminal device can also associate the first QoS flow with the third terminal device, which facilitates the execution of subsequent control plane processes, thereby ensuring normal communication between the first terminal device and the third terminal device.

[0221] Optionally, the first message also includes QoS parameters corresponding to the first QoS flow. The method 300 also includes: S340, the second terminal device sends a second message to the first terminal device, and accordingly, the first terminal device receives the second message.

[0222] Among them, the second message includes a first packet delay budget and a first indication information. The first packet delay budget is determined according to the QoS parameter. The first packet delay budget is used to indicate the packet delay budget corresponding to the first QoS flow on the first link. The first link is the link between the first terminal device and the second terminal device.

[0223] In this application, QoS parameters include PC5 5G QoS Identifier (PQI), priority, packet delay budget (PDB), packet error rate and other parameters.

[0224] As shown in S206, the second terminal device can determine the PDB on the first link or the first-hop PDB, i.e., the first packet delay budget, based on the QoS parameters corresponding to the first QoS flow. Further, the second terminal device can send the first packet delay budget and the first indication information to the first terminal device via a second message.

[0225] It should be understood that if the first indication information is QFI, the QoS parameters and QFI corresponding to the first QoS flow can both be referred to as QoS information of the first QoS flow. In other words, the first message can include QoS information of the first QoS flow.

[0226] Continuing with the scenario in Example 1, the second terminal device determines that the first PDB of the QoS flow corresponding to QFI#1 is PDB parameter #1, the first PDB of the QoS flow corresponding to QFI#2 is PDB parameter #2, the first PDB of the QoS flow corresponding to QFI#3 is PDB parameter #3, the first PDB of the QoS flow corresponding to QFI#1 is PDB parameter #4, and the first PDB of the QoS flow corresponding to QFI#5 is PDB parameter #5. Then, the second message may include {QFI#1, PDB parameter #1}, {QFI#2, PDB parameter #2}, {QFI#3, PDB parameter #3}, {QFI#4, PDB parameter #4}, and {QFI#5, PDB parameter #5}.

[0227] Exemplarily, the second message is a user information response (UEInformationResponseSidelink) message in the sidelink, or a PC5 RRC message.

[0228] Optionally, the method 300 further includes: S350, the first terminal device determines the correspondence between the first packet delay budget and the first QoS flow according to the first indication information.

[0229] Specifically, the first terminal device can associate the first PDB with the first QoS flow one by one according to the first indication information.

[0230] Continuing with the scenario in Example 1, UE1 can associate PDB parameters #1 to 3 with PFIs #1 to 3 between UE1 and UE3, and associate PDB parameters #4 to 5 with PFIs #1 to 2 between UE1 and UE4, respectively, based on the first message and the second message.

[0231] It should be understood that the correspondence between the first packet delay budget and the first QoS flow can be used to determine the PC5 configuration index in the first correspondence.

[0232] Specifically, the first terminal device may determine the first SLRB configuration according to the QoS flow parameters corresponding to the first QoS flow and the first PDB, including the PC5 configuration index. This application does not limit the specific method of determining the SLRB configuration.

[0233] Based on the above solution, through the first indication information, the first terminal device can determine the correspondence between the first packet delay budget and the first QoS flow, so as to facilitate the normal implementation of subsequent control plane processes.

[0234] FIG7 is a schematic flow chart of a sidelink communication method 400 provided by the present application. The method 400 may include the following steps:

[0235] S410, the first terminal device sends a first message to the second terminal device, and accordingly, the second terminal device receives the first message.

[0236] The first message includes the second indication information and the identifier of the third terminal device.

[0237] It should be understood that the relationship between the first terminal device, the second terminal device and the third terminal device can be referred to the description in S310 and will not be repeated here.

[0238] The second indication information is used to indicate the first QoS flow within the range of the third terminal device, and the first QoS flow is the QoS flow between the first terminal device and the third terminal device.

[0239] For an introduction to the first QoS flow, please refer to S310 and will not be repeated here.

[0240] The second indication information can be understood as: used to uniquely indicate the E2E QoS flow within the range of the third terminal device, or in other words, used to uniquely indicate the E2E QoS flow between the first terminal device and the third terminal device.

[0241] For example, the first terminal device includes UE1, the third terminal device includes UE3 and UE4, there are three QoS flows between UE1 and UE3, and there are two QoS flows between UE1 and UE4. Then the three QoS flows between UE1 and UE3 can be indicated by different second indication information, that is, they are unique within the scope of UE3 and do not conflict with each other; the two QoS flows between UE1 and UE4 can be indicated by different second indication information, that is, they are unique within the scope of UE4 and do not conflict with each other.

[0242] As an example, the second indication information is PFI.

[0243] For example (recorded as Example 2), the first terminal device includes UE1, and the third terminal device includes UE3 and UE4. There are three QoS flows between UE1 and UE3, whose PFIs are PFI#1, PFI#2, and PFI#3 respectively. There are two QoS flows between UE1 and UE4, whose PFIs are PFI#1 and PFI#2 respectively. Then, the second indication information can be PFI#1, PFI#2, PFI#3 as well as PFI#1 and PFI#2.

[0244] It should be understood that as long as the second indication information can uniquely indicate the E2E QoS flow within the range of the third terminal device, this application does not limit the form of the second indication information.

[0245] The identifier of the third terminal device may be an L2ID or a local identifier determined for the second terminal device.

[0246] Exemplarily, the first message is a user information request (UEInformationRequestSidelink) message in a sidelink, or a PC5 RRC message.

[0247] It should be understood that the identifier of the third terminal device and the first message can refer to the description of S310 and will not be repeated here.

[0248] Optionally, the "second indication information and the identifier of the third terminal device" in the first message can be understood as a group of information, for example, recorded as second information, and the amount of second information in the first message is determined according to the number of third terminal devices.

[0249] For example, there may be N third terminal devices (N is a positive integer). In other words, the first terminal device can communicate with N third terminal devices through the second terminal device. In this case, the first message may include N second information, each of which includes second indication information and the identifier of one third terminal device. In other words, the first message carries a list, the number of entries in the list being determined by the number of third terminal devices, and each entry includes the identifier of a third terminal device and the first indication information corresponding to the third terminal device.

[0250] After receiving the first message, the second terminal device may determine the correspondence between the identifier of the third terminal device and the first indication information, and save the correspondence.

[0251] Let's continue with the scenario in Example 2. In this scenario, the third terminal device includes UE3 and UE4, that is, N=2. Therefore, the list in the first message can include two entries, one of which is {UE3's L2ID, {PFI#1, QoS parameters}, {PFI#2, QoS parameters}, {PFI#3, QoS parameters}}; and the other is {UE4's L2ID, {PFI#1, QoS parameters}, {PFI#2, QoS parameters}}. Each of the above entries is an example of the second information. Based on the first message, the second terminal device can determine that UE3 corresponds to PFI#1-3 and UE4 corresponds to PFI#4-5. The corresponding relationship stored by the second terminal device can be shown in Table 3.

[0252] Table 3

[0253] S420, the first terminal device sends a third message to the second terminal device, and accordingly, the second terminal device receives the third message.

[0254] The third message includes the identifier of the third terminal device and the second correspondence, which is the correspondence between the second indication information and the PC5 configuration index. The second correspondence can be understood as a mapping list of the second indication information and the PC5 configuration index.

[0255] The PC5 configuration index is used to identify the SLRB configuration between the first terminal device and the third terminal device. For an introduction, please refer to S320 and will not be repeated here.

[0256] It should be understood that the definitions of the first QoS flow, the first SLRB configuration and the first SLRB and their relationship can refer to method 300 and are not repeated here. The first terminal device can determine the mapping relationship between the first QoS flow and the first SLRB configuration and indicate the mapping relationship through the second corresponding relationship.

[0257] Optionally, the "identification of the third terminal device and the second corresponding relationship" in the third message can be understood as a group of information, for example, recorded as third information, and the amount of third information in the third message is determined according to the number of third terminal devices.

[0258] For example, there may be N third terminal devices (N is a positive integer). In other words, the first terminal device can communicate with N third terminal devices through the second terminal device. In this case, the third message may include N third information, each of which includes the identifier of a third terminal device and the second correspondence. In other words, the third message carries a list, the number of entries in the list being determined by the number of third terminal devices, and each entry includes the identifier of a third terminal device and the second correspondence corresponding to the third terminal device.

[0259] For example, let's continue with the scenario in Example 2. In this scenario, if two SLRBs are configured between UE1 and UE3, their PC5 configuration indexes are Index#1 and Index#2, respectively, and PFI#1 between UE1 and UE3 is mapped to Index#1, while PFI#2 and PFI#3 are mapped to Index#2. There is one SLRB configured between UE1 and UE4, whose PC5 configuration index is Index#1. Both PFI#1 and PFI#2 between UE1 and UE4 are mapped to Index#1. Therefore, N=2, and the third message may include two entries: one entry is {UE3's L2ID, {Index#1, {PFI#1}}, {Index#2, {PFI#2, PFI#3}}}, and the other entry is {UE4's L2ID, {Index#1, {PFI#1, PFI#2}}}. Each of these entries is an example of the third information. The second corresponding relationship may be: {Index#1, {PFI#1}}, {Index#2, {PFI#2, PFI#3}}, {Index#1, {PFI#2, PFI#2}}, for example, as shown in Table 4.

[0260] Table 4

[0261] Exemplarily, the third message is an RRC reconfiguration message.

[0262] S430: The second terminal device determines a correspondence between the PC5 configuration index and the third terminal device according to the first message and the third message.

[0263] Specifically, the second terminal device may associate the third terminal device with the PC5 configuration index one by one according to the identifier of the third terminal device and the second indication information.

[0264] For example, according to Table 1 and Table 4 above, the second terminal device can determine that Index#1 corresponding to PFI#1, and Index#2 corresponding to PFI#2 and PFI#3 represent the SLRB configuration between UE1 and UE3, and Index#1 corresponding to PFI#1 and PFI#2 represents the SLRB configuration between UE1 and UE4.

[0265] Based on the above scheme, through the second indication information and the second correspondence, the second terminal device can associate the SLRB configuration between the first terminal device and the third terminal device with the corresponding third terminal device, so that when the SLRB configuration is subsequently obtained, the third terminal device corresponding to the configuration can be determined, ensuring the correct execution of the control plane process, thereby ensuring normal communication between the first terminal device and the third terminal device.

[0266] On the other hand, in the above scheme, there is also a corresponding relationship between the second indication information and the third terminal device. Through the second indication information, the second terminal device can also associate the first QoS flow with the third terminal device, which facilitates the execution of subsequent control plane processes, thereby ensuring normal communication between the first terminal device and the third terminal device.

[0267] Optionally, the first message also includes QoS parameters corresponding to the first QoS flow. The method 400 also includes: S440, the second terminal device sends a second message to the first terminal device, and accordingly, the first terminal device receives the second message.

[0268] The second message includes the first packet delay budget, the identifier of the third terminal device and the second indication information.

[0269] For an introduction to the first packet delay budget, refer to S340 and will not be repeated here.

[0270] As shown in S206, the second terminal device can determine the PDB on the first link or the first-hop PDB, i.e., the first packet delay budget, based on the QoS parameters corresponding to the first QoS flow. Further, the second terminal device can send the first packet delay budget, the identifier of the third terminal device, and the second indication information to the first terminal device via a second message.

[0271] It should be understood that if the second indication information is PFI, the QoS parameters and PFI corresponding to the first QoS flow can both be called QoS information of the first QoS flow. In other words, the first message can include QoS information of the first QoS flow.

[0272] Optionally, the "identification of the third terminal device and the second indication information" in the second message can be understood as a group of information, for example, recorded as fourth information, and the number of fourth information in the second message is determined according to the number of third terminal devices.

[0273] For example, there may be N third terminal devices (N is a positive integer). In other words, the first terminal device can communicate with N third terminal devices through the second terminal device. In this case, the second message may include N fourth information, each of which includes the identifier of a third terminal device and the second indication information. In other words, the second message carries a list, the number of entries in the list being determined by the number of third terminal devices, and each entry includes the identifier of a third terminal device and the second indication information corresponding to the third terminal device.

[0274] Continuing with the scenario in Example 2, the following description is provided. In this scenario, the second terminal device determines that the first PDBs of the QoS flows identified by PFI#1, PFI#2, and PFI#3 between UE1 and UE3 are PDB parameters #1, PDB parameters #2, and PDB parameters #3, respectively, and that the first PDBs of the QoS flows identified by PFI#1 and PFI#2 between UE1 and UE4 are PDB parameters #4 and PDB parameters #5, respectively. The second message may include two entries, one entry being {UE3's L2ID, {PFI#1, PDB parameter #1}, {PFI#2, PDB parameter #2}, {PFI#3, PDB parameter #3}}, and the other entry being {UE4's L2ID, {PFI#1, PDB parameter #4}, {PFI#2, PDB parameter #5}}. Each of the above entries is an example of the fourth information.

[0275] Exemplarily, the second message is a user information response (UEInformationResponseSidelink) message in the sidelink, or a PC5 RRC message.

[0276] Optionally, the method 400 further includes: S450, the first terminal device determines the correspondence between the first packet delay budget and the first QoS flow according to the second indication information.

[0277] Specifically, the first terminal device can associate the first PDB with the first QoS flow one by one according to the identifier of the third terminal device and the second indication information.

[0278] Continuing with the scenario in Example 2, UE1 can associate PDB parameters #1 to 3 in the first entry with PFI #1 to 3 between UE1 and UE3 based on the first message and the second message, and UE1 associates PDB parameters #4 to 5 in the second entry with PFI #1 to 2 between UE1 and UE4.

[0279] It should be understood that the correspondence between the first packet delay budget and the first QoS flow can be used to determine the PC5 configuration index in the second correspondence.

[0280] Specifically, the first terminal device may determine the first SLRB configuration according to the QoS flow parameters corresponding to the first QoS flow and the first PDB, including the PC5 configuration index. This application does not limit the specific method of determining the SLRB configuration.

[0281] Based on the above solution, through the second indication information and the identifier of the third terminal device, the first terminal device can determine the correspondence between the first packet delay budget and the first QoS flow, so as to facilitate the normal implementation of subsequent control plane processes.

[0282] FIG8 is a schematic flow chart of a sidelink communication method 500 provided by the present application. The method 500 may include the following steps:

[0283] S510, the second terminal device sends a fourth message to the access network device, and accordingly, the access network device receives the fourth message.

[0284] The fourth message includes third indication information, and the third indication information identifies the first SLRB between the second terminal device and the access network device, and the first SLRB is the SLRB between the first terminal device and the third terminal device.

[0285] It should be understood that the relationship between the first terminal device, the second terminal device and the third terminal device can be referred to the description in S310 and will not be repeated here.

[0286] The third indication information can be understood as uniquely identifying the first SLRB between the second terminal device and the access network device, or uniquely identifying the first SLRB within the scope of the second terminal device. The third indication information can be called an SLRB index (SLRB Index).

[0287] For example (recorded as Example 3), the first terminal device includes UE1 and UE2, the third terminal device includes UE3 and UE4, there are 2 SLRBs between UE1 and UE3, and their PC5 configuration indexes are Index#1 and Index#2 respectively, there is 1 SLRB between UE1 and UE4, and its PC5 configuration index is Index#1, there are 2 SLRBs between UE2 and UE3, and their PC5 configuration indexes are Index#1 and Index#2 respectively, then the second terminal device can identify these 5 SLRBs by SLRB Index#1, SLRB Index#2, SLRB Index#3, SLRB Index#4, and SLRB Index#5 respectively, and the second terminal device can save the correspondence between PC5 configuration index, SLRB index, first terminal device, and third terminal device, as shown in Table 5.

[0288] Table 5

[0289] It should be understood that the first terminal device and the second terminal device can execute method 300 or method 400 to obtain the correspondence between the PC5 configuration index and the remote UE.

[0290] Among them, the access network device is a service base station of the second terminal device, and the fourth message can be a SUI message.

[0291] The fourth message may further include an identifier of the third terminal device.

[0292] Optionally, the fourth message includes QoS parameters at SLRB granularity.

[0293] It should be understood that the second terminal device can aggregate the QoS parameters of the second hop into QoS parameters of SLRB granularity based on the mapping relationship between the first QoS flow and the first SLRB, that is, the QoS parameters that the E2E SLRB needs to meet on the second hop, and further, carry the QoS parameters through the fourth message.

[0294] S520, the access network device sends a fifth message to the second terminal device, and accordingly, the second terminal device receives the fifth message.

[0295] The fifth message includes a third corresponding relationship, and the third corresponding relationship is a corresponding relationship between the third indication information and the RLC channel.

[0296] Specifically, the access network device can determine the RLC channel for each SLRB and indicate it to the second terminal device through the third corresponding relationship.

[0297] It should be understood that the access network device can determine the SRAP configuration based on the QoS parameters in the fourth message, where the SRAP configuration includes a mapping relationship between the SLRB and the RLC channel, and the third corresponding relationship can be understood as a mapping relationship between the SLRB and the RLC channel. Further, the access network device can carry the SRAP configuration through the fifth message.

[0298] It should also be understood that the above SRAP configuration is a configuration between the second terminal device and the third terminal device. Therefore, the RLC channel is the RLC channel between the second terminal device and the third terminal device, that is, the RLC channel of the second hop.

[0299] Let's continue with the scenario in Example 3. In this scenario, the access network device determines that the SLRBs identified by SLRB Index#1 to 2 and 4 are all mapped to RLC channel ID#1, the SLRB identified by SLRB Index#3 is mapped to RLC channel ID#2, and the SLRB identified by SLRB Index#5 is mapped to RLC channel ID#3. The fifth message includes {SLRB Index#1, RLC channel ID#1}, {SLRB Index#2, RLC channel ID#1}, {SLRB Index#3, RLC channel ID#2}, {SLRB Index#4, RLC channel ID#1}, and {SLRB Index#5, RLC channel ID#3}.

[0300] Exemplarily, the fifth message is an RRC reconfiguration message of the Uu interface.

[0301] S530, the second terminal device determines the correspondence between the RLC channel and the third terminal device according to the third indication information and the third correspondence.

[0302] Specifically, the second terminal device can associate the RLC channel and the third terminal device one by one according to the third indication information.

[0303] Let's continue with the scenario in Example 3. Based on the fourth and fifth messages, the second terminal device can determine that Index#1 and Index#2 between UE1 and UE3 are mapped to RLC channel ID#1, Index#1 between UE1 and UE4 is mapped to RLC channel ID#2, Index#1 between UE2 and UE3 is mapped to RLC channel ID#1, and Index#2 between UE2 and UE2 is mapped to RLC channel ID#3. Furthermore, the bearer ID is defined as the lower 5 bits of the PC5 configuration index. In the L2 U2U relay scenario, it can be considered that the PC5 configuration index and the bearer identifier are the same value. Then, the second terminal device can determine the correspondence between the bearer ID and the RLC channel ID as well as the first and third terminal devices, as shown in Table 6.

[0304] Table 6

[0305] Based on the above scheme, through the third indication information and the third corresponding relationship, the second terminal device can associate the RLC channel with the corresponding first terminal device, so that in subsequent data transmission, the RLC channel corresponding to the data packet can be determined to ensure the normal execution of the data plane process, thereby ensuring normal communication between the first terminal device and the third terminal device.

[0306] Optionally, the method 500 further includes: S501, the second terminal device maps a PC5 configuration index to third indication information, where the PC5 configuration index is used to identify the SLRB configuration between the first terminal device and the third terminal device.

[0307] Specifically, the second terminal device may map the PC5 configuration index to the third indication information one by one, and save the corresponding relationship between the PC5 configuration index, the third indication information, and the first terminal device and the third terminal device.

[0308] Let's continue with the scenario in Example 3. In this scenario, the second terminal device can map the PC5 Config Index of the five SLRBs to the SLRB Index one by one. That is, the PC5 Config Index of the two SLRBs between UE1 and UE3 are mapped to SLRB Index#1 and SLRB Index#2, respectively, the PC5 Config Index of the one SLRB between UE1 and UE4 is mapped to SLRB Index#3, and the PC5 Config Index of the two SLRBs between UE2 and UE3 are mapped to SLRB Index#4 and SLRB Index#5, respectively.

[0309] Based on the above solution, the PC5 configuration index is mapped one by one to the third indication information, so that the third indication information can uniquely identify the first SLRB between the second terminal device and the access network device, which is concise and efficient.

[0310] FIG9 is a schematic flow chart of a sidelink communication method 600 provided by the present application. The method 600 may include the following steps:

[0311] S610, the second terminal device sends a fourth message to the access network device, and accordingly, the access network device receives the fourth message.

[0312] The fourth message includes fourth indication information and the identifier of the first terminal device.

[0313] Among them, the fourth indication information is used to identify the first SLRB on the first unicast connection, the first unicast connection is the unicast connection between the first terminal device and the third terminal device, and the first SLRB is the SLRB between the first terminal device and the third terminal device.

[0314] The fourth indication information can be understood as: used to uniquely identify the first SLRB between the first terminal device and the third terminal device, or used to uniquely identify the first SLRB within the range of the third terminal device. The fourth indication information can be called an SLRB index.

[0315] The fourth indication information can also be understood as: an SLRB used to uniquely identify an E2E unicast connection between the second terminal device and the access network device.

[0316] For example (recorded as Example 4), the first terminal device includes UE1 and UE2, the third terminal device includes UE3 and UE4, there are 2 SLRBs between UE1 and UE3, and their PC5 configuration indexes are Index#1 and Index#2 respectively, there is 1 SLRB between UE1 and UE4, and its PC5 configuration index is Index#1, there are 2 SLRBs between UE2 and UE3, and their PC5 configuration indexes are Index#1 and Index#2 respectively, then there are 2 SLRBs between UE1 and UE3, which can be indicated by different fourth indication information, that is, they are unique within the scope of UE3, for example, the second terminal device determines them as SLRB Index#1 and SLRB Index#2. There are 2 SLRBs between UE2 and UE3, which can be indicated by different fourth indication information, that is, they are unique within the scope of UE3, for example, the second terminal device determines them as SLRB Index#1 and SLRB Index#2. There is one SLRB between UE1 and UE4, which can independently determine the fourth indication information, that is, it is unique within the scope of UE4. For example, the second terminal device determines it as SLRB Index#1. The second terminal device can save the correspondence between the PC5 configuration index, SLRB index, first terminal device, and third terminal device, as shown in Table 7.

[0317] Table 7

[0318] It should be understood that in method 600, the second terminal device can set the value of the SLRB index to the same value as the PC5 configuration index, that is, the value of the SLRB index = the value of the PC5 configuration index.

[0319] Among them, the access network device is a service base station of the second terminal device, and the fourth message can be a SUI message.

[0320] The identifier of the first terminal device may be an L2ID or a local identifier determined for the second terminal device.

[0321] The fourth message may further include an identifier of the third terminal device.

[0322] Optionally, the fourth message includes QoS parameters at SLRB granularity.

[0323] It should be understood that the second terminal device can aggregate the QoS parameters of the second hop into QoS parameters of SLRB granularity based on the mapping relationship between the first QoS flow and the first SLRB, that is, the QoS parameters that the E2E SLRB needs to meet on the second hop, and further, carry the QoS parameters through the fourth message.

[0324] Optionally, the "fourth indication information and the identifier of the first terminal device" in the fourth message can be understood as a group of information, for example, recorded as fifth information, and the number of fifth information in the fourth message is determined according to the number of first terminal devices.

[0325] For example, there may be M first terminal devices (M is a positive integer). In other words, M first terminal devices can communicate with one third terminal device through the second terminal device. In this case, the fourth message may include the identifier of the third terminal device and M fifth information, each fifth information including the fourth indication information and the identifier of one first terminal device. In other words, the fourth message carries a list, the number of entries in the list is determined by the number of first terminal devices, and each entry includes the identifier of a first terminal device and the fourth indication information corresponding to the first terminal device.

[0326] Let's continue to use the scenario in Example 4 as an example. In this scenario, for UE3, the first terminal device includes UE1 and UE2, that is, M=2, so the list of the fourth message can include 2 entries, one is: {UE1's L2ID, {SLRB Index#1, QoS parameters}, {SLRB Index#2, QoS parameters}}; the other is: {UE2's L2ID, {SLRB Index#1, QoS parameters 1}, {SLRB Index#2, QoS parameters}}. For UE4, the first terminal device includes UE1, that is, M=1, so the fourth message can include 1 entry, namely {UE1's L2ID, {SLRB Index#1, QoS parameters}}. Each of the above entries is an example of the fifth information. In summary, in the scenario given in Example 4, the fourth message can be: {UE3's L2ID, {UE1's L2ID, {SLRB Index#1, QoS parameters}, {SLRB Index#2, QoS parameters}}, {UE2's L2ID, {SLRB Index#1, QoS parameters 1}, {SLRB Index#2, QoS parameters}}}, {UE4's L2ID, {UE1's L2ID, {SLRB Index#1, QoS parameters}}}.

[0327] S620, the access network device sends a fifth message to the second terminal device, and accordingly, the second terminal device receives the fifth message.

[0328] The fifth message includes the identifier of the first terminal device and the fourth corresponding relationship, and the fourth corresponding relationship is the corresponding relationship between the fourth indication information and the RLC channel.

[0329] Specifically, the access network device can determine the RLC channel for each SLRB and indicate it to the second terminal device through the third corresponding relationship.

[0330] It should be understood that the access network device can determine the SRAP configuration based on the QoS parameters in the fourth message, where the SRAP configuration includes a mapping relationship between the SLRB and the RLC channel, and the fourth corresponding relationship can be understood as a mapping relationship between the SLRB and the RLC channel. Further, the access network device can carry the SRAP configuration through the fifth message.

[0331] It should also be understood that the above SRAP configuration is a configuration between the second terminal device and the third terminal device. Therefore, the RLC channel is the RLC channel between the second terminal device and the third terminal device, that is, the RLC channel of the second hop.

[0332] Optionally, the "identification of the first terminal device and the fourth corresponding relationship" in the fifth message can be understood as a group of information, for example, recorded as sixth information, and the number of sixth information in the fifth message is determined according to the number of first terminal devices.

[0333] For example, there may be M first terminal devices (M is a positive integer). In other words, M first terminal devices can communicate with one third terminal device through the second terminal device. In this case, the fifth message may include the identifier of the third terminal device and M sixth information, each sixth information including the fourth indication information and the identifier of one first terminal device. In other words, the fifth message carries a list, the number of entries in the list is determined by the number of first terminal devices, and each entry includes the identifier of a first terminal device and the fourth indication information corresponding to the first terminal device.

[0334] Continuing with the scenario in Example 4, the description is given. In this scenario, the access network device determines that Index#1 and Index#2 between UE1 and UE3 are mapped to RLC channel ID#1, Index#1 between UE1 and UE4 is mapped to RLC channel ID#2, Index#1 between UE2 and UE3 is mapped to RLC channel ID#1, and Index#2 between UE2 and UE3 is mapped to RLC channel ID#3. For UE3, the first terminal device includes UE1 and UE2, that is, M=2. Therefore, the list of the fifth message may include two entries, one is: {UE1's L2ID, {SLRB Index#1, RLC channel ID#1}, {SLRB Index#2, RLC channel ID#1}}; and the other is: {UE2's L2ID, {SLRB Index#1, RLC channel ID#1}, {SLRB Index#2, RLC channel ID#3}}. For UE4, the first terminal device includes UE1, that is, M=1, so the fifth message can include 1 entry, namely {UE1's L2ID, {SLRB Index#1, RLC channel ID#2}}. Each of the above entries is an example of the sixth information. In summary, in the scenario given in Example 4, the fifth message includes {UE3's L2ID, {UE1's L2ID, {SLRB Index#1, RLC channel ID#1}, {SLRB Index#2, RLC channel ID#1}}, {UE2's L2ID, {SLRB Index#1, RLC channel ID#1}, {SLRB Index#2, RLC channel ID#3}}}, {UE4's L2ID, {UE1's L2ID, {SLRB Index#1, RLC channel ID#2}}}.

[0335] The fifth message is the RRC reconfiguration message of the Uu interface.

[0336] S630, the second terminal device determines the correspondence between the RLC channel and the third terminal device according to the fourth indication information and the fifth message.

[0337] The RLC channel and the third terminal device are associated one-to-one according to the fourth indication information and the identifier of the first terminal device.

[0338] Continuing with the scenario in Example 3, the following description will be made. Based on the fourth indication information and the identifier of the first terminal device, the second terminal device can determine that Index#1 and Index#2 between UE1 and UE3 are mapped to RLC channel ID#1, Index#1 between UE1 and UE4 is mapped to RLC channel ID#2, Index#1 between UE2 and UE3 is mapped to RLC channel ID#1, and Index#2 between UE2 and UE2 is mapped to RLC channel ID#3. Furthermore, the bearer ID is defined as the lower 5 bits of the PC5 configuration index. In the L2 U2U relay scenario, it can be considered that the PC5 configuration index and the bearer identifier have the same value, and then the second terminal device can determine the correspondence between the bearer ID and the RLC channel ID as well as the first terminal device and the third terminal device, as shown in Table 6.

[0339] Based on the above scheme, through the fourth indication information and the fourth corresponding relationship, the second terminal device can associate the RLC channel with the corresponding first terminal device, so that in subsequent data transmission, the RLC channel corresponding to the data packet can be determined to ensure the normal execution of the data plane process, thereby ensuring normal communication between the first terminal device and the third terminal device.

[0340] Optionally, the method 500 or the method 600 further includes: the first terminal device sends a data packet to the second terminal device, and correspondingly, the second terminal device receives the data packet.

[0341] The data packet carries an SRAP header, and the SRAP header includes the local IDs and the bearer ID of the first terminal device and the third terminal device.

[0342] Optionally, the method 500 or method 600 further includes: the second terminal device forwarding the data packet.

[0343] Specifically, the second terminal device can forward the data in the data packet according to the SRAP header of the data packet and the SRAP configuration in the fifth message. For example, the L2ID of the first terminal device and the third terminal device can be determined based on the local ID, thereby determining the RLC channel ID corresponding to the bearer ID based on the third correspondence, and then forwarding the data packet through the RLC channel corresponding to the RLC channel ID.

[0344] Continuing with the scenario in Example 3, for example, when the second terminal device receives a data packet from UE1, whose SRAP header carries the local IDs of UE1 and UE3, as well as bearer ID #1, the second terminal device determines, based on Table 6, that bearer ID #1 between UE1 and UE3 corresponds to RLC channel ID #1, and thus forwards the data in the data packet to UE3 via the RLC channel corresponding to RLC channel ID #1.

[0345] FIG10 is a schematic flow chart of a sidelink communication method 700 provided by the present application. The method 700 may include the following steps:

[0346] S710: The second terminal device determines the sixth message.

[0347] It should be understood that the relationship between the first terminal device, the second terminal device and the third terminal device can be referred to the description in S310 and will not be repeated here.

[0348] The sixth message SUI message includes fifth indication information, and the fifth indication information is used to indicate the RLC mode of the RLC channel between the first terminal device and the second terminal device.

[0349] Specifically, the RLC channel between the first terminal device and the second terminal device is initiated by the first terminal device, and the access network device has not yet configured the RLC channel to the second terminal device, that is, in method 700, the second terminal device acts as the RX UE between the second terminal device and the first terminal device.

[0350] It should be understood that the RLC mode may include an unacknowledged mode (UM) and an acknowledged mode (AM). If the second terminal device is configured with an AM RLC channel, the second terminal device will feed back an RLC status report to the first terminal device. The RLC status report may indicate the status of data transmission, for example, which data packets were successfully transmitted and which data packets were not successfully transmitted. If the second terminal device is configured with a UM RLC channel, the second terminal device will not feed back an RLC status report to the first terminal device.

[0351] In the present application, the fifth indication information can indicate which RLC mode the RLC channel between the first terminal device and the second terminal device belongs to.

[0352] In addition, when there are multiple RLC channels between the first terminal device and the second terminal device, the fifth indication information can be reported through a list, and the number of entries in the list is the same as the number of RLC channels.

[0353] The sixth message does not include information about the first QoS flow, and the first QoS flow is the QoS flow between the first terminal device and the third terminal device.

[0354] Specifically, the sixth message does not include information about the first QoS flow, which may mean that the sixth message does not include a QoS information indication field, or that the QoS information indication field in the sixth message is an optional information element, and the QoS information indication field is used to indicate information about the first QoS flow.

[0355] As an example, the sixth message does not include a QoS information indication field, and the information element indicating the RLC mode in the sixth message may be as follows:

[0356] As another example, the QoS information indication field in the sixth message is an optional information element, and the information element indicating the RLC mode in the sixth message and the QoS information indication field may be as follows:

[0357] S720, the second terminal device sends a sixth message to the access network device, and accordingly, the access network device receives the sixth message.

[0358] Exemplarily, the sixth message is used to obtain configuration information of the sidelink. For example, the sixth message is a SUI message.

[0359] Specifically, through the fifth indication information, the second terminal device can indicate the RLC mode of the RLC channel between the first terminal device and the second terminal device to the access network device, and the sixth message does not include information about the first QoS flow.

[0360] It should be understood that in the U2U relay scenario, the second terminal device only forwards data and does not generate data. Therefore, when the second terminal device reports the SUI as an RX UE, it does not need to report the QoS information of the E2E QoS flow.

[0361] Based on the above solution, the second terminal device can correctly report the RLC mode when acting as an RX UE, which facilitates the normal operation of the control plane process, thereby ensuring normal communication between the source UE and the target UE.

[0362] On the other hand, the method can avoid reporting redundant information and reduce the waste of resources.

[0363] Optionally, the method further includes: S730, the access network device sends a seventh message to the second terminal device, and accordingly, the second terminal device receives the seventh message.

[0364] The seventh message includes the channel configuration (channel config) of the RLC channel between the first terminal device and the second terminal device.

[0365] Exemplarily, the seventh message is an RRC reconfiguration message.

[0366] The method 700 is described below in different situations.

[0367] Case 1: Prior to S710, the first terminal device configured an AM RLC channel for the second terminal device, and the AM RLC channel was established between the second terminal device and the first terminal device. In this case, the value of the fifth indication information carried in the sixth message is AM. In addition, method 700 includes S730, in which the access network device sends a channel configuration related to the RLC channel to the second terminal device, so that the second terminal device can provide the first terminal device with a feedback RLC status report of the AM RLC channel based on the channel configuration in the seventh message.

[0368] Case 2: Before S710, the first terminal device configured a UM RLC channel for the second terminal device, and the UM RLC channel was established between the second terminal device and the first terminal device. In this case, the value of the fifth indication information carried in the sixth message is UM. Furthermore, method 700 may not include S730 because the second terminal device does not need to provide feedback of an RLC status report to the first terminal device.

[0369] It should be understood that the second terminal device not only acts as an RX UE between the first terminal device and the second terminal device (first hop), but also acts as a TX UE between the second terminal device and the third terminal device (second hop). Methods 300 and 400 illustrate the case where the second terminal device obtains the link configuration from the first terminal device as an RX, methods 500 and 600 illustrate the case where the second terminal device reports a SUI message as a TX UE, and method 700 illustrates the case where the second terminal device reports a SUI message as a TX UE. Therefore, the above methods can be combined with each other. For example, methods 500, 600, and 700 can be performed after method 300, or after method 400.

[0370] In addition, the present application does not limit the execution order of the second terminal device reporting the SUI message as the RX UE and the second terminal device reporting the SUI message as the RX UE. In other words, the present application does not limit the execution order of method 500 (or method 600) and method 700, and method 500 (or method 600) and method 700 can also be executed simultaneously. For example, after the second terminal device receives the configuration information from the first terminal device (that is, after executing method 300 or method 400), the second terminal device acts as both the RX UE on the first hop and the TX UE on the second hop, so the second terminal device can send the fourth message (in method 500 or method 600) and the sixth message (in method 700) at the same time. In this case, the access network device can also send the fifth message (in method 500 or method 600) and the seventh message (in method 700) at the same time.

[0371] It should also be understood that SL communication can be bidirectional. In this application, after the first terminal device sends data to the third terminal device through the second terminal device, the third terminal device can also send data to the first terminal device through the second terminal device. At this time, the first terminal device, the second terminal device, and the third terminal device can not only execute the configuration process from the first terminal device to the third terminal device (denoted as direction 1) (i.e., method 300 or method 400, method 500 or method 600, method 700), but also execute the configuration process from the third terminal device to the first terminal device (denoted as direction 2). Among them, the configuration process of direction 2 is similar to the aforementioned method 300 or method 400, method 500 or method 600, method 700. The difference is that if the configuration process of direction 1 is executed first, and in this process, the access network device configures the sending-related RLC channel configuration to the second terminal device on the first hop (refer to case 1 of method 700), then in the configuration process of direction 2, the access network device can map the SLRB of direction 2 to the RLC channel in the SRAP configuration, thereby being able to reuse the RLC channel and reduce resource waste.

[0372] In this application, the access network device that communicates with the first terminal device, the access network device that communicates with the second terminal device, and the access network device that communicates with the third terminal device can be the same or different, without limitation.

[0373] Optionally, method 700 is described by taking the second terminal device as the RX UE reporting the SUI as an example, and the above solution can be extended to the case where the remote UE reports the SUI when serving as the RX UE.

[0374] It should be understood that when the access network device includes a CU and a DU, the actions of the access network device sending and receiving messages from the second terminal device in Figures 8 to 10 can be performed by the DU. When the DU receives a message from the second terminal device, it can forward it to the CU, which then performs processing actions based on the content of the message. When the DU sends a message to the second terminal device, the CU can first generate the message and forward it to the DU, which then forwards it to the second terminal device. In addition, the CU can also be used to perform message or data processing actions.

[0375] For example, in S510 described above, the second terminal device sends the fourth message to the access network device, specifically including: the second terminal device sends the fourth message to the DU of the access network device. The access network device receives the fourth message from the second terminal device, specifically including: the DU of the access network device receives the fourth message from the second terminal device. The specific processes of S610 and S720 described above are similar to the specific process of S510 and will not be repeated here.

[0376] For another example, in S520 described above, the access network device sending the fifth message to the second terminal device specifically includes: the CU of the access network device generates the fifth message, sends the fifth message to the DU of the access network device, and the DU of the access network device then forwards the fifth message to the second terminal device. The second terminal device receives the fifth message from the access network device, specifically including: the second terminal device receives the fifth message sent by the DU of the access network device. The specific process of S620 described above is similar to the specific process of S520 and will not be repeated here.

[0377] Figure 11 is a schematic flow chart of a sidelink communication method 800 provided by the present application. Method 800 can be considered as a specific implementation of the combination of method 300, method 500, and method 700. Method 800 may include the following steps.

[0378] S801, UE1 (an example of a first terminal device) sends message #1 (an example of a first message) to a relay UE (an example of a second terminal device).

[0379] Message #1 includes the L2ID and QoS information of UE3 (an example of a third terminal device). The QoS information includes QFI (an example of first indication information) and QoS parameters. QFI is used to identify the identifier of the QoS flow (i.e., E2E QoS flow) between UE1 and UE3, and the QoS parameters are the parameters of the QoS flow between UE1 and UE3.

[0380] According to message #1, the relay UE may save the correspondence #1 between the L2ID and QFI of UE3.

[0381] For details of S801, please refer to S310.

[0382] S802, the relay UE sends message #2 (an example of a second message) to UE1.

[0383] The relay UE may split the PDB in the QoS parameters to obtain the split PDBs, and reply to UE1 with message #2, where the message #2 includes the QFI and the split PDB (an example of the first PDB).

[0384] For details of S802, please refer to S320.

[0385] S803, UE1 determines the SLRB configuration.

[0386] After receiving message #2, UE1 matches the split PDB with the E2E QoS flow according to the QFI.

[0387] Furthermore, according to the correspondence between the split PDB and the E2E QoS flow, UE1 may determine the SLRB configuration corresponding to the SLRB mapped to each E2E QoS flow, and the SLRB configuration may include a PC5 configuration index.

[0388] For details of S803, please refer to S350.

[0389] S804, UE1 sends a mapping list to the relay UE.

[0390] The mapping list includes a mapping relationship between QFI and PC5 configuration index (an example of a first corresponding relationship).

[0391] For details of S804, please refer to S320.

[0392] S805: The relay UE determines the correspondence between the configuration index of PC5 and UE3.

[0393] According to the QFI, the above correspondence #1, and the mapping list, the relay UE can associate UE3 with the PC5 configuration index, ie, determine the correspondence between the PC5 configuration index and UE1 and UE3, which is recorded as correspondence #2.

[0394] For details of S805, please refer to S330.

[0395] S806: The relay UE sends message #4 (an example of the fourth message) to the gNB.

[0396] The relay UE maps the PC5 configuration index one by one to the SLRB index (an example of the third indication information), and saves the correspondence between the SLRB index and the PC5 configuration index as well as UE1 and UE3, recorded as correspondence #3. The SLRB index is used to uniquely identify an E2E SLRB between the relay UE and the gNB.

[0397] When the relay UE is in the connected state, the relay UE sends message #4 to the gNB. Message #4 includes the SLRB index, the L2ID of UE3, and QoS parameters.

[0398] For details of S806, please refer to S510.

[0399] S807: The gNB sends message #5 to the relay UE.

[0400] The gNB determines the SRAP configuration based on the QoS parameters, including the mapping between the SLRB and the RLC channel ID. Furthermore, the gNB sends message #5 to the relay UE, which includes the mapping between the SLRB index and the RLC channel ID (an example of the third mapping relationship).

[0401] For details of S807, please refer to S520.

[0402] S808: The relay UE determines the correspondence between the RLC channel ID and UE1 and UE3.

[0403] Specifically, the relay UE can determine the correspondence between the PC5 configuration index, RLC channel ID, and UE1 and UE3 based on the SLRB index and correspondence #3. Furthermore, the relay can determine the correspondence between the bearer ID and RLC channel ID, as well as UE1 and UE3, which is recorded as correspondence #4.

[0404] For details of S808, please refer to S530.

[0405] S809: The relay UE sends message #6 (an example of the sixth message) to the gNB.

[0406] The message #6 includes an RLC mode indication field, which is used to indicate that the RLC mode of the RLC channel between UE1 and the relay UE is the AM mode. The message #6 does not include QoS flow information.

[0407] For details of S809, please refer to S720.

[0408] S810: The gNB sends an RRC reconfiguration message (an example of the seventh message) to the relay UE, which includes the RLC channel configuration.

[0409] For details about S810, please refer to S730.

[0410] S811, UE1 sends data packet #1 to the relay.

[0411] The data packet #1 carries an SRAP header including the local IDs and bearer IDs of UE1 and UE3.

[0412] S812, relay UE forwards data packet #1 to UE3 (an example of a third terminal device).

[0413] Specifically, the relay UE can determine the L2IDs of UE1 and UE3 according to the local ID, thereby determining the RLC channel ID corresponding to the bearer ID in the data packet according to the correspondence #4, and then forward the data packet through the RLC channel corresponding to the RLC channel ID.

[0414] S813, the relay UE feeds back an RLC status report to UE1.

[0415] Specifically, the relay UE may feed back an RLC status report to UE1 according to the RLC channel configuration obtained in S810. The status report may indicate whether the data packet #1 is successfully transmitted.

[0416] It should be understood that the size of the serial numbers of the above processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0417] For example, in method 800, S806 and S809 can be executed separately or simultaneously, that is, message #4 and message #6 can be different messages or the same message. Similarly, S807 and S810 can be executed separately or simultaneously, that is, message #5 and message #7 can be different messages or the same message.

[0418] It should also be understood that in the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other, and the technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships.

[0419] It should also be understood that in some of the above embodiments, the devices in the existing network architecture are mainly used as examples for illustrative description (such as network devices, terminal devices, etc.), and it should be understood that the embodiments of the present application are not limited to the specific form of the devices. For example, devices that can achieve the same functions in the future are applicable to the embodiments of the present application.

[0420] It can be understood that in the above-mentioned various method embodiments, the methods and operations implemented by devices (such as access network devices, terminal devices) can also be implemented by components of the devices (such as chips or circuits).

[0421] The sidelink communication method provided by the embodiment of the present application is described in detail above with reference to Figures 3 to 11. The communication device provided by the embodiment of the present application is described in detail below with reference to Figures 12 to 14.

[0422] Figure 12 is a schematic block diagram of an example communication device provided in an embodiment of the present application. As shown in Figure 12, the communication device 1200 includes a transceiver unit 1210 and a processing unit 1220. The transceiver unit 1210 can implement corresponding communication functions, and the processing unit 1220 is used to perform data processing to enable the communication device to implement the aforementioned method embodiment. The transceiver unit 1210 can also be referred to as a communication interface or a communication unit.

[0423] Optionally, the communication device 1200 may further include a storage unit, which may be used to store instructions and / or data. The processing unit 1220 may read the instructions and / or data in the storage unit so that the communication device implements the aforementioned method embodiment.

[0424] The communication device 1200 can be used to execute the actions performed by the first terminal device in the above method embodiment. In this case, the communication device 1200 can be the first terminal device, or a component that can be configured on the first terminal device. The transceiver unit 1210 is used to execute the transceiver-related operations on the first terminal device side in the above method embodiment. The storage unit is used to execute the data or instruction storage-related operations on the first terminal device side in the above method embodiment. The processing unit 1220 is used to execute the processing-related operations on the first terminal device side in the above method embodiment.

[0425] Alternatively, the communication device 1200 can be used to execute the actions performed by the second terminal device in the above method embodiment. In this case, the communication device 1200 can be a second terminal device, or a component that can be configured on the second terminal device. The transceiver unit 1210 is used to execute the transceiver-related operations on the second terminal device side in the above method embodiment, the storage unit is used to execute the data or instruction storage-related operations on the second terminal device side in the above method embodiment, and the processing unit 1220 is used to execute the processing-related operations on the second terminal device side in the above method embodiment.

[0426] Alternatively, the communication device 1200 can be used to execute the actions performed by the access network device in the above method embodiment. In this case, the communication device 1200 can be an access network device, or a component that can be configured on the access network device. The transceiver unit 1210 is used to execute the transceiver-related operations on the access network device side in the above method embodiment. The storage unit is used to execute the data or instruction storage-related operations on the access network device side in the above method embodiment. The processing unit 1220 is used to execute the processing-related operations on the access network device side in the above method embodiment.

[0427] It should be understood that the specific process of each unit executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0428] The processing unit 1220 in the above embodiment can be implemented by at least one processor or processor-related circuits. The transceiver unit 1210 can be implemented by a transceiver or transceiver-related circuits. The transceiver unit 1210 can also be referred to as a communication unit or communication interface. The storage unit can be implemented by at least one memory.

[0429] Figure 13 is a schematic block diagram of another example communication device 1300 provided in an embodiment of the present application. As shown in the figure, the device 1300 includes: at least one processor 1310 and a transceiver 1320. The processor 1310 is coupled to a memory and is configured to execute instructions stored in the memory to send and / or receive signals. Optionally, the device 1300 also includes a memory 1330 for storing instructions. Optionally, the device 1300 also includes a transceiver 1320, and the processor 1310 controls the transceiver 1320 to send and / or receive signals.

[0430] It should be understood that the processor 1310 and memory 1330 may be combined into a processing device, and the processor 1310 is used to execute the program code stored in the memory 1330 to implement the above functions. In specific implementations, the memory 1330 may also be integrated into the processor 1310 or independent of the processor 1310.

[0431] It should also be understood that the transceiver 1320 may include a transceiver (or receiver) and a transmitter (or transmitter). The transceiver may further include an antenna, and the number of antennas may be one or more. The transceiver 1320 may also be a communication interface or interface circuit.

[0432] For example, the transceiver 1320 in the device 1300 may correspond to the transceiver unit in the above embodiment, and the processor 1310 in the device 1300 may correspond to the processing unit in the above embodiment.

[0433] As a solution, the apparatus 1300 is used to implement the operations performed by the first terminal device in each of the above method embodiments.

[0434] For example, the processor 1310 is used to execute the computer program or instructions stored in the memory 1320 to implement the relevant operations of the first terminal device in each of the above method embodiments.

[0435] As another solution, the apparatus 1300 is used to implement the operations performed by the second terminal device in the above method embodiments.

[0436] For example, the processor 1310 is used to execute the computer program or instructions stored in the memory 1320 to implement the relevant operations of the second terminal device in each of the above method embodiments.

[0437] As another solution, the apparatus 1300 is used to implement the operations performed by the access network device in the above various method embodiments.

[0438] For example, the processor 1310 is configured to execute computer programs or instructions stored in the memory 1320 to implement relevant operations of the access network device in the above various method embodiments.

[0439] It should be understood that the specific process of each transceiver processor executing the above corresponding steps has been described in detail in the above method embodiment, and for the sake of brevity, it will not be repeated here.

[0440] 14 is a schematic block diagram of a chip system 1400 according to an embodiment of the present application. The chip system 1400 (or also referred to as a processing system) includes a logic circuit 1410 and an input / output interface 1420 .

[0441] Logic circuit 1410 may be a processing circuit within chip system 1400. Logic circuit 1410 may be coupled to a storage unit and invoke instructions within the storage unit, enabling chip system 1400 to implement the methods and functions of various embodiments of the present application. Input / output interface 1420 may be an input / output circuit within chip system 1400, outputting information processed by chip system 1400 or inputting data or signaling information to be processed into chip system 1400 for processing.

[0442] As a solution, the chip system 1400 is used to implement the operations performed by the first terminal device in each of the above method embodiments.

[0443] For example, the logic circuit 1410 is used to implement the processing-related operations performed by the terminal device in the above method embodiment; the input / output interface 1420 is used to implement the sending and / or receiving-related operations performed by the first terminal device in the above method embodiment.

[0444] As another solution, the chip system 1400 is used to implement the operations performed by the second terminal device in the above various method embodiments.

[0445] For example, the logic circuit 1410 is used to implement the processing-related operations performed by the second terminal device in the above method embodiment; the input / output interface 1420 is used to implement the sending and / or receiving-related operations performed by the second terminal device in the above method embodiment.

[0446] As another solution, the chip system 1400 is used to implement the operations performed by the access network device in the above various method embodiments.

[0447] For example, the logic circuit 1410 is used to implement the processing-related operations performed by the access network device in the above method embodiment; the input / output interface 1420 is used to implement the sending and / or receiving-related operations performed by the access network device in the above method embodiment.

[0448] An embodiment of the present application also provides a computer-readable storage medium on which computer instructions are stored for implementing the methods executed by a communication device (such as a first terminal device, a second terminal device, or an access network device) in the above-mentioned method embodiments.

[0449] An embodiment of the present application also provides a computer program product comprising instructions, which, when executed by a computer, implement the methods performed by a communication device (such as a first terminal device, a second terminal device, or an access network device) in the above-mentioned method embodiments.

[0450] An embodiment of the present application also provides a communication system, which includes one or more of the first terminal device, the second terminal device, and the access network device in the above embodiments.

[0451] The explanation of the relevant contents and beneficial effects of any of the above-mentioned devices can be referred to the corresponding method embodiments provided above, which will not be repeated here.

[0452] In the above-mentioned embodiments, unless otherwise specified or provided for, the terms and / or descriptions of the different embodiments are consistent and can be referenced to each other. The technical features of the different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0453] In each of the above embodiments, “optionally, the method further includes…” can be understood as these steps may be executed in full, none, or only part of them, which is not limited in this application.

[0454] In the embodiments of this application, words such as "exemplary" and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "exemplary" should not be construed as preferred or advantageous over other embodiments or designs. Rather, the use of the word "exemplary" is intended to present concepts in a concrete way.

[0455] It should be understood that references to "embodiments" throughout this specification mean that a particular feature, structure, or characteristic associated with the embodiment is included in at least one embodiment of the present application. Therefore, various embodiments throughout this specification do not necessarily refer to the same embodiment. Furthermore, these particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0456] It should be understood that in the various embodiments of the present application, the size of the sequence number of each process does not mean the order of execution, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application. The names of all nodes and messages in this application are merely names set by this application for the convenience of description. The names in the actual network may be different. It should not be understood that this application limits the names of various nodes and messages. On the contrary, any name with the same or similar function as the node or message used in this application is regarded as the method or equivalent replacement of this application, and is within the scope of protection of this application.

[0457] It should also be understood that in this application, "when", "if" and "if" all mean that the network element will take corresponding measures under certain objective circumstances. It does not limit the time, nor does it require the network element to take judgment actions when implementing it, nor does it mean that there are other limitations.

[0458] It should be noted that in the embodiments of the present application, "pre-setting", "pre-configuration", etc. can be achieved by pre-saving corresponding codes, tables or other methods that can be used to indicate relevant information in a device (for example, a terminal device). This application does not limit its specific implementation method, such as the preset rules, preset constants, etc. in the embodiments of the present application.

[0459] Additionally, the terms "system" and "network" are often used interchangeably herein.

[0460] As used herein, the term "at least one of" or "at least one of" refers to all or any combination of the listed items. For example, "at least one of A, B, and C" can mean: A alone, B alone, C alone, A and B together, B and C together, and A, B, and C together. As used herein, "at least one" means one or more. "A plurality" means two or more.

[0461] It should be understood that in each embodiment of the present application, "B corresponding to A" means that B is associated with A and B can be determined based on A. However, it should also be understood that determining B based on A does not mean determining B based solely on A, but B can also be determined based on A and / or other information.

[0462] In addition, "of", "corresponding", "relevant", "corresponding" and "associated" are sometimes used interchangeably. It should be noted that when the distinction is not emphasized, the meanings they intend to express are consistent. The terms "include", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized.

[0463] It should be understood that in various embodiments of the present application, the first, second, and various numerical numbers are merely distinctions for ease of description and are not intended to limit the scope of the embodiments of the present application.

[0464] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0465] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0466] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0467] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0468] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0469] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0470] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A method for sidelink communication, characterized in that, The method is applied to a first terminal device, and the method includes: Sending a first message to a second terminal device, the first message including first indication information and an identifier of a third terminal device, the first indication information being used to indicate a first Quality of Service (QoS) flow between the first terminal device and the second terminal device, the first QoS flow being a QoS flow between the first terminal device and the third terminal device, the first terminal device communicating with the third terminal device through the second terminal device, and the first indication information including a QoS flow identifier (QFI); Sending a first correspondence relationship to the second terminal device, the first correspondence relationship being a correspondence relationship between the first indication information and a PC5 configuration index, the PC5 configuration index being used to identify a sidelink radio bearer (SLRB) configuration between the first terminal device and the third terminal device.

2. The method according to claim 1, characterized in that, The first message further includes QoS parameters corresponding to the first QoS flow, and the method further includes: Receiving a second message from the second terminal device, the second message including a first packet delay budget and the first indication information, the first packet delay budget being determined according to the QoS parameters, the first packet delay budget being used to indicate a packet delay budget corresponding to the first QoS flow on a first link, the first link being a link between the first terminal device and the second terminal device.

3. The method according to claim 2, wherein The method further includes: Determining a correspondence relationship between the first packet delay budget and the first QoS flow according to the first indication information.

4. The method according to any one of claims 1 to 3, characterized in that The identifier of the third terminal device is a layer 2 identifier.

5. A method for sidelink communication, characterized in that, The communication method is applied to a second terminal device, and the method includes: Receiving a first message from a first terminal device, the first message including first indication information and an identifier of a third terminal device, the first indication information being used to indicate a first Quality of Service (QoS) flow between the first terminal device and the second terminal device, the first QoS flow being a QoS flow between the first terminal device and the third terminal device, the first terminal device communicating with the third terminal device through the second terminal device, and the first indication information including a QoS flow identifier (QFI); Receiving a first correspondence relationship from the first terminal device, the first correspondence relationship being a correspondence relationship between the first indication information and a PC5 configuration index, the PC5 configuration index being used to identify an SLRB configuration between the first terminal device and the third terminal device; Determining a correspondence relationship between the PC5 configuration index and the third terminal device according to the first message and the first correspondence relationship.

6. The method according to claim 5, wherein The determining the correspondence relationship between the PC5 configuration index and the third terminal device according to the first message and the first correspondence relationship includes: Associating the third terminal device with the PC5 configuration index one by one according to the first indication information.

7. The method according to claim 5 or 6, characterized in that, The first message further includes QoS parameters corresponding to the first QoS flow, and the method further includes: Determine a first packet delay budget according to the QoS parameter, where the first packet delay budget is used to indicate the packet delay budget corresponding to the first QoS flow on a first link, and the first link is the link between the first terminal device and the second terminal device; Send a second message to the first terminal device, where the second message includes the first packet delay budget and the first indication information.

8. A method for sidelink communication, characterized in that, The communication method is applied to a first terminal device, and the method includes: Send a first message to a second terminal device, where the first message includes second indication information and an identifier of a third terminal device, and the second indication information is used to indicate a first QoS flow within the range of the third terminal device. The first QoS flow is the QoS flow between the first terminal device and the third terminal device. The first terminal device communicates with the third terminal device through the second terminal device, and the second indication information includes a PC5 QoS flow identifier PFI; Send a third message to the second terminal device, where the third message includes the identifier of the third terminal device and a second correspondence, and the second correspondence is the correspondence between the second indication information and a PC5 configuration index. The PC5 configuration index is used to identify the SLRB configuration between the first terminal device and the third terminal device.

9. The method according to claim 8, characterized in that The first message further includes QoS parameters corresponding to the first QoS flow, and the method further includes: Receive a second message from the second terminal device, where the second message includes a first packet delay budget, the identifier of the third terminal device, and the second indication information. The first packet delay budget is determined according to the QoS parameter, and the first packet delay budget is used to indicate the packet delay budget corresponding to the first QoS flow on a first link, and the first link is the link between the first terminal device and the second terminal device.

10. The method according to claim 9, characterized in that, The method further includes: Determine the relationship between the first packet delay budget and the first QoS flow according to the identifier of the third terminal device and the second indication information.

11. The method according to any one of claims 8 to 10, characterized in that, The identifier of the third terminal device is a layer 2 identifier.

12. A method for sidelink communication, characterized in that, The communication method is applied to a second terminal device, and the method includes: Receive a first message from a first terminal device, where the first message includes second indication information and an identifier of a third terminal device, and the second indication information is used to indicate a first QoS flow within the range of the third terminal device. The first QoS flow is the QoS flow between the first terminal device and the third terminal device. The first terminal device communicates with the third terminal device through the second terminal device, and the second indication information includes PFI; Receive a third message from the first terminal device, where the third message includes the identifier of the third terminal device and a second correspondence, and the second correspondence is the correspondence between the second indication information and a PC5 configuration index. The PC5 configuration index is used to identify the SLRB configuration between the first terminal device and the third terminal device; Determine the correspondence between the PC5 configuration index and the third terminal device according to the first message and the third message.

13. The method according to claim 12, wherein The determining the correspondence between the PC5 configuration index and the third terminal device according to the first message and the third message includes: Associate the third terminal device with the PC5 configuration index one by one according to the identifier of the third terminal device and the second indication information.

14. The method according to claim 12 or 13, characterized in that, The first message further includes QoS parameters corresponding to the QoS flow, and the method further includes: Determine a first packet delay budget according to the QoS parameters, where the first packet delay budget is used to indicate the packet delay budget corresponding to the first QoS flow on a first link, and the first link is the link between the first terminal device and the second terminal device; Send a second message to the first terminal device, where the second message includes the identifier of the third terminal device, the second indication information, and the first packet delay budget.

15. A method for sidelink communication, characterized in that, The communication method is applied to a second terminal device, and the method includes: Send third indication information to an access network device, where the third indication information is used to identify a first SLRB between the second terminal device and the access network device, the first SLRB is an SLRB between a first terminal device and a third terminal device, and the first terminal device communicates with the third terminal device through the second terminal device; Receive a third correspondence from the access network device, where the third correspondence is the correspondence between the third indication information and a radio link control (RLC) channel; Determine the correspondence between the RLC channel and the third terminal device according to the third indication information and the third correspondence.

16. The method according to claim 15, wherein The determining the correspondence between the RLC channel and the third terminal device according to the third indication information and the third correspondence includes: Associate the RLC channel with the third terminal device one by one according to the third indication information.

17. The method according to claim 15 or 16, characterized in that, The method further includes: Map the PC5 configuration index to the third indication information, where the PC5 configuration index is used to identify the SLRB configuration between the first terminal device and the third terminal device.

18. A method for sidelink communication, characterized in that The communication method is applied to an access network device, and the method includes: Receive third indication information from a second terminal device, where the third indication information identifies a first SLRB between the second terminal device and the access network device, the first SLRB is an SLRB between a first terminal device and a third terminal device, and the first terminal device communicates with the third terminal device through the second terminal device; Send a third correspondence to the second terminal device, where the third correspondence is the correspondence between the third indication information and the RLC channel.

19. A method for sidelink communication, characterized in that, The communication method is applied to a second terminal device, and the method includes: Send a fourth message to the access network device, where the fourth message includes fourth indication information and an identifier of a first terminal device. The fourth indication information is used to identify a first SLRB on a first unicast connection. The first unicast connection is a unicast connection between the first terminal device and a third terminal device. The first SLRB is an SLRB between the first terminal device and the third terminal device. The first terminal device communicates with the third terminal device through the second terminal device; Receive a fifth message from the access network device, where the fifth message includes the identifier of the first terminal device and a fourth correspondence relationship. The fourth correspondence relationship is a correspondence relationship between the fourth indication information and an RLC channel; Determine a correspondence relationship between the first terminal device and the RLC channel according to the fourth message and the fifth message.

20. The method according to claim 19, wherein The determining the correspondence relationship between the first terminal device and the RLC channel according to the fourth message and the fifth message includes: Associate the first terminal device and the RLC channel one by one according to the fourth indication information and the identifier of the first terminal device.

21. A method for sidelink communication, characterized in that, The communication method is applied to an access network device. The method includes: Receive a fourth message from a second terminal device. The fourth message includes fourth indication information and an identifier of a first terminal device. The fourth indication information is used to identify a first SLRB on a first unicast connection. The first unicast connection is a unicast connection between the first terminal device and a third terminal device. The first SLRB is an SLRB between the first terminal device and the third terminal device. The first terminal device communicates with the third terminal device through the second terminal device; Send a fifth message to the second terminal device. The fifth message includes the identifier of the first terminal device and a fourth correspondence relationship. The fourth correspondence relationship is a correspondence relationship between the fourth indication information and an RLC channel.

22. The method according to claim 21, wherein The identifier of the first terminal device is a layer 2 identifier.

23. A method for sidelink communication, characterized in that, The communication method is applied to a second terminal device. The method includes: Determine a sixth message, where the sixth message includes fifth indication information. The fifth indication information is used to indicate an RLC mode of an RLC channel between a first terminal device and the second terminal device. The sixth message does not include information about a first QoS flow. The first QoS flow is a QoS flow between the first terminal device and the third terminal device. The first terminal device communicates with the third terminal device through the second terminal device; Send the sixth message to the access network device.

24. A communication device, characterized in that, The device includes a unit for executing the method according to any one of claims 1 to 23.

25. A communication device, characterized in that, Includes: A processor, where the processor is coupled to a memory. The memory stores instructions. When the instructions are run by the processor, the device executes the method according to any one of claims 1 to 23.

26. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store a computer program. When the computer program runs on a computer, the computer executes the method according to any one of claims 1 to 23.

27. A computer program product, characterized in that, The computer program product includes computer program code which, when run on a communication device, implements the method according to any one of claims 1 to 23.

28. A chip, characterized in that, Comprising at least one processor and a communication interface, the communication interface being configured to receive data and / or information and transmit the received data and / or information to the processor, the processor processing the data and / or information to perform the communication method according to any one of claims 1 to 23.

29. A communication system, characterized in that, The communication system includes one or more of a first terminal device, a second terminal device, and an access network device; wherein, the first terminal device is configured to perform the communication method according to any one of claims 1 to 4, or, the first terminal device is configured to perform the communication method according to any one of claims 8 to 11; or, the second terminal device is configured to perform the communication method according to any one of claims 5 to 7, or, the second terminal device is configured to perform the communication method according to any one of claims 12 to 17, or, the second terminal device is configured to perform the communication method according to claim 19 or 20, or, the second terminal device is configured to perform the communication method according to claim 23; or, the access network device is configured to perform the communication method according to any one of claims 18, 21, 22.

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