Communication method, apparatus and system

Abstract

The embodiments of the present application relate to the technical field of communications. Disclosed are a communication method, apparatus and system, which enable a remote device to sense a relay device beyond an adjacent hop. The method comprises: sending a first message, which is used for indicating that providing a second terminal device with a relay service between the second terminal device and a network device is supported, and a first terminal device communicates with the second terminal device by means of at least one third terminal device acting as a relay; and receiving a second message, which is used for indicating that a unicast connection between the second terminal device and the first terminal device should be established, wherein the unicast connection is established by means of the at least one third terminal device. The embodiments of the present application are applied to a relay process.

Description

Communication method, device and system

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on December 29, 2023, with application number "202311868717.3" and application name "Communication Methods, Devices and Systems", 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 communication technologies, and in particular, to a communication method, device, and system. Background Art

[0003] In the scenario where a remote device accesses a network device through a multi-hop relay device, since the remote device only establishes a direct connection with the relay device in the adjacent hop, the remote device can only perceive the relay device in the adjacent hop and cannot perceive the relay devices in other hops. Summary of the Invention

[0004] The embodiments of the present application provide a communication method and apparatus that enable a remote device to perceive a relay device beyond an adjacent hop.

[0005] To achieve the above objectives, this application provides the following technical solutions:

[0006] In a first aspect, a communication method is provided. The method can be executed by a first terminal device, or by a component of the first terminal device, such as a processor, chip, or chip system of the first terminal device, or by a logic module or software that can implement all or part of the first terminal device. The following description takes the method executed by the first terminal device as an example. The communication method includes: sending a first message, the first message is used to indicate: support for providing a relay service between the second terminal device and the network device, and relaying between the first terminal device and the second terminal device through at least one third terminal device; receiving a second message, the second message is used to indicate the establishment of a unicast connection between the second terminal device and the first terminal device; wherein the unicast connection is established through at least one third terminal device.

[0007] The present application provides a communication method, in which a unicast connection is established between a first terminal device directly connected to a network device and a second terminal device when the second terminal device is connected to a first terminal device via a multi-hop relay, so that the second terminal device can directly perceive the first terminal device directly connected to the network device.

[0008] In one possible implementation, the first message is used to indicate, including: the first message includes first indication information and / or second indication information, the first indication information and / or the second indication information is used to indicate: support for providing relay service for the second terminal device, and relay between the first terminal device and the second terminal device is performed through at least one third terminal device.

[0009] Based on this, the first message can indicate the relay capability of the first terminal device by carrying the first indication information and / or second indication information, so that after other devices receive the first message, they can determine the relay capability of the first terminal device based on the first indication information and / or second indication information in the first message.

[0010] In a possible implementation, the second message includes one or more of the following: an identifier of at least one third terminal device, or hop count information between the first terminal device and the second terminal device.

[0011] Based on this, based on the second message, the first terminal device can determine the terminal information between the first terminal device and the second terminal device and / or the number of hops between the first terminal device and the second terminal device, and based on this information, the first terminal device can determine whether to establish a unicast connection with the second terminal device.

[0012] In one possible implementation, the second message includes: first indication information and / or second indication information, and the first indication information and / or the second indication information are used to indicate: support for providing relay service for the second terminal device, and relay between the first terminal device and the second terminal device is performed through at least one third terminal device.

[0013] Based on this, the first terminal device can determine, based on the first indication information and / or the second indication information in the second message, that the unicast connection established this time is a unicast connection that provides a multi-hop relay service for the second terminal device.

[0014] In a possible implementation, the method further includes: receiving a third message; the third message is used to request provision of a relay service.

[0015] Based on this, the first terminal device can send the first message after receiving the third message for requesting to provide a relay service request for the second terminal device, thereby saving the resource overhead of the first terminal device in sending the first message.

[0016] In a possible implementation, the third message includes one or more of the following: an identifier of at least one third terminal device, or hop count information between the first terminal device and the second terminal device.

[0017] Based on this, the first terminal device can determine the terminal information between the first terminal device and the second terminal device and / or the number of hops between the first terminal device and the second terminal device. Based on this information, the first terminal device can determine whether to provide the required relay service for the second terminal device.

[0018] In one possible implementation, the third message includes: third indication information and / or fourth indication information; the third indication information and / or fourth indication information is used to request that relay service be provided for the second terminal device, and relay is performed between the first terminal device and the second terminal device through at least one third terminal device.

[0019] Based on this, the first terminal device can determine that a multi-hop relay service needs to be provided to the second terminal device based on the third indication information and / or the fourth indication information in the third message.

[0020] In one possible implementation, the method also includes: receiving a first data packet; the first data packet includes one or more of the following: first data or a first local identifier; the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device; sending a second data packet to the network device; the second data packet includes one or more of the following: first data, or a second local identifier; the second local identifier is used to identify the second terminal device between the first terminal device and the network device.

[0021] Based on this, the first terminal device can adjust the first data packet transmitted between the first terminal device and the second terminal device to the second data packet transmitted between the first terminal device and the network device during the uplink transmission process, thereby allowing the first terminal device to send the first data in the data packet to the network device.

[0022] In a possible implementation, the first data packet further includes a first identifier, and the first identifier is used to identify a radio bearer corresponding to data of the second terminal device transmitted between the first terminal device and the second terminal device.

[0023] Based on this, the first terminal device can determine the wireless bearer corresponding to the above-mentioned first data according to the first identifier in the first data packet.

[0024] In a possible implementation, the second data packet further includes a second identifier, and the second identifier is used to identify a radio bearer corresponding to data of the second terminal device transmitted between the network device and the first terminal device.

[0025] Based on this, the first terminal device can send the second data packet according to the wireless bearer identified by the second identifier in the second data packet.

[0026] In a possible implementation, the method further includes: determining a first configuration, where the first configuration includes a second local identifier, and the first configuration is used to send a second data packet.

[0027] Based on this, the first terminal device can determine the second local identifier based on the first configuration, and adjust the first data packet to the second data packet based on the second local identifier.

[0028] In a possible implementation, the method further includes: sending a second data packet to the network device based on a first RLC channel indicated in the first configuration, where the first RLC channel is a channel associated with a radio bearer corresponding to the first data.

[0029] Based on this, the first terminal device can determine a channel for transmitting the first data between the first terminal device and the network device based on the first configuration, and transmit the second data packet on the channel.

[0030] In a possible implementation manner, the method further includes: receiving a first configuration from a network device.

[0031] Based on this, the first terminal device can obtain the first configuration from the network device, reducing the resources required for the first terminal device to determine the first configuration.

[0032] In one possible implementation, the method also includes: receiving a third data packet from the network device; the third data packet includes one or more of the following: second data, or a second local identifier; the second local identifier is used to identify the second terminal device between the first terminal device and the network device; sending a fourth data packet; the fourth data packet includes one or more of the following: second data, or a first local identifier; the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device.

[0033] Based on this, during downlink transmission, the first terminal device can adjust the third data packet transmitted between the first terminal device's network device to a fourth data packet transmitted between the first terminal device and the second terminal device, thereby allowing the first terminal device to send the second data in the data packet to the second terminal device.

[0034] In a possible implementation, the third data packet further includes a second identifier, and the second identifier is used to identify a radio bearer corresponding to data of the second terminal device transmitted between the network device and the first terminal device.

[0035] Based on this, the first terminal device can determine the wireless bearer corresponding to the second data in the network device and the first terminal device according to the second identifier in the third data packet.

[0036] In a possible implementation, the fourth data packet further includes a first identifier, where the first identifier is used to identify a radio bearer corresponding to data of the second terminal device transmitted between the first terminal device and the second terminal device.

[0037] Based on this, the first terminal device can send the fourth data packet according to the wireless bearer identified by the first identifier in the fourth data packet.

[0038] In a possible implementation, the method further includes: determining a second configuration, where the second configuration includes the first local identifier, and the second configuration is used to send a fourth data packet.

[0039] Based on this, the first terminal device can determine the first local identifier based on the second configuration, and adjust the third data packet to the fourth data packet based on the first local identifier.

[0040] In a possible implementation, the method further includes: sending a fourth data packet based on a second RLC channel indicated in the second configuration, where the second RLC channel is a channel associated with a radio bearer corresponding to the fourth data packet.

[0041] Based on this, the first terminal device may determine a channel for transmitting the second data between the first terminal device and the second terminal device based on the second configuration, and transmit the fourth data packet on the channel.

[0042] In a possible implementation, the second configuration is a configuration determined based on downlink QoS information between the first terminal device and the adjacent terminal device.

[0043] Based on this, the first terminal device can meet the downlink QoS requirements between the first terminal device and the adjacent terminal device when transmitting downlink data based on the second configuration.

[0044] In a possible implementation, the method further includes: receiving downlink QoS information between the first terminal device and the second terminal device; and determining a second configuration based on the downlink QoS information between the first terminal device and the second terminal device.

[0045] Based on this, the first terminal device can determine the downlink QoS information of one hop of the first terminal device in the downlink direction from the downlink QoS information between the first terminal device and the second terminal device.

[0046] In one possible implementation, the second configuration is determined based on the downlink QoS information between the first terminal device and the second terminal device, including: determining the downlink QoS information between the first terminal device and the second terminal device based on the downlink QoS information between the first terminal device and the second terminal device; determining the second configuration based on the downlink QoS information between the first terminal device and the adjacent terminal device.

[0047] Based on this, the first terminal device can autonomously determine a second configuration that meets the downlink QoS requirements between the first terminal device and the adjacent terminal device.

[0048] In one possible implementation, based on the downlink QoS information between the first terminal device and the second terminal device, the downlink QoS information between the first terminal device and the adjacent terminal device is determined, including: sending the downlink QoS information between the first terminal device and the second terminal device to the adjacent terminal device; receiving the downlink QoS information between the first terminal device and the adjacent terminal device from the adjacent terminal device.

[0049] Based on this, the first terminal device can autonomously obtain a second configuration from the adjacent terminal device that meets the downlink QoS requirements between the first terminal device and the adjacent terminal device.

[0050] In a second aspect, a communication method is provided, which can be executed by a first device, or by a component of the first device, such as a processor, chip, or chip system of the first device, or by a logic module or software that can implement all or part of the first device. The following description takes the method being executed by the first device as an example. The first device includes a second terminal device or a third terminal device; the communication method includes: receiving a fourth message, the fourth message is used to indicate: support for providing a relay service between the second terminal device and the network device, and relaying between the first terminal device and the second terminal device through at least one third terminal device; sending a fifth message, the fifth message is used to indicate the establishment of a unicast connection between the second terminal device and the first terminal device; wherein the unicast connection is established through at least one third terminal device.

[0051] In one possible implementation, the fourth message is used to indicate, including: the fourth message includes first indication information and / or second indication information, the first indication information and / or the second indication information is used to indicate: support for providing relay service for the second terminal device, and relay between the first terminal device and the second terminal device is performed through at least one third terminal device.

[0052] In a possible implementation, the fifth message includes one or more of the following: an identifier of at least one third terminal device, or hop count information between the first terminal device and the second terminal device.

[0053] In one possible implementation, the fifth message includes: first indication information and / or second indication information, and the first indication information and / or the second indication information are used to indicate: support for providing relay service for the second terminal device, and relay between the first terminal device and the second terminal device is performed through at least one third terminal device.

[0054] In a possible implementation, the method further includes: sending a sixth message; the sixth message is used to request provision of a relay service.

[0055] In one possible implementation, the sixth message includes: third indication information and / or fourth indication information; the third indication information and / or fourth indication information is used to request that relay service be provided for the second terminal device, and relay is performed between the first terminal device and the second terminal device through at least one third terminal device.

[0056] In one possible implementation, the method is applied to a fourth terminal device, and the sixth message includes one or more of the following: an identifier of the fourth terminal device, identifiers of one or more third terminal devices between the fourth terminal device and the second terminal device, or hop count information between the fourth terminal device and the second terminal device, and the fourth terminal device is one of the at least one third terminal device.

[0057] In one possible implementation, the method further includes: sending a first data packet; the first data packet includes one or more of the following: first data, or a first local identifier; the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device.

[0058] In a possible implementation, the first data packet further includes a first identifier, and the first identifier is used to identify a radio bearer corresponding to data of the second terminal device transmitted between the first terminal device and the second terminal device.

[0059] In one possible implementation, the method is applied to a fourth terminal device, which is a third terminal device among at least one third terminal device; the method also includes: receiving a fifth data packet, generating a first data packet based on the fifth data packet, wherein the fifth data packet includes first data, or a first local identifier; the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device.

[0060] In a possible implementation, the method further includes: determining a third configuration, where the third configuration includes the first local identifier, and the third configuration is used to send the first data packet.

[0061] In a possible implementation, the method includes sending a first data packet based on a third RLC channel indicated in a third configuration; the third RLC channel is a channel associated with a radio bearer corresponding to the first data packet.

[0062] In a possible implementation, the third configuration is a configuration determined based on uplink QoS information between the first device and a next-hop terminal device in the uplink direction.

[0063] In one possible implementation, the method further includes: obtaining uplink QoS information between the first device and the first terminal device; and determining uplink QoS information between the first device and the next-hop terminal device in the uplink direction based on the uplink QoS information between the first device and the first terminal device.

[0064] In a possible implementation, the method includes: receiving uplink QoS information between the first device and a next-hop terminal device in the uplink direction.

[0065] In one possible implementation, the method further includes: receiving a fourth data packet, the fourth data packet including one or more of the following: first data, or a first local identifier; wherein the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device.

[0066] In a possible implementation, the fourth data packet further includes a first identifier, where the first identifier is used to identify a radio bearer corresponding to data of the second terminal device transmitted between the first terminal device and the second terminal device.

[0067] In one possible implementation, the method is applied to a fourth terminal device, which is a third terminal device among at least one third terminal device; the method also includes: sending a sixth data packet, wherein the sixth data packet includes one or more of the following: second data, or a first local identifier; the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device.

[0068] In a possible implementation, the method further includes: determining a fourth configuration, where the fourth configuration includes the first local identifier, and the fourth configuration is used to send a sixth data packet.

[0069] In a possible implementation, sending the sixth data packet includes: sending the sixth data packet based on a fourth RLC channel indicated in the fourth configuration; the fourth RLC channel is a channel associated with a radio bearer corresponding to the fourth data.

[0070] In a possible implementation, the fourth configuration is a configuration determined based on downlink QoS information between the fourth terminal device and the next-hop terminal device in the downlink direction.

[0071] In a possible implementation, the method further includes: receiving downlink QoS information between the fourth terminal device and a next-hop terminal device in the downlink direction.

[0072] In one possible implementation, the method further includes: obtaining downlink QoS information between the fourth terminal device and the second terminal device; and determining downlink QoS information between the fourth terminal device and the next-hop terminal device in the downlink direction based on the downlink QoS information between the fourth terminal device and the second terminal device.

[0073] In a third aspect, a communication method is provided. The method can be executed by a third terminal device, or by a component of the third terminal device, such as a processor, chip, or chip system of the third terminal device. The method can also be implemented by a logic module or software that can implement all or part of the third terminal device. The following description takes the method executed by the third terminal device as an example. The communication method includes: sending a fourth message, the fourth message is used to indicate: support for providing a relay service between the second terminal device and the network device, and relaying between the first terminal device and the second terminal device through at least one third terminal device; receiving a fifth message, the fifth message is used to indicate the establishment of a unicast connection between the second terminal device and the first terminal device; wherein the unicast connection is established through at least one third terminal device.

[0074] In one possible implementation, the fourth message is used to indicate, including: the fourth message includes first indication information and / or second indication information, the first indication information and / or the second indication information is used to indicate: support for providing relay service for the second terminal device, and relay between the first terminal device and the second terminal device is performed through at least one third terminal device.

[0075] In a possible implementation, the fifth message includes one or more of the following: an identifier of at least one third terminal device, or hop count information between the first terminal device and the second terminal device.

[0076] In one possible implementation, the fifth message includes: first indication information and / or second indication information, and the first indication information and / or the second indication information are used to indicate: support for providing relay service for the second terminal device, and relay between the first terminal device and the second terminal device is performed through at least one third terminal device.

[0077] In a fourth aspect, a communication method is provided. This method can be performed by a network device, or by a component of the network device, such as a processor, chip, or chip system of the network device. It can also be implemented by a logic module or software that implements all or part of the network device. The following description uses the method performed by a network device as an example. The communication method includes: obtaining QoS information between a first terminal device and a second terminal device; and transmitting QoS information between the first terminal device and the second terminal device.

[0078] In a possible implementation, the QoS information between the first terminal device and the second terminal device includes: uplink QoS information between the first terminal device and the second terminal device, and / or downlink QoS information between the first terminal device and the second terminal device.

[0079] In a possible implementation, sending QoS information between the first terminal device and the second terminal device includes: sending downlink QoS information between the first terminal device and the second terminal device to the first terminal device.

[0080] In a possible implementation, sending QoS information between a first terminal device and a second terminal device includes: sending the uplink QoS information between the first terminal device and the second terminal device to the second terminal device.

[0081] In a possible implementation, the method further includes: sending a first configuration to the first terminal device; the first configuration is determined based on QoS information between the first terminal device and the network device.

[0082] In a possible implementation, the method further includes: sending a second configuration to the first terminal device; the second configuration is determined based on QoS information between the first terminal device and an adjacent terminal device.

[0083] In a fifth aspect, a communication method is provided. The method can be executed by a first terminal device, or by a component of the first terminal device, such as a processor, chip, or chip system of the first terminal device, or by a logic module or software that can implement all or part of the first terminal device. The following description takes the method being executed by the first terminal device as an example. The communication method includes: determining a first configuration and sending a second data packet according to the first configuration, the first configuration including a second local identifier, the first configuration being used to send the second data packet, the second data packet including one or more of the following: first data, or a second local identifier; the second local identifier being used to identify the second terminal device between the first terminal device and the network device, and the first terminal device and the second terminal device being relayed through at least one third terminal device.

[0084] In a possible implementation, sending the second data packet according to the first configuration includes: sending the second data packet to the network device based on a first RLC channel indicated in the first configuration, where the first RLC channel is a channel associated with a radio bearer corresponding to the first data.

[0085] In a possible implementation manner, the method further includes: receiving a first configuration from a network device.

[0086] In a sixth aspect, a communication method is provided. The method can be executed by a first terminal device, or by a component of the first terminal device, such as a processor, chip, or chip system of the first terminal device, or by a logic module or software that can implement all or part of the first terminal device. The following description takes the method being executed by the first terminal device as an example. The communication method includes: determining a second configuration and sending a fourth data packet according to the second configuration, the second configuration including a first local identifier, and the second configuration being used to send the fourth data packet; the fourth data packet includes one or more of the following: second data, or a first local identifier; the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device, and the first terminal device and the second terminal device are relayed through at least one third terminal device.

[0087] In a possible implementation, sending the fourth data packet according to the second configuration includes: sending the fourth data packet based on a second RLC channel indicated in the second configuration, where the second RLC channel is a channel associated with a radio bearer corresponding to the fourth data packet.

[0088] In a possible implementation, the second configuration is a configuration determined based on downlink QoS information between the first terminal device and the adjacent terminal device.

[0089] In one possible implementation, determining the second configuration includes: receiving downlink QoS information between the first terminal device and the second terminal device; and determining the second configuration based on the downlink QoS information between the first terminal device and the second terminal device.

[0090] In one possible implementation, the second configuration is determined based on the downlink QoS information between the first terminal device and the second terminal device, including: determining the downlink QoS information between the first terminal device and the second terminal device based on the downlink QoS information between the first terminal device and the second terminal device; determining the second configuration based on the downlink QoS information between the first terminal device and the adjacent terminal device.

[0091] In one possible implementation, based on the downlink QoS information between the first terminal device and the second terminal device, the downlink QoS information between the first terminal device and the adjacent terminal device is determined, including: sending the downlink QoS information between the first terminal device and the second terminal device to the adjacent terminal device; receiving the downlink QoS information between the first terminal device and the adjacent terminal device from the adjacent terminal device.

[0092] In the seventh aspect, a communication method is provided, which can be executed by a first device, or by a component of the first device, such as a processor, chip, or chip system of the first device, or by a logic module or software that can implement all or part of the first device. The following is an illustration of the method being executed by the first device. The first device includes a second terminal device or a third terminal device; the communication method includes: determining a third configuration, and sending a first data packet according to the third configuration, the third configuration includes a first local identifier, the third configuration is used to send a first data packet, the first data packet includes one or more of the following: first data, or a first local identifier; the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device, and the first terminal device and the second terminal device are relayed through at least one third terminal device.

[0093] In a possible implementation, sending the first data packet according to the third configuration includes: sending the first data packet based on a third RLC channel indicated in the third configuration; the third RLC channel is a channel associated with a radio bearer corresponding to the first data.

[0094] In a possible implementation, the third configuration is a configuration determined based on uplink QoS information between the first device and a next-hop terminal device in the uplink direction.

[0095] In an eighth aspect, a communication method is provided, which can be executed by a first device, or by a component of the first device, such as a processor, chip, or chip system of the first device, or by a logic module or software that can implement all or part of the first device. The following description takes the method being executed by the first device as an example. The first device includes a second terminal device or a third terminal device; the communication method includes: determining a fourth configuration, and sending a sixth data packet according to the fourth configuration, the fourth configuration including a first local identifier, the fourth configuration being used to send a sixth data packet, the sixth data packet including one or more of the following: second data, or a first local identifier; wherein the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device, and the first terminal device and the second terminal device are relayed through at least one third terminal device.

[0096] In a possible implementation, sending the sixth data packet according to the fourth configuration includes: sending the sixth data packet based on a fourth RLC channel indicated in the fourth configuration; the fourth RLC channel is a channel associated with a radio bearer corresponding to the fourth data.

[0097] In a possible implementation, the fourth configuration is a configuration determined based on downlink QoS information between the fourth terminal device and the next-hop terminal device in the downlink direction.

[0098] In a possible implementation, the method further includes: receiving downlink QoS information between the fourth terminal device and a next-hop terminal device in the downlink direction.

[0099] In one possible implementation, the method further includes: obtaining downlink QoS information between the fourth terminal device and the second terminal device; and determining downlink QoS information between the fourth terminal device and the next-hop terminal device in the downlink direction based on the downlink QoS information between the fourth terminal device and the second terminal device.

[0100] In a ninth aspect, a communication device is provided for implementing the various methods described above. The communication device may be the first terminal device described in the first, fifth, or sixth aspects, or a device including the first terminal device, or a device included in the first terminal device, such as a chip. Alternatively, the communication device may be the first device described in the second, seventh, or eighth aspects, or a device including the first device, or a device included in the first device, such as a chip. Alternatively, the communication device may be the third terminal device described in the third aspect, or any implementation of the third aspect, or a device including the third terminal device, or a device included in the third terminal device, such as a chip. Alternatively, the communication device may be the network device described in the fourth aspect, or any implementation of the fourth aspect, or a device including the network device, or a device included in the network device, such as a chip. The communication device includes modules, units, or means corresponding to implementing the methods described above. The modules, units, or means may be implemented in hardware, software, or by hardware executing corresponding software implementations. The hardware or software includes one or more modules or units corresponding to the functions described above.

[0101] In some possible designs, the communication device may include a processing module and a transceiver module. The transceiver module, also referred to as a transceiver unit, is configured to implement the transmitting and / or receiving functions described in any of the above aspects and any possible implementations thereof. The transceiver module may be comprised of a transceiver circuit, a transceiver, a transceiver, or a communication interface. The processing module may be configured to implement the processing functions described in any of the above aspects and any possible implementations thereof.

[0102] In some possible designs, the transceiver module includes a sending module and a receiving module, which are respectively used to implement the sending and receiving functions in any of the above aspects and any possible implementation methods.

[0103] In a tenth aspect, a communication device is provided, comprising: at least one processor; the processor is configured to execute a computer program or instructions stored in a memory, so that the communication device performs the method of any of the above aspects. The memory may be coupled to the processor or independent of the processor. The communication device may be the first terminal device described in the first, fifth, or sixth aspects, or a device including the first terminal device, or a device included in the first terminal device, such as a chip. Alternatively, the communication device may be the first device described in the second, seventh, or eighth aspects, or a device including the first device, or a device included in the first device, such as a chip. Alternatively, the communication device may be the third terminal device described in the third aspect or any implementation of the third aspect, or a device including the third terminal device, or a device included in the third terminal device, such as a chip. Alternatively, the communication device may be the network device described in the fourth aspect or any implementation of the fourth aspect, or a device including the network device, or a device included in the network device, such as a chip. In some possible designs, the communication device includes a memory, and the memory is configured to store necessary program instructions and data.

[0104] In a possible implementation, the processor includes a logic circuit and an input interface and / or an output interface, wherein the output interface is used to perform the sending action in the corresponding method, and the input interface is used to perform the receiving action in the corresponding method.

[0105] In one possible implementation, the communication device further includes a communication interface and a communication bus, and the processor, memory, and communication interface are connected via the communication bus. The communication interface is used to perform the sending and receiving actions in the corresponding method. The communication interface may also be referred to as a transceiver. Optionally, the communication interface includes a transmitter and a receiver. In this case, the transmitter is used to perform the sending action in the corresponding method, and the receiver is used to perform the receiving action in the corresponding method.

[0106] In some possible designs, the communication device may be a chip or a chip system. When the communication device is a chip system, it may be composed solely of a chip or may include a chip and other discrete components. When the communication device is a chip, the aforementioned sending action / function may be understood as output, and the aforementioned receiving action / function may be understood as input.

[0107] In an eleventh aspect, a chip is provided, which includes a processor for implementing the functions involved in any of the above aspects or any of its implementation methods.

[0108] In some possible designs, the chip includes a memory for storing necessary program instructions and data.

[0109] In the twelfth aspect, a computer-readable storage medium is provided, which stores a computer program or instruction. When the computer program or instruction is run on a communication device, the communication device can execute any of the above aspects or any of its implementation methods.

[0110] In a thirteenth aspect, a computer program product comprising instructions is provided, which, when executed on a communication device, enables the communication device to execute the method of any of the above aspects or any of its implementation methods.

[0111] In a fourteenth aspect, a communication system is provided, comprising the first terminal device of the first aspect, the first device of the second aspect, and the network device of the fourth aspect; or, the communication system comprises the first terminal device of the first aspect, the third terminal device of the third aspect, and the network device of the fourth aspect. Alternatively, the communication system comprises the first terminal device of the fifth or sixth aspect, the first device of the second aspect, and the network device of the fourth aspect; or, the communication system comprises the first device of the seventh or eighth aspect, the first terminal device of the first aspect, and the network device of the fourth aspect.

[0112] The technical effects brought about by any implementation method of the second aspect to the fourteenth aspect can refer to the technical effects brought about by the corresponding implementation method of the first aspect, and will not be repeated here.

[0113] It should be noted that various possible implementations of any of the above aspects can be combined under the premise that the solutions are not contradictory. BRIEF DESCRIPTION OF THE DRAWINGS

[0114] FIG1 is a schematic diagram of a scenario in which terminal devices communicate based on a sidelink, provided in an embodiment of the present application;

[0115] FIG2 is a schematic diagram of a user plane protocol stack for communication between terminal devices based on a side link according to an embodiment of the present application;

[0116] FIG3 is a schematic diagram of a control plane protocol stack for communication between terminal devices based on a sidelink according to an embodiment of the present application;

[0117] FIG4 is a schematic diagram of a protocol stack for discovering messages in a discovery process according to an embodiment of the present application;

[0118] FIG5 is a flow chart of a discovery process provided in an embodiment of the present application;

[0119] FIG6 is a flowchart of another discovery process provided in an embodiment of the present application;

[0120] FIG7 is a schematic diagram of a unicast connection establishment process provided in an embodiment of the present application;

[0121] FIG8 is a schematic diagram of a system architecture of a SL U2N relay network architecture provided by an embodiment of the present application;

[0122] FIG9 is a schematic diagram of a protocol stack of a layer 2 SL U2N relay provided in an embodiment of the present application;

[0123] FIG10 is a schematic diagram of a communication architecture of an SL U2U relay provided in an embodiment of the present application;

[0124] FIG11 is a schematic diagram of a user plane protocol stack based on a layer 3 relay method in an SL U2U relay scenario provided by an embodiment of the present application;

[0125] FIG12 is a schematic diagram of a user plane protocol stack and a control plane protocol stack in a layer 2 relay mode in an SL U2U relay scenario provided by an embodiment of the present application;

[0126] FIG13 is a schematic diagram of an IAB system architecture provided in an embodiment of the present application;

[0127] FIG14 is a schematic diagram of the architecture of a communication system provided in an embodiment of the present application;

[0128] FIG15 is a schematic diagram of the composition of a communication device provided in an embodiment of the present application;

[0129] FIG16 is a flow chart of a communication method provided in an embodiment of the present application;

[0130] FIG17 is a flow chart of another communication method provided in an embodiment of the present application;

[0131] FIG18 is a flow chart of another communication method provided in an embodiment of the present application;

[0132] FIG19 is a flow chart of another communication method provided in an embodiment of the present application;

[0133] FIG20 is a flow chart of another communication method provided in an embodiment of the present application;

[0134] FIG21 is a flow chart of another communication method provided in an embodiment of the present application;

[0135] FIG22 is a schematic diagram of a control plane protocol stack for a sidelink between a first terminal device and a second terminal device provided in an embodiment of the present application;

[0136] FIG23 is a schematic diagram of a user plane protocol stack between a network device and a second terminal device provided in an embodiment of the present application;

[0137] FIG24 is a schematic diagram of a control plane protocol stack between a network device and a second terminal device provided in an embodiment of the present application;

[0138] FIG25 is a flow chart of another communication method provided in an embodiment of the present application;

[0139] FIG26 is a schematic diagram of a format of data forwarded between a first terminal device and a network device according to an embodiment of the present application;

[0140] FIG27 is a schematic diagram of a format of data forwarded between a first terminal device and a second terminal device provided by an embodiment of the present application;

[0141] FIG28 is a flow chart of another communication method provided in an embodiment of the present application;

[0142] Figure 29 is a structural diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0143] To facilitate understanding of the technical solutions provided by the embodiments of this application, a brief introduction to the relevant technologies of this application is first given. The brief introduction is as follows:

[0144] 1. Direct communication between terminal devices

[0145] Direct communication between terminal devices, also known as direct communication between different terminal devices, includes wireless fidelity (WiFi), Bluetooth, or sidelink communication. Sidelink communication is used as an example for the following description.

[0146] Sidelink, also known as sidelink, is a transmission link for communication between terminal devices in a wireless communication system. Based on the sidelink, terminal devices can communicate directly with each other without the help of network equipment, thereby effectively reducing the delay in communication between terminal devices. As shown in Figure 1, Figure 1 shows a schematic diagram of a scenario in which terminal devices 1 and terminal devices 2 communicate based on sidelink. The communication interface between terminal devices when communicating via sidelink is called the PC5 interface. When terminal devices communicate with each other via sidelink, they need to communicate through the sidelink-related protocol stack. Figure 2 shows the user plane protocol stack when terminal devices 1 and terminal devices 2 communicate based on sidelink. Figure 3 shows the control plane protocol stack when terminal devices 1 and terminal devices 2 communicate based on sidelink.

[0147] When terminal devices communicate with each other via sidelink, broadcast communication, unicast communication, and multicast communication can be achieved. During broadcast communication based on sidelink, the terminal device sends unencrypted broadcast service data via sidelink broadcast; all terminal devices within the sidelink broadcast reception range can receive the broadcast service data broadcast by the terminal device. Multicast communication based on sidelink means that terminal devices within a communication group can communicate with each other via sidelink; terminal devices within a communication group can send and receive multicast service data to each other via sidelink. When unicast communication based on sidelink is performed between terminal devices, a unicast connection is established on the sidelink between the two terminal devices in unicast communication. After the unicast connection is established, the two terminal devices can communicate based on the negotiated identifier. The data transmitted during the communication process can be encrypted data or unencrypted data. During unicast communication, the sender and the receiver need to communicate through the source layer 2 identifier (source layer-2 identifier) ​​and the destination layer 2 identifier (destination layer-2 identifier). The data packets transmitted between the transmitter and receiver are sidelink media access control (MAC) layer protocol data units (PDUs). The header of the sidelink MAC PDU carries the aforementioned source layer 2 identifier and destination layer 2 identifier to ensure that data can be correctly transmitted from the transmitter to the receiver.

[0148] 2. Radio bearer (RB)

[0149] A radio bearer is a service provided by Layer 2 for transmitting user data between terminal devices and network equipment. A radio bearer comprises a series of protocol entities and configurations allocated by the network equipment to the terminal device, including but not limited to: resources allocated to the packet data convergence protocol (PDCP) entity, the radio link control (RLC) protocol entity, the MAC protocol entity, and the physical layer (PHY). Radio bearers include data radio bearers, which carry data, and signaling radio bearers, which carry signaling.

[0150] In the sidelink scenario, signaling and data are transmitted between terminal devices through the sidelink radio bearer (SL RB). SL RB specifically includes SL data radio bearer (DRB) and SL signaling radio bearer (SRB). SL DRB is used to carry sidelink data, and SL SRB is used to carry sidelink signaling. In this scenario, the radio bearer configuration includes the configuration of the PDCP layer and the service data adaptation protocol (SDAP) layer; the protocol entity below the RLC layer is the RLC bearer, and the corresponding configuration is given in the RLC bearer configuration.

[0151] 3. Discovery Procedure

[0152] The discovery process refers to the process in which a terminal device searches for nearby terminal devices with which it can directly communicate through the discovery process. After the discovery process, the terminal device can establish a unicast connection with the discovered terminal device to achieve data transmission. Taking sidelink communication as an example, the protocol stack of the discovery message used in the discovery process is shown in Figure 4. During the discovery process, the protocol layer of the terminal device generates a discovery message (discovery message), submits the discovery message to the PDCP layer, and sends it to the opposite terminal device through the bottom layer (RLC layer, MAC layer, and PHY layer). The current discovery process includes two models: Model A and Model B, which are described below.

[0153] 3.1. Discovery Process of Model A

[0154] As shown in FIG5 , the discovery process of model A can be specifically implemented through the following steps 501 and 502 .

[0155] Step 501: The announcing UE broadcasts a discovery message, and the monitoring UE receives the discovery message.

[0156] In Model A, the discovery message can also be called an announcement message; the discovery message carries relevant information about the announcing terminal device, such as the types of services that the announcing terminal device can provide, and is used to enable the monitoring terminal device to determine whether it needs to announce the types of services that the announcing terminal device can provide.

[0157] As shown in FIG5 , after the announcing terminal device broadcasts the discovery message, the monitoring terminal device 1 , the monitoring terminal device 2 , the monitoring terminal device 3 , and the monitoring terminal device 4 respectively receive the discovery message.

[0158] Step 502: The monitoring terminal device determines whether to establish sidelink communication with the announcing terminal device.

[0159] In a possible implementation, after receiving the discovery message, the monitoring terminal device determines whether to establish sidelink communication with the announcing terminal device based on the relevant information of the announcing terminal device carried in the announcement message.

[0160] As shown in FIG6 , the discovery process of model B can be specifically implemented through the following steps 601 to 603 .

[0161] Step 601: A discoverer UE broadcasts a discovery message, and the discovered UE receives the discovery message.

[0162] In model B, the discovery message may be a solicitation message, which carries information on the service type required by the terminal device for discovery.

[0163] As shown in FIG6 , after the discovery terminal device broadcasts the discovery message, the discovered terminal device 1 , the discovered terminal device 2 , the discovered terminal device 3 , and the discovered terminal device 4 respectively receive the discovery message.

[0164] Step 602: The discovered terminal device determines whether to establish sidelink communication with the discovered terminal device.

[0165] As an implementation manner, the discovered terminal device determines whether it can provide the service type required by the discovered terminal device, or whether it is the opposite terminal device required by the discovered terminal device.

[0166] In one possible implementation, after receiving a discovery message, the discovered terminal device determines whether it can provide the service type required by the discovered terminal device based on the information about the service type required by the discovered terminal device carried in the discovery message. If the discovered terminal device determines that it can provide the service type required by the discovered terminal device, the discovered terminal device determines to establish sidelink communication with the discovered terminal device. Furthermore, the discovered terminal device executes the following step 603. If the discovered terminal device determines that it cannot provide the service type required by the discovered terminal device, the discovered terminal device does not need to reply to the discovered terminal device.

[0167] Step 603: The discovered terminal sends a reply message to the discovered terminal device. Correspondingly, the discovered terminal device receives the reply message from the discovered terminal device.

[0168] The reply message is used to indicate that the discovered terminal can provide the required service type for the discovered terminal device. As shown in Figure 6, if the discovered terminal device 2 and the discovered terminal device 3 determine that they can provide the required service type for the discovered terminal device, the discovered terminal device 2 and the discovered terminal device 3 will send a reply message to the discovered terminal.

[0169] It should be noted that in the discovery processes of Model A and Model B above, the discovery message carries a source layer 2 identifier and a destination layer 2 identifier, which are used by the terminal device to send or receive discovery messages. The source layer 2 identifier is an identifier assigned by the terminal device itself, and the destination layer 2 identifier is a predefined or preconfigured default identifier.

[0170] 4. Unicast connection establishment process

[0171] After the above discovery process, the terminal device may establish a unicast connection with the discovered terminal device, so that the terminal device performs unicast communication with the discovered terminal device.

[0172] In the unicast connection establishment process, the terminal device that initiates the unicast connection establishment process can be called an initiating terminal device, and the terminal device at the other end can be called a target terminal device.

[0173] As shown in FIG. 7 , the current unicast connection establishment process includes the following steps 701 to 704 .

[0174] Step 701: The initiating terminal device sends a unicast connection establishment request (direct communication request, DCR) message to the target terminal device. Correspondingly, the target terminal device receives the unicast connection establishment request message from the initiating terminal device.

[0175] Step 702: The target terminal device determines whether to establish a unicast connection with the initiating terminal device.

[0176] If the target terminal device determines to establish a unicast connection with the initiating terminal device, the target terminal device executes the following step 703. Alternatively, if the target terminal device determines not to establish a unicast connection with the initiating terminal device, the target terminal device executes the following step 704.

[0177] Step 703: The target terminal device sends a unicast connection establishment accept (DCA) message to the initiating terminal device. Correspondingly, the initiating terminal device receives the DCA message from the target terminal device.

[0178] Step 704: The target terminal device sends a reject message to the initiating terminal device. Correspondingly, the initiating terminal device receives the reject message from the target terminal device.

[0179] 5. SL User Equipment (UE) to Network (U2N) Relay

[0180] SL U2N relay, also known as sidelink UE-to-network relay, refers to a technology that allows one terminal device to communicate with a network device through another terminal device. The SL U2N relay network architecture, shown in Figure 8, includes network devices, a relay device (U2N), and a remote device. The remote device communicates with the network device through the relay device. The remote device and the relay device communicate via sidelink, using the PC5 interface. The relay device is directly connected to the network device, using the Uu interface.

[0181] SL U2N relay includes two solutions: Layer 2 and Layer 3. The protocol stack of the Layer 2 SL U2N relay (including the user plane protocol and the control plane protocol) is shown in Figure 9. Data packets from the remote device are relayed below the PDCP layer of the relay device. The relay device only maintains the relay RLC bearer, which includes the RLC layer, MAC layer, and PHY layer. In other words, there is an end-to-end PDCP layer, SDAP layer, and radio resource control (RRC) layer between the remote device and the network device, but no end-to-end RLC layer, MAC layer, and PHY layer. In the Layer 3 SL U2N relay, data packets from the remote device are forwarded at the Internet Protocol (IP) layer, which interconnects the networks of the relay device.

[0182] 5.1、Data transmission of SL U2N relay

[0183] The SRAP layer (or adaptation layer) is added to the protocol architecture of the Layer 2 SL U2N relay. The SRAP layer is used to provide radio bearer multiplexing and demultiplexing functions, that is, the function of multiplexing different end-to-end radio bearers onto the same RLC bearer, as well as the corresponding demultiplexing functions. During the multiplexing process, different radio bearers of a remote device can be multiplexed on a PC5 relay RLC channel, and radio bearers between a relay device and multiple remote devices can be multiplexed on a Uu relay RLC channel.

[0184] Taking downlink transmission between a network device and a remote device as an example, the SRAP layer of the network device can multiplex the radio bearers of one or more remote devices onto a Uu Relay RLC channel, and the data of one or more radio bearers of the remote device can also be mapped to a PC5 Relay RLC channel.

[0185] Taking uplink transmission between a network device and a remote device as an example, the SRAP layer of the remote device can map the data of multiple radio bearers of the remote device to a PC5 Relay RLC channel, and the relay device can map the data of multiple radio bearers of a remote device to a Uu Relay RLC channel.

[0186] The PC5 relay RLC channel refers to the RLC bearer between the remote device and the relay device; the Uu relay RLC channel refers to the RLC bearer between the relay device and the network device.

[0187] 6. SL User Equipment to User Equipment (UE-to-UE, U2U) relay

[0188] SL U2U relay is a technical solution for relaying communication between terminal devices through a relay device. It is used to solve the current problem of short distance between terminal devices when communicating directly through side links due to insufficient hardware capabilities of terminal devices.

[0189] Based on SL U2U relay technology, terminal devices can communicate with each other through one or more relay devices, which greatly improves the communication distance between terminal devices. The communication architecture of SL U2U relay is shown in Figure 10. Data and signaling are transmitted between terminal device 1 and terminal device 2 through a relay device. The relay device is also called a U2U relay device. Terminal device 1 and terminal device 2 can be called a remote device and a remote device at the opposite end, respectively. The terminal device that initiates the U2U relay connection is also called a source terminal device (source UE), and the terminal device that receives the relay connection is also called a target terminal device (target UE). It should be pointed out that in the system architecture shown in Figure 10, terminal device 1 and terminal device 2 can communicate with each other through one or more relay devices. Figure 10 only takes one relay device as an example for illustration.

[0190] U2U relay implementations include Layer 3-based and Layer 2-based relaying. In the Layer 3-based relaying approach, user plane data is relayed at the IP layer. The corresponding user plane protocol stack is shown in Figure 11. When relaying data packets sent from terminal device 1 to terminal device 2, the relay device must parse the data at the IP layer and determine the destination terminal device based on information such as the IP address. In the Layer 2-based relaying approach, user plane data is relayed below the PDCP layer. The user plane protocol stack and control plane protocol stack are shown in Figure 12. The relay device only maintains the relayed PC5 relay RLC channel, which includes the RLC, MAC, and PHY layers. In addition, this protocol architecture adds the SRAP layer between the RLC and PDCP layers. The SRAP layer primarily functions for bearer multiplexing and splitting, enabling the multiplexing of different sidelink radio bearers onto a single PC5 RLC bearer and the splitting of sidelink radio bearer data multiplexed on a single PC5 RLC bearer.

[0191] 7. Integrated Access and Backhaul (IAB)

[0192] IAB is used to support wireless backhaul and relay links for wireless communications, enabling flexible and dense deployment of new radio (NR) cells. The IAB system architecture is shown in Figure 13. As shown in Figure 13, the nodes in the IAB system include: IAB-node and IAB-donor. Among them, the IAB-node is used to support the access and backhaul functions of NR. The IAB-node consists of two parts: IAB-node-mobile-termination (MT) (also known as IAB-MT) and IAB-node-distributed unit (DU) (also known as IAB-DU). As a normal terminal device, the IAB-node-MT is connected to the DU or IAB-donor-DU of its parent node as a wireless transmission backhaul link. The IAB-node-DU is the pole station cell on the access side under the IAB-node, used to provide blind spot coverage and provide access for normal terminal devices or lower-level IAB-node-MT.

[0193] An IAB-donor is a gNodeB (also called a gNodeB-donor) that supports additional IAB functions and is connected to the core network through a non-IAB network, such as fiber. The IAB-donor consists of an IAB-donor central unit (CU) and an IAB-donor-DU. The IAB-donor-CU provides connectivity for the IAB-donor-DU and IAB-node-DU, while the IAB-donor-DU provides access for UEs or IAB-MTs.

[0194] The IAB node or IAB donor DU also configures a mapping configuration for data forwarding, including a mapping between (previous hop BAP address, backhaul RLC channel ID) and (next hop BAP address, backhaul RLC channel ID). The IAB node forwards data based on this mapping, including: upon receiving a data packet, the IAB node first queries the routing table to determine whether the data is its own data. If so, it delivers the data to its upper layer. If not, it delivers the data to the backhaul RLC channel corresponding to the next hop IAB node according to the mapping configuration.

[0195] The above is a brief introduction to the related technologies of this application.

[0196] In the current relay scenario, when the distance between the remote device and the network device is far and the remote device cannot access the network device through a single-hop relay device, the remote device can access the network device through a multi-hop relay device and communicate with the network device through the multi-hop relay device.

[0197] In the scenario where the remote device is connected to the network device through a multi-hop relay device, if its network architecture is similar to the existing IAB networking architecture, the remote device will be connected to a relay device, and the relay device and the network device are also connected through a relay. Each relay device is configured with the forwarding configuration of the previous hop and the next hop. When forwarding the data transmitted between the network device and the remote device, the relay device forwards the data hop by hop according to the forwarding configuration. However, in this scenario, since the remote device only establishes a direct connection with the U2N relay device of its adjacent hop, the remote device can only perceive the U2N relay device of its adjacent hop, and cannot perceive the relay devices of other hops. For example, when a link abnormality occurs on the Uu port of a relay device directly connected to the network device, it will not be able to directly inform the remote device, which may cause communication interruption of the remote device.

[0198] To solve the above technical problems, the present application provides a communication method. When the second terminal device is connected to the first terminal device through a multi-hop relay device, the first terminal device directly connected to the network device can establish a unicast connection with the second terminal device, so that the second terminal device can directly perceive the first terminal device directly connected to the network device.

[0199] The following is a detailed description of the solution provided by the embodiment of the present application. Before introducing the embodiment of the present application, the following points are explained.

[0200] In the description of this application, unless otherwise specified, " / " indicates that the objects associated before and after are in an "or" relationship, for example, A / B can represent A or B; "and / or" in this application is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural.

[0201] In the description of this application, A sending a message to B can be understood as A sending a message to B through one or more network elements.

[0202] In the description of this application, unless otherwise specified, "plurality" means two or more than two. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, and / or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0203] In addition, to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, the words "first" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. Those skilled in the art will understand that the words "first" and "second" do not limit the quantity or execution order, and the words "first" and "second" do not necessarily mean different.

[0204] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner to facilitate understanding.

[0205] It will be understood that the “embodiment” mentioned throughout the specification means that the specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, the various embodiments throughout the specification do not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It will 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. 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.

[0206] It can be understood that in this application, "when" and "if" both mean that corresponding processing will be taken under certain objective circumstances, and do not limit the time, nor do they require any judgment action when implementing it, nor do they mean that there are other limitations.

[0207] It is understood that some optional features in the embodiments of the present application may, in certain scenarios, be implemented independently of other features, such as the solution on which they are currently based, to solve corresponding technical problems and achieve corresponding effects. They may also be combined with other features in certain scenarios as needed. Accordingly, the devices provided in the embodiments of the present application may also implement these features or functions accordingly, which will not be described in detail here.

[0208] In this application, unless otherwise specified, the same or similar parts between the various embodiments can refer to each other. In the various embodiments in this application, and the various implementation methods / implementation methods / implementation methods in each embodiment, if there is no special explanation and logical conflict, the terms and / or descriptions between different embodiments and the various implementation methods / implementation methods / implementation methods in each embodiment are consistent and can be referenced to each other. The technical features in different embodiments and the various implementation methods / implementation methods / implementation methods in each embodiment can be combined to form new embodiments, implementation methods, implementation methods, or implementation methods according to their inherent logical relationships. The implementation methods of this application described below do not constitute a limitation on the scope of protection of this application.

[0209] The technical solutions provided in the embodiments of the present application can be used in various communication systems, which may be a third generation partnership project (3GPP) communication system, for example, a fourth generation (4G) long term evolution (LTE) system, a fifth generation mobile communication technology (5G) NR system, a sixth generation (6G) communication system, a vehicle to everything (V2X) system, a system of hybrid networking of LTE and NR, or a device to device (D2D) system, a machine to machine (M2M) communication system, an Internet of Things (IoT), and other next generation communication systems. Alternatively, the communication system may also be a non-3GPP communication system, which is not limited by the embodiments of the present application.

[0210] The communication method provided in the embodiments of the present application can be applied to a scenario where a second terminal device needs to access a network device via a multi-hop relay device. In this scenario, the second terminal device discovers a relay device that supports multi-hop access to the network device through a discovery process, establishes a unicast connection with the relay device, and then accesses the network device.

[0211] For example, as shown in Figure 14, which is a schematic diagram of the architecture of a communication system provided in an embodiment of the present application, the communication system includes: a first terminal device 1401, a second terminal device 1402, at least one third terminal device 1403, and a network device 1404.

[0212] Among them, second terminal device 1402 is a remote device that needs to access the network device through a multi-hop relay device. First terminal device 1401 is a relay device directly connected to network device 1404, which can also be called a U2N relay device. At least one third terminal device 1403 is a relay device between second terminal device 1402 and first terminal device 1401, used to provide relay services between first terminal device 1401 and second terminal device 1402.

[0213] In some scenarios, at least one third terminal device 1403 may be a U2U relay device, that is, a relay device that provides a relay service between terminal devices.

[0214] In some other scenarios, at least one third terminal device 1403 may establish a unicast connection with the first terminal device 1401, and then access the network device 1404 through the first terminal device 1401. In this case, the at least one third terminal device 1403 may be understood as a U2N relay device connected to the network device 1403.

[0215] In FIG14 , a second terminal device 1402 is connected to a network device 1404 via at least one third terminal device 1403 and the first terminal device 1401 in sequence.

[0216] It should be noted that the embodiments of this application are mainly described using one third terminal device as an example. Of course, the number of third terminal devices can be greater than one. In this case, the operations performed by other third terminal devices can refer to the third terminal devices described in the following embodiments of this application. They are described here uniformly and will not be repeated below.

[0217] Optionally, the terminal device involved in the present application (including the first terminal device, the second terminal device or the third terminal device, etc.) can be a user equipment (UE), access terminal, terminal unit, user station, terminal station, mobile station, mobile station, remote station, remote terminal, user terminal terminal equipment, TE), mobile device, wireless communication device, terminal agent, tablet computer (pad), handheld device with wireless communication function, computing device or other processing device connected to a wireless modem, vehicle-mounted device, vehicle-mounted transceiver unit, wearable device, or terminal device, the access terminal can be a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, a drone, a robot, a smart point of sale (POS), a customer-premises terminal device ( The terminal device may be a wireless terminal in the Internet of Things (IoT), such as a terminal in V2X (such as a vehicle-to-everything (V2X) device, a terminal in D2D communication, or a terminal in M2M communication. The terminal device may be mobile or fixed.

[0218] The embodiments of this application do not limit the form of the terminal device. The device used to implement the functions of the terminal device can be the terminal device; it can also be a device that supports 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 the embodiments of this application, the chip system can be composed of a chip or include a chip and other discrete devices.

[0219] Optionally, the network device involved in the present application (which may also be referred to as an access network device or access node, etc.) may be a device for communicating with a terminal device. The network device may be, for example, a network device in a 3GPP-related cellular system, such as a 4G or 5G mobile communication system, or a network device in a future-oriented evolution system (such as a 6G mobile communication system). Alternatively, the network device may also be a network device in an open access network (open RAN, O-RAN or ORAN), a cloud radio access network (cloud radio access network, CRAN), or a WiFi system. Alternatively, the network device may also be a network device in a communication system in which two or more of the above systems are integrated, and the embodiments of the present application do not specifically limit this.

[0220] In one possible scenario, the network device may be a base station, an evolved NodeB (eNodeB), an access point (AP), a transmission reception point (TRP), a next-generation NodeB (gNB), a next-generation base station in a 6G mobile communication system, a base station in a future mobile communication system, or an access node in a WiFi system. The network device may be a macro base station, a micro base station or an indoor station, a relay node or a donor node, or a wireless controller in a CRAN scenario. Optionally, the network device may also be a server, a wearable device, a vehicle, or an onboard device. For example, the network device in V2X technology may be a road side unit (RSU).

[0221] In another possible scenario, multiple network devices collaborate to assist the terminal in achieving wireless access, and different network nodes respectively implement part of the functions of the base station. For example, the network device can also be a centralized unit (CU), a distributed unit (DU), a CU-control plane (CP), a CU-user plane (UP), or a radio unit (RU). The CU and DU can be set separately, or they can be included in the same network element, such as a baseband unit (BBU). The RU can be included in a radio frequency device or radio frequency unit, such as a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH).

[0222] 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, the network device may be a network device or a module of a network device in an open radio access network (open RAN, ORAN) system. In the ORAN system, CU may also be referred to as open (open, O)-CU, DU may also be referred to as O-DU, CU-CP may also be referred to as O-CU-CP, CU-UP may also be referred to as O-CU-UP, and RU may also be referred to as O-RU. Any of the CU (or CU-CP, CU-UP), DU and RU in this application may be implemented by a software module, a hardware module, or a combination of a software module and a hardware module.

[0223] In the embodiments of the present application, the form of the network device is not limited. The device used to implement the function of the network device can be a network device; it can also be a device that can support the network device to implement the function, such as a chip system. The device can be installed in the network device or used in conjunction with the network device.

[0224] In one possible implementation, the network device and terminal device in the embodiment of the present application may also be referred to as a communication device, which may be a general device or a dedicated device, and the embodiment of the present application does not specifically limit this.

[0225] In one possible implementation, the relevant functions of the terminal device or network device in the embodiments of the present application can be implemented by a single device, or by multiple devices, or by one or more functional modules within a single device, and the embodiments of the present application do not specifically limit this. It is understood that the above functions can be network elements in hardware devices, software functions running on dedicated hardware, a combination of hardware and software, or virtualized functions instantiated on a platform (e.g., a cloud platform).

[0226] In one possible implementation, FIG15 is a schematic diagram of the composition of a communication device 1500 provided in an embodiment of the present application. The network device and terminal device shown in FIG14 can both adopt the composition structure shown in FIG15 or include the components shown in FIG15; alternatively, the components (e.g., chips) in the network device and terminal device shown in FIG14 can both adopt the composition structure shown in FIG15 or include the components shown in FIG15. It is understood that the communication device 1500 includes necessary means such as modules, units, elements, circuits, or interfaces, which are appropriately configured together to implement the present solution.

[0227] As shown in Figure 15 , communication device 1500 includes one or more processors 111. Processor 111 can be a general-purpose processor or a dedicated processor. For example, it can be a baseband processor or a central processing unit (CPU). The baseband processor can be used to process communication protocols and communication data, while the CPU can be used to control the communication device (e.g., a RAN node, terminal, or chip), execute software programs, and process software program data.

[0228] Optionally, in one design, the processor 111 may include a program 113 (sometimes also referred to as code or instructions), which may be executed on the processor 111 so that the communication device 1500 performs the methods described in the following embodiments.

[0229] Optionally, the communication device 1500 may include one or more memories 112 on which a program 114 (sometimes also referred to as code or instructions) is stored. The program 114 can be run on the processor 111, so that the communication device 1500 performs the method described in the following method embodiment.

[0230] Optionally, the processor 111 and / or the memory 112 may include an artificial intelligence (AI) module 117 and an AI module 118, each of which is configured to implement AI-related functions. The AI ​​module may be implemented using software, hardware, or a combination of software and hardware. For example, the AI ​​module may include an intelligent RAN intelligence controller (RIC) module. For example, the AI ​​module may be a near real-time RIC or a non-real-time RIC.

[0231] Optionally, data may be stored in the processor 111 and / or the memory 112. The processor and the memory may be provided separately or integrated together.

[0232] Optionally, the communication device 1500 may further include a transceiver 115 and / or an antenna 116. The processor 111 may also be sometimes referred to as a processing unit, and controls the communication device (e.g., a RAN node or terminal). The transceiver 115 may also be sometimes referred to as a transceiver unit, a transceiver, a transceiver circuit, or a transceiver, and is configured to implement the transceiver functions of the communication device through the antenna 116.

[0233] It should be noted that the composition structure shown in Figure 15 does not constitute a limitation on the communication device. In addition to the components shown in Figure 15, the communication device may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0234] In the embodiment of the present application, the chip system can be composed of chips, or can include chips and other discrete devices.

[0235] In addition, the actions and terms involved in the various embodiments of this application can refer to each other without limitation. The message names or parameter names in the messages exchanged between the various devices in the embodiments of this application are only examples, and other names can also be used in specific implementations without limitation.

[0236] The communication method provided in the embodiment of the present application is described below with reference to Figures 1 to 15.

[0237] It should be noted that in the following embodiments of the present application, the message names, parameter names, or information names between network elements are only examples. In other embodiments, they may also be other names. The communication method provided in this application does not make specific limitations on this.

[0238] It is understood that in the embodiments of the present application, each network element may perform some or all of the steps in the embodiments of the present application. These steps or operations are merely examples, and the embodiments of the present application may also perform other operations or variations of various operations. In addition, the steps may be performed in a different order than those presented in the embodiments of the present application, and it is possible that not all operations in the embodiments of the present application need to be performed.

[0239] Figure 16 is a flow chart of a communication method provided by an embodiment of the present application. In an embodiment of the present application, the second terminal device discovers the first terminal device through at least one third terminal device. After discovering the first terminal device, the second terminal device establishes a connection with the first terminal device and accesses the network device through the first terminal device. After accessing the network device, the second terminal device can communicate and transmit data with the network device through the first terminal device and at least one third terminal device. Below, in combination with the above-mentioned discovery process and connection establishment process, taking the establishment of a unicast connection as an example, the functions and execution actions of each device in the communication system provided by an embodiment of the present application are introduced. As shown in Figure 16, the communication method includes the following steps:

[0240] Step 1601: The first terminal device sends message 1. Correspondingly, the third terminal device receives message 1 from the first terminal device.

[0241] Among them, message 1 is used to indicate that the first terminal device supports providing a relay service between the second terminal device and the network device, and supports relaying between the first terminal device and the second terminal device through at least one third terminal device (it can be understood that message 1 is used to indicate the relay capability of the first terminal device). Alternatively, message 1 is used to indicate that the first terminal device supports providing a multi-hop relay service between the terminal device and the network device. It should be pointed out that in the embodiment of the present application, providing a relay service between the second terminal device and the network device can be understood as providing a relay service between the remote device that needs to be relayed through the relay device and the network device, rather than providing a relay service between the remote device and the network device for a specific terminal device. For example, supporting the provision of a relay service between the second terminal device and the network device can be understood as supporting the provision of a relay service between the remote device that needs to be relayed through the relay device and the network device. Requesting the provision of a relay service between the second terminal device and the network device can be understood as requesting the provision of a relay service between the remote device that needs to be relayed through the relay device and the network device, and this application does not limit this.

[0242] In one possible implementation, message 1 is used to indicate that the first terminal device supports providing a relay service between the second terminal device and the network device, and supports relaying between the first terminal device and the second terminal device through at least one third terminal device. It can be understood that message 1 carries indication information, and the indication information is used to indicate that the first terminal device supports providing a relay service between the second terminal device and the network device, and relaying between the first terminal device and the second terminal device through at least one third terminal device. Or the indication information is used to indicate that the first terminal device supports providing a multi-hop relay service between the terminal device and the network device.

[0243] Optionally, message 1 includes first indication information and / or second indication information, and the first indication information and / or the second indication information are used to indicate that the first terminal device supports providing a relay service between the second terminal device and the network device, and supports relaying between the first terminal device and the second terminal device through at least one third terminal device. For example, message 1 includes first indication information, and the first indication information is used to indicate that the first terminal device supports providing a relay service between the second terminal device and the network device, and supports relaying between the first terminal device and the second terminal device through at least one third terminal device, or the first indication information is used to indicate that the first terminal device supports providing a multi-hop relay service between the terminal device and the network device. For another example, message 1 includes second indication information, and the second indication information is used to indicate that the first terminal device supports providing a relay service between the second terminal device and the network device, and supports relaying between the first terminal device and the second terminal device through at least one third terminal device, or the first indication information is used to indicate that the first terminal device supports providing a multi-hop relay service between the terminal device and the network device. For another example, message 1 includes first indication information and second indication information, the first indication information is used to indicate that the first terminal device supports providing a relay service between the second terminal device and the network device, and the second indication information is used to indicate support for relaying between the first terminal device and the second terminal device through at least one third terminal device. Message 1 indicates through the first indication information and the second indication information that the first terminal device supports providing a relay service between the second terminal device and the network device, and supports relaying between the first terminal device and the second terminal device through at least one third terminal device. Alternatively, message 1 indicates through the first indication information and the second indication information that the first terminal device supports providing a multi-hop relay service between the terminal device and the network device. As an example, the first indication information may be a relay service code (RSC), and the second indication information may be a relay indication.

[0244] In a possible implementation, the message 1 includes one or more of the following: an identifier of the second terminal device, or an identifier of the first terminal device.

[0245] For example, Message 1 includes the identifier of the first terminal device. The first terminal device can use the identifier of the first terminal device and the above-mentioned indication information to indicate the relay capability of the first terminal device. In this case, Message 1 is used, for example, to indicate the relay capability of the first terminal device; or, for example, to indicate that the first terminal device supports providing a multi-hop relay service between the second terminal device and the network device. Alternatively, Message 1 is used to indicate a response to establish a unicast connection with the second terminal device.

[0246] Or for example, message 1 includes one or more of the following: an identifier of the second terminal device, an identifier of the first terminal device, an identifier of at least one third terminal device, or hop count information between the first terminal device and the second terminal device. The at least one third terminal device refers to all or part of the third terminal devices between the first terminal device and the second terminal device. In one possible manner, message 1 is a discovery message that is replied based on a request from the second terminal device, and is used to indicate that a multi-hop relay service is provided for the second terminal device. In another possible manner, the first terminal device requests the second terminal device to establish a unicast connection through the identifier of the second terminal device and the identifier of the first terminal device in message 1, so that the second terminal device can determine that the established unicast connection is a unicast connection between the first terminal device and the second terminal device based on the identifier of the second terminal device and the identifier of the first terminal device. At this time, message 1 is used, for example, to indicate the relay capability of the first terminal device, and to request to establish a unicast connection with the second terminal device.

[0247] Optionally, message 1 in the embodiment of the present application can also be referred to as the first message or the fourth message, which are uniformly described here and will not be repeated below.

[0248] Step 1602: The third terminal device sends message 2. Correspondingly, the second terminal device receives message 2.

[0249] Message 2 is used to indicate that the third terminal device supports providing a relay service between the second terminal device and the network device, and that the first terminal device and the second terminal device are relayed through at least one third terminal device. Alternatively, message 2 is used to indicate that the third terminal device supports providing a multi-hop relay service between the second terminal device and the network device. Alternatively, message 2 is used to indicate that the first terminal device and the third terminal device support providing a multi-hop relay service between the second terminal device and the network device.

[0250] In a possible implementation, the third terminal device receives message 1 and generates message 2 according to message 1. Thereafter, the third terminal device sends message 2. Correspondingly, the second terminal device receives message 2.

[0251] Optionally, referring to the above-mentioned message 1, message 2 may also include the above-mentioned first indication information and / or second indication information, and the first indication information and / or the second indication information are used to indicate that: the third terminal device supports providing relay services between the second terminal device and the network device, and the first terminal device supports relaying with the second terminal device through at least one third terminal device. Alternatively, the first indication information and / or the second indication information are used to indicate that: the third terminal device supports providing multi-hop relay services between the second terminal device and the network device. Alternatively, the first indication information and / or the second indication information are used to indicate that: the first terminal device and the third terminal device support providing multi-hop relay services between the second terminal device and the network device. For the specific description of the first indication information and the second indication information, please refer to the above-mentioned step 1601, which will not be repeated here.

[0252] In one possible implementation, Message 2 includes one or more of the following: an identifier of the first terminal device, an identifier of a terminal device between the first terminal device and the current third terminal device, or information about the number of hops between the first terminal device and the current third terminal device. The current third terminal device refers to the third terminal device that sent Message 2. For example, after the first terminal device broadcasts Message 1, multiple third terminal devices sequentially send Message 2 corresponding to Message 1. The third terminal devices correspond to Message 2 on a one-to-one basis. In this case, the current third terminal device may be the third terminal device corresponding to Message 2 received by the second terminal device, or the third terminal device corresponding to another Message 2.

[0253] For example, message 2 includes one or more of the following: an identifier of the first terminal device, an identifier of the terminal device between the first terminal device and the current third terminal device, or information on the number of hops between the first terminal device and the current third terminal device. At this time, message 2 is used, for example, to indicate the relay capability of the third terminal device (correspondingly, message 1 is also only used to indicate the relay capability of the first terminal device at this time); or, message 2 is used to indicate that the third terminal device supports providing a multi-hop relay service between the second terminal device and the network device (correspondingly, message 1 is also used to indicate that the first terminal device supports providing a multi-hop relay service between the terminal device and the network device); or, message 1 is also used to indicate a response to establish a unicast connection with the second terminal device (correspondingly, message 1 is also used to indicate a response to establish a unicast connection with the second terminal device).

[0254] Based on this, the second terminal device can determine the relay service capability of the first terminal device based on the identifier of the first terminal device in message 2 and the first indication information and / or the second indication information, and determine whether to select the first terminal device to establish a unicast connection based on the identifier of the terminal device between the first terminal device and the current third terminal device, or the number of hops between the first terminal device and the current third terminal device.

[0255] Alternatively, for example, Message 2 includes one or more of the following: the identifier of the second terminal device, the identifier of the first terminal device, the identifier of at least one third terminal device, or information about the number of hops between the first terminal device and the second terminal device. In this case, Message 2 is used, for example, to indicate the relay capability of the third terminal device. In one possible scenario, Message 2 is a discovery reply message, indicating that a multi-hop relay service is provided for the second terminal device. In one possible embodiment, message 2 is used to indicate the relay capability of the third terminal device and to request to establish a unicast connection with the second terminal device (correspondingly, message 1 is also used to indicate the relay capability of the first terminal device and to request to establish a unicast connection with the second terminal device); or, message 2 is used, for example, to indicate that the third terminal device supports providing a multi-hop relay service between the second terminal device and the network device and to request to establish a unicast connection with the second terminal device (correspondingly, message 1 is also used to indicate that the first terminal device supports providing a multi-hop relay service between the terminal device and the network device and to request to establish a unicast connection with the second terminal device); or, message 2 is also used to indicate the establishment of a unicast connection in response to the second terminal device and to request to establish a unicast connection with the second terminal device (correspondingly, message 1 is also used to indicate the establishment of a unicast connection in response to the second terminal device and to request to establish a unicast connection with the second terminal device).

[0256] Optionally, message 2 in the embodiment of the present application can also be referred to as the fourth message, which is uniformly explained here and will not be repeated below.

[0257] Step 1603: The second terminal device sends message 3 to the third terminal device. Correspondingly, the third terminal device receives message 3 from the second terminal device.

[0258] Message 3 is used to instruct the establishment of a unicast connection between the second terminal device and the first terminal device, wherein the unicast connection is established through at least one third terminal device.

[0259] Optionally, referring to the above-mentioned message 1, message 3 may also include the above-mentioned first indication information and / or second indication information, and the first indication information and / or second indication information indicate that the first terminal device supports providing a relay service between the second terminal device and the network device, and that the first terminal device and the second terminal device are relayed through at least one third terminal device. For a specific description of the first indication information and the second indication information, please refer to the above-mentioned step 1601 and will not be repeated here.

[0260] In a possible implementation, message 3 includes one or more of the following: an identifier of at least one of the third terminal devices, or hop count information between the first terminal device and the second terminal device.

[0261] For example, message 3 includes one or more of the following: an identifier of the second terminal device, an identifier of the first terminal device, an identifier of at least one third terminal device, or information about the number of hops between the first terminal device and the second terminal device. In this case, message 3 is used, for example, to request the establishment of a unicast connection between the second terminal device and the first terminal device (correspondingly, in this case, message 1 is used, for example, to indicate the relay capability of the first terminal device, and message 2 is used, for example, to indicate the relay capability of the first terminal device).

[0262] Alternatively, for example, Message 3 includes one or more of the following: an identifier of the second terminal device, or an identifier of the first terminal device. In this case, Message 3 is used, for example, to respond to establishing a unicast connection between the second terminal device and the first terminal device (correspondingly, in this case, Message 1 is used, for example, to indicate the relay capability of the first terminal device and, for example, to request establishing a unicast connection with the second terminal device; Message 2 is used, for example, to indicate the relay capability of the second terminal device and, for example, to request establishing a unicast connection with the second terminal device).

[0263] Optionally, message 3 in the embodiment of the present application can also be referred to as the fifth message, which is explained here uniformly and will not be repeated below.

[0264] Step 1604: The third terminal device sends message 4. Correspondingly, the first terminal device receives message 4.

[0265] Among them, message 4 is used to indicate the establishment of a unicast connection between the second terminal device and the first terminal device.

[0266] In one possible manner, message 3 and message 4 may include the same content. That is, after receiving message 3, the third terminal device directly forwards message 3 through the adaptation layer.

[0267] Optionally, referring to the above-mentioned message 1, message 4 may also include the above-mentioned first indication information and / or second indication information, and the first indication information and / or the second indication information are used to indicate that the third terminal device supports providing a relay service between the second terminal device and the network device, and supports relaying between the first terminal device and the second terminal device through at least one third terminal device. Alternatively, the first indication information and / or the second indication information are used to indicate that the third terminal device supports providing a multi-hop relay service between the second terminal device and the network device. Alternatively, the first indication information and / or the second indication information are used to indicate that the first terminal device and the third terminal device support providing a multi-hop relay service between the second terminal device and the network device. For a specific description of the first indication information and the second indication information, please refer to the above-mentioned step 1601 and will not be repeated here.

[0268] In a possible implementation, message 4 includes one or more of the following: an identifier of at least one third terminal device, or hop count information between the first terminal device and the second terminal device.

[0269] For example, message 4 includes one or more of the following: an identifier of the second terminal device, an identifier of the first terminal device, an identifier of at least one third terminal device, or information about the number of hops between the first terminal device and the second terminal device. In this case, message 4 is used, for example, to indicate the establishment of a unicast connection between the second terminal device and the first terminal device (in this case, message 1 is used, for example, to indicate the relay capability of the first terminal device, message 2 is used, for example, to indicate the relay capability of the first terminal device, and message 3 is used to request the establishment of a unicast connection between the second terminal device and the first terminal device).

[0270] Or, for example, message 4 includes one or more of the following: an identifier of the second terminal device, or an identifier of the first terminal device. In this case, message 4 is used to respond to establishing a unicast connection between the second terminal device and the first terminal device (correspondingly, in this case, message 1 is used, for example, to indicate the relay capability of the first terminal device, and, for example, to request establishing a unicast connection with the second terminal device; message 2 is used, for example, to indicate the relay capability of the second terminal device, and, for example, to request establishing a unicast connection with the second terminal device; and message 3 is used, for example, to respond to establishing a unicast connection between the second terminal device and the first terminal device).

[0271] It should be noted that the present embodiment does not limit the order in which the first terminal device sends message 1 and receives message 4. For example, the first terminal device may first send message 1 and then receive message 4; or the first terminal device may first receive message 4 and then send message 1; or the first terminal device may receive message 4 at the same time as sending message 1. This embodiment does not limit this.

[0272] For example, when a first terminal device initiates a unicast connection establishment process with a second terminal device, the first terminal device sends Message 1 to request the establishment of a unicast connection with the second terminal device. A third terminal device sends Message 2 to the second terminal device to request the establishment of a unicast connection with the second terminal device. When the second terminal device determines to establish a unicast connection with the first terminal device, the second terminal device sends Message 3 in response to establish a unicast connection with the first terminal device. The third terminal device sends Message 4 to the first terminal device in response to establish a unicast connection with the first terminal device.

[0273] For another example, when a second terminal device initiates a unicast connection establishment process with a first terminal device, the second terminal device sends Message 3 to request the establishment of a unicast connection with the first terminal device. A third terminal device sends Message 4 to the first terminal device to request the establishment of a unicast connection with the first terminal device. When the first terminal device determines to establish a unicast connection with the second terminal device, the first terminal device sends Message 1 in response to establish a unicast connection with the second terminal device. The third terminal device sends Message 2 to the second terminal device in response to establish a unicast connection with the second terminal device.

[0274] Optionally, message 4 in the embodiment of the present application can also be referred to as the fifth message or the second message, which are explained uniformly here and will not be repeated below.

[0275] The present application provides a communication method, in which a unicast connection is established between a first terminal device directly connected to a network device and a second terminal device when the second terminal device is connected to a first terminal device via a multi-hop relay, so that the second terminal device can directly perceive the first terminal device directly connected to the network device.

[0276] In one possible implementation, when message 1 is used to indicate the relay capability of the first terminal device, the first terminal device can actively send message 1 so that other terminal devices can determine the relay capability of the first terminal device based on message 1; or, the first terminal device can also send the relay capability of the first terminal device based on the request of other terminal devices.

[0277] In the case where the first terminal device sends the relay capability of the first terminal device based on the request of other terminal devices, in combination with FIG16 , as shown in FIG17 , the communication method provided in the embodiment of the present application further includes:

[0278] Step 1701: The second terminal device sends message 5. Correspondingly, the third terminal device receives message 5.

[0279] Message 5 is used to request the provision of a relay service (ie, message 5 is used to request the provision of a relay service between the second terminal device and the network device).

[0280] In a possible implementation, message 5 is used to request the provision of a relay service. It can be understood that message 5 carries indication information, and the indication information is used to request the provision of a relay service.

[0281] Optionally, message 5 includes: third indication information and / or fourth indication information; the third indication information and / or fourth indication information is used to request the provision of a relay service, and the first terminal device and the second terminal device are relayed through at least one third terminal device. For example, message 5 includes the third indication information, the third indication information is used to request the relay service (that is, to provide the relay service between the second terminal device and the network device), and the first terminal device and the second terminal device are relayed through at least one third terminal device. For another example, message 5 includes the fourth indication information, the fourth indication information is used to provide the relay service, and the first terminal device and the second terminal device are relayed through at least one third terminal device. For another example, message 5 includes the third indication information and the fourth indication information, the third indication information is used to request the provision of a relay service, and the fourth indication information is used to instruct the first terminal device and the second terminal device to relay through at least one third terminal device; message 5 uses the third indication information and the fourth indication information to jointly instruct the second terminal device to request the provision of a relay service, and the first terminal device and the second terminal device are relayed through at least one third terminal device.

[0282] As an example, the third indication information may be a relay service code, and the fourth indication information may be a relay indication. It should be noted that the relay service code corresponding to the third indication information may be the same as or different from the relay service code corresponding to the first indication information, and the relay indication corresponding to the fourth indication information may be the same as or different from the relay indication corresponding to the second indication information, and this application does not limit this.

[0283] In one possible implementation, message 5 includes one or more of the following: an identifier of the first terminal device, or an identifier of the second terminal device. Message 5 may indicate the terminal device initiating the discovery process through the identifier of the second terminal device, or may indicate the terminal device to be discovered through the identifier of the first terminal device. It should be noted that if the second terminal device has pre-determined the first terminal device to be discovered, message 5 may include the identifier of the first terminal device; if the second terminal device has not pre-determined the first terminal device to be discovered, message 5 may not include the identifier of the first terminal device.

[0284] Optionally, message 5 in the embodiment of the present application can also be referred to as the sixth message, which is explained here uniformly and will not be repeated below.

[0285] Step 1702: The third terminal device sends message 6. Correspondingly, the first terminal device receives message 6.

[0286] Message 6 is used to request the provision of relay service (ie, message 6 is used to request the provision of relay service between the second terminal device and the network device). Optionally, message 6 is also used to indicate that the third terminal device supports multi-hop relay service.

[0287] It is understandable that message 6 may also carry indication information that is the same as or similar to the indication information of message 5. For specific understanding, please refer to the indication information in the above message 5, and this application will not elaborate on this.

[0288] In one possible implementation, message 6 includes one or more of the following: an identifier of at least one third terminal device, or the number of hops between the first terminal device and the second terminal device. Message 6 is a message sent by the third terminal device to the first terminal device for discovering the first terminal device. In this message, each third terminal device that forwards the message will add its own identifier to the message or update the hop information. Therefore, the message 6 finally received by the first terminal device will include the identifier of each third terminal device, or the number of hops between the first terminal device and the second terminal device. It can be understood that in the case where there are multiple third terminal devices between the first terminal device and the second terminal device, the message 6 sent by the other terminal devices except the third terminal device connected to the first terminal device includes one or more of the following: the identifier of the third terminal device between the other third terminal device and the second terminal device, the identifier of the other third terminal device, and the number of hops between the other third terminal device and the second terminal device.

[0289] In addition, the message 6 may further include one or more of the following: an identifier of the first terminal device, or an identifier of the second terminal device.

[0290] Optionally, message 6 in the embodiment of the present application can also be referred to as the sixth message or the third message, which are explained uniformly here and will not be repeated below.

[0291] It should be pointed out that the above steps 1701-1702 are optional steps. For example, when the first terminal device sends the relay capability of the first terminal device based on the request of other terminal devices, the above steps 1701-1702 are executed. When the first terminal device actively sends the relay capability of the first terminal device, there is no need to execute the above steps 1701-1702.

[0292] The above steps 1601-step 1604 and step 1701-step 1702 are mainly related to the discovery process and the unicast establishment process. Referring to the discovery process of the SL U2U relay in the above-mentioned related technology SL U2U relay, in the embodiment of the present application, the discovery process and the unicast establishment process can also include the following three methods: method a, method b and method c, which are described in detail below.

[0293] Method a, as shown in Figure 18, the discovery process of method a can be specifically implemented through the following steps:

[0294] Step 1801: A first terminal device sends a relay capability, and a third terminal device receives the relay capability from the first terminal device.

[0295] Optionally, in method a, the relay capability sent by the first terminal device to the third terminal device can be carried in the message 1 recorded above, which is not elaborated in this application.

[0296] It should be noted that in method a, there may be multiple U2N-capable relay devices that transmit their relay capabilities to surrounding U2U relay devices (the first terminal device is one of the multiple U2N-capable relay devices). Figure 18 only uses the example of the first terminal device transmitting its relay capabilities to the third terminal device.

[0297] In a possible implementation, the first terminal device sends the relay capability in a broadcasting manner, and the third terminal devices around the first terminal device can obtain the relay capability of the first terminal device by monitoring the broadcast message.

[0298] Step 1802: The third terminal device sends an announcement message. Correspondingly, the second terminal device receives the announcement message from the third terminal device.

[0299] Optionally, in method a, the announcement message sent by the third terminal device can be carried in the message 2 recorded above, which is not elaborated in this application.

[0300] In a possible implementation, the third terminal device sends the announcement message in the form of broadcasting, and the second terminal devices around the third terminal device can obtain the announcement message by monitoring the broadcast message.

[0301] Optionally, other third-party devices in the vicinity of the third-party device can also listen to the broadcast message to obtain the announcement message, generate a new announcement message based on the content of the announcement message, and broadcast the new announcement message. The new announcement message includes the terminal device's identification and capability information from the original announcement message. In this case, the second-party device obtains the announcement message from the third-party device. Accordingly, there are multiple third-party devices. The figure only uses one third-party device as an example for illustration.

[0302] In one example, the announcement message includes a U2N relay device information list, where the U2N relay device information list includes one or more of the following: a user information identifier of the first terminal device, a user information identifier of the third terminal device between the first terminal device and the third terminal device, or information about the number of hops between the first terminal device and the third terminal device. Furthermore, the announcement message also includes one or more of the following: a relay service code, a relay indication, or a discovery message type indication.

[0303] Step 1803: The second terminal device selects the first terminal device based on the announcement information.

[0304] In one possible implementation, the second terminal device can receive announcement information broadcast from one or more third terminal devices to indicate capability information of different U2N relay devices. The second terminal device selects the first terminal device from these different U2N relay devices based on the announcement information of the capability information of different U2N relay devices.

[0305] The above is a process for the second terminal device to discover the first terminal device. After the second terminal device discovers the first terminal device, the second terminal device can establish a unicast connection with the first terminal device.

[0306] Step 1804: The second terminal device sends a first unicast connection establishment request message to the third terminal device. Correspondingly, the third terminal device receives the first unicast connection establishment request message from the second terminal device.

[0307] Optionally, in method a, the first unicast connection establishment request message sent by the second terminal device to the third terminal device can be carried in the message 3 recorded above, which is not elaborated in this application.

[0308] Step 1805: The third terminal device sends a second unicast connection establishment request message to the first terminal device. Correspondingly, the first terminal device receives the second unicast connection establishment request message from the third terminal device.

[0309] Optionally, in mode a, the second unicast connection establishment request message sent by the third terminal device to the first terminal device can be carried in the message 4 recorded above, which is not elaborated in this application.

[0310] In one possible implementation, after receiving the first unicast connection establishment request message, the third terminal device adds its user information identifier and the number of hops between the second terminal device and the first terminal device to the first unicast connection establishment request message, thereby generating a second unicast connection establishment request message. Optionally, when there are multiple third terminal devices, each third terminal device adds its own user information identifier to the unicast connection establishment request message and increments the hop count by one when forwarding the unicast connection establishment request message.

[0311] In another possible implementation, the first unicast connection establishment request message and the second unicast connection establishment request message are the same unicast connection establishment request message. In other words, after receiving the first unicast connection establishment request message, the third terminal device directly forwards the first unicast connection establishment request message without processing the first unicast connection establishment request message.

[0312] Step 1806: The first terminal device sends a unicast connection establishment reply message to the third terminal device. Correspondingly, the third terminal device receives the unicast connection establishment reply message from the first terminal device.

[0313] Step 1807: The third terminal device sends a unicast connection establishment reply message to the second terminal device. Correspondingly, the second terminal device receives the unicast connection establishment reply message from the first terminal device.

[0314] After the second terminal device receives the unicast connection establishment reply message, the unicast connection establishment between the second terminal device and the first terminal device is completed.

[0315] In one possible implementation, there may be multiple third terminal devices between the first terminal device and the second terminal device. At this time, the actions performed by each third terminal device can refer to the actions performed by the third terminal device in the above process, and this application will not go into details.

[0316] Method b, as shown in Figure 19, the discovery process of method b can be specifically implemented through the following steps:

[0317] Step 1901: The second terminal device sends a first request message. Correspondingly, the third terminal device 1 and the third terminal device 2 receive the first request message from the second terminal device.

[0318] Optionally, the first request message sent by the second terminal device in mode b may be carried in the message 5 described above, which will not be elaborated in this application.

[0319] In one possible implementation, when the second terminal device needs to discover the first terminal device (for example, discover the first terminal device 1 and the first terminal device 2), the second terminal device generates a first request message based on information such as the user information identifier of the second terminal device, the user identification information of the first terminal device, the relay service code, the relay indication, or one or more of the discovery message types. Optionally, when the second terminal device has determined the first terminal device, the user identification information of the first terminal device may be added to the first request message to facilitate the discovery of the first terminal device. Optionally, when the second terminal device is not sure of the first terminal device, the second terminal device may not add the user information identifier of the first terminal device to the first request message, and indicate through messages such as the relay service code and the relay indication that it needs to discover a relay device that can provide relay service between the second terminal device and the network device, and includes at least one third terminal device between the second terminal device and the second terminal device. After generating the first request message, the second terminal device broadcasts the first request message so that the surrounding relay devices can monitor the first request message.

[0320] In one example, the first request message sent by the second terminal device includes one or more of the following: a user information identifier of the second terminal device, a user information identifier of the first terminal device, a relay service code, a relay indication, or a discovery message type.

[0321] Step 1902: The third terminal device 1 sends a second request message. Correspondingly, the third terminal device 3 receives the second request message from the third terminal device 1.

[0322] Optionally, in mode b, the second request message sent by the third terminal device 1 can be carried in the message 6 recorded above, which is not elaborated in this application.

[0323] In one possible implementation, after receiving the first request message, third terminal device 1 determines that relay service can be provided. It then adds one or more of the user information identifier of third terminal device 1 and the current hop count information to the first request message to generate a second request message. Thereafter, third terminal device 1 broadcasts the second request message.

[0324] In one example, the second request message includes one or more of the following: a user information identifier of the second terminal device, a user information identifier of the third terminal device 1, a user information identifier of the first terminal device 1, a relay service code, a relay indicator, a relay hop indicator, or a discovery message type. The relay hop indicator is used to indicate the U2U relay device to which the request message is sent. For example, the relay hop indicator in step 1902 may have a value of 1, indicating that the first request message is sent by the U2U relay device of the first hop.

[0325] Step 1903: The third terminal device 3 sends a third request message. Correspondingly, the first terminal device 1 receives the third request message.

[0326] Optionally, in mode b, the third request message sent by the third terminal device 3 can be carried in the message 6 recorded above, which is not elaborated in this application.

[0327] In one possible implementation, after receiving the first request message, the third terminal device 3 determines that the relay service can be provided. It then adds the user information identifier of the third terminal device 3 to the second request message and modifies the relay hop count indication in the second request message (for example, by increasing the hop count by 1), thereby generating a third request message. Thereafter, the third terminal device 3 broadcasts the third request message.

[0328] In one example, the third request message includes one or more of the following: a user information identifier of the second terminal device, a user information identifier of the third terminal device 3, a user information identifier of the third terminal device 1, a user information identifier of the first terminal device 1, a relay service code, a relay indication, a relay hop indication, or a discovery message type. The relay hop indication is used to indicate the U2U relay device to which the request message is sent. For example, the relay hop indication in step 1903 may have a value of 2, indicating that the third request message is sent by the U2U relay device of the second hop.

[0329] Step 1904: The first terminal device 1 sends a first response message to the third terminal device 3. Correspondingly, the third terminal device 3 receives the first response message from the first terminal device 1.

[0330] Optionally, in mode b, the first response message sent by the first terminal device 1 to the third terminal device 3 may be carried in the message 1 described above, which will not be elaborated in this application.

[0331] In one possible implementation, after receiving the third request message, first terminal device 1 determines, based on the relay service code and relay indication in the third request message, that the third request message is for requesting a relay service between the second terminal device and the network device. If first terminal device 1 determines that it can provide the corresponding relay service for the second terminal device, it generates a first response message and sends it to third terminal device 3.

[0332] In one example, the first response message includes one or more of the following: user identification information of the first terminal device, user identification information of the second terminal device, a relay service code, a relay indication, or a discovery message type.

[0333] Step 1905: The third terminal device 3 sends a second response message to the third terminal device 1. Correspondingly, the third terminal device 1 receives the second response message from the third terminal device 3.

[0334] Optionally, in mode b, the second response message sent by the third terminal device 3 to the third terminal device 1 can be carried in the message 2 recorded above, which is not elaborated in this application.

[0335] In one possible implementation, after receiving the first response message from the first terminal device 1, the third terminal device 3 determines that the first response message is response information that needs to be forwarded to the second terminal device. The third terminal device 3 then adds the user identification information of the third terminal device 3 to the first response message to generate a second response message. The third terminal device 3 then sends the second response message to the third terminal device 1.

[0336] In one example, the second response message includes one or more of the following: user identification information of the third terminal device 3, user identification information of the first terminal device 1, user identification information of the second terminal device, a relay service code, a relay indication, or a discovery message type.

[0337] Step 1906: The third terminal device 1 sends a third response message to the second terminal device. Correspondingly, the second terminal device receives the third response message from the third terminal device 1.

[0338] Optionally, in mode b, the third request message sent by the third terminal device 3 may be carried in the message 2 described above, which will not be described in detail in this application.

[0339] In one possible implementation, after receiving the second response message from the first terminal device 3, the third terminal device 1 determines that the second response message is response information that needs to be forwarded to the second terminal device. The third terminal device 1 then adds the user identification information of the third terminal device 1 to the second response message to generate a third response message. The third terminal device 1 sends the third response message to the second terminal device.

[0340] In one example, the third response message includes one or more of the following: user identification information of the third terminal device 1, user identification information of the third terminal device 3, user identification information of the first terminal device 1, user identification information of the second terminal device, a relay service code, a relay indication, or a discovery message type.

[0341] Step 1907: The third terminal device 2 sends a fourth request message. Correspondingly, the third terminal device 4 receives the fourth request message from the third terminal device 2.

[0342] Optionally, in mode b, the fourth request message sent by the third terminal device 2 can be carried in the message 6 recorded above, which is not described in detail in this application.

[0343] In one possible implementation, after receiving the first request message, third terminal device 2 determines that relay service can be provided. It then adds one or more of the user information identifier of third terminal device 2 and the current hop count information to the first request message to generate a fourth request message. Thereafter, third terminal device 2 broadcasts the fourth request message.

[0344] In one example, the fourth request message includes one or more of the following: user information identifier of the second terminal device, user information identifier of the third terminal device 2, user information identifier of the first terminal device 2, relay service code, relay indication, relay hop indication, or discovery message type.

[0345] Step 1908: The third terminal device 4 sends a fifth request message. Correspondingly, the first terminal device 2 receives the fifth request message from the third terminal device 4.

[0346] Optionally, in mode b, the fifth request message sent by the third terminal device 4 can be carried in the message 6 recorded above, which is not elaborated in this application.

[0347] In one possible implementation, after receiving the fourth request message, the third terminal device 4 determines that it can provide relay services for the second terminal device. It then adds the user information identifier of the third terminal device 4 to the fourth request message and modifies the relay hop count indication in the fourth request message (e.g., by increasing the hop count by 1), thereby generating a fifth request message. Thereafter, the third terminal device 4 broadcasts the fifth request message.

[0348] In one example, the fifth request message includes one or more of the following: user information identifier of the second terminal device 2, user information identifier of the third terminal device 4, user information identifier of the third terminal device 2, user information identifier of the first terminal device, relay service code, relay indication, relay hop indication, or discovery message type.

[0349] Step 1909: The first terminal device 2 sends a fourth response message to the third terminal device 4. Correspondingly, the third terminal device 4 receives the fourth response message from the first terminal device 2.

[0350] Optionally, in mode b, the fourth response message sent by the first terminal device 2 to the third terminal device 4 can be carried in the message 1 recorded above, which is not elaborated in this application.

[0351] In one possible implementation, after receiving the fifth request message, first terminal device 2 determines, based on the relay service code and relay indication in the fifth request message, that the fifth request message is for requesting a relay service between the second terminal device and the network device, and that the relay device between the first terminal device and the second terminal device includes at least one third terminal device. If first terminal device 2 determines that it can provide the corresponding relay service for the second terminal device, it generates a fourth response message and sends it to third terminal device 3.

[0352] In one example, the fourth response message includes one or more of the following: user identification information of the first terminal device, user identification information of the second terminal device, a relay service code, a relay indication, or a discovery message type.

[0353] Step 1910: The third terminal device 4 sends a fifth response message to the third terminal device 2. Correspondingly, the third terminal device 2 receives the fifth response message from the third terminal device 4.

[0354] Optionally, in mode b, the fifth response message sent by the third terminal device 4 to the third terminal device 2 can be carried in the message 2 recorded above, which is not elaborated in this application.

[0355] In one possible implementation, after receiving the fourth response message from the first terminal device 2, the third terminal device 4 determines that the fourth response message is response information that needs to be forwarded to the second terminal device. The third terminal device 4 then adds the user identification information of the third terminal device 4 to the fourth response message to generate a fifth response message. The third terminal device 4 sends the fifth response message to the third terminal device 2.

[0356] In one example, the fifth response message includes one or more of the following: user identification information of the third terminal device 4, user identification information of the first terminal device, user identification information of the second terminal device, a relay service code, a relay indication, or a discovery message type.

[0357] Step 1911: The third terminal device 2 sends a sixth response message to the second terminal device. Correspondingly, the second terminal device receives the sixth response message from the third terminal device 2.

[0358] Optionally, in mode b, the sixth response message sent by the third terminal device 2 to the second terminal device can be carried in the message 2 recorded above, which is not elaborated in this application.

[0359] In one possible implementation, after receiving the fifth response message from the first terminal device 4, the third terminal device 2 determines that the fifth response message is response information that needs to be forwarded to the second terminal device. The third terminal device 2 then adds the user identification information of the third terminal device 2 to the fifth response message to generate a sixth response message. The third terminal device 2 sends the sixth response message to the second terminal device.

[0360] In one example, the third response message includes one or more of the following: user identification information of the third terminal device 2, user identification information of the third terminal device 4, user identification information of the first terminal device 2, user identification information of the second terminal device, a relay service code, a relay indication, or a discovery message type.

[0361] Step 1912: The second terminal device determines the first terminal device based on the third response message and the sixth response message.

[0362] In one possible implementation, after receiving the third and sixth response messages, the second terminal device determines, based on the third response message, that first terminal device 1 can provide relay services for the second terminal device, and determines, based on the sixth response message, that first terminal device 2 can provide relay services for the second terminal device. At this point, the second terminal device can select one of first terminal device 1 and first terminal device 2 as the first terminal device based on its own needs, network conditions, and other parameters. For example, if the second terminal device selects first terminal device 1 as the first terminal device, the second terminal device will send a unicast connection establishment request message to first terminal device 1 to establish a unicast connection between the second terminal device and first terminal device 1.

[0363] Afterwards, the first terminal device, the second terminal device, and the third terminal device perform steps similar to those described in steps 1804 to 1807 above to establish a unicast connection between the first terminal device and the third terminal device.

[0364] It should be noted that the figure only illustrates the example of two third terminal devices between the first terminal device and the second terminal device. In a specific implementation, there can be at least one third terminal device between the first terminal device and the second terminal device, and this application does not limit the number of third terminal devices.

[0365] Method c, as shown in Figure 20, the discovery process of method c can be specifically implemented by the following steps:

[0366] Step 2001: The second terminal device sends a first unicast connection establishment request message. Correspondingly, the third terminal device 1 receives the first unicast connection establishment request message from the second terminal device.

[0367] Optionally, the first unicast connection establishment request message sent by the second terminal device can be carried in the message 3 recorded above, which is not elaborated in this application.

[0368] In one example, the first unicast connection establishment request message includes one or more of the following: a user information identifier of the second terminal device, a user information identifier of the first terminal device, a relay service code, a relay indication, or security-related information. The relay service code is used to indicate a request for multi-hop relay service; the relay indication is used to indicate that the U2U relay device can forward the DCR message; and the security-related information is used to indicate a secure connection between END device 1 and the relay device.

[0369] Step 2002: The third terminal device 1 sends a second unicast connection establishment request message. Correspondingly, the third terminal device 3 receives the second unicast connection establishment request message from the third terminal device 1.

[0370] Optionally, the second unicast connection establishment request message sent by the third terminal device 1 can be carried in the message 4 recorded above, which is not elaborated in this application.

[0371] Step 2003: The third terminal device 3 sends a third unicast connection establishment request message. Correspondingly, the first terminal device 1 receives the third unicast connection establishment request message.

[0372] Optionally, the third unicast connection establishment request message sent by the third terminal device 3 can be carried in the message 4 recorded above, which is not elaborated in this application.

[0373] Step 2004: The first terminal device 1 sends a unicast connection establishment request response message to the third terminal device 3. Correspondingly, the third terminal device 3 receives the unicast connection establishment request response message from the first terminal device 1.

[0374] Optionally, the unicast connection establishment request response message sent by the first terminal device 1 to the third terminal device 3 can be carried in the message 1 recorded above, which is not elaborated in this application.

[0375] Step 2005: The third terminal device 3 sends a unicast connection establishment request response message to the third terminal device 1. Correspondingly, the third terminal device 1 receives the unicast connection establishment request response message from the third terminal device 3.

[0376] Optionally, the second unicast connection establishment request response message sent by the third terminal device 3 to the third terminal device 1 can be carried in the message 2 recorded above, which is not elaborated in this application.

[0377] Step 2006: The third terminal device 1 sends a unicast connection establishment request response message to the second terminal device. Correspondingly, the second terminal device receives the unicast connection establishment request response message from the third terminal device 1.

[0378] Optionally, the unicast connection establishment request response message sent by the first terminal device 1 to the third terminal device 3 can be carried in the message 2 recorded above, which is not elaborated in this application.

[0379] Optionally, the unicast connection establishment request response message sent by the third terminal device 2 to the second terminal device can be carried in the message 2 recorded above, which is not elaborated in this application.

[0380] Step 2007: The second terminal device determines to establish a unicast connection with the first terminal device based on the unicast connection establishment request response message.

[0381] After the second terminal device determines the first terminal device, a unicast connection is established between the second terminal device and the first terminal device.

[0382] In one possible implementation, Figure 20 illustrates an example of a second terminal device initiating a unicast connection establishment request to a first terminal device via a relay link. In a specific implementation, the second terminal device may initiate a unicast connection establishment request to the first terminal device via multiple relay links, with the first terminal device selecting one of the multiple relay links to send a unicast connection establishment request response message. This application does not impose any limitations on this.

[0383] It should be noted that Figures 18 to 20 above mainly illustrate the discovery and unicast establishment process between the second terminal device and the first terminal device. In the case where the third terminal device is a U2N relay device that is one or more hops away from the network device, the second terminal device can discover the third terminal device and determine the first terminal device connected to the third terminal device through the third terminal device, and then establish a unicast connection with the first terminal device. The process of the second terminal device discovering the third terminal device is similar to the process of the second terminal device discovering the first terminal device described above, and this application will not elaborate on this.

[0384] In conjunction with Figure 14, in some scenarios, the third terminal device is a terminal device that establishes a unicast connection with the first terminal device and then accesses the network device. The third terminal device is directly connected to the first terminal device or establishes a unicast connection through multiple relay devices. In this scenario, when the second terminal device needs to access the network device, it can access the network device by discovering the third terminal device. Specifically: the second terminal device discovers the third terminal device through the discovery process and establishes a unicast connection with the third terminal device. After the unicast connection is established between the second terminal device and the third terminal device, the second terminal device can also establish a unicast connection with the first terminal device to transmit indication information between the first terminal device and the third terminal device, including but not limited to: one or more items of the Uu RLF or paging message of the first terminal device.

[0385] In one possible implementation, the process of establishing a unicast connection between the second terminal device and the first terminal device includes: after the second terminal device and the third terminal device establish a unicast connection, the third terminal device sends the identifier of the second terminal device (such as the layer 2 identifier of the second terminal device, the user information identifier of the second terminal device) to the first terminal device. The first terminal device sends a unicast connection establishment request to the second terminal device based on the identifier of the second terminal device, and establishes a unicast connection between the second terminal device and the first terminal device. Among them, the process of the first terminal device sending a unicast connection establishment request to the second terminal device and establishing a unicast connection between the second terminal device and the first terminal device is similar to steps 1804 to 1807 of Figure 18 above, and the only difference is that the devices for sending and receiving unicast connection establishment request messages and unicast connection establishment response messages are different. The specific process can refer to the contents recorded in steps 1804 to 1807 of Figure 18 above, and this application will not go into details about it.

[0386] In another possible implementation, the process of establishing a unicast connection between the second terminal device and the first terminal device also includes: after the second terminal device and the third terminal device establish a unicast connection, the third terminal device sends the identifier of the first terminal device (such as the layer 2 identifier of the first terminal device, the user information identifier of the first terminal device) to the second terminal device. The second terminal device sends a unicast connection establishment request to the first terminal device based on the identifier of the first terminal device, and establishes a unicast connection between the second terminal device and the first terminal device. Among them, the process of the second terminal device sending a unicast connection establishment request to the first terminal device and establishing a unicast connection between the second terminal device and the first terminal device can refer to steps 1804 to 1807 of Figure 18 above, and this application will not repeat them again.

[0387] It should be noted that the process of the second terminal device discovering the third terminal device through the discovery process can be implemented by referring to the method described in Model A of FIG5 or Model B of FIG6 in the above description of the related art, and this application does not elaborate on this. The process of the second terminal device establishing a unicast connection with the third terminal device can be implemented by referring to the method described in FIG7 in the above description of the related art, and this application does not elaborate on this.

[0388] The above describes in detail the discovery process and the unicast connection establishment process in the communication method provided in the embodiment of the present application.

[0389] Figure 21 is a flow chart of a communication method provided by an embodiment of the present application. In the embodiment of the present application, after the discovery process and the connection establishment process, data can be transmitted between the first terminal device, the second terminal device, at least one third terminal device, and the network device. Below, in conjunction with the process of data transmission between the first terminal device, the second terminal device, at least one third terminal device, and the network device, the functions and actions performed by each device in the communication system provided by the embodiment of the present application are introduced, as shown in Figure 21, including the following steps:

[0390] Step 2101: The second terminal device sends a fifth data packet to the third terminal device. Correspondingly, the third terminal device receives the fifth data packet from the second terminal device.

[0391] The fifth data packet includes the first data, or the first local identifier; the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device.

[0392] Optionally, the fifth data packet further includes a first identifier, and the first identifier is used to identify the wireless bearer corresponding to the data of the second terminal device transmitted between the first terminal device and the second terminal device.

[0393] In one possible implementation, the second terminal device sends a fifth data packet according to a fifth configuration. The fifth configuration includes one or more of the following: a first local identifier, a fifth RLC channel, the first identifier, or an identifier of the second terminal device. The fifth RLC channel is a channel associated with the radio bearer corresponding to the first data packet. The fifth RLC channel is a PC5 relay RLC channel. There is a correspondence between the first identifier and the fifth RLC channel.

[0394] In a specific implementation, after the second terminal device obtains the first data, it generates a fifth data packet according to the fifth configuration. For example, the second terminal device receives the first data from an upper layer (e.g., PDCP), and the first data belongs to the first radio bearer. According to the fifth configuration, the second terminal device determines the first local identifier and the first identifier in the fifth data packet, and determines the RLC channel associated with the corresponding radio bearer of the first data (i.e., the above-mentioned fifth RLC channel) according to the fifth configuration. The second terminal device sends the fifth data packet to the third terminal device on the fifth RLC channel.

[0395] In one possible implementation, the first local identifier in the embodiment of the present application includes a first local identifier 1 (denoted as local ID1) and a first local identifier 2 (denoted as local ID2). The first local identifier 1 is used to identify the second terminal device between the second terminal device and the first terminal device; the first local identifier 2 is used to identify the first terminal device between the second terminal device and the first terminal device.

[0396] Step 2102: The third terminal device sends a first data packet to the first terminal device. Correspondingly, the first terminal device receives the first data packet from the third terminal device.

[0397] Optionally, in an embodiment of the present application, the third terminal device sends a first data packet to the first terminal device according to a third configuration. The third configuration includes one or more of the following: a first local identifier, a third RLC channel, a first identifier, or an identifier of the second terminal device. Optionally, the first data packet sent by the third terminal device to the first terminal device and the fifth data packet sent by the second terminal device to the third terminal device can be the same data packet (for example, the content of the fifth data packet and the first data packet can be the same), or can be different data packets, and this application does not limit this.

[0398] In one possible implementation, after the third terminal device receives the fifth data packet from the second terminal device on the fifth RLC channel, it parses the packet header of the fifth data packet to determine the first local identifier and / or the first identifier in the fifth data packet. The third terminal device determines the third configuration corresponding to the fifth data packet and the uplink RLC channel associated with the first identifier on the third terminal device side (which is the PC5 relay RLC channel, such as the third RLC channel) based on the first local identifier and / or the first identifier in the fifth data packet. The third terminal device sends the first data packet to the first terminal device on the RLC channel associated with the first identifier on the third terminal device side based on the third configuration corresponding to the fifth data packet.

[0399] Step 2103: The first terminal device sends a second data packet to the network device. Correspondingly, the network device receives the second data packet from the first terminal device.

[0400] The second data packet includes one or more of the following: first data, or a second local identifier; the second local identifier is used to identify the second terminal device between the first terminal device and the network device.

[0401] Optionally, the second data packet further includes a second identifier, and the second identifier is used to identify the wireless bearer corresponding to the data of the second terminal device transmitted between the network device and the first terminal device.

[0402] In one possible implementation, the network device in the embodiment of the present application may be an O-CU or a CU. In the case where the network device is an O-CU, the above step S2103 may be replaced by: the first terminal device sends a second data packet to the O-CU through the O-DU. Accordingly, the O-CU receives the first data from the first terminal device through the O-DU. In one possible manner, the first terminal device sends a second data packet to the O-DU, the O-DU obtains the first data based on the second data packet, and delivers the first data to the O-CU; or the first terminal device sends a second data packet to the O-DU, and the O-DU delivers the second data packet to the O-CU. In the case where the network device is a CU, the above step S2103 may be replaced by: the first terminal device sends the second data to the CU through the DU. Accordingly, the CU receives the first data from the first terminal device through the DU. In one possible manner, the first terminal device sends a second data packet to the DU, the DU obtains the first data based on the second data packet, and delivers the first data to the CU; or the first terminal device sends a second data packet to the DU, and the DU delivers the second data packet to the CU.

[0403] In one possible implementation, after receiving the fifth data packet, the first terminal device determines the first configuration based on the first local identifier and / or the first identifier in the fifth data packet, and the first configuration includes the second local identifier. Exemplarily, the first terminal device determines that the fifth data packet corresponds to the first radio bearer of the second terminal device based on the first local identifier and / or the first identifier in the fifth data packet, and the first terminal device determines the first configuration associated with the first radio bearer of the second terminal device. In addition, the first terminal device generates a second data packet based on the fifth data packet and the second local identifier and / or the second identifier. Further, the first terminal device sends the second data packet to the network device according to the first RLC channel indicated by the first configuration. The first configuration indicates a mapping relationship between the first RLC channel and the radio bearer corresponding to the first data. For example, the first RLC channel is a Uu relay RLC channel.

[0404] In a specific implementation method, after the first terminal device receives the fifth data packet, it parses the packet header of the fifth data packet and determines that the fifth data packet includes the first local identifier and / or the first identifier. The first terminal device determines that the first data is the wireless bearer data of the second terminal device based on the first local identifier. The first terminal device determines that the first data corresponds to the first wireless bearer of the second terminal device based on the first identifier. After that, the first terminal device determines the associated first configuration, and the first configuration includes the second local identifier of the second terminal device, the second identifier of the first wireless bearer, and the correspondence between the first wireless bearer of the second terminal device and the first RLC channel. Based on the first configuration, the first terminal device generates a second data packet, and the second data packet includes the second local identifier and the second identifier. The first terminal device sends the second data packet to the network device based on the first RLC channel associated with the second identifier.

[0405] It should be noted that, in the embodiment of the present application, the first local identifier and / or the first identifier, the second local identifier and / or the second identifier may all be in the header of the data packet.

[0406] The above describes the process of uplink data transmission between the first terminal device, the second terminal device, the third terminal device, and the network device. The following describes the process of downlink data transmission between the first terminal device, the second terminal device, the third terminal device, and the network device.

[0407] As shown in FIG. 21 , the downlink data packet forwarding process may be specifically implemented through the following steps 2104 to 2106 .

[0408] Step 2104: The network device sends a third data packet to the first terminal device. Correspondingly, the first terminal device receives the third data packet from the network device.

[0409] The third data packet includes one or more of the following: the second data, or the second local identifier; the second local identifier is used to identify the second terminal device between the first terminal device and the network device. Optionally, the third data packet also includes the second identifier.

[0410] As described above, in one possible implementation, the network device in the embodiment of the present application may be an O-CU or a CU. In the case where the network device is an O-CU, the above step S2104 may be replaced by: the O-CU sends the second data to the first terminal device through the O-DU. Accordingly, the first terminal device receives the third data packet from the O-CU through the O-DU. In one possible manner, the O-CU sends the second data to the O-DU, the O-DU generates a third data packet based on the second data, and sends the third data packet to the first terminal device. Or the O-CU sends the third data packet to the O-DU, and the O-DU sends the third data packet to the first terminal device. In the case where the network device is a CU, the above step S2104 may be replaced by: the CU sends the third data packet to the first terminal device through the DU. Accordingly, the first terminal device receives the third data packet from the CU through the DU. In one possible manner, the CU sends the second data to the DU, the DU generates a third data packet based on the second data, and sends the third data packet to the first terminal device. Or the CU sends the third data packet to the DU, and the DU sends the third data packet to the first terminal device.

[0411] Step 2105: The first terminal device sends a fourth data packet to the third terminal device. Correspondingly, the third terminal device receives the fourth data packet from the first terminal device.

[0412] The fourth data packet includes one or more of the following: second data, or a first local identifier; the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device.

[0413] Optionally, the fourth data packet also includes a first identifier.

[0414] In one possible implementation, after the first terminal device receives the third data packet from the network device, it determines the second configuration based on the second local identifier and / or the second identifier in the third data packet, and the second configuration includes the first local identifier. Exemplarily, the first terminal device determines that the third data packet corresponds to the second radio bearer of the second terminal device based on the second local identifier and / or the second identifier in the third data packet, and the first terminal device determines the second configuration associated with the second radio bearer of the second terminal device. In addition, the first terminal device generates a fourth data packet based on the third data packet and the first local identifier and / or the first identifier. Further, the first terminal device sends the fourth data packet to the third terminal device according to the second RLC channel indicated by the second configuration. The second RLC channel is a channel associated with the radio bearer corresponding to the fourth data. For example, the second RLC channel is a PC5 relay RLC channel.

[0415] In a specific implementation method, after the first terminal device receives the third data packet, it parses the third data packet and determines that the third data packet includes the second local identifier and / or the second identifier. The first terminal device determines that the second data is the wireless bearer data of the second terminal device based on the second local identifier. The first terminal device determines that the second data corresponds to the second wireless bearer of the second terminal device based on the second identifier. After that, the first terminal device determines the associated second configuration, and the second configuration includes the first local identifier of the second terminal device, the first identifier of the second wireless bearer, and the correspondence between the second wireless bearer of the second terminal device and the second RLC channel. Based on the second configuration, the first terminal device generates a fourth data packet, and the fourth data packet includes the first local identifier and the first identifier. The first terminal device sends the fourth data packet to the third terminal device based on the second RLC channel associated with the first identifier.

[0416] Step 2106: The third terminal device sends a sixth data packet to the second terminal device. Correspondingly, the second terminal device receives the sixth data packet from the third terminal device.

[0417] The sixth data packet includes one or more of the following: second data, or a first local identifier; the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device.

[0418] Optionally, the sixth data packet also includes a first identifier.

[0419] Optionally, in an embodiment of the present application, the third terminal device sends a sixth data packet to the second terminal device according to the fourth configuration. The fourth configuration includes one or more of the following: a first local identifier, a fourth RLC channel, a second identifier, or an identifier of the second terminal device. Optionally, the sixth data packet sent by the third terminal device to the first terminal device and the fourth data packet sent by the first terminal device to the third terminal device can be the same data packet (for example, the third terminal device generates a new data packet based on the fourth data packet, and the contents of the fourth data packet and the new data packet can be the same), or can be different data packets, and this application does not limit this.

[0420] In one possible implementation, after receiving the fourth data packet, the third terminal device parses the packet header of the fourth data packet to determine the first local identifier and / or the first identifier in the fourth data packet. The third terminal device determines the fourth configuration corresponding to the fourth data packet and the downlink RLC channel associated with the first identifier on the third terminal device side (which is a PC5 relay RLC channel, such as the fourth RLC channel) based on the first local identifier and / or the first identifier in the fourth data packet. The third terminal device sends a sixth data packet to the second terminal device on the downlink RLC channel associated with the first identifier on the third terminal device side based on the fourth configuration corresponding to the fourth data packet.

[0421] It should be pointed out that in the above embodiments, only a third terminal device is included between the first terminal device and the second terminal device. When the number of third terminal devices is multiple, the actions performed by each third terminal device are similar, and can be understood by referring to the actions of the above-mentioned third terminal device. This application will not go into details.

[0422] In one possible implementation, an embodiment of the present application provides a protocol stack architecture used when data is transmitted between a second terminal device and a network device. In the protocol stack used when data is transmitted between the second terminal device and the network device: the control plane protocol stack of the side link between the first terminal device and the second terminal device is shown in Figure 22, the user plane protocol stack between the network device and the second terminal device is shown in Figure 23, and the control plane protocol stack between the network device and the second terminal device is shown in Figure 24.

[0423] It should be pointed out that the data forwarding process in Figure 21 above can be based on the discovery process and connection establishment process provided in the above-mentioned embodiment of the present application, or it can be based on other processes, and the embodiment of the present application does not limit this.

[0424] During the above data forwarding process, each terminal device needs to forward the data packet according to the forwarding configuration corresponding to the data packet.

[0425] Figure 25 is a flow chart of a communication method provided by an embodiment of the present application. In this embodiment of the present application, the first terminal device, the second terminal device, and at least one third terminal device need to determine the corresponding configuration when forwarding data. Below, in conjunction with the process of the first terminal device, the second terminal device, and at least one third terminal device determining the corresponding configuration when forwarding data, the functions and actions performed by each device in the communication system provided by the embodiment of the present application are introduced, as shown in Figure 25, including the following steps:

[0426] Step 2501: The second device determines a data forwarding configuration and sends data according to the data forwarding configuration.

[0427] The second device may be the first terminal device, the second terminal device, or the third terminal device. Different terminal devices have different processes for determining data forwarding configurations, and the determined data forwarding configurations are also different, which are described below:

[0428] Configuration for the first terminal device:

[0429] The configuration of the first terminal device includes an uplink configuration for forwarding data packets uplink (such as the first configuration mentioned above), and a downlink configuration for forwarding data packets downlink (such as the second configuration mentioned above).

[0430] The uplink configuration of the first terminal device includes one or more of the following: the identifier of the second terminal device, the second local identifier, the second identifier, or the identifier of RLC channel 1. Optionally, the uplink configuration of the first terminal device can also represent the association relationship with the identifier of RLC channel 1. At this time, the process of the first terminal device performing uplink forwarding based on the uplink configuration includes: after the first terminal device receives the uplink data packet 1 (which may be a data packet sent by the third terminal device to the first terminal device), it parses the header of the data packet 1 to determine the first identifier and / or the first local identifier carried in the header of the data packet 1. The first terminal device determines that the data packet 1 is a data packet sent by the second terminal device based on the first local identifier, and determines the identifier of the second terminal device (such as the layer 2 identifier of the second terminal device). The first terminal device determines the uplink configuration including the identifier of the second terminal device, and obtains the second identifier, the second local identifier and the identifier of RLC channel 1 in the uplink configuration. The first terminal device determines data packet 2 based on data packet 1 and the second identifier and the second local identifier, and sends data packet 2 to the network device based on the RLC channel 1 associated with the second identifier, and data packet 2 includes the second identifier and the second local identifier.

[0431] The downlink configuration of the first terminal device includes one or more of the following: the identifier of the second terminal device, the identifier of the first terminal device, the first local identifier, the first identifier, or the identifier of RLC channel 2. Optionally, the downlink configuration of the first terminal device can also characterize the association relationship between the first identifier and the identifier of RLC channel 2. At this time, the process of downlink forwarding by the first terminal device based on the downlink configuration includes: after the first terminal device receives the downlink data packet 3, it parses the header of the data packet 3 to determine the second identifier and / or the second local identifier carried in the header of the data packet 3. The first terminal device determines that the data packet 3 is a data packet sent to the second terminal device based on the second local identifier, and determines the identifier of the second terminal device (such as the layer 2 identifier of the second terminal device). The first terminal device determines the downlink configuration including the identifier of the second terminal device, and obtains the first identifier, the first local identifier and the identifier of RLC channel 2 in the downlink configuration. The first terminal device determines the data packet 4 based on the data packet 3 and the first identifier and the first local identifier, and sends the data packet 4 to the third terminal device based on the RLC channel 2 associated with the first identifier, and the data packet 4 includes the first identifier and the first local identifier.

[0432] In one possible implementation, the format of data forwarded between the first terminal device and the network device is shown in FIG26 , and the format of data forwarded between the first terminal device and the second terminal device is shown in FIG27 .

[0433] Configuration for third-party terminal devices:

[0434] The configuration of the third terminal device includes an uplink configuration for forwarding data packets uplink (such as the third configuration mentioned above), and a downlink configuration for forwarding data packets downlink (such as the fourth configuration mentioned above).

[0435] The uplink configuration of the third terminal device includes one or more of the following: the identifier of the first terminal device, the identifier of the second terminal device, the identifier of the third terminal device, the first identifier, the first local identifier, or the identifier of RLC channel 3. Optionally, the uplink configuration of the third terminal device can also represent the association between the first identifier and the identifier of RLC channel 3. At this time, the process of the third terminal device performing uplink forwarding based on the uplink configuration includes: after the third terminal device receives data packet 1 (which can be a data packet sent by the second terminal device or the third terminal device of the previous hop in the uplink direction), it parses the header of data packet 1 to determine the first identifier and the first local identifier carried in the header of data packet 1. The third terminal device determines that data packet 1 is a data packet sent by the second terminal device based on the first local identifier, and determines the identifier of the second terminal device. The third terminal device determines the uplink configuration including the identifier of the second terminal device, and obtains the identifier of RLC channel 3 that has an association relationship with the first identifier in the uplink configuration. The third terminal device continues to forward data packet 1 uplink based on RLC channel 3 (for example, to the first terminal device or to the third terminal device of the next hop).

[0436] The downlink configuration of the third terminal device includes one or more of the following: the identifier of the first terminal device, the identifier of the second terminal device, the identifier of the third terminal device, the first identifier, the first local identifier, or the identifier of RLC channel 4. Optionally, the downlink configuration of the third terminal device can also characterize the association between the second identifier and the identifier of RLC channel 4. At this time, the process of the third terminal device forwarding downlink based on the downlink configuration includes: after the third terminal device receives data packet 4 (which can be a data packet sent by the first terminal device or the third terminal device of the previous hop in the downlink direction), it parses the header of data packet 4 to determine the first identifier and the first local identifier carried in the header of data packet 4. The third terminal device determines that the data packet 4 is a data packet sent by the second terminal device based on the first local identifier, and determines the identifier of the second terminal device. The third terminal device determines the downlink configuration including the identifier of the second terminal device, and obtains the identifier of the RLC channel 4 that has an association with the first identifier in the downlink configuration. The third terminal device continues to forward data packet 4 downlink based on RLC channel 4 (for example, to the second terminal device or to the third terminal device of the next hop in the downlink direction).

[0437] Configuration for the second terminal device:

[0438] Since the second terminal device is the last hop in the downlink direction, the second terminal device does not need to forward downlink to other devices. Therefore, the configuration of the second terminal device does not include downlink configuration for downlink forwarding, but only includes downlink configuration for uplink sending (such as the fifth configuration mentioned above).

[0439] The uplink configuration of the second terminal device includes one or more of the following: the identifier of the first terminal device, the identifier of the second terminal device, the first identifier, the first local identifier, and the identifier of the RLC channel 5. Optionally, the uplink configuration of the second terminal device can also characterize the association between the first identifier and the identifier of the RLC channel 5. At this time, the process of the second terminal device performing uplink transmission based on the uplink configuration includes: when the second terminal device determines that it needs to send uplink data to the network device, it obtains the uplink configuration of the second terminal device, determines the first identifier and the first local identifier in the uplink configuration of the second terminal device, and encapsulates the first identifier and the first local identifier into the header of the data packet to obtain data packet 1. The second terminal device sends data packet 1 to the third terminal device according to the RLC channel 5 that has an association relationship with the first identifier.

[0440] The data forwarding configurations of the first terminal device, the second terminal device, and the third terminal device are described in detail above.

[0441] In a possible implementation, the uplink configuration and / or downlink configuration of each of the above-mentioned terminal devices is determined based on corresponding QoS information.

[0442] For example, the uplink configuration of the first terminal device is determined based on the QoS information between the first terminal device and the network device. Optionally, the process of determining the uplink configuration information of the first terminal includes: the network device determines the QoS information between the first terminal device and the network device, and determines the uplink configuration of the first terminal device based on the QoS information; the network device sends the uplink configuration of the first terminal device to the first terminal device. In addition, the network device can also determine the configuration information of RLC channel 1 based on the QoS information between the first terminal device and the network device, and send the configuration information of RLC channel 1 to the first terminal device, so that the first terminal device configures RLC channel 1 according to the configuration information of RLC channel 1.

[0443] The downlink configuration information of the first terminal device is determined based on the QoS information between the first terminal device and an adjacent third terminal device. Optionally, the network device determines the downlink QoS information between the first terminal device and the second terminal device, and sends the downlink QoS information between the first terminal device and the second terminal device to the first terminal device. The first terminal device determines the QoS information between the first terminal device and the adjacent third terminal device based on the downlink QoS information between the first terminal device and the second terminal device, and determines the downlink configuration information of the first terminal device based on the QoS information between the first terminal device and the adjacent third terminal device. In addition, the first terminal device may also determine the configuration information of RLC channel 2 based on the QoS information between the first terminal device and the adjacent third terminal device, and configure RLC channel 2 based on the configuration information of RLC channel 2. It should be noted that after the first terminal device obtains the downlink QoS information between the first terminal device and the second terminal device, it may send the downlink QoS information between the first terminal device and the second terminal device to the adjacent terminal device; so that the adjacent terminal device determines the QoS information between the first terminal device and the adjacent third terminal device based on the downlink QoS information between the first terminal device and the second terminal device, and sends the QoS information between the first terminal device and the adjacent third terminal device to the first terminal device. The first terminal device may also obtain QoS information between the first terminal device and the adjacent third terminal device through other means, which is not limited in this application. In addition, the first terminal device may also obtain the downlink configuration information of the first terminal device and / or the configuration information of RLC channel 2 from other devices (such as network devices or adjacent terminal devices), which is not limited in this application.

[0444] The uplink configuration of the second terminal device is determined based on the uplink QoS information between the second terminal device and the next-hop terminal device in the uplink direction. Optionally, the network device determines the uplink QoS information between the first terminal device and the second terminal device, and sends the uplink QoS information between the first terminal device and the second terminal device to the second terminal device. The second terminal device determines the uplink QoS information between the second terminal device and the next-hop terminal device in the uplink direction based on the uplink QoS information between the first terminal device and the second terminal device, and determines the uplink configuration of the second terminal device based on the uplink QoS information between the second terminal device and the next-hop terminal device in the uplink direction. In addition, the second terminal device determines the configuration information of RLC channel 5 based on the uplink QoS information between the second terminal device and the next-hop terminal device in the uplink direction, and configures RLC channel 5 based on the configuration information of RLC channel 5. It should be pointed out that the embodiments of the present application do not limit the device for determining the uplink QoS information between the second terminal device and the next-hop terminal device in the uplink direction, and the device for determining the uplink configuration of the second terminal device and / or the configuration information of the RLC channel 5 based on the uplink QoS information between the second terminal device and the next-hop terminal device in the uplink direction. The device that performs these processes can be the second terminal device, the next-hop terminal device in the uplink direction of the second terminal device, or other devices, and the present application does not limit this.

[0445] The uplink configuration of the third terminal device is determined based on the uplink QoS information between the third terminal device and the next-hop terminal device in the uplink direction. Optionally, the third terminal device can obtain the uplink QoS information between the third terminal device and the next-hop terminal device in the uplink direction, and determine the uplink configuration of the third terminal device based on the uplink QoS information between the third terminal device and the next-hop terminal device in the uplink direction. In addition, the third terminal device can also determine the configuration information of RLC channel 3 based on the uplink QoS information between the third terminal device and the next-hop terminal device in the uplink direction, and configure RLC channel 3 according to the configuration information of RLC channel 3. It should be noted that the embodiment of the present application does not limit the device for determining the uplink QoS information between the third terminal device and the next-hop terminal device in the uplink direction, and the device for determining the uplink configuration of the third terminal device and / or the configuration information of RLC channel 3 based on the uplink QoS information between the third terminal device and the next-hop terminal device in the uplink direction. The device that performs these processes can be the third terminal device, or the next-hop terminal device in the uplink direction of the third terminal device, or other devices, and the present application does not limit this.

[0446] The downlink configuration of the third terminal device is determined based on the downlink QoS information between the third terminal device and the next-hop terminal device in the downlink direction. Optionally, the third terminal device can obtain the downlink QoS information between the third terminal device and the next-hop terminal device in the downlink direction, and determine the downlink configuration of the third terminal device based on the downlink QoS information between the third terminal device and the next-hop terminal device in the downlink direction. In addition, the third terminal device can also determine the configuration information of RLC channel 4 based on the downlink QoS information between the third terminal device and the next-hop terminal device in the downlink direction, and configure RLC channel 4 according to the configuration information of RLC channel 4. It should be pointed out that the embodiment of the present application does not limit the device for determining the downlink QoS information between the third terminal device and the next-hop terminal device in the downlink direction, and the device for determining the downlink configuration of the third terminal device and / or the configuration information of RLC channel 4 based on the downlink QoS information between the third terminal device and the next-hop terminal device in the downlink direction. The device that performs these processes can be the third terminal device, or the next-hop terminal device in the downlink direction of the third terminal device, or other devices, and the present application does not limit this.

[0447] With reference to Figure 14, in some scenarios, the third terminal device is a terminal device that has established a unicast connection with the first terminal device and thus accessed the network device. In this scenario, when the second terminal device needs to access the network device, it can access the network device by discovering the third terminal device. After the unicast connection is established between the second terminal device and the third terminal device, the second terminal device also establishes a unicast connection with the first terminal device.

[0448] At this time, since the second terminal device has established a unicast connection with the first terminal device and the third terminal device respectively and accessed the network device, the third terminal device has also established a unicast connection with the first terminal device and accessed the network device, and the first terminal device is a terminal device directly connected to the network device, therefore, after the second terminal device accesses the network device, the network device can obtain the parameters of each hop node between the network device and the second terminal device (including but not limited to one or more of the relay hop count or relay identifier). The network device can directly allocate QoS information, configure the relay RLC link, and configure one or more of the SRAP configurations for each hop node based on the parameters of each hop node. This application does not limit this.

[0449] In one possible implementation, the data forwarded during the data forwarding process may be signaling data related to signaling, such as an SRB0 message, an SRB1 message, or an SRB2 message; or service data related to a service, such as a DRB message. The following will describe in detail the initial access process and the RRC configuration process between the second terminal device and the network device.

[0450] As shown in FIG28 , the initial access and RRC configuration process between the first terminal device, the second terminal device, the third terminal device, and the network device can be specifically implemented by the following steps:

[0451] Step 2801: A relay link is established between the second terminal device, the third terminal device, and the first terminal device.

[0452] In one possible implementation, there may be multiple third terminal devices between the first terminal device and the second terminal device. At this time, the actions performed by each third terminal device can refer to the actions performed by the third terminal device in the above process, and this application will not go into details.

[0453] Step 2802: Configuration information for transmitting SRB0 messages (hereinafter referred to as SRB0 message transmission configuration) is configured between the second terminal device, the third terminal device, and the first terminal device. The SRB0 message includes an RRC connection establishment request message and an RRC connection establishment message.

[0454] The SRB0 message transmission configuration includes: configuration of a local ID. In addition, the SRB0 message transmission configuration may also include: configuration of a PC5 relay RLC channel and PC5 SRAP configuration. The PC5 SRAP configuration includes configuration of a mapping relationship between the SRB0 and PC5 relay RLC channels.

[0455] Regarding local identifier configuration: the third terminal device assigns a first local identifier 1 to the second terminal device based on the second terminal device's Layer 2 identifier; the third terminal device assigns a first local identifier 2 to the first terminal device based on the first terminal device's Layer 2 identifier. When the third terminal device assigns local identifiers to the second and first terminal devices, the assignment can be performed by a single third terminal device or by negotiation between all third terminal devices between the second and first terminal devices. This application does not limit this.

[0456] There are several possible ways to configure the PC5 relay RLC channel and PC5 SRAP.

[0457] In one possible approach, a dedicated or default PC5 RLC channel is used to transmit the SRB0 message. For example, the dedicated or default PC5 RLC channel corresponds to a specific logical channel (the logical channel is identified by x). In this approach, when the second terminal device receives an SRB0 message from an upper layer, it is directly delivered to the dedicated or default PC5 RLC channel. The third terminal device receives the SRB0 message from the dedicated or default PC5 RLC channel between the second terminal device and the third terminal device, and delivers the SRB0 message to the first terminal device through the dedicated or default PC5 RLC channel between the third terminal device and the first terminal device.

[0458] In another possible manner, a configured PC5 RLC channel is used to transmit the SRB0 message. The PC5 RLC channel may be configured by the network, or the terminal device may configure the PC5 RLC channel itself, for example, based on a system message or pre-configured information.

[0459] For the latter case, the second or third terminal device also needs to determine the mapping relationship between the SRB0 message and the PC5 RLC channel. This mapping relationship, for example, includes: a mapping relationship between the SRB0 message of the second terminal device and the PC5 relay RLC channel between the second terminal device and third terminal device 1; third terminal device 1 is a third terminal device connected to the second terminal device. The PC5 SRAP configuration of the third terminal device, for example, may include: a mapping relationship between the SRB0 message of the second terminal device and the previous-hop PC5 relay RLC channel of the third terminal device, and a mapping relationship between the SRB0 message of the second terminal device and the next-hop PC5 relay RLC channel of the third terminal device; the previous-hop of the third terminal device can be between two third terminal devices or between the third terminal device and the second terminal device; the next-hop of the third terminal device can be between two relay devices or between the third terminal device and the first terminal device. The PC5 SRAP configuration of the first terminal device, for example, includes: a mapping relationship between the SRB0 message of the second terminal device and the PC5 relay RLC channel between the first terminal device and third terminal device 2; third terminal device 2 is a third terminal device connected to the first terminal device.

[0460] It should be pointed out that the second terminal device, the third terminal device and the first terminal device are all configured with the relevant configuration of the above-mentioned SRB0 message, and the relevant configuration of the SRB0 message can be understood in combination with the above-mentioned uplink and downlink transmission configuration of the second terminal device, the third terminal device and the first terminal device.

[0461] Optionally, the layer 2 identifier used by the second terminal device and the first terminal device in the discovery process and the unicast establishment process is a layer 2 identifier allocated by the upper layer for the multi-hop U2N relay scenario. The second terminal device or the first terminal device can perform the discovery process and connection establishment process described in the embodiment of the present application based on the layer 2 identifier.

[0462] Step 2803: The second terminal device sends an uplink SRB0 message.

[0463] Optionally, the SRB0 message in the embodiment of the present application may be, for example, an RRC establishment request message sent by the second terminal device.

[0464] Optionally, the second terminal device sends an uplink SRB0 message based on the PC5 relay RLC channel in the above step 2802. Specifically, the second terminal device generates a first data packet, and the first data packet includes the uplink SRB0 message, the above-mentioned first local identifier 1, the first local identifier 2, and the SRB0 identifier. The first data packet is a PC5 SRAP PDU generated by the SRAP protocol layer of the second terminal device, and the above-mentioned first local identifier 1, the first local identifier 2, and the SRB0 identifier are located in the header of the PC5 SRAP PDU. In one possible implementation, if a dedicated PC5 relay RLC channel is used to carry the SRB0 message, the SRB0 identifier may not be carried in the header.

[0465] It should be noted that the identification information of the above-mentioned uplink SRB 0 message can be index 0, which is an index occupying 5 bits; or the identification information of the above-mentioned SRB 0 message is the index allocated to the second terminal device, which is not limited in this application.

[0466] Step 2804: The first terminal device sends a SUI message (SidelinkUEInformationNR message) to the network device.

[0467] The SUI message is used to request the network device to allocate a second local identifier to the second terminal device.

[0468] Optionally, the SUI message includes the layer 2 identifier of the second terminal device. Based on this, after receiving the layer 2 identifier of the second terminal device, the network device allocates a second local identifier to the second terminal device according to the layer 2 identifier of the second terminal device.

[0469] Step 2805: The network device configures a Uu configuration for transmitting an uplink SRB 0 message for the first terminal device.

[0470] The Uu configuration used to transmit the uplink SRB 0 message includes one or more of the following: a Uu relay RLC channel, a second local identifier of the second terminal device, or a mapping relationship between the uplink SRB0 and the Uu relay RLC channel.

[0471] Step 2806: The first terminal device sends an uplink SRB0 message to the network device.

[0472] In one possible manner, the first terminal device receives an uplink SRB0 message of the second terminal device from the third terminal device, and generates a second data packet, where the second data packet includes the SRB0 message, a second local identifier, and an identifier of the uplink SRB0 message.

[0473] In a specific implementation, the first terminal device receives a first data packet from a third terminal device, including a first local identifier 1, a first local identifier 2, and an SRB 0 identifier. Furthermore, the first terminal device can determine an SRB0 message based on the first data packet. Taking the first data packet as a PC5 SRAP PDU as an example, after the first terminal device receives the first data packet, it removes the header of the PC5 SRAP PDU and generates a header of the Uu SRAP PDU according to predetermined configuration information. The header of the Uu SRAP PDU includes a second local identifier and an identifier of an uplink SRB 0 message. The first terminal device delivers the Uu SRAP PDU to the Uu relay RLC channel with the mapping relationship between the uplink SRB0 message and the Uu relay RLC channel, and sends an uplink SRB0 message to the network device through the Uu relay RLC channel.

[0474] It can be understood that the SRAP header of the PC5 SRAP PDU includes the first local identifier 1, the first local identifier 2, and the identifier of the uplink SRB 0 message.

[0475] Step 2807: The network device sends a downlink SRB0 message.

[0476] The downlink SRB0 message may be, for example, an RRC connection establishment message.

[0477] In a specific implementation, the network device sends a third data packet to the first terminal device. The third data packet includes a downlink SRB 0 message, a second local identifier, and an SRB 0 identifier. The first terminal device generates a fourth data packet. The fourth data packet includes the downlink SRB 0 message, the first local identifier 1, the first local identifier 2, and the downlink SRB 0 message identifier. The first terminal device delivers the fourth data packet to the PC5 relay RLC channel corresponding to the SRB 0 message. The third data packet may be, for example, a UuSRAP PDU, and the fourth data packet may be, for example, a PC5 SRAP PDU.

[0478] The first terminal device receives a third data packet from the network device and determines an SRB0 message based on the third data packet. Taking the third data packet as an example, after receiving the third data packet, the first terminal device removes the header of the Uu SRAP PDU and generates a header of the PC5 SRAP PDU based on predetermined configuration information. The header of the PC5 SRAP PDU includes the first local identifier 1 and the first local identifier 2, as well as the identifier of the downlink SRB0 message. Based on the mapping relationship between the downlink SRB0 message and the PC5 relay RLC channel, the first terminal device delivers the PC5 SRAP PDU to the PC5 relay RLC channel with the mapping relationship, and sends the downlink SRB0 message to the third terminal device through the PC5 relay RLC channel.

[0479] In one possible implementation, the downlink SRB0 message also includes QoS information between the network device and the first terminal device. Specifically, the network device determines the QoS information of SRB1; the QoS information includes QoS information between the network device and the first terminal device, and QoS information between the first terminal device and the second terminal device. The network device carries the QoS information between the first terminal device and the second terminal device in the above-mentioned RRC establishment message and sends it to the second terminal device, so that the second terminal device configures SRBI according to the QoS information between the first terminal device and the second terminal device. In addition, the network device can also configure the SRB1 related configuration between the network device and the first terminal device based on the QoS information between the network device and the first terminal device.

[0480] Step 2808: Configuration information of the SRB1 message is configured between the second terminal device, the first terminal device, the third terminal device, and the network device.

[0481] In one possible implementation, after receiving the RRC message, the second terminal device obtains the uplink QoS information between the first terminal device and the second terminal device carried in the RRC message. The second terminal device or the third terminal device can divide the uplink QoS information of each hop between the first terminal device and the second terminal device based on the uplink QoS information between the first terminal device and the second terminal device. The device of each hop configures the PC5 relay RLC channel and the adaptation layer configuration for uplink transmission SRB1 based on the uplink QoS information of the hop.

[0482] For example, when the second terminal device divides uplink QoS information, the second terminal device can divide uplink QoS information for each hop based on the uplink QoS information between the first terminal device and the second terminal device, and the information of each hop between the first terminal device and the second terminal device.

[0483] Or, for example, when a third terminal device divides uplink QoS information, any third terminal device can divide uplink QoS information for each hop based on the uplink QoS information between the first terminal device and the second terminal device, as well as the information of each hop between the first terminal device and the second terminal device. The third terminal device at each hop can also divide uplink QoS information for the corresponding hop separately. For example, after the second terminal device obtains the uplink QoS information between the first terminal device and the second terminal device, it sends it to the third terminal device a connected to the second terminal device, and the third terminal device a divides uplink QoS information for the number of hops between the third terminal device a and the second terminal device. After that, the third terminal device a sends the remaining uplink QoS information to the next hop third terminal device b, and the third terminal device b continues to divide the uplink QoS information between the third terminal device a and the third terminal device b, and so on, until the uplink QoS information division is completed. It should be noted that the last hop third terminal device can divide uplink QoS information for two hops, namely, the uplink QoS information between it and the previous hop third terminal device, and the uplink QoS information between it and the first terminal device. Alternatively, the third terminal device a may also perform two-hop uplink QoS information division, namely, the uplink QoS information between the third terminal device a and the second terminal device a, and the uplink QoS information between the third terminal device a and the third terminal device b. In this case, the third terminal device b is responsible for dividing the uplink QoS information between the third terminal device b and the next hop after the third terminal device b. This application does not elaborate on this.

[0484] It should be noted that the network device may also configure the Uu relay RLC channel for transmitting SRB1 between the network device and the first terminal device, as well as the adaptation layer configuration, based on the QoS information between the network device and the first terminal device. In addition, the network device may also send the QoS information between the first terminal device and the second terminal device to the first terminal device for the relevant configuration of the downlink SRB1 message. The specific configuration process can refer to the above process, and this application will not repeat it in detail.

[0485] It should be pointed out that the second terminal device, the third terminal device and the first terminal device are all configured with the relevant configuration of the above-mentioned SRB1 message, and the relevant configuration of the SRB1 message can be understood in combination with the above-mentioned uplink and downlink transmission configuration of the second terminal device, the third terminal device and the first terminal device.

[0486] In another possible implementation, the first terminal device receives downlink QoS information between the first terminal device and the second terminal device sent by the network. The first terminal device and the third terminal device can divide the downlink QoS information of each hop between the first terminal device and the second terminal device based on the downlink QoS information between the first terminal device and the second terminal device. The device at each hop determines the PC5 relay RLC channel and adaptation layer configuration for downlink transmission of SRB1 based on the downlink QoS information of the hop.

[0487] When the first terminal device divides downlink QoS information, the first terminal device can divide the downlink QoS information for each hop based on the downlink QoS information between the first terminal device and the second terminal device, and the information of each hop between the first terminal device and the second terminal device.

[0488] In the case where the third terminal device divides the downlink QoS information, any third terminal device can divide the downlink QoS information for each hop based on the downlink QoS information between the first terminal device and the second terminal device, as well as the information of each hop between the first terminal device and the second terminal device. The third terminal device of each hop can also divide the downlink QoS information of the corresponding hop separately. For example, after the first terminal device obtains the downlink QoS information between the first terminal device and the second terminal device, it sends it to the third terminal device c connected to the first terminal device, and the third terminal device c divides the downlink QoS information of the number of hops between the third terminal device c and the first terminal device. After that, the third terminal device c sends the remaining downlink QoS information to the next hop third terminal device d, and the third terminal device d continues to divide the downlink QoS information between the third terminal device d and the third terminal device c, and so on, until the downlink QoS information division is completed. It should be noted that the last hop third terminal device can divide the downlink QoS information of two hops, namely the downlink QoS information between it and the previous hop third terminal device, and the downlink QoS information between it and the second terminal device. Alternatively, the third terminal device a may also perform two-hop downlink QoS information division, namely the downlink QoS information between the first terminal device and the third terminal device b. In this case, the third terminal device b is responsible for dividing the downlink QoS information between the third terminal device b and the next hop after the third terminal device b. This application does not elaborate on this.

[0489] Step 2809: The second terminal device sends an RRC establishment completion message.

[0490] Step 2810: The network device sends a first RRC reconfiguration message to the first terminal device.

[0491] The first RRC reconfiguration message is used to configure the Uu relay RLC channel, the mapping relationship between SRB2 and the Uu relay RLC channel, and the mapping relationship between DRB and the Uu relay RLC channel.

[0492] Optionally, the first RRC reconfiguration message includes QoS information of SRB2 and DRB in the downlink direction, so that the PC5 relay RLC channel configuration and PC5 SRAP configuration of SRB2 and DRB in the downlink transmission process are completed between the first terminal device, the second terminal device, and the third terminal device. The specific configuration process can refer to step 2807 or step 2808 above and will not be repeated here.

[0493] In one example, the QoS information of SRB2 and DRB in the downlink direction is the QoS information of SRB2 and DRB in the downlink direction between the first terminal device and the second terminal device.

[0494] Step 2811: The network device sends a second RRC reconfiguration message to the second terminal device.

[0495] The second RRC reconfiguration message is used to configure SRB2 and DRB.

[0496] Optionally, the second RRC reconfiguration message also includes QoS information of SRB2 and DRB in the uplink direction, so that the PC5 relay RLC channel configuration and PC5 SRAP configuration of SRB2 and DRB in the uplink transmission process are completed between the first terminal device, the second terminal device, and the third terminal device. The specific configuration process can refer to step 2807 or step 2808 above and will not be repeated here.

[0497] In one example, the QoS information of SRB2 and DRB in the uplink direction is the QoS information of SRB2 and DRB in the uplink direction between the first terminal device and the second terminal device.

[0498] It should be noted that the QoS information in the embodiments of the present application can also be understood as QoS parameters, which are used to indicate the QoS parameter requirements that should be met when transmitting radio bearers between devices (such as the second terminal device, the third terminal device, the first terminal device, or the network device). Based on the QoS information, the corresponding device can configure the channel configuration and SRAP configuration for transmitting the signaling or data corresponding to the QoS information. This application does not elaborate on this.

[0499] Step 2812: The second terminal device, the third terminal device and the first terminal device configure the configuration information of SRB2 and DRB according to the first RRC reconfiguration message and the second RRC reconfiguration message.

[0500] Optionally, the configuration information of SRB2 and DRB includes one or more of the following: PC5 relay RLC channel, or PC5 SRAP.

[0501] It should be pointed out that the second terminal device, the third terminal device and the first terminal device are all configured with the above-mentioned SRB2 and DRB message related configurations, and the above-mentioned SRB2 and DRB message related configurations can be understood in combination with the above-mentioned uplink and downlink transmission configurations of the second terminal device, the third terminal device and the first terminal device.

[0502] It should be pointed out that the configuration process in Figure 25 or Figure 28 can be applied to the discovery process and unicast connection establishment process, and / or data forwarding process provided in the above-mentioned embodiment of the present application, and can also be applied to other processes. The embodiment of the present application does not limit this.

[0503] It should be noted that the first identifier and the second identifier in the embodiment of the present application are both used to identify the radio bearer of the data packet. The first identifier and the second identifier can be the same identifier, that is, the same identifier is used in the uplink and downlink configuration of the terminal device to identify the radio bearer of the data packet. Alternatively, the first identifier and the second identifier can be different identifiers, that is, different identifiers are used in the uplink and downlink configuration of the terminal device to identify the radio bearer of the data packet.

[0504] It can be understood that when executing the communication method recorded in the embodiments of the present application, all the process steps in the above embodiments can be executed, or some of the process steps in the above embodiments can be executed. The embodiments of the present application do not limit this.

[0505] It should be noted that the identifier of the terminal device in the embodiment of the present application can be, for example, the user information identifier (user Info ID) of the relay device. Through the user Info ID, the capabilities of the relay device can be identified, such as whether the relay device supports U2U relay, whether it supports U2N relay, etc., and this application does not limit this. In other words, in the embodiment of the present application, the identifier of the first terminal device can be understood as the user information identifier of the first terminal device, the identifier of the second terminal device can be understood as the user information identifier of the second terminal device, the identifier of the third terminal device can be understood as the user information identifier of the third terminal device, and the identifier of the fourth terminal device can be understood as the user information identifier of the fourth terminal device.

[0506] The above primarily describes the solutions provided by the embodiments of the present application from the perspective of interaction between network elements. Accordingly, the embodiments of the present application also provide a communication device for implementing the various methods described above. The communication device may be the first terminal device in the method embodiments described above, or a device including the first terminal device, or a component usable for the first terminal device; or the communication device may be the second terminal device in the method embodiments described above, or a device including the second terminal device, or a component usable for the second terminal device; or the communication device may be the third terminal device in the method embodiments described above, or a device including the third terminal device, or a component usable for the third terminal device; or the communication device may be the network device in the method embodiments described above, or a device including the network device, or a component usable for the network device. It will be understood that, to implement the aforementioned functions, the communication device includes hardware structures and / or software modules corresponding to the respective functions. Those skilled in the art will readily appreciate that, in conjunction with the various exemplary units and algorithm steps described in the embodiments disclosed herein, the present application can be implemented in hardware or a combination of hardware and computer software. Whether a function is implemented in hardware or in a hardware-driven manner by computer software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0507] In the embodiment of the present application, the communication device can be divided into functional modules according to the above method embodiment. For example, each functional module can be divided according to each function, or two or more functions can be integrated into one processing module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. It should be understood that the division of modules in the embodiment of the present application is schematic and is only a logical functional division. In actual implementation, there may be other division methods.

[0508] For example, FIG29 is a schematic diagram of a communication device 2900 provided in an embodiment of the present application, which includes a transceiver module 2910 and optionally a processing module 2920. The transceiver module 2910, which may also be referred to as a transceiver unit, is used to implement transceiver functions and may be, for example, a transceiver circuit, a transceiver, a transceiver, or a communication interface.

[0509] Taking the communication device 2900 as the first terminal device described in the above method embodiment as an example, in a possible implementation manner:

[0510] Transceiver module 2910 is configured to send a first message indicating that a relay service between the second terminal device and the network device is supported, and that relay between the first terminal device and the second terminal device is performed via at least one third terminal device. Transceiver module 2910 is further configured to receive a second message indicating that a unicast connection is established between the second terminal device and the first terminal device; the unicast connection is established via the at least one third terminal device.

[0511] Taking the communication device 2900 as the second terminal device or the third terminal device described in the above method embodiment as an example, in a possible implementation manner:

[0512] Transceiver module 2910 is configured to receive a fourth message indicating that a relay service between the second terminal device and the network device is supported, and that relay between the first terminal device and the second terminal device is performed via at least one third terminal device. Transceiver module 2910 is further configured to send a fifth message indicating that a unicast connection is established between the second terminal device and the first terminal device; the unicast connection is established via the at least one third terminal device.

[0513] Taking the communication device 2900 as the third terminal device described in the above method embodiment as an example, in one possible implementation manner:

[0514] Transceiver module 2910 is further configured to send a fourth message indicating that a relay service between the second terminal device and the network device is supported, and that relay between the first terminal device and the second terminal device is performed via at least one third terminal device. Transceiver module 2910 is further configured to receive a fifth message indicating establishment of a unicast connection between the second terminal device and the first terminal device; the unicast connection is established via the at least one third terminal device.

[0515] Taking the communication device 2900 as the network terminal device described in the above method embodiment as an example, in a possible implementation manner:

[0516] The processing module 2920 is configured to obtain QoS information between the first terminal device and the second terminal device. The transceiver module 2910 is configured to send QoS information between the first terminal device and the second terminal device.

[0517] Taking the communication device 2900 as the first terminal device described in the above method embodiment as an example, in another possible implementation manner:

[0518] Processing module 2920 is configured to determine a first configuration, the first configuration including a second local identifier, for sending a second data packet, the second data packet including one or more of the following: first data or a second local identifier; the second local identifier is used to identify the second terminal device between the first terminal device and the network device, and the first and second terminal devices are relayed via at least one third terminal device. Transceiver module 2910 is configured to send the second data packet according to the first configuration.

[0519] Taking the communication device 2900 as the first terminal device described in the above method embodiment as an example, in another possible implementation manner:

[0520] Processing module 2920 is configured to determine a second configuration, the second configuration including a first local identifier, for sending a fourth data packet; the fourth data packet includes one or more of the following: second data or the first local identifier; the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device, and the first terminal device and the second terminal device are relayed via at least one third terminal device. Transceiver module 2910 is configured to send the fourth data packet according to the second configuration.

[0521] Taking the communication device 2900 as the second terminal device or the third terminal device described in the above method embodiment as an example, in another possible implementation manner:

[0522] Processing module 2920 is configured to determine a third configuration, the third configuration including a first local identifier, for sending a first data packet. The first data packet includes one or more of the following: first data or a first local identifier; the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device, and the first terminal device and the second terminal device are relayed via at least one third terminal device. Transceiver module 2910 is configured to send the first data packet according to the third configuration.

[0523] Taking the communication device 2900 as the second terminal device or the third terminal device described in the above method embodiment as an example, in another possible implementation manner:

[0524] Processing module 2920 is configured to determine a fourth configuration, the fourth configuration including a first local identifier, for sending a fourth data packet, the fourth data packet including one or more of the following: first data or a first local identifier; wherein the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device, and the first terminal device and the second terminal device are relayed via at least one third terminal device. Transceiver module 2910 is configured to send the fourth data packet according to the fourth configuration.

[0525] All relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module and will not be repeated here. Optionally, the communication device 2900 may further include a storage module 2930, which can be used to store instructions and / or data, and the processing module 2920 can read the instructions and / or data in the storage module 2930.

[0526] In the embodiment of the present application, the communication device 2900 is presented in the form of various functional modules divided in an integrated manner. The "module" here can refer to a specific ASIC, circuit, processor and memory that executes one or more software or firmware programs, integrated logic circuit, and / or other devices that can provide the above functions. In a simple embodiment, those skilled in the art can imagine that the communication device can take the form of the communication device 1500 shown in Figure 15.

[0527] For example, the processor 111 in the communication device 1500 shown in FIG15 may call computer-executable instructions stored in the memory 112 to enable the communication device 1500 to execute the communication method in the above method embodiment.

[0528] Specifically, the functions / implementation processes of the transceiver module 2910 and the processing module 2920 in FIG29 can be implemented by the processor 111 in the communication device 1500 shown in FIG15 calling computer-executable instructions stored in the memory 112. Alternatively, the functions / implementation processes of the processing module 2920 in FIG29 can be implemented by the processor 111 in the communication device 1500 shown in FIG15 calling computer-executable instructions stored in the memory 112, and the functions / implementation processes of the transceiver module 2910 in FIG29 can be implemented by the transceiver 115 in the communication device 1500 shown in FIG15.

[0529] Since the communication device provided in the embodiment of the present application can execute the above-mentioned communication method, the technical effects that can be obtained can be referred to the above-mentioned method embodiment and will not be repeated here.

[0530] It should be understood that one or more of the above modules or units can be implemented by software, hardware, or a combination of the two. When any of the above modules or units is implemented in software, the software exists in the form of computer program instructions and is stored in a memory, and a processor can be used to execute the program instructions and implement the above method flow. The processor can be built into an SoC (system on chip) or an ASIC, or it can be an independent semiconductor chip. In addition to the core used to execute software instructions to perform calculations or processing within the processor, it can further include necessary hardware accelerators, such as field programmable gate arrays (FPGAs), PLDs (programmable logic devices), or logic circuits that implement dedicated logic operations.

[0531] When the above modules or units are implemented in hardware, the hardware can be any one or any combination of a CPU, a microprocessor, a digital signal processing (DSP) chip, a microcontroller unit (MCU), an artificial intelligence processor, an ASIC, a SoC, an FPGA, a PLD, a dedicated digital circuit, a hardware accelerator or a non-integrated discrete device, which can run the necessary software or not rely on the software to execute the above method flow.

[0532] Optionally, an embodiment of the present application further provides a communication device (for example, the communication device may be a chip or a chip system), which includes a processor for implementing the method in any of the above method embodiments. In one possible design, the communication device also includes a memory. The memory is used to store necessary program instructions and data, and the processor can call the program code stored in the memory to instruct the communication device to execute the method in any of the above method embodiments. Of course, the memory may not be in the communication device. When the communication device is a chip system, it may be composed of a chip, or it may include a chip and other discrete devices, which is not specifically limited in the embodiment of the present application.

[0533] Optionally, an embodiment of the present application also provides a computer-readable storage medium, which stores a computer program or instruction. When the computer program or instruction is run on a communication device, the communication device can execute the method described in any of the above method embodiments or any of its implementation methods.

[0534] Optionally, an embodiment of the present application further provides a communication system, which includes the network device described in the above method embodiment and the terminal device described in the above method embodiment.

[0535] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware, or any combination thereof. When implemented using a software program, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions according to the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more media integrated therein. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (eg, a solid state disk (SSD)).

[0536] Although the present application is described herein in conjunction with various embodiments, in the process of implementing the claimed application, those skilled in the art may understand and implement other variations of the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0537] Although the present application has been described with reference to specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the scope of the present application. Accordingly, this specification and the drawings are merely illustrative of the present application as defined by the appended claims and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, those skilled in the art may make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, the present application is intended to include such modifications and variations as fall within the scope of the claims of the present application and their equivalents.

Claims

1. A communication method, characterized in that, Applied to a first terminal device, the method includes: Sending a first message, where the first message is used to indicate: supporting providing a relay service between the second terminal device and a network device, and relaying between the first terminal device and the second terminal device through at least one third terminal device; Receiving a second message, where the second message is used to indicate establishing a unicast connection between the second terminal device and the first terminal device; wherein, the unicast connection is established through the at least one third terminal device.

2. The method according to claim 1, wherein The first message is used to indicate, including: The first message includes first indication information and / or second indication information, and the first indication information and / or second indication information are used to indicate: supporting providing the relay service for the second terminal device, and relaying between the first terminal device and the second terminal device through the at least one third terminal device.

3. The method according to claim 1 or 2, characterized in that The second message includes one or more of the following: the identifier of the at least one third terminal device, or the hop count information between the first terminal device and the second terminal device.

4. The method according to any one of claims 1 to 3, characterized in that, The second message includes: first indication information and / or second indication information, and the first indication information and / or second indication information are used to indicate: supporting providing the relay service for the second terminal device, and relaying between the first terminal device and the second terminal device through the at least one third terminal device.

5. The method according to any one of claims 1-4, characterized in that, The method further includes: Receiving a third message; the third message is used to request providing the relay service.

6. The method according to claim 5, wherein The third message includes one or more of the following: the identifier of the at least one third terminal device, or the hop count information between the first terminal device and the second terminal device.

7. The method according to claim 5 or 6, characterized in that, The third message includes: third indication information and / or fourth indication information; the third indication information and / or fourth indication information are used to request providing the relay service, and relaying between the first terminal device and the second terminal device through the at least one third terminal device.

8. The method according to any one of claims 1-7, characterized in that, The method further includes: Receiving a first data packet; the first data packet includes one or more of the following: first data or a first local identifier; the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device; Sending a second data packet to the network device; the second data packet includes one or more of the following: the first data, or a second local identifier; the second local identifier is used to identify the second terminal device between the first terminal device and the network device.

9. The method according to claim 8, wherein The method further includes: Determining a first configuration, where the first configuration includes the second local identifier, and the first configuration is used to send the second data packet.

10. The method according to claim 9, wherein Sending the second data packet to the network device: Based on the first RLC channel indicated in the first configuration, sending the second data packet to the network device, and the first RLC channel is a channel associated with the radio bearer corresponding to the first data.

11. The method according to any one of claims 1-10, characterized in that, The method further includes: Receive a third data packet from the network device; the third data packet includes one or more of the following: second data, or a second local identifier; the second local identifier is used to identify the second terminal device between the first terminal device and the network device. Send a fourth data packet; the fourth data packet includes one or more of the following: the second data, or a first local identifier; the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device.

12. The method according to claim 14, characterized in that, The method further includes: Determine a second configuration, the second configuration includes the first local identifier, and the second configuration is used to send the fourth data packet.

13. The method according to claim 12, characterized in that, The sending of the fourth data packet includes: Based on a second RLC channel indicated in the second configuration, send the fourth data packet, where the second RLC channel is a channel associated with a radio bearer corresponding to the fourth data.

14. The method according to claim 12 or 13, characterized in that, The second configuration is a configuration determined based on downlink QoS information between the first terminal device and an adjacent terminal device.

15. The method according to any one of claims 12 - 14, characterized in that, The determining of the second configuration includes: Receive downlink QoS information between the first terminal device and the second terminal device; Determine the second configuration based on the downlink QoS information between the first terminal device and the second terminal device.

16. The method according to claim 15, wherein The determining the second configuration based on the downlink QoS information between the first terminal device and the second terminal device includes: Based on the downlink QoS information between the first terminal device and the second terminal device, determine the downlink QoS information between the first terminal device and the adjacent terminal device; Based on the downlink QoS information between the first terminal device and the adjacent terminal device, determine the second configuration.

17. A communication method, characterized in that, Applied to a first device, the first device includes a second terminal device or a third terminal device; the method includes: Receive a fourth message, the fourth message is used to indicate: support for providing a relay service between the second terminal device and the network device, and the first terminal device and the second terminal device are relayed through at least one of the third terminal devices. Send a fifth message, the fifth message is used to indicate the establishment of a unicast connection between the second terminal device and the first terminal device; wherein, the unicast connection is established through at least one of the third terminal devices.

18. The method according to claim 17, wherein The fourth message is used to indicate, including: The fourth message includes first indication information and / or second indication information, the first indication information and / or second indication information are used to indicate: support for providing the relay service for the second terminal device, and the first terminal device and the second terminal device are relayed through at least one of the third terminal devices.

19. The method according to claim 17 or 18, characterized in that The fifth message includes one or more of the following: an identifier of at least one of the third terminal devices, or hop count information between the first terminal device and the second terminal device.

20. The method according to any one of claims 17-19, characterized in that, The fifth message includes: first indication information and / or second indication information, where the first indication information and / or the second indication information are used to indicate: support for providing the relay service for the second terminal device, and relaying between the first terminal device and the second terminal device through the at least one third terminal device.

21. The method according to any one of claims 17-20, characterized in that, The method further includes: Sending a sixth message; the sixth message is used to request the provision of the relay service.

22. The method according to claim 21, wherein The sixth message includes: third indication information and / or fourth indication information; the third indication information and / or the fourth indication information are used to request the provision of the relay service, and relaying between the first terminal device and the second terminal device through the at least one third terminal device.

23. The method according to claim 21 or 22, characterized in that The method is applied to a fourth terminal device, and the sixth message includes one or more of the following: an identifier of the fourth terminal device, identifiers of one or more third terminal devices between the fourth terminal device and the second terminal device, or hop count information between the fourth terminal device and the second terminal device, where the fourth terminal device is one of the at least one third terminal device.

24. The method according to any one of claims 17-23, characterized in that, The method further includes: Sending a first data packet; the first data packet includes one or more of the following: first data, or a first local identifier; the first local identifier is used to identify the first terminal device and / or the second terminal device between the second terminal device and the first terminal device.

25. The method according to claim 24, wherein The method is applied to a fourth terminal device, and the fourth terminal device is one of the at least one third terminal device; the method further includes: Receiving the fifth data packet.

26. The method according to claim 24 or 25, characterized in that, The method further includes: Determining a third configuration, where the first configuration includes the first local identifier, and the third configuration is used to send the first data packet.

27. The method according to claim 26, wherein The sending of the first data packet includes: Sending the first data packet based on a third RLC channel indicated in the third configuration; the third RLC channel is a channel associated with a radio bearer corresponding to the first data.

28. A communication device, characterized in that, Includes: Functional units for performing the functions of the method according to any one of claims 1-27; wherein the actions performed by the functional units are implemented by hardware or by hardware executing corresponding software.

29. A communication device, characterized in that, Includes: A processor; The processor is connected to a memory, and the memory is used to store computer execution instructions. The processor executes the computer execution instructions stored in the memory so that the communication device implements the method according to any one of claims 1-27.

30. A computer-readable storage medium, characterized in that, Includes instructions that, when run on a computer, cause the computer to execute the method according to any one of claims 1-27.

31. A chip, characterized in that, The chip includes a processor; the processor is connected to a memory, and the memory is used to store computer execution instructions. The processor executes the computer execution instructions stored in the memory so that the communication device implements the method according to any one of claims 1-27.

32. A computer program product comprising instructions, characterized in that, When running on a communication device, it causes the communication device to implement the method according to any one of claims 1-27.

33. A communication system, characterized in that, The communication system includes a first terminal device as described in any one of claims 1-16 and a first device as described in any one of claims 17-27.

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