Relay communication method and device

Abstract

The invention provides a communication method and device. Before a source terminal establishes unicast connection with a first target terminal, the source terminal allocates a first identifier to the first target terminal according to a request of a relay terminal. The bit length of the first identifier is less than or equal to 8 bits. A source terminal sends first data to a first target terminal, a first identifier is configured in the first data, and a relay terminal forwards the first data to the first target terminal for the source terminal according to the first identifier. According to the scheme, the source terminal can send the message to the specific target terminal based on the first identifier, and communication between the source terminal and the specific target terminal can be realized under the condition that the unicast connection between the source terminal and the relay terminal is multiplexed; the bit length of the first identifier is less than or equal to 8 bits, so that the signaling overhead can be saved.

Description

Technical Field

[0001] The present application relates to the field of wireless communications, and more specifically, to a relay communication method and device. Background Art

[0002] In order to promote the coverage enhancement or capacity improvement of the side link, the user equipment (UE) to UE relay technology can be used, that is, the technology of the source UE communicating with the target UE through the relay UE. Specifically, when the source UE and multiple target UEs transmit data and signaling through the relay UE, how to reduce the overhead of the air interface resources between the source UE and the relay UE is a technical problem to be solved by this application. Summary of the invention

[0003] The present application provides a relay communication method and device, which can save air interface resources.

[0004] In the first aspect, a relay communication method is provided, which can be executed by a relay terminal, or can also be executed by a component of the relay terminal. The method includes: receiving a first unicast connection establishment request message from a source terminal; sending a second unicast connection establishment request message to the first target terminal, requesting to establish a unicast connection between the relay terminal and the first target terminal; receiving a second unicast connection establishment acceptance message from the first target terminal, used to indicate that the first target terminal has accepted the unicast connection establishment request between the relay terminal and the first target terminal; sending an identifier allocation request message to the source terminal, requesting the source terminal to allocate an identifier to the first target terminal; receiving an identifier allocation response message from the source terminal, the identifier allocation response message including a first identifier but not including the layer 2 address of the first target terminal, the bit length of the first identifier being less than or equal to 8 bits, and the first identifier being used to identify the first target terminal; receiving a third unicast connection establishment request from the source terminal; The method comprises: receiving a first unicast connection establishment request message to request to establish a unicast connection between the source terminal and the first target terminal; sending a fourth unicast connection establishment request message to the first target terminal to request to establish a unicast connection between the source terminal and the first target terminal; receiving a fourth unicast connection establishment acceptance message from the first target terminal to indicate that the first target terminal has accepted the unicast connection establishment request between the source terminal and the first target terminal; sending a third unicast connection establishment acceptance message to the source terminal to indicate that the first target terminal has accepted the unicast connection establishment request between the source terminal and the first target terminal, the third unicast connection establishment acceptance message including the first identifier; receiving a first data packet from the source terminal, the first data packet including the first identifier and first data; and sending the first data to the first target terminal according to the first identifier.

[0005] In a possible implementation manner, the identifier allocation request message here may also be used to indicate that a unicast connection has been established between the relay terminal and the first target terminal.

[0006] In another possible implementation, the relay terminal does not perform the above step of "receiving an identifier allocation response message from the source terminal", and the third unicast connection establishment request message received by the relay terminal from the source terminal includes a first identifier but does not include the layer 2 address of the first target terminal, the bit length of the first identifier is less than or equal to 8 bits, and the first identifier is used to identify the first target terminal.

[0007] Based on the above scheme, before the source terminal establishes a unicast connection with the first target terminal, the relay terminal requests the source terminal to allocate an identifier for the first target terminal, and the bit length of the first identifier allocated by the source terminal to the first target terminal is less than or equal to 8 bits. The source terminal sends data to the first target terminal, carrying the first identifier. In the above scheme, the relay terminal forwards the message from the source terminal to the first target terminal according to the first identifier allocated by the source terminal, and the source terminal can communicate with a specific target terminal while multiplexing the unicast connection between the source terminal and the relay terminal; the bit length of the first identifier is less than or equal to 8 bits, which can save signaling overhead.

[0008] In one possible implementation, the method also includes: receiving a third security activation command message from the first target terminal; sending the fourth security activation command message to the source terminal, the fourth security activation command message including the first identifier, used to indicate that the fourth security activation command message comes from the first target terminal; receiving a fourth security activation completion message from the source terminal, the fourth security activation completion message including the first identifier, used to indicate that the fourth security activation completion message is sent to the first target terminal; sending a third security activation completion message to the first target terminal.

[0009] In combination with the first aspect, in certain implementations of the first aspect, the method further includes: receiving a second data packet from the source terminal, the second data packet including a second identifier, second data and a layer 2 address of the relay terminal, the first data packet also including the layer 2 address of the relay terminal.

[0010] Exemplarily, the second identifier is used to identify the second target terminal, and the second data is data sent by the source terminal to the second target terminal based on the relay terminal. The target layer 2 addresses of the first data packet and the second data packet are both the layer 2 addresses of the relay terminal. It can be understood that the source terminal can send data to the first target terminal and the second target terminal respectively based on the relay terminal, and the first data packet and the second data packet are carried on the same unicast connection between the source terminal and the relay terminal, or in other words, the unicast connection between the source terminal and the relay terminal is multiplexed.

[0011] The above scheme reuses the unicast connection between the source terminal and the relay terminal, so that the source terminal can communicate with multiple target terminals through the same relay terminal, thereby saving air interface overhead.

[0012] In a possible implementation manner, sending the first data to the first target terminal according to the first identifier includes: sending the first data packet to the first target terminal according to the first identifier.

[0013] In a possible implementation, the method further includes: receiving a third data packet from the first target terminal, the third data packet including third data and the first identifier; and sending the third data packet to the source terminal according to the first identifier.

[0014] In a possible implementation manner, the method further includes: sending a first identifier to the first target terminal.

[0015] The above scheme sends the first identifier to the first target terminal through the relay terminal, so that when the source terminal sends data to the first target terminal based on the relay terminal, the protocol data unit format of the two unicast connection transmissions between the source terminal to the relay terminal and the relay terminal to the first target terminal is consistent, and forward compatibility can be achieved.

[0016] In a possible implementation, the method also includes: receiving fourth data from the first target terminal; configuring the first identifier for the fourth data according to the association relationship to obtain a fourth data packet; sending the fourth data packet to the source terminal, the fourth data packet including the fourth data and the first identifier.

[0017] In the above solution, the first identifier is sent to the first target terminal through the relay terminal, so that when the first target terminal sends data to the source terminal based on the relay terminal, the first identifier can also be included to achieve forward compatibility.

[0018] In a second aspect, a relay communication method is provided, which is a method executed by a source terminal corresponding to the method of the first aspect, and thus can also achieve the beneficial effects that can be achieved by the method of the first aspect. The method can also be executed by components of the source terminal. The method comprises: sending a first unicast connection establishment request message to a relay terminal; receiving a first unicast connection establishment acceptance message from the relay terminal, used to indicate that the first target terminal has accepted the unicast connection establishment request between the relay terminal and the first target terminal; receiving an identifier allocation request message from the relay terminal, the identifier allocation request message being used to request the source terminal to allocate an identifier to the first target terminal; sending an identifier allocation response message to the relay terminal, the identifier allocation response message comprising a first identifier but not comprising a layer 2 address of the first target terminal, the bit length of the first identifier being less than or equal to 8 bits, the first identifier being used for the source terminal and the relay terminal to identify the first target terminal; sending a third unicast connection establishment request message to the relay terminal, requesting to establish a unicast connection between the source terminal and the first target terminal; receiving a third unicast connection establishment acceptance message from the relay terminal, used to indicate that the first target terminal has accepted the unicast connection establishment request between the source terminal and the first target terminal; the source terminal sending a first data packet to the relay terminal, the first data packet comprising the first identifier and first data.

[0019] In a possible implementation manner, the identifier allocation request message here may also be used to indicate that a unicast connection has been established between the relay terminal and the first target terminal.

[0020] In another possible implementation, the source terminal does not perform the above-mentioned step of "sending an identifier allocation response message to the relay terminal", and the third unicast connection establishment request message sent by the source terminal to the relay terminal includes a first identifier but does not include the layer 2 address of the first target terminal, the bit length of the first identifier is less than or equal to 8 bits, and the first identifier is used to identify the first target terminal.

[0021] In one possible implementation, the method also includes: receiving a fourth security activation command message from the relay terminal, the fourth security activation command message including the first identifier, used to indicate that the fourth security activation command message comes from the first target terminal; sending a fourth security activation completion message to the relay terminal, the fourth security activation completion message including the first identifier, used to indicate that the fourth security activation completion message is sent to the first target terminal.

[0022] It should be understood that during the process of securely establishing a connection between the source terminal and the first target terminal, the source terminal can securely establish a connection with a specific target terminal based on the first identifier carried in the message forwarded by the relay terminal.

[0023] In a possible implementation, a second data packet is sent to the relay terminal, the second data packet includes a second identifier, second data, and a layer 2 address of the relay terminal, and the first data packet also includes the layer 2 address of the relay terminal.

[0024] The above solution can realize unicast connection between multiplexing source terminals and relay terminals, saving air interface resources.

[0025] Exemplarily, the second identifier is used to identify the second target terminal, and the second data is data sent by the source terminal to the second target terminal based on the relay terminal. The target layer 2 addresses of the first data packet and the second data packet are both the layer 2 addresses of the relay terminal. It can be understood that the source terminal can send data to the first target terminal and the second target terminal respectively based on the relay terminal, and the first data packet and the second data packet are carried on the same unicast connection between the source terminal and the relay terminal, or in other words, the unicast connection between the source terminal and the relay terminal is multiplexed.

[0026] In a third aspect, a relay communication method is provided, which can be executed by a relay terminal, or can also be executed by a component of the relay terminal. The method includes: receiving a first unicast connection establishment request message from a source terminal, the first unicast connection establishment request message including a first identifier, the bit length of the first identifier is less than or equal to 8 bits, and the first identifier is associated with a first target terminal; sending a second unicast connection establishment request message to the first target terminal to request to establish a unicast connection between the source terminal and the first target terminal; receiving a second unicast connection establishment acceptance message from the first target terminal, used to indicate that the first target terminal has accepted the unicast connection establishment request between the relay terminal and the first target terminal; receiving a third unicast connection establishment request message from the source terminal, requesting to establish a unicast connection between the source terminal and the first target terminal, the third unicast connection establishment request message The method comprises: receiving a connection establishment request message including a first identifier; sending a fourth unicast connection establishment request message to the first target terminal, requesting to establish a unicast connection between the source terminal and the first target terminal; receiving a fourth unicast connection establishment acceptance message from the first target terminal, indicating that the first target terminal has accepted the unicast connection establishment request between the source terminal and the first target terminal; sending a third unicast connection establishment acceptance message to the source terminal, indicating that the first target terminal has accepted the unicast connection establishment request between the source terminal and the first target terminal; receiving a first data packet from the source terminal, the first data packet including the first identifier and first data; and sending the first data to the first target terminal according to the first identifier.

[0027] In the above scheme, the relay terminal forwards the first data from the source terminal to the first target terminal according to the first identifier assigned by the source terminal to the first target terminal, and can realize communication between the source terminal and the specific target terminal while multiplexing the unicast connection between the source terminal and the relay terminal.

[0028] In a possible implementation, the method further includes: receiving a third security activation command message from the first target terminal; sending the fourth security activation command message to the source terminal, the fourth security activation command message including the first identifier, used to indicate that the fourth security activation command message comes from the first target terminal; receiving a fourth security activation completion message from the source terminal, the fourth security activation completion message including the first identifier, used to indicate that the fourth security activation completion message is sent to the first target terminal; sending the third security activation completion message to the first target terminal. It should be understood that in the process of the source terminal and the first target terminal establishing security, the relay terminal can carry the first identifier when forwarding the message, so as to facilitate the source terminal to establish security with a specific target terminal.

[0029] In a possible implementation manner, the first unicast connection establishment request message includes a first set, the first set includes multiple identifiers, and the multiple identifiers include the first identifier.

[0030] In a possible implementation, the method further includes: receiving a second data packet from the source terminal, the second data packet including a second identifier, second data and a layer 2 address of the relay terminal, and the first data packet also including the layer 2 address of the relay terminal.

[0031] In a possible implementation manner, sending the first data to the first target terminal according to the first identifier includes: sending the first data packet to the first target terminal according to the first identifier.

[0032] In a possible implementation, the method further includes: receiving a third data packet from the first target terminal, the third data packet including third data and the first identifier; and sending the third data packet to the source terminal.

[0033] In a possible implementation manner, the method further includes: sending the first identifier to the first target terminal.

[0034] In a possible implementation, the method also includes: receiving fourth data from the first target terminal; configuring the first identifier for the fourth data according to the association relationship to obtain a fourth data packet; sending the fourth data packet to the source terminal, the fourth data packet including the fourth data and the first identifier.

[0035] In the above solution, when the first target terminal sends data to the source terminal based on the relay terminal, the first identifier is used to identify the data to achieve forward compatibility.

[0036] In a fourth aspect, a relay communication method is provided, which is a method executed by a source terminal corresponding to the method of the third aspect, and therefore can also achieve the beneficial effects that can be achieved by the method of the third aspect. The method can also be executed by a component of the source terminal. The method includes: sending a first unicast connection establishment request message to a relay terminal, the first unicast connection establishment request message including a first identifier, the first identifier being associated with a first target terminal; sending a third unicast connection establishment request message to the relay terminal, requesting to establish a unicast connection between the source terminal and the first target terminal; receiving a third unicast connection establishment acceptance message from the relay terminal, indicating that the first target terminal has accepted the unicast connection establishment request between the source terminal and the first target terminal; sending a first data packet to the relay terminal, the first data packet including the first identifier and first data.

[0037] In one possible implementation, the method also includes: receiving a fourth security activation command message from the relay terminal, the fourth security activation command message including the first identifier, used to indicate that the fourth security activation command message comes from the first target terminal; sending a fourth security activation completion message to the relay terminal, the fourth security activation completion message including the first identifier, used to indicate that the fourth security activation completion message is sent to the first target terminal.

[0038] It should be understood that during the process of securely establishing a connection between the source terminal and the first target terminal, the source terminal can securely establish a connection with a specific target terminal based on the first identifier carried in the message forwarded by the relay terminal.

[0039] In a possible implementation manner, the first unicast connection establishment request message includes a first set, the first set includes multiple identifiers, and the multiple identifiers include the first identifier.

[0040] In the above solution, the source terminal allocates the identifier set through the first unicast connection establishment request message, which can save signaling overhead compared to allocating one identifier at a time.

[0041] In a fifth aspect, a relay communication method is provided, which can be executed by a relay terminal, or can also be executed by a component of a relay terminal. The method includes: receiving a first discovery request message from a source terminal, for requesting to discover a first target terminal, the first discovery request message includes a first identifier, and the first identifier is associated with the first target terminal; sending a second discovery request message to the first target terminal, for requesting to discover the first target terminal; receiving a second discovery response message from the first target terminal, for indicating that the first target terminal replies to the relay terminal with the layer 2 address of the first target terminal according to the second discovery request message; receiving a first discovery response message from the first target terminal, for indicating that the first target terminal replies to the source terminal with the layer 2 address of the first target terminal device according to the first discovery request message and the second discovery request message; sending the first discovery response message to the source terminal; receiving a first data packet from the source terminal, the first data packet includes the first identifier and first data; sending the first data to the first target terminal according to the first identifier.

[0042] In a possible implementation, the first discovery request message includes a first set, the first set includes multiple identifiers, and the multiple identifiers include the first identifier.

[0043] In a possible implementation, the method further includes: receiving a second data packet from the source terminal, the second data packet including a second identifier, second data and a layer 2 address of the relay terminal, and the first data packet also including the layer 2 address of the relay terminal.

[0044] Exemplarily, the second identifier is used to identify the second target terminal, and the second data is data sent by the source terminal to the second target terminal based on the relay terminal. The target layer 2 addresses of the first data packet and the second data packet are both the layer 2 addresses of the relay terminal. It can be understood that the source terminal can send data to the first target terminal and the second target terminal respectively based on the relay terminal, and the first data packet and the second data packet are carried on the same unicast connection between the source terminal and the relay terminal, or in other words, the unicast connection between the source terminal and the relay terminal is multiplexed.

[0045] In a possible implementation manner, sending the first data to the first target terminal according to the first identifier includes: sending the first data packet to the first target terminal according to the first identifier.

[0046] In a possible implementation, the method further includes: receiving a third data packet from the first target terminal, the third data packet including third data and the first identifier; and sending the third data packet to the source terminal according to the first identifier.

[0047] In a possible implementation manner, the method further includes: sending the first identifier to the first target terminal.

[0048] The above scheme sends the first identifier to the first target terminal through the relay terminal, so that when the source terminal sends data to the first target terminal based on the relay terminal, the protocol data unit format of the two unicast connection transmissions between the source terminal to the relay terminal and the relay terminal to the first target terminal is consistent, and forward compatibility can be achieved.

[0049] In a possible implementation, the method also includes: receiving fourth data from the first target terminal; configuring the first identifier for the fourth data according to the association relationship to obtain a fourth data packet; sending the fourth data packet to the source terminal, the fourth data packet including the fourth data and the first identifier.

[0050] In the sixth aspect, a relay communication method is provided, which is a method executed by a source terminal corresponding to the method in the fifth aspect, and therefore can also achieve the beneficial effects that can be achieved by the method in the fifth aspect. The method can also be executed by a component of the source terminal. The method includes: sending a first discovery request message to a relay terminal to request discovery of a first target terminal, the first discovery request message including a first identifier, the first identifier being associated with the first target terminal; receiving a first discovery response message from the relay terminal to indicate that the first target terminal replies to the relay terminal with the layer 2 address of the first target terminal according to the second discovery request message; sending a first data packet to the relay terminal, the first data packet including a first identifier and first data, the first identifier being used to indicate that the first data is to be sent to the first target terminal, and indicating that the first target terminal replies to the source terminal with the layer 2 address of the first target terminal device according to the first discovery request message and the second discovery request message.

[0051] In a possible implementation, the first discovery request message includes a first set, the first set includes multiple identifiers, and the multiple identifiers include the first identifier.

[0052] In the above solution, the source terminal allocates the identifier set through the first unicast connection establishment request message, which can save signaling overhead compared to allocating one identifier at a time.

[0053] In the seventh aspect, a relay communication method is provided, which can be executed by a relay terminal, or can also be executed by a component of a relay terminal. The method includes: receiving a first unicast connection establishment request message from a source terminal; sending a second unicast connection establishment request message to the first target terminal; receiving a second unicast connection establishment acceptance message from the first target terminal, indicating that the first target terminal has established a unicast connection with the relay terminal according to the second unicast connection establishment request message; allocating a first identifier to the first target terminal; receiving a third unicast connection establishment request message from the source terminal; sending the third unicast connection establishment request message to the first target terminal; receiving a third unicast connection establishment acceptance message from the first target terminal, indicating that the first target terminal has established a unicast connection with the source terminal according to the third unicast connection establishment request message; sending the third unicast connection establishment acceptance message to the source terminal; receiving a first data packet from the source terminal, the first data packet including the first identifier and first data; sending the first data to the first target terminal according to the first identifier.

[0054] Based on the above scheme, before the source terminal establishes a unicast connection with the first target terminal, the relay terminal allocates a first identifier to the first target terminal, and the relay terminal forwards the first data to the first target terminal according to the first identifier in the first data packet from the source terminal. The above scheme can realize communication between the source terminal and a specific target terminal while multiplexing the unicast connection between the source terminal and the relay terminal; and, since the volume of the target terminals served by the relay terminal is much smaller than that of the target terminals served by the base station, compared with the base station allocating identifiers to each target terminal, the number of bits of the identifier field allocated by the relay terminal to each target terminal is smaller, which can save signaling overhead.

[0055] In a possible implementation, after the relay terminal sends the third unicast connection establishment acceptance message to the source terminal, the method further includes: the relay terminal sends the association relationship between the first identifier and the first target terminal to the source terminal. In this case, the third unicast connection establishment request message includes the first identifier, which is used to indicate a request to establish a unicast connection with the first target terminal.

[0056] In one possible implementation, the method also includes: receiving a third security activation command message from the first target terminal; sending the fourth security activation command message to the source terminal, the fourth security activation command message including the first identifier, used to indicate that the fourth security activation command message comes from the first target terminal; receiving a fourth security activation completion message from the source terminal, the fourth security activation completion message including the first identifier, used to indicate that the fourth security activation completion message is sent to the first target terminal; and sending a third security activation completion message to the first target terminal.

[0057] It should be understood that during the process of securely establishing a connection between the source terminal and the first target terminal, the relay terminal may carry the first identifier when forwarding a message, so as to facilitate securely establishing a connection between the source terminal and the specific target terminal.

[0058] In a possible implementation manner, the method further includes: sending an association relationship between the first target terminal and the first identifier to the source terminal.

[0059] In a possible implementation, the method further includes: receiving a second data packet from the source terminal, the second data packet including a second identifier, second data and a layer 2 address of the relay terminal, and the first data packet also including the layer 2 address of the relay terminal.

[0060] Exemplarily, the second identifier is used to identify the second target terminal, and the second data is data sent by the source terminal to the second target terminal based on the relay terminal. The target layer 2 addresses of the first data packet and the second data packet are both the layer 2 addresses of the relay terminal. It can be understood that the source terminal can send data to the first target terminal and the second target terminal respectively based on the relay terminal, and the first data packet and the second data packet are carried on the same unicast connection between the source terminal and the relay terminal, or in other words, the unicast connection between the source terminal and the relay terminal is multiplexed.

[0061] In a possible implementation manner, sending the first data to the first target terminal according to the first identifier includes: sending the first data packet to the first target terminal according to the first identifier.

[0062] In a possible implementation, the method further includes: receiving a third data packet from the first target terminal, the third data packet including third data and the first identifier; and sending the third data packet to the source terminal according to the first identifier.

[0063] In a possible implementation manner, the method further includes: sending the first identifier to the first target terminal.

[0064] The above scheme sends the first identifier to the first target terminal through the relay terminal, so that when the source terminal sends data to the first target terminal based on the relay terminal, the protocol data unit format of the two unicast connection transmissions between the source terminal to the relay terminal and the relay terminal to the first target terminal is consistent, and forward compatibility can be achieved.

[0065] In a possible implementation, the method also includes: receiving fourth data from the first target terminal; configuring the first identifier for the fourth data according to the association relationship to obtain a fourth data packet; sending the fourth data packet to the source terminal, the fourth data packet including the fourth data and the first identifier.

[0066] In the eighth aspect, a relay communication method is provided, which is a method executed by a source terminal corresponding to the method in the seventh aspect, and therefore can also achieve the beneficial effects that can be achieved by the method in the seventh aspect. The method can also be executed by a component of the source terminal. The method includes: sending a first unicast connection establishment request message to a relay terminal; sending a third unicast connection establishment request message to the relay terminal, requesting to establish a unicast connection between the source terminal and the first target terminal; receiving a third unicast connection establishment acceptance message from the relay terminal, indicating that the first target terminal has accepted the unicast connection establishment request between the source terminal and the first target terminal; receiving an association relationship between the first target terminal and the first identifier from the relay terminal; and sending a first data packet to the relay terminal according to the association relationship, the first data packet including a first identifier and first data.

[0067] In one possible implementation, the method also includes: receiving a third security activation command message from the first target terminal; sending the fourth security activation command message to the source terminal, the fourth security activation command message including the first identifier, used to indicate that the fourth security activation command message comes from the first target terminal; receiving a fourth security activation completion message from the source terminal, the fourth security activation completion message including the first identifier, used to indicate that the fourth security activation completion message is sent to the first target terminal; and sending a third security activation completion message to the first target terminal.

[0068] It should be understood that during the process of securely establishing a connection between the source terminal and the first target terminal, the relay terminal may carry the first identifier when forwarding a message, so as to facilitate securely establishing a connection between the source terminal and the specific target terminal.

[0069] In a possible implementation, a second data packet is sent to the relay terminal, the second data packet includes a second identifier, second data, and a layer 2 address of the relay terminal, and the first data packet also includes the layer 2 address of the relay terminal.

[0070] The above solution can realize unicast connection between multiplexing source terminals and relay terminals, saving air interface resources.

[0071] Exemplarily, the second identifier is used to identify the second target terminal, and the second data is data sent by the source terminal to the second target terminal based on the relay terminal. The target layer 2 addresses of the first data packet and the second data packet are both the layer 2 addresses of the relay terminal. It can be understood that the source terminal can send data to the first target terminal and the second target terminal respectively based on the relay terminal, and the first data packet and the second data packet are carried on the same unicast connection between the source terminal and the relay terminal, or in other words, the unicast connection between the source terminal and the relay terminal is multiplexed.

[0072] In the ninth aspect, a relay communication method is provided, which can be executed by a relay terminal, or can also be executed by a component of a source terminal. The method includes: receiving a first discovery request message from a source terminal for discovering a first target terminal; sending a second discovery request message to the first target terminal for discovering the first target terminal; receiving a second discovery response message from the first target terminal for indicating that the first target terminal replies to the relay terminal with the layer 2 address of the first target terminal according to the second discovery request message; receiving a first discovery response message from the first target terminal for indicating that the first target terminal replies to the source terminal with the layer 2 address of the first target terminal device according to the first discovery request message and the second discovery request message; assigning a first identifier to the first target terminal; sending the first discovery response message to the source terminal; receiving a first data packet from the source terminal, the first data packet including the first identifier and first data; sending the first data to the first target terminal according to the first identifier.

[0073] Based on the above solution, in the process of the source terminal searching for the first target terminal through the discovery process, the relay terminal assigns a first identifier to the first target terminal, and the relay terminal forwards the first data to the first target terminal according to the first identifier in the first data packet from the source terminal. The beneficial effects of the above solution can refer to the beneficial effects of the seventh aspect.

[0074] In a possible implementation manner, the method further includes: sending an association relationship between the first target terminal and the first identifier to the source terminal.

[0075] In a possible implementation, the method further includes: receiving a second data packet from the source terminal, the second data packet including a second identifier, second data and a layer 2 address of the relay terminal, and the first data packet also including the layer 2 address of the relay terminal.

[0076] Exemplarily, the second identifier is used to identify the second target terminal, and the second data is data sent by the source terminal to the second target terminal based on the relay terminal. The target layer 2 addresses of the first data packet and the second data packet are both the layer 2 addresses of the relay terminal. It can be understood that the source terminal can send data to the first target terminal and the second target terminal respectively based on the relay terminal, and the first data packet and the second data packet are carried on the same unicast connection between the source terminal and the relay terminal, or in other words, the unicast connection between the source terminal and the relay terminal is multiplexed.

[0077] In a possible implementation manner, sending the first data to the first target terminal according to the first identifier includes: sending the first data packet to the first target terminal according to the first identifier.

[0078] In a possible implementation, the method further includes: receiving a third data packet from the first target terminal, the third data packet including third data and the first identifier; and sending the third data packet to the source terminal according to the first identifier.

[0079] In a possible implementation manner, the method further includes: sending the first identifier to the first target terminal.

[0080] The above scheme sends the first identifier to the first target terminal through the relay terminal, so that when the source terminal sends data to the first target terminal based on the relay terminal, the protocol data unit format of the two unicast connection transmissions between the source terminal to the relay terminal and the relay terminal to the first target terminal is consistent, and forward compatibility can be achieved.

[0081] In a possible implementation, the method also includes: receiving fourth data from the first target terminal; configuring the first identifier for the fourth data according to the association relationship to obtain a fourth data packet; sending the fourth data packet to the source terminal, the fourth data packet including the fourth data and the first identifier.

[0082] In the tenth aspect, a relay communication method is provided, which is a method executed by a source terminal corresponding to the method in the ninth aspect, and therefore can also achieve the beneficial effects that can be achieved by the method in the ninth aspect. The method can also be executed by components of the source terminal. The method includes: sending a first discovery request message to a relay terminal; receiving a first discovery response message from the relay terminal, which is used to instruct the first target terminal to reply to the source terminal with the layer 2 address of the first target terminal device according to the first discovery request message and the second discovery request message; receiving an association relationship between the first target terminal and the first identifier from the relay terminal; the source terminal sends a first data packet to the relay terminal according to the association relationship, and the first data packet includes a first identifier and first data.

[0083] Based on the above scheme, during the process of discovering the first target terminal, the source terminal receives the association relationship between the first target terminal and the first identifier from the relay terminal, and sends data to the first target terminal according to the association relationship. The above scheme can realize communication between the source terminal and a specific target terminal while multiplexing the unicast connection between the source terminal and the relay terminal.

[0084] In an eleventh aspect, a communication device is provided, which is used to execute the method in any possible implementation of the first aspect to the tenth aspect. Specifically, the device may include a unit and / or module, such as a transceiver unit and / or a processing unit, for executing the method in any possible implementation of the first aspect to the tenth aspect.

[0085] In a possible implementation, the transceiver unit may be a transceiver, or an input / output interface; the processing unit may be at least one processor, or a processing circuit. Optionally, the transceiver may be a transceiver circuit. Optionally, the input / output interface may be an input / output circuit.

[0086] In the twelfth aspect, a communication device is provided, characterized in that it includes a processor and an interface circuit, the interface circuit is used to receive signals from other communication devices and transmit them to the processor or send signals from the processor to other communication devices, and the processor is used to implement the method in any possible implementation of the first to tenth aspects through logic circuits or execution code instructions.

[0087] In a thirteenth aspect, a processing device is provided, comprising a processor and a memory. The processor is used to read instructions stored in the memory, and can receive signals through a transceiver and transmit signals through a transmitter to execute the method in any possible implementation of the first to tenth aspects.

[0088] In the fourteenth aspect, a computer-readable storage medium is provided, characterized in that a computer program or instruction is stored in the storage medium, and when the computer program or instruction is executed by a communication device, the method in any possible implementation manner of the first to tenth aspects is implemented.

[0089] In a fifteenth aspect, a computer program product comprising instructions is provided. When the computer program product is run on a communication device, the communication device executes a method in any possible implementation of the first to tenth aspects.

[0090] In a sixteenth aspect, a computer program instruction is provided, which, when executed on a computer, enables the computer to execute a method in any possible implementation of the first to tenth aspects above. BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Figure 1 A schematic diagram of a vehicle-to-object communication architecture is shown;

[0092] Figure 2 A schematic diagram of a terminal-to-terminal relay scenario is shown;

[0093] Figure 3 is a schematic diagram of a protocol stack of a user plane of an end-to-end relay based on layer 2;

[0094] Figure 4 The model B method of the UE to UE relay discovery process is shown;

[0095] Figure 5 A schematic diagram of a relay communication method 200 provided in the present application is shown;

[0096] Figure 6 A schematic diagram of a relay communication method 200 provided by the present application is shown;

[0097] Figure 7 A schematic diagram of a relay communication method 300 provided in the present application is shown;

[0098] Figure 8 A schematic diagram of a relay communication method 400 provided in the present application is shown;

[0099] Fig. 9 A schematic diagram of a relay communication method 500 provided in the present application is shown;

[0100] Fig.10 A schematic diagram of a relay communication method 600 provided in the present application is shown;

[0101] Fig.11 is a schematic block diagram of a communication device provided by the present application;

[0102] Fig.12 It is another schematic block diagram of the communication device provided in this application. DETAILED DESCRIPTION

[0103] The embodiments of the present application can be applied to a fifth generation (5G) mobile communication system, a sixth generation (6G) mobile communication system, a WiFi system or a future mobile communication system.

[0104] The base station in this application can be an evolved NodeB (eNodeB), a transmission reception point (TRP), a next-generation NodeB (gNB) in a 5G mobile communication system, 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, etc.; it can also be a module or unit that completes some functions of a base station.

[0105] UE is a device with wireless transceiver function, which can send signals to the base station or receive signals from the base station. UE can also be called terminal, mobile station, mobile terminal, etc. Terminals can be widely used in various scenarios, for example, device-to-device (D2D), vehicle to everything (V2X) communication, machine-type communication (MTC), Internet of Things (IOT), virtual reality, augmented reality, industrial control, automatic driving, telemedicine, smart grid, smart furniture, smart office, smart wear, smart transportation, smart city, etc. The terminal can be a mobile phone, a tablet computer, a computer with wireless transceiver function, a wearable device, a vehicle, an airplane, a ship, a robot, a mechanical arm, a smart home device, etc. The embodiments of the present application do not limit the specific technology and specific device form adopted by the terminal.

[0106] In the embodiments of the present application, the functions of the base station may also be performed by a module (such as a chip) in the base station, or by a control subsystem including the base station function. The control subsystem including the base station function here may be a control center in the above-mentioned application scenarios such as smart grid, industrial control, smart transportation, and smart city. The functions of the terminal may also be performed by a module (such as a chip or a modem) in the terminal, or by a device including the terminal function.

[0107] The following will be combined Figures 1 to 4 The following sections introduce the V2X communication architecture, UE to UE relay (U2U relay) scenario, user plane protocol stack, and D2D discovery process examples applicable to the present application.

[0108] Figure 1 A schematic diagram of the V2X communication architecture is shown. Figure 1 As shown, the architecture includes two wireless communication interfaces, namely, the proximity-based services communication 5 (PC5) interface between UEs and the Uu interface between the base station and the UE. Figure 1As shown, V2X UE1 and V2X UE2 can communicate directly through the PC5 interface, and this communication link is also defined as a sidelink (SL); V2X UE1 and V2X UE2 can also communicate through the Uu interface. V2X UE1 sends V2X data to the base station through the Uu interface, and the base station sends it to the V2X application server for processing, and then the V2X application server sends it to the base station, and then sends it to V2X UE2 through the base station). In the Uu interface communication mode, the base station that receives the uplink data of V2X UE1 and the base station that sends the downlink data to V2X UE2 can be the same base station or different base stations, which can be determined by the location of the V2X UE.

[0109] V2X supports three communication modes, namely broadcast, multicast and unicast communication modes. In the broadcast communication mode, the broadcast data sent can be received and parsed by any interested V2X UE; in the multicast communication mode, a V2X UE can send multicast data to other V2X UEs belonging to the communication group, and V2X UEs that do not belong to the communication group will not receive and parse the multicast data or cannot correctly parse the multicast data; in the unicast communication mode, two V2X UEs need to establish a unicast connection first. After the unicast connection is established, one V2X UE can send unicast data to the other V2X UE. Only the V2X UE that has established a unicast connection can correctly parse the data sent by the other party.

[0110] The 3rd Generation Partnership Project (3GPP) international standardization organization introduced device to device (D2D) technology in long term evolution (LTE), which includes D2D communication and D2D discovery. D2D communication is oriented to public safety and supports multicast communication, unicast communication and UE-to-network relay; D2D discovery supports simple commercial broadcasts (such as advertising broadcasts, etc.).

[0111] As technology develops to 5G new radio (NR), UE to UE relay (U2U relay) communication begins to be discussed in the 3GPP standard. It is understood that in this application, the terms D2D and U2U can be interchangeable.

[0112] Figure 2 A schematic diagram of a U2U relay scenario is shown. Figure 2As shown, U2U relay refers to a technology in which a source UE communicates with a target UE through a relay UE, which can be used for sidelink coverage enhancement (for example, the source UE and the target UE have poor coverage signals or are out of coverage) or capacity improvement (for example, the relay UE is a very capable device). The source UE and the relay UE, as well as the relay UE and the target UE, communicate through the sidelink.

[0113] Currently, there are two possible implementations of U2U relay: a relay method based on layer 3 (L3) and a relay method based on layer 2 (L2). In the relay method based on L3, user-plane data is forwarded at the Internet Protocol (IP) layer, that is, the data packet sent by the source UE to the target UE needs to be parsed by the Relay UE to the IP layer and forwarded to the target UE based on information such as the IP address. In the relay method based on L2, user-plane data is forwarded below the packet data convergence protocol (PDCP) layer. At this time, the user-plane protocol stack is as follows: Figure 3 shown. Figure 3 FIG. 1 is a schematic diagram of a protocol stack of a U2U relay user plane based on L2. The relay UE relays and forwards SL data transmission between a source UE (or a sending UE) and a target UE (or a receiving UE).

[0114] The user plane protocol stack of the source UE includes a PDCP layer, a service data adaptation protocol (SDAP) layer, an IP / non-IP layer for information interaction with the target UE, and an adaptation layer, a radio link control (RLC) layer, a medium access control layer (MAC) layer, and a physical layer (PHY) for information interaction with the relay UE; the user plane protocol stack of the relay UE includes an adaptation layer, an RLC layer, a MAC layer, and a PHY layer for information interaction with the source UE, and an adaptation layer, an RLC layer, a MAC layer, and a PHY layer for information interaction with the target UE; the user plane protocol stack of the target UE includes a PDCP layer, an SDAP layer, an IP / non-IP layer for information interaction with the source UE, and an adaptation layer, an RLC layer, a MAC layer, and a PHY layer for information interaction with the relay UE.

[0115] In the scenario where the source UE and N target UEs transmit data and signaling through the relay UE (N is an integer greater than 1), N unicast connections can be established between the source UE and the relay UE, and the N unicast connections correspond to the N target UEs respectively. This communication method consumes too much air interface resources between the source UE and the relay UE.

[0116] It should also be understood that before establishing a unicast connection between two UEs, in order to obtain the destination layer 2 (layer 2, L2) identifier (ID) of the other UE, it may be necessary to discover the other party through a discovery process. Figure 3 Introduced U2U relay communication, the following is combined Figure 4 Introduce a possible U2U discovery process, model B.

[0117] Figure 4 The model B method of the U2U discovery process is shown. Taking UE1 searching for other UEs as an example, UE1 broadcasts a discovery solicitation message to the surrounding area to search for other UEs (including but not limited to UE2 and UE3 in the figure). After receiving the message, other UEs can reply with a discovery response message if conditions permit, so that UE1 can learn about the existence of other UEs; both the discovery request message and the discovery response message are PC5-S (PC5-signaling) messages. Figure 4 UE1, UE2 or UE3 in the example may all be the aforementioned source UE, relay UE or target UE.

[0118] The following will be combined Figures 5 to 11 The communication method and device provided by the present application are introduced in detail.

[0119] The communication method provided by the present application supports a source terminal to establish an end-to-end unicast connection with one or more target terminals through a relay terminal. Only one unicast connection for forwarding messages can be established between the source terminal and the relay terminal. The source terminal can perform end-to-end communication with any one of the one or more target terminals based on the unicast connection.

[0120] In a specific implementation, the communication method provided in the present application may have multiple possible implementation methods, depending on whether the source terminal knows the existence of the relay terminal (the source terminal directly sends a message to the relay terminal or performs a discovery process and sends a message after learning the existence of the relay terminal), or depending on the different terminals that assign the first identifier to the target terminal (the source terminal or the relay terminal), or depending on the different counterpart terminals to which the source terminal needs to transmit data or signaling (a specific target terminal or a target terminal that is interested in the corresponding service (or can be understood as having a demand for the corresponding service)).

[0121] Combine the following Figures 5 to 9 The communication methods 200 to 600 provided in the present application are described by taking the source terminal as the source UE, the relay terminal as the relay UE, and the target terminals as the target UE1 and the target UE2 as examples. And the U2U communication involved in the present application is all performed based on the L2 relay mode.

[0122] Among them, in methods 200 to 400, the source UE is taken as an example to know the existence of the relay UE. Further, according to the establishment of a unicast connection triggered by the UE or the service, methods 200 and 300 have two different implementation methods. In methods 500 and 600, the source UE uses the U2U discovery process of model B to obtain the existence of the relay UE as an example.

[0123] Among them, in methods 200, 300, and 500, the source UE is taken as an example to allocate the first identifier, and in methods 400 and 600, the relay UE is taken as an example to allocate the first identifier.

[0124] Figure 5 A schematic diagram of a communication method 200 provided in the present application is shown. Figure 6 A schematic diagram of a communication method 200" provided in the present application is shown. In method 200, the source UE broadcasts a request message to establish a unicast connection with the target UE to the relay UE, and an end-to-end connection is established with a specific target UE through the relay UE, thereby enabling end-to-end communication between the source UE and the target UE. In method 200", the source UE broadcasts a unicast connection establishment request message to the relay UE, and an end-to-end connection is established with multiple target UEs interested in the service through the relay UE, thereby enabling end-to-end communication between the source UE and the target UE.

[0125] S201, the source UE broadcasts a first unicast connection establishment request message for the target UE2, and accordingly, multiple relay UEs receive the first unicast connection establishment request message from the source UE. In the present application, the unicast connection establishment request may also be referred to as a direct communication request. The first unicast connection establishment request message carries the application layer identifier and the first identifier of the target UE, and the first identifier is allocated by the source UE to the target UE. The first identifier may be a local identifier. Optionally, the bit length of the first identifier is less than or equal to 8 bits. The first unicast connection establishment request message may also carry the application layer identifier of the source UE, indication information of supporting relay communication, etc. The source address of the message is the layer 2 (layer 2, L2) identifier (identifier, ID) of the source UE. The L2 ID involved in the present application is used at the MAC layer. The first identifier involved in the present application is used at the adaptation layer.

[0126] After the relay UE receives the first unicast connection establishment request message sent by the source UE, it allocates an L2 address (for example, R-L2-ID-a) associated with the L2ID of the source UE. After the relay UE receives information from the source UE and needs to be forwarded to the target UE, it forwards the information to the target UE using R-L2-ID-a as the source address. In this application, the information sent can be signaling or data. The relay UE can store the association between the L2 ID of the source UE and R-L2-ID-a. Among them, there may be multiple relay UEs that have received the first unicast connection establishment request message. Figure 5 In the description, relay UE1 and relay UE2 are taken as examples, but the number of relay UEs is not limited.

[0127] Alternatively, in the case that a unicast connection has been established between the source UE and the relay UE, in S201 the source UE sends a first unicast connection establishment request message to the relay UE through the unicast connection.

[0128] The relay UE may record the first identifier, and may further record the corresponding relationship between the target UE and the first identifier.

[0129] S202, the relay UE broadcasts a second unicast connection establishment request message, and accordingly, the target UE receives the second unicast connection establishment request message from the relay UE. The target UEs here include target UE1 and target UE2. The message may also carry at least one of the application layer identifier of the target UE2, the application layer identifier of the source UE, the indication information of supporting relay, and the unique relay identifier (RID) of the relay UE. After receiving the first unicast connection establishment request message, the relay UE changes the source address of the first unicast connection establishment request message sent by the source UE, that is, changes the original source UE L2 ID to R-L2-ID-a, and generates a second unicast connection establishment request message. The second unicast connection establishment request message does not carry the first identifier. At the same time, the RID of the relay UE is added to the second unicast connection establishment request message.

[0130] The target UE determines whether the message is sent to the target UE according to whether the second unicast connection establishment request message carries the application layer identifier of the target UE. If the message carries the application layer identifier of the target UE, it is determined that the message is sent to the target UE.

[0131] There may be multiple relay UEs broadcasting the second unicast connection establishment request message, and accordingly, there may be multiple target UEs receiving the second unicast connection establishment request. Figure 5 The example in which relay UE1 and relay UE2 broadcast the second unicast connection establishment request message respectively, and target UE1 and target UE2 receive the second unicast connection establishment request message from relay UE1 and relay UE2 respectively is used for explanation, but the number of relay UEs or target UEs is not limited.

[0132] S203, the target UE replies a second unicast connection establishment accept message to the relay UE, and accordingly, the relay UE receives the second unicast connection establishment accept message from the target UE. In the present application, the unicast connection establishment accept message may also be referred to as a direct communication accept message.

[0133] After receiving the second unicast connection establishment reception message, the relay UE allocates a layer 2 address (e.g., R-L2-ID-b) associated with the target UE2, and uses the R-L2-ID-b for the relay UE to receive information from the target UE2 and to be forwarded to the source UE, that is, the R-L2-ID-b is used as the source address to forward the information from the target UE2 to the source UE. The relay UE stores the association between the R-L2-ID-b and the L2 ID of the target UE2.

[0134] Figure 5Take the example of target UE2 replying to relay UE1 with a second unicast connection establishment acceptance message. Target UE2 receives second unicast connection establishment request messages from multiple relay UEs and chooses to establish a unicast connection with relay UE1. That is, target UE2 replies to relay UE1 with a second unicast connection establishment acceptance message. It should be noted that target UE2 may receive multiple unicast connection establishment request messages from source UE, and these multiple messages are forwarded by different relay UEs. Target UE2 can choose one of the relay UEs to reply. The above scheme is based on the target UE replying Figure 5 The relay UE1 in the example is used for explanation, but the target UE is not limited to replying only to the relay UE1. The target UE2 can select a relay UE based on the link quality between the target UE2 and multiple relay UEs.

[0135] The source address of the second unicast connection establishment acceptance message is the L2 ID of the target UE2, and the destination layer 2 address is R-L2-ID-a. The target UE2 sends the second unicast connection establishment acceptance message indicating that the target UE has accepted the request to establish a unicast connection between the relay UE1 and the target UE2.

[0136] Optionally, before executing S203, the method 200 may further include the step of establishing security between the target UE2 and the relay UE1:

[0137] S203-a1, the target UE2 sends a first security activation command message to the relay UE1. In the present application, the security activation command message may also be referred to as a direct security mode command message.

[0138] S203-a2, the relay UE1 replies a first security activation complete message to the target UE2. In the present application, the security activation complete message may also be referred to as a direct security mode complete message.

[0139] S202, S203-a1, S203-a2, and S203 constitute a unicast connection establishment process between the relay UE1 and the target UE2.

[0140] Optionally, the relay UE1 associates the target UE2 with the first identifier, or associates the unicast link between the relay UE1 and the target UE2 with the first identifier, based on the consistency between the destination address of the second unicast connection establishment acceptance message and the source address of the second unicast connection establishment request message. Alternatively, the relay UE1 may associate the target UE2 with the first identifier, or associate the unicast link between the relay UE1 and the target UE2 with the first identifier, based on the consistency between the destination address of the first security activation command message and the source address of the second unicast connection establishment request message.

[0141] Optionally, corresponding to S201, in S204, the relay UE1 sends a first unicast connection establishment acceptance message to the source UE. Accordingly, the source UE receives the first unicast connection establishment acceptance message from the relay UE1, and the source address of the first unicast connection establishment acceptance message is R-L2-ID-b, and the destination address is the L2 ID of the source UE. When the source UE receives the first unicast connection establishment acceptance message, the unicast connection establishment between the source UE and the relay UE is completed.

[0142] It should be noted that in S204, the unicast connection established between the relay UE1 and the source UE is used to forward messages between the source UE and the target UE, and is not used for communication between the relay UE1 and the source UE. When the relay UE1 wants to communicate with the source UE, the relay UE1 can establish a new unicast connection with the source UE using another layer 2 address.

[0143] It should also be noted that if a unicast connection for forwarding messages for the source UE and the target UE already exists between the relay UE1 and the source UE, step S204 is not performed. Instead, the message can be directly forwarded for the source UE and the target UE2 through the existing unicast connection. Exemplarily, if S204 is not performed, the existing unicast connection between the source UE and the relay UE may be established when the source UE establishes an end-to-end unicast connection with other target UEs other than the target UE2 based on the relay UE.

[0144] As an example, in the case where S204 needs to be executed, before executing S204, the implementation method may further include the step of establishing security between the source UE and the relay UE1: S204-a1, the relay UE1 sends a second security activation command message to the source UE; S204-a2, the source UE replies with a second security activation completion message to the relay UE1. S201, S204-a1, S204-a2, S204 constitute a unicast connection establishment process between the source UE and the relay UE1.

[0145] Depending on whether the target UE2 sends the first identifier to the relay UE1 when sending information to the relay UE1, S205-S210 may be implemented in two ways.

[0146] Implementation method 1: When the target UE2 sends signaling and data to the relay UE1, the target UE2 does not send the first identifier to the relay UE1.

[0147] S205, the source UE sends a third unicast connection establishment request message to the relay UE1, and accordingly, the relay UE1 receives the third unicast connection establishment request message from the source UE. The third unicast connection establishment request message includes a first identifier, which is used to indicate that the message is sent to the target UE2. The third unicast connection establishment request message is used to establish an end-to-end unicast connection between the source UE and the target UE2 through the relay UE1. The first identifier is added to the third unicast connection establishment request message in the adaptation layer of the source UE.

[0148] S206, the relay UE1 sends a fourth unicast connection establishment request message to the target UE2, and accordingly, the target UE2 receives the fourth unicast connection establishment request message from the relay UE1. The relay UE1 associates R-L2-ID-a with the L2 ID of the source UE, and determines that the source address of the fourth unicast connection establishment request message is R-L2-ID-a, and the destination address is the L2 ID of the target UE2.

[0149] After receiving the third unicast connection establishment request message, the relay UE1 removes the first identifier in the third unicast connection establishment request message and generates a fourth unicast connection establishment request message. That is, the fourth unicast connection establishment request message includes other contents in the third unicast connection establishment request message except the first identifier.

[0150] S207, the target UE2 sends a fourth unicast connection establishment acceptance message to the relay UE1, and accordingly, the relay UE1 receives the fourth unicast connection establishment acceptance message from the target UE2. The source address of the fourth unicast connection establishment acceptance message is the L2 ID of the target UE2, and the destination address is R-L2-ID-a.

[0151] After receiving the fourth unicast connection establishment acceptance message, relay UE1 determines to forward the message to the source UE based on the destination address of the message being R-L2-ID-a and the association between R-L2-ID-a and the source UE L2 ID.

[0152] S208, the relay UE1 sends a third unicast connection establishment acceptance message to the source UE, and accordingly, the source UE receives the third unicast connection establishment acceptance message from the relay UE1. The source address of the third unicast connection establishment acceptance message is R-L2-ID-a, and the destination address is the L2 ID of the source UE. The source UE determines that the third unicast connection establishment acceptance message is from the target UE2 according to the first identifier.

[0153] After receiving the fourth unicast connection establishment acceptance message, the relay UE1 adds the first identifier to the fourth unicast connection establishment acceptance message to generate a third unicast connection establishment acceptance message. That is, the third unicast connection establishment acceptance message includes the content of the fourth unicast connection establishment acceptance message and the first identifier.

[0154] Optionally, steps S206 - a1 , S206 - a2 , S207 - a1 , and S207 - a2 are performed between S206 and S207 .

[0155] S206-a1, the target UE2 sends a third security activation command message to the relay UE1, and accordingly, the relay UE1 receives the third security activation command message from the target UE2. The source address of the third security activation command message is the L2ID of the target UE2, and the destination address is R-L2-ID-a. The third security activation command message may carry the RID.

[0156] Accordingly, the relay UE1 receives the third security activation command message from the target UE2 and can determine that the message needs to be forwarded as a relay according to the RID. The relay UE1 determines that the message needs to be forwarded to the source UE according to the association relationship between the stored R-L2-ID-a and the source UE L2 ID.

[0157] S206-a2, the relay UE1 sends a fourth security activation command message to the source UE. Accordingly, the source UE receives the fourth security activation command message from the relay UE1, the source address of the fourth security activation command message is R-L2-ID-b, and the destination address is the layer 2 address of the source UE. The fourth security activation command message carries the RID and the first identifier. The first identifier may be configured by the relay UE1 at the adaptation layer.

[0158] After receiving the fourth security activation command message from the relay UE1, the source UE can determine according to the RID that the third security activation command message is forwarded by the relay UE1, and determine according to the first identifier that the fourth security activation command message is from the target UE2.

[0159] S207-a1, the source UE sends a third security activation completion message to the relay UE1, and accordingly, the relay UE1 receives the third security activation completion message from the source UE, the third security activation completion message carrying the first identifier. The source address of the third security activation completion message is the L2 ID of the source UE, and the destination address is R-L2-ID-b.

[0160] After receiving the third security activation completion message, the relay UE1 may determine, according to the first identifier, that the third security activation completion message needs to be forwarded to the target UE2.

[0161] S207-a2, relay UE1 sends a fourth security activation completion message to target UE2, and accordingly, target UE2 receives the fourth security activation completion message from relay UE1. The destination address of the message is the L2 ID of target UE2, and the source address is R-L2-ID-a. The fourth security activation completion message does not carry the first identifier.

[0162] S209, the source UE sends a first data packet to the relay UE1, and accordingly, the relay UE1 receives the first data packet from the source UE, the header of the first data packet carries a first identifier, and the content of the first data packet is first data. The relay UE1 determines that the first data needs to be forwarded to the target UE2 according to the first identifier.

[0163] S210, relay UE1 sends the first data to target UE2, and accordingly, target UE2 receives the first data from relay UE1. That is, when relay UE1 forwards the first data packet, it removes the first identifier in the header of the first data packet and does not send the first identifier to target UE2.

[0164] Similarly, the target UE2 may also send data to the source UE based on the relay UE1. For example, the target UE2 sends third data to the relay UE1, and correspondingly, the relay UE1 receives fourth data from the target UE2; the relay UE1 generates a fourth data packet according to the association between the first identifier and the target UE2 and the fourth data; the relay UE1 sends the fourth data packet to the source UE, and the fourth data packet includes the fourth data and the first identifier.

[0165] Implementation method 2: When the target UE2 sends signaling and data to the relay UE1, the target UE2 sends a first identifier to the relay UE1:

[0166] S205-S210 can refer to S205-S210 of implementation method 1, the difference is:

[0167] In S206, the fourth unicast connection establishment request message sent by relay UE1 to target UE2 includes the first identifier. In S207, the fourth unicast connection establishment acceptance message sent by target UE2 to relay UE1 includes the first identifier. In S206-a1, the third security activation command message sent by target UE2 to relay UE1 includes the first identifier. In S207-a2, the fourth security activation completion message sent by relay UE1 to target UE2 includes the first identifier. In S210, relay UE1 sends the first data packet to target UE2, and accordingly, target UE2 receives the first data packet from relay UE1.

[0168] Similarly, the target UE2 can also send data to the source UE based on the relay UE1. For example, the target UE2 sends the third data packet to the relay UE1, and accordingly, the relay UE1 receives three data packets from the target UE2; the relay UE1 sends the third data packet to the source UE, and accordingly, the source UE receives the third data packet from the relay UE1, and the third data packet includes the third data and the first identifier. It should be understood that in the second implementation method, before the target UE2 sends the first identifier to the relay UE1, the target UE2 needs to obtain the first identifier, specifically, the adaptation layer of the target UE2 obtains the first identifier. The target UE2 can obtain the first identifier through the following two possible methods.

[0169] Method 1 for the target UE2 to obtain the first identifier: the relay UE1 sends an indication message to the target UE2, and the indication message indicates the first identifier corresponding to the target UE2. Accordingly, the target UE2 receives the indication message from the relay UE. The indication message may be sent after the relay UE1 and the target UE2 complete the establishment of the unicast connection and the relay UE1 learns the correspondence between the target UE2 and the first identifier, for example, after S203. Alternatively, the indication message may be sent after the source UE and the target UE2 establish an end-to-end unicast connection (i.e., after S208) and before S209.

[0170] Method 2 for target UE2 to obtain the first identifier: In S206, when relay UE1 sends a fourth unicast connection establishment request message, the first identifier may be carried in the fourth unicast connection establishment request message. After receiving the fourth unicast connection establishment request message, target UE2 may obtain the first identifier. Alternatively, in S207-a2, when relay UE1 sends a fourth security activation completion message, the first identifier may be carried in the fourth security activation completion message. After receiving the fourth security activation completion message, target UE2 may obtain the first identifier.

[0171] It should be understood that by allowing the target UE2 to also know the first identifier, it can be achieved that when the source UE and the target UE2 transmit data based on the relay UE1, the data packet format of the two unicast connections between the source UE to the relay UE1 and the relay UE1 to the target UE2 is consistent, and forward compatibility can be achieved.

[0172] S211, the source UE sends the fifth unicast connection establishment request message to the relay UE1, and accordingly, the relay UE1 receives the fifth unicast connection establishment request message from the source UE. The fifth unicast connection establishment request message carries the application layer identifier and the second identifier of the target UE1, and the second identifier is allocated by the source UE to the target UE1. The definition of the second identifier can refer to the first identifier in S201, wherein the first identifier is used to identify the target UE2, and the second identifier here is used to identify the target UE1. The source address of the fifth unicast connection establishment request message is the L2 ID of the source UE, and the destination address is R-L2-ID-b. Relay UE1 stores the association relationship between R-L2-ID-b and the L2 ID of the target UE1.

[0173] When the source UE and the relay UE1 communicate, the source address and the destination address used by the message sent by the source UE to the target UE1 are the same as the source address and the destination address used by the message sent by the source UE to the target UE2, and the wireless link between the source UE and the relay UE1 is reused. In other words, on the communication link between the source UE and the relay UE1, the messages sent to the target UE1 and the target UE2 reuse the same unicast connection.

[0174] After the relay UE1 receives the fifth unicast connection establishment request message sent by the source UE, it allocates an L2 address associated with the L2 ID of the source UE (for example, R-L2-ID-c). After the relay UE1 receives information from the source UE and needs to be forwarded to the target UE1, it forwards the information to the target UE using R-L2-ID-c as the source address.

[0175] S212 , the relay UE1 broadcasts a sixth unicast connection establishment request message, and correspondingly, the target UE1 receives the sixth unicast connection establishment request message from the relay UE1 .

[0176] For the specific content, please refer to the corresponding description in S202, the difference is: the second unicast connection establishment request message in S202 is replaced by the sixth unicast connection establishment request message; the R-L2-ID-a in S202 is replaced by R-L2-ID-c, and the target UE2 in S202 is replaced by the target UE1.

[0177] S213, the target UE1 replies to the relay UE1 with the sixth unicast connection establishment acceptance message, and accordingly, the relay UE1 receives the sixth unicast connection establishment acceptance message from the target UE1. For specific content, please refer to the description of S203, the difference is: the second unicast connection establishment acceptance message in S203 is replaced by the sixth unicast connection establishment acceptance message; the R-L2-ID-a in S203 is replaced by R-L2-ID-c, and the target UE2 in S203 is replaced by the target UE1. Optionally, before executing S213, the implementation method may also include the step of establishing security between the target UE1 and the relay UE1, and specifically refer to the description of S203-a1 and S203-a2, the difference is: the first security activation command message in S203 is replaced by the fifth security activation command message; the first security activation completion message in S203 is replaced by the fifth security activation completion message.

[0178] S214, the relay UE1 sends an indication message to the source UE, where the indication message is used to indicate that the relay UE1 has established a unicast connection with the target UE1.

[0179] For S215-S220, please refer to the corresponding description of S205-S210, with the difference being: replacing the target UE2 with the target UE1, replacing the first identifier with the second identifier, and replacing R-L2-ID-a with R-L2-ID-c.

[0180] S215 , the source UE sends a seventh unicast connection establishment request message to the relay UE1 , and correspondingly, the relay UE1 receives the seventh unicast connection establishment request message from the source UE.

[0181] S216 , the relay UE1 sends an eighth unicast connection establishment request message to the target UE1 , and correspondingly, the target UE1 receives the eighth unicast connection establishment request message from the relay UE1 .

[0182] S217 , the target UE1 sends an eighth unicast connection establishment accept message to the relay UE1 , and correspondingly, the relay UE1 receives the eighth unicast connection establishment accept message from the target UE1 .

[0183] S218, the relay UE1 sends a seventh unicast connection establishment accept message to the source UE, the source address of the message is R-L2-ID-b, and the destination address is the L2 ID of the source UE.

[0184] S219, the source UE sends a second data packet to the relay UE1, and correspondingly, the relay UE1 receives the second data packet from the source UE.

[0185] The source address of the second data packet here is the L2 ID of the source UE, and the destination address is R-L2-ID-b. It should be understood that S201 and S204 constitute the process of establishing a unicast connection link between the source UE and the relay UE1, and in the aforementioned steps, the relay UE1 associates R-L2-ID-b with the target UE1 and the target UE2 respectively. The destination address of the fifth unicast connection establishment request message here is also R-L2-ID-b, indicating that when the source UE communicates with different target UEs, the unicast connection between the source UE and the relay UE1 can be reused.

[0186] S220, the relay UE1 sends second data to the target UE1.

[0187] The above S211 to S218 are optional, and the source UE may also establish a unicast connection with the target UE1 in other ways (for example, through the method in method 200 ”), and then perform data transmission with the target UE1 through S219 and S220.

[0188] In method 200, the source UE performs end-to-end communication with the target UE1 and the target UE2 respectively through the relay UE1. On the communication link between the source UE and the relay UE1, the data sent to the target UE1 and the target UE2 can reuse the same unicast connection (that is, the original address and the destination address of the communication between the source UE and the relay UE1 are the same, for example, the source address of the message sent by the source UE to the relay UE1 is the L2 ID of the source UE, and the destination address is R-L2-ID-b; or, the source address of the message sent by the relay UE1 to the source UE is R-L2-ID-b, and the destination address is the L2 ID of the source UE), thereby saving the air interface overhead between the source UE and the relay UE1; and the relay UE1 can determine whether the data packet is sent to the target UE1 or the target UE2 through the first identifier corresponding to the target UE2 or the second identifier corresponding to the target UE1 carried in the data packet, thereby realizing end-to-end communication between the source UE and the target UE1 or the target UE2. In addition, the source UE configures an identifier for the target UE and carries the identifier in the message requesting to establish a unicast connection with the target UE. This allows the source UE and the target UE to communicate based on the identifier configured by the source UE after a unicast connection is established. This avoids the need for the source UE to use separate signaling to tell the relay UE the identifier configured for the target UE before the relay UE can forward information to the target UE, thereby saving signaling overhead.

[0189] Figure 6 A schematic diagram of a communication method 200 provided by the present application is shown.

[0190] S201", the source UE broadcasts a unicast connection establishment request message A, and accordingly, the relay UE receives the unicast connection establishment request message A from the source UE.

[0191] The message carries an application identifier or V2X service information, which is used to indicate the establishment of an end-to-end unicast connection with the target UE interested in the application or service. The message also carries an identifier set, which includes one or more identifiers assigned by the source UE to the target UE interested in the application or service. The identifier in the identifier set can be the first identifier or the second identifier in method 200, and each identifier in the identifier set can be correspondingly assigned to a target UE. The source address of the message is the source UE L2 ID. Optionally, the message can also carry the application layer identifier of the source UE, indication information supporting relay, etc.

[0192] After the relay UE receives the unicast connection establishment request message A sent by the source UE, the relay UE allocates a layer 2 address (for example, R-L2-ID-a) associated with the L2 ID of the source UE. For a detailed description of R-L2-ID-a, please refer to S201.

[0193] S202", the relay UE broadcasts a unicast connection establishment request message B, and accordingly, the target UE receives the unicast connection establishment request message B from the relay UE, where the target UE includes target UE1 and target UE2.

[0194] The difference between S202" and S202 is that in S202, the target UE determines whether it is the recipient of the message based on whether the second unicast connection establishment request message carries the application layer identifier of the corresponding target UE, while in S202", the target UE determines whether the unicast connection establishment request message B is related to itself based on whether it is interested in the service, or whether it has demand for the service. The method for generating the unicast connection establishment request message B can be directly obtained by referring to the method for generating the second unicast connection establishment request message.

[0195] For a detailed description of the process of S203, please refer to S203, the difference is that the second unicast connection establishment reception message in S203 is replaced by the unicast connection establishment reception message B1.

[0196] Optionally, before executing S203", method 200" may further include the steps of establishing security between target UE2 and relay UE1: S203"-a1, S203"-a2. S203"-a1, S203"-a2 may refer to the descriptions corresponding to S203-a1 and S203-a2 respectively.

[0197] S202", S203"-a1, S203"-a2, S203" constitute the unicast connection establishment process between the relay UE1 and the target UE2.

[0198] After the relay UE1 establishes a unicast connection with the target UE2, the relay UE1 may associate the target UE2 with an identifier in the identifier set, for example, associating the target UE2 with the first identifier. It should be understood that in a specific implementation, the relay UE1 does not necessarily save the association relationship between the target UE2 and a specific identifier, but may associate the target UE2 with the identifier set. After the relay UE1 establishes a unicast connection with other target UEs, the other target UEs will also be associated with the identifier set. Optionally, if the number of target UEs establishing unicast connections with the relay UE1 is greater than the number of identifiers included in the identifier set, the relay UE may request the source UE to allocate more identifiers.

[0199] The remaining steps S205"-S210" may refer to the description of S205-S210.

[0200] The following steps S211"-S217" are described by taking the end-to-end communication between the source UE and the target UE1 as an example.

[0201] In S202", after the target UE1 receives the unicast connection establishment request message B broadcast by the relay UE1, the target UE1 determines to execute S211" based on the application identifier carried in the unicast connection establishment request message B, and the target UE1 replies with a unicast connection establishment acceptance message B2 to the relay UE. For details, please refer to the description of S213. After the relay UE1 establishes a unicast connection with the target UE1, the relay UE1 can associate the target UE1 with one of the identifiers in the identifier set, for example, associating the target UE1 with the second identifier.

[0202] Optionally, after S211", the relay UE1 sends an indication message to the source UE, where the indication message is used to indicate that the relay UE1 has established a unicast connection with the target UE1.

[0203] For the specific process of S212" to S217", reference may be made to the specific description of S215 to S220 in method 200.

[0204] Figure 7A schematic diagram of a communication method 300 provided in the present application is shown. Different from method 200 or method 200″, in method 300, the source UE does not send the identifier allocated for the target UE to the relay UE in the unicast connection establishment request message, but the source UE allocates the identifier to the target UE after the relay UE indicates the identifier of the target UE to the source UE; or, the source UE allocates the identifier to the target UE after the relay UE indicates to the source UE that a unicast connection has been established with the target UE. Further, in method 300, the source UE broadcasts a request message to establish a unicast connection with the target UE to the relay UE, and an end-to-end connection is established with a specific target UE through the relay UE, thereby enabling end-to-end communication between the source UE and the target UE. In method 300″, the source UE broadcasts a unicast connection establishment request message to the relay UE, and an end-to-end connection is established with multiple target UEs interested in the service through the relay UE, thereby enabling end-to-end communication between the source UE and the target UE. The beneficial effects of methods 300 and 300″ can be directly referred to methods 200 and 200″.

[0205] S301, the source UE broadcasts a first unicast connection establishment request message for the target UE, and accordingly, multiple relay UEs receive the first unicast connection establishment request message from the source UE. The first unicast connection establishment request message carries the application layer identifier of the target UE. The first unicast connection establishment request message may also carry the application layer identifier of the source UE, indication information of supporting relay communication, etc. The source address of the message is the source UE L2 ID.

[0206] Compared with S201, the first unicast connection establishment request message here does not carry the first identifier. The other processing procedures in S301 are the same as S201.

[0207] For details of S302-S304, please refer to the corresponding description in S202-S204.

[0208] S305, the relay UE sends an identity allocation request message 01 to the source UE. Correspondingly, the source UE receives the identity allocation request message 01 from the relay UE. The message 01 is used to request the source terminal to allocate an identity to the target UE2.

[0209] The identity allocation request message 01 may carry the L2 ID of the target UE2, and may also carry indication information indicating that the relay UE has established a unicast connection with the target UE2.

[0210] S306, the source UE sends an identifier allocation response message 01 to the relay UE. Accordingly, the relay UE receives the identifier allocation response message 01 from the source UE. The identifier allocation response message 01 includes a first identifier but does not include the L2 ID of the target UE2. The bit length of the first identifier is less than or equal to 8 bits. The first identifier is used to identify the target UE2.

[0211] Correspondingly, the relay UE determines the association relationship between the first identifier and the target UE2.

[0212] Optionally, the relay UE may establish a unicast connection with M target UEs, where M is a positive integer and the M target UEs include the target UE 2. In S305, the identity allocation request message 01 sent by the relay UE to the source UE may include a quantity M, and the quantity M is used to request the source UE to allocate M identities to the M target UEs. The M identities include the first identity.

[0213] For the remaining steps S307 - S312 , please refer to the corresponding descriptions of S205 - S210 , respectively.

[0214] S313 - S316 refer to the description of S211 - S214 respectively, except that: the fifth unicast connection establishment request message of S313 does not carry the second identifier.

[0215] S317-S318 can refer to the description of S305-S306, with the following differences: the identifier allocation request message 01 in S305-S306 is replaced with the identifier allocation request message 02, the identifier allocation response message 01 in S305-S306 is replaced with the identifier allocation response message 02, the first identifier is replaced with the second identifier, the target UE2 is replaced with the target UE1, the first data packet is replaced with the second data packet, and the first data is replaced with the second data.

[0216] S319 - S324 may refer to the description of S215 to S220 .

[0217] In method 300", S301"-S324" can refer to the description of S301-S324 in method 300, with the difference that: the first unicast connection establishment request message in S301 carries an application identifier, the second unicast connection establishment request message sent by relay UE1 also carries the application identifier, and the target UE2 in S303" replies to the second unicast connection establishment request message based on the application identifier. The fifth unicast connection establishment request message in S313 carries an application identifier, the sixth unicast connection establishment request message sent by relay UE1 also carries the application identifier, and the target UE2 in S303" replies to the sixth unicast connection establishment request message based on the application identifier.

[0218] Figure 8A schematic diagram of a communication method 400 provided by the present application is shown. The difference between method 400 and method 300 is that in method 300, the source UE allocates an identifier to the target UE, while in method 400, the relay UE allocates an identifier to the target UE. Each time the relay UE receives a unicast connection establishment acceptance message from the target UE, it allocates an identifier to the target UE and sends the identifier to the source UE.

[0219] For S401 - S403 , reference may be made to the description of S301 - S303 in method 300 .

[0220] S404, the relay UE allocates a first identifier to the target UE 2. For the description of the first identifier, reference may be made to the description related to the first identifier in S201.

[0221] For S405 , reference may be made to the corresponding description of S304 .

[0222] For S406 - S411 , reference may be made to the description of S305 - S310 .

[0223] S412-S422 can refer to the description of S401-S411, the difference is:

[0224] Replace the first unicast connection establishment request message with the fifth unicast connection establishment request message, replace the second unicast connection establishment request message with the sixth unicast connection establishment request message, replace the second unicast connection establishment acceptance message with the sixth unicast connection establishment acceptance message, replace the target UE2 with the target UE1, replace the third unicast connection establishment request message with the seventh unicast connection establishment request message, replace the fourth unicast connection establishment request message with the eighth unicast connection establishment request message, replace the fourth unicast connection establishment acceptance message with the eighth unicast connection establishment acceptance message, replace the third unicast connection establishment acceptance message with the seventh unicast connection establishment acceptance message, replace the first data packet with the second data.

[0225] In addition, in S417, since the relay UE1 has established a unicast connection with the source UE, it will not send a unicast connection establishment acceptance message, but send indication information to the source UE to indicate the association relationship between the first identifier and the target UE2.

[0226] Among them, the first unicast connection establishment request message in S401 carries the first application identifier (or V2X service information), and the second unicast connection establishment request message in S402 also carries the first application identifier. The target UE1 determines that it does not need to reply to the second unicast connection establishment request message according to the first application identifier in S402. The fifth unicast connection establishment request in S412 includes the second application identifier, and the sixth unicast connection establishment request message in S413 also includes the second application identifier, which is different from the first application identifier. The target UE1 determines that it needs to reply to the sixth unicast connection establishment request message according to the second application identifier, and executes S415.

[0227] In another possible implementation, the first unicast connection establishment request message in S401 carries the first application identifier (or V2X service information), and the second unicast connection establishment request message in S402 also carries the first application identifier. The target UE1 and the target UE2 both determine that they need to reply to the second unicast connection establishment request message based on the application identifier. Then, S412-S414 may not be executed, and the sixth unicast connection establishment reception message of S415 may be used to reply to the second unicast connection establishment request message of S402.

[0228] In the embodiments of the present application, firstly, the unicast connection between the source UE and the relay UE is multiplexed, so that the source UE can communicate with multiple target UEs through the same relay UE, thereby saving air interface overhead; secondly, an identifier is allocated to the target UE by the relay UE, and the identifier is sent to the source UE, so that the source UE can communicate with a specific target UE while multiplexing the unicast connection between the source UE and the relay UE; thirdly, since the volume of target UEs served by the relay UE is much smaller than that of the target UEs served by the base station, compared with the base station allocating identifiers to each target UE, the number of bits of the identifier field allocated by the relay UE to each target UE is smaller, thereby saving signaling overhead.

[0229] Fig. 9 A schematic diagram of a communication method 500 provided in the present application is shown. Different from the above method, in method 500, before the source UE sends a unicast connection establishment request message for the target UE, the source UE has already allocated an identifier for the target UE and broadcast the identifier. Specifically, in the U2U discovery process of the model B method, the source UE carries the identifier allocated to the target UE in the broadcast discovery request message. When the relay UE receives the discovery response message from the target UE, it will associate the target UE with the identifier, and during the establishment of the end-to-end unicast connection between the source UE and the target UE, the correspondence between the identifier and the target UE is sent to the source UE.

[0230] S501, the source UE broadcasts a first discovery solicitation message. Accordingly, the relay UE1 receives the first discovery request message. The first discovery request message carries source UE information (for example, it may be a source UE application layer identifier), target UE2 information (for example, it may be a target UE application layer identifier), and a first identifier assigned by the source UE to the target UE2. For the description of the first identifier, please refer to the relevant description in S201. The source address of the first discovery request message is the source UE L2 ID. The first discovery request message is used to discover possible relay UEs and target UE2.

[0231] It should be understood that in the discovery process of model B, the source UE searches for possible relay UEs by broadcasting a discovery request message, and the source UE can only obtain the existence of the relay UE after receiving a discovery response message from the relay UE. In method 500, relay UE1 is used as an example for introduction, but there may be other relays that receive the first discovery request message.

[0232] It should also be understood that the example here is only that the source UE broadcasts the first discovery request message. The source UE may also broadcast other discovery request messages, such as a third discovery request message, which carries source UE information, target UE1 information, and a second identifier assigned by the source UE to the target UE1.

[0233] After receiving the first discovery request message, the relay UE allocates an L2 address associated with the source UE L2 ID, such as R-L2-ID-d, and changes the source UE L2 ID of the first discovery request message to R-L2-ID-d, generating a second discovery request message. The second discovery request message does not carry the first identifier. At the same time, the RID of the relay UE is added to the second discovery request message.

[0234] S502, relay UE1 broadcasts a second discovery request message, and accordingly, target UE1 and target UE2 receive the second discovery request message from relay UE1. The second discovery request message carries source UE information, target UE2 information, and relay UE information (eg, RID).

[0235] It should be understood that after receiving the first discovery request message sent by the source UE, the relay UE1 decides to forward the message for the source UE as a relay, that is, broadcast the second discovery request message. The source address of the message is R-L2-ID-d. R-L2-ID-d is the L2 ID associated with the source UE assigned by the relay UE1. For related descriptions, refer to the description related to R-L2-ID-a in S202.

[0236] S503, the target UE2 replies a second discovery response message to the possible relay UE, and accordingly, the possible relay UE receives the second discovery response message from the target UE2. The second discovery response message carries source UE information and target UE2 information, and the source address of the second discovery response message is the L2 ID of the target UE2, and the destination address is R-L2-ID-d.

[0237] If in S502, the target UE2 receives the second discovery request message from M possible relay UEs, the target UE2 may reply the second discovery request message to N possible relay UEs, where 1≤N≤M, and N and M are both integers.

[0238] S502 and S503 constitute the process of the relay UE discovering the target UE.

[0239] S504, relay UE1 replies to the source UE with a first discovery response message, and accordingly, the source UE receives the first discovery response message from relay UE1. The first discovery response message carries source UE information and target UE2 information. Relay UE1 allocates an R-L2-ID-e associated with target UE2, and uses R-L2-ID-e as the source address of the first discovery response message. The destination address of the first discovery response message is the source UE ID.

[0240] Correspondingly, the source UE can obtain the association relationship between the target UE2 and the first identifier according to that the destination address of the first discovery response message is the source address of the first discovery request message.

[0241] Optionally, N possible relay UEs discover the target UE 2 according to the first discovery request message and reply a first discovery response message to the source UE. The source UE may select a relay UE1 from the N possible relay UEs that reply to the first discovery response message based on factors such as link quality, and send data to the target UE 2 through the relay UE1 in subsequent steps, where N is a positive integer.

[0242] S501 and S504 constitute a process in which the source UE discovers the relay UE1, and S501 to S504 constitute a process in which the source UE discovers the target UE2.

[0243] Optionally, S505 , a PC5 link is established between the source UE and the relay UE1 , for details, please refer to the corresponding descriptions of S201 and S205 in method 200 .

[0244] If an available PC5 link already exists between the source UE and the relay UE, S505 is not executed.

[0245] Optionally, S506 , a PC5 link is established between the target UE2 and the relay UE1 , for details, please refer to the corresponding descriptions of S202 and S203 in method 200 .

[0246] If an available PC5 link already exists between the target UE2 and the relay UE, S506 is not executed.

[0247] Optionally, S507 , a PC5 link is established between the source UE and the target UE2 , for details, please refer to the description corresponding to S205 - S208 in method 200 .

[0248] If an available PC5 link already exists between the target UE2 and the source UE, S507 is not executed.

[0249] For details of S508-S509, please refer to the corresponding description in S209-S210.

[0250] S510-S513 can refer to the description of S501-S504, the difference is:

[0251] Replace the first discovery request message with the third discovery request message, replace the second discovery request message with the fourth discovery request message, replace the second discovery response message with the fourth discovery response message, replace the first discovery response message with the third discovery response message, replace the target UE2 with the target UE1, replace the first identifier with the second identifier, and.

[0252] S514-S517, for details, please refer to the corresponding description of S506-S509. The difference is that the target UE2 is replaced by the target UE1, the first identifier is replaced by the second identifier, the first data packet is replaced by the second data packet, the first data is replaced by the second data, the target UE2 L2 ID is replaced by the target UE1 L2 ID, and R-L2-ID-e is replaced by R-L2-ID-f. The R-L2-ID-f is associated with the source UE and serves as the source address of the relay for forwarding the message from the source UE to the target UE1.

[0253] Among them, in S515-S517, the relay UE1 forwards the message for the source UE and the target UE1. After receiving the message from the target UE1, the relay UE1 changes the source address of the message from the target UE1 to R-L2-ID-d, and the destination address to the L2ID of the source UE. Accordingly, when the source UE sends a message to the relay UE1 for the target UE1 or the target UE2, the destination address of the message is R-L2-ID-d. Therefore, the unicast connection between the source UE and the relay UE1 can be reused.

[0254] In the embodiments of the present application, firstly, the unicast connection between the source UE and the relay UE is multiplexed, so that the source UE can communicate with multiple target UEs through the same relay UE, thereby saving air interface overhead; secondly, the source UE allocates an identifier to the target UE, so that the source UE can communicate with a specific target UE while multiplexing the unicast connection between the source UE and the relay UE; thirdly, the source UE carries the identifier configured for the specific target UE in the message requesting to discover the target UE, so that after the unicast connection is established between the source UE and the target UE, communication can be carried out based on the identifier configured by the source UE, thereby avoiding allocating an identifier to the target UE after the source UE and the target UE establish a unicast connection, thereby saving signaling overhead.

[0255] Fig.10 The schematic diagram of the communication method 600 provided by the present application is shown. The difference between the method 600 and the method 500 is that in the method 500, the source UE allocates an identifier to the target UE, and in the method 600, the relay UE allocates an identifier to the target UE. Specifically, each time a possible relay UE finds a target UE, it allocates an identifier to the target UE. The beneficial effects of the method 600 can be directly referred to the method 500.

[0256] S601, the source UE broadcasts a first discovery solicitation message, and correspondingly, multiple possible relay UEs receive the first discovery solicitation message. For details, please refer to the corresponding description of S501, except that the first discovery solicitation message in S601 does not carry the first identifier.

[0257] S602, the potential relay UE broadcasts a second discovery request message, and accordingly, the target UE1 and the target UE2 receive the second discovery request message from the potential relay UE. For details, please refer to the corresponding description of S502.

[0258] S603, the target UE2 replies with a second discovery response message, and accordingly, the potential relay UE receives the second discovery response message from the target UE2. For details, please refer to the description of S503.

[0259] S604, the potential relay UE allocates a first identifier to the target UE2.

[0260] It should be understood that even if the source UE has not yet selected the possible relay UE as the relay UE to help the source UE and the target UE2 forward messages, the possible relay UE can still first assign an identifier to the target UE2 after receiving the second discovery response message replied by the target UE2, so that the source UE can directly use it when establishing an end-to-end unicast connection with the target UE2 based on the possible relay UE.

[0261] S605, the potential relay UE replies a first discovery response message to the source UE, and accordingly, the source UE receives the first discovery response message from the potential relay UE. For details, please refer to the corresponding description in S504.

[0262] For S606-S610, please refer to the corresponding descriptions in S505-S509 respectively.

[0263] S611-S615 can refer to the description of S601-S605, the difference is:

[0264] Replace the first discovery request message with the third discovery request message, replace the second discovery request message with the fourth discovery request message, replace the second discovery response message with the fourth discovery response message, replace the first discovery response message with the third discovery response message, replace the target UE2 with the target UE1, and replace the first identifier with the second identifier.

[0265] S616-S619, for details, please refer to the corresponding description of S607-S610, the difference is that the target UE2 is replaced by the target UE1, the first identifier is replaced by the second identifier, the first data packet is replaced by the second data packet, and the first data is replaced by the second data.

[0266] Based on similar reasons as those in method 500 , method 600 may also implement a unicast connection between a multiplexing source UE and a relay UE1 .

[0267] It is understandable that, in order to implement the functions in the above embodiments, the base station and the terminal include hardware structures and / or software modules corresponding to the execution of each function. It should be easily appreciated by those skilled in the art that, in combination with the units and method steps of each example described in the embodiments disclosed in this application, the present application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in the form of hardware or computer software driving hardware depends on the specific application scenario and design constraints of the technical solution.

[0268] Fig.11 and Fig.12 A schematic diagram of the structure of possible communication devices provided for embodiments of the present application. These communication devices can be used to implement the functions of the source UE or relay UE1 or target UE in the above method embodiments, and thus can also achieve the beneficial effects possessed by the above method embodiments. In an embodiment of the present application, the communication device can be a source UE or relay UE1 or target UE, and can also be a module (such as a chip) applied to the source UE or relay UE1 or target UE.

[0269] like Fig.11 As shown, the communication device 1100 includes a processing unit 1110 and a transceiver unit 1120. The communication device 1100 is used to implement the above Figure 5-Figure 10 The functions of the source UE or relay UE1 or target UE in the method embodiment shown in FIG.

[0270] When the communication device 1100 is used to implement Figure 7 In the method embodiment shown, when the function of relaying UE1 is performed: the transceiver unit 1120 is used to receive a first unicast connection establishment request message from the source UE; send a second unicast connection establishment request message to the target UE2, requesting to establish a unicast connection between the relay UE1 and the target UE2; receive a second unicast connection establishment acceptance message from the target UE2, used to indicate that the target UE2 has accepted the unicast connection establishment request between the relay UE1 and the target UE2; send an identifier allocation request message to the source UE, requesting the source UE to allocate an identifier to the target UE2; receive an identifier allocation response message from the source UE, the identifier allocation response message including a first identifier but not including a layer 2 address of the target UE2, the bit length of the first identifier being less than or equal to 8 bits, and the first identifier being used to identify ... A third unicast connection establishment request message from the source UE, requesting to establish a unicast connection between the source UE and the target UE2; sending a fourth unicast connection establishment request message to the target UE2, requesting to establish a unicast connection between the source UE and the target UE2; receiving a fourth unicast connection establishment acceptance message from the target UE2, used to indicate that the target UE2 has accepted the unicast connection establishment request between the source UE and the target UE2; sending the third unicast connection establishment acceptance message to the source UE, used to indicate that the target UE2 has accepted the unicast connection establishment request between the source UE and the target UE2, the third unicast connection establishment acceptance message including the first identifier; receiving a first data packet from the source UE, the first data packet including the first identifier and first data; sending the first data to the target UE2 according to the first identifier.

[0271] When the communication device 1100 is used to implement Figure 7In the method embodiment shown, the function of the source UE is as follows: the transceiver unit 1120 is used to send a first unicast connection establishment request message to the relay UE1; receive a first unicast connection establishment acceptance message from the relay UE1, used to indicate that the target UE2 has accepted the unicast connection establishment request between the relay UE1 and the target UE2; receive an identity allocation request message from the relay UE1, the identity allocation request message is used to request the source UE to allocate an identity to the target UE2; send an identity allocation response message to the relay UE1, the identity allocation response message includes the first identity but does not include the The layer 2 address of the target UE2, the bit length of the first identifier is less than or equal to 8 bits, and the first identifier is used for the source UE and the relay UE1 to identify the target UE2; sending a third unicast connection establishment request message to the relay UE1, requesting to establish a unicast connection between the source UE and the target UE2; receiving a third unicast connection establishment acceptance message from the relay UE1, used to indicate that the target UE2 has accepted the unicast connection establishment request between the source UE and the target UE2; the source UE sends a first data packet to the relay UE1, and the first data packet includes the first identifier and first data.

[0272] When the communication device 1100 is used to implement Figure 5 Or the function of the relay UE1 in the method embodiment shown in 6: the transceiver unit 1120 is used to receive a first unicast connection establishment request message from the source UE, the first unicast connection establishment request message includes a first identifier, the bit length of the first identifier is less than or equal to 8 bits, and the first identifier is associated with the target UE2; send a second unicast connection establishment request message to the target UE2 to request to establish a unicast connection between the source UE and the target UE2; receive a second unicast connection establishment acceptance message from the target UE2, used to indicate that the target UE2 has accepted the unicast connection establishment request between the relay UE1 and the target UE2; receive a third unicast connection establishment request message from the source UE, requesting to establish a unicast connection between the source UE and the target UE2 The method comprises the following steps: establishing a unicast connection between the source UE and the target UE2, wherein the third unicast connection establishment request message includes a first identifier; sending a fourth unicast connection establishment request message to the target UE2, requesting to establish a unicast connection between the source UE and the target UE2; receiving a fourth unicast connection establishment acceptance message from the target UE2, used to indicate that the target UE2 has accepted the unicast connection establishment request between the source UE and the target UE2; sending a third unicast connection establishment acceptance message to the source UE, used to indicate that the target UE2 has accepted the unicast connection establishment request between the source UE and the target UE2; receiving a first data packet from the source UE, the first data packet including the first identifier and first data; and sending the first data to the target UE2 according to the first identifier.

[0273] When the communication device 1100 is used to implement Figure 7 When the function of the source UE in the method embodiment shown is: the transceiver unit 1120 is used to send a first unicast connection establishment request message to the relay UE1, and the first unicast connection establishment request message includes a first identifier, and the first identifier is associated with the target UE2; send a third unicast connection establishment request message to the relay UE1, requesting to establish a unicast connection between the source UE and the target UE2; receive a third unicast connection establishment acceptance message from the relay UE1, which is used to indicate that the target UE2 has accepted the unicast connection establishment request between the source UE and the target UE2; send a first data packet to the relay UE1, and the first data packet includes the first identifier and first data.

[0274] When the communication device 1100 is used to implement Fig. 9 When the function of the relay UE1 in the method embodiment shown is performed: the transceiver unit 1120 is used to receive a first discovery request message from the source UE, which is used to request the discovery of the target UE2, and the first discovery request message includes a first identifier, and the first identifier is associated with the target UE2; a second discovery request message is sent to the target UE2, which is used to request the discovery of the target UE2; a second discovery response message is received from the target UE2, which is used to indicate that the target UE2 replies to the relay UE1 with the layer 2 address of the target UE2 according to the second discovery request message; a first discovery response message is received from the target UE2, which is used to indicate that the target UE2 replies to the source UE with the layer 2 address of the target UE2 device according to the first discovery request message and the second discovery request message; the first discovery response message is sent to the source UE; a first data packet is received from the source UE, and the first data packet includes the first identifier and first data; and the first data is sent to the target UE2 according to the first identifier.

[0275] When the communication device 1100 is used to implement Fig. 9 When the function of the source UE in the method embodiment shown is: the transceiver unit 1120 is used to send a first discovery request message to the relay UE1, requesting to discover the target UE2, the first discovery request message including a first identifier, and the first identifier is associated with the target UE2; receiving a first discovery response message from the relay UE1, used to instruct the target UE2 to reply the layer 2 address of the target UE2 to the relay UE1 according to the second discovery request message; sending a first data packet to the relay UE1, the first data packet including a first identifier and first data, the first identifier being used to indicate that the first data is to be sent to the target UE2, and being used to instruct the target UE2 to reply the layer 2 address of the target UE2 device to the source UE according to the first discovery request message and the second discovery request message.

[0276] When the communication device 1100 is used to implement Figure 8When the function of the relay UE1 in the method embodiment shown is: the transceiver unit 1120 is used to receive a first unicast connection establishment request message from the source UE; send a second unicast connection establishment request message to the target UE2; receive a second unicast connection establishment acceptance message from the target UE2, used to indicate that the target UE2 has established a unicast connection with the relay UE1 according to the second unicast connection establishment request message; receive a third unicast connection establishment request message from the source UE; send the third unicast connection establishment request message to the target UE2; receive a third unicast connection establishment acceptance message from the target UE2, used to indicate that the target UE2 has established a unicast connection with the source UE according to the third unicast connection establishment request message; send the third unicast connection establishment acceptance message to the source UE; receive a first data packet from the source UE, the first data packet including the first identifier and first data; send the first data to the target UE2 according to the first identifier; the processing unit 1110 is used to assign a first identifier to the target UE2.

[0277] When the communication device 1100 is used to implement Figure 8 When the functions of the source UE in the method embodiment shown are: the transceiver unit 1120 is used to send a first unicast connection establishment request message to the relay UE1; send a third unicast connection establishment request message to the relay UE1, requesting to establish a unicast connection between the source UE and the target UE2; receive a third unicast connection establishment acceptance message from the relay UE1, used to indicate that the target UE2 has accepted the unicast connection establishment request between the source UE and the target UE2; receive an association relationship between the target UE2 and the first identifier from the relay UE1; and send a first data packet to the relay UE1 according to the association relationship, the first data packet including the first identifier and the first data.

[0278] When the communication device 1100 is used to implement Fig.10 When the function of the relay UE1 in the method embodiment shown is: the transceiver unit 1120 is used to receive a first discovery request message from the source UE, which is used to discover the target UE2; send a second discovery request message to the target UE2, which is used to discover the target UE2; receive a second discovery response message from the target UE2, which is used to instruct the target UE2 to reply the layer 2 address of the target UE2 to the relay UE1 according to the second discovery request message; receive a first discovery response message from the target UE2, which is used to instruct the target UE2 to reply the layer 2 address of the target UE2 device to the source UE according to the first discovery request message and the second discovery request message; assign a first identifier to the target UE2; send the first discovery response message to the source UE; receive a first data packet from the source UE, the first data packet including the first identifier and first data; send the first data to the target UE2 according to the first identifier.

[0279] When the communication device 1100 is used to implement Fig.10 When the functions of the source UE in the method embodiment shown are: the transceiver unit 1120 is used to send a first discovery request message to the relay UE1; receive a first discovery response message from the relay UE1, used to instruct the target UE2 to reply the layer 2 address of the target UE2 device to the source UE according to the first discovery request message and the second discovery request message; receive the association relationship between the target UE2 and the first identifier from the relay UE1; the source UE sends a first data packet to the relay UE1 according to the association relationship, and the first data packet includes a first identifier and first data.

[0280] For more detailed description of the processing unit 1110 and the transceiver unit 1120, please refer to Figures 5 to 10 The method embodiment shown is described in detail.

[0281] like Fig.12 As shown, the communication device 1200 includes a processor 1210 and an interface circuit 1220. The processor 1210 and the interface circuit 1220 are coupled to each other. It is understood that the interface circuit 1220 can be a transceiver or an input-output interface. Optionally, the communication device 1200 may also include a memory 1230 for storing instructions executed by the processor 1210 or storing input data required by the processor 1210 to execute instructions or storing data generated after the processor 1210 executes instructions.

[0282] When the communication device 1200 is used to implement Fig.12 When the method is shown, the processor 1210 is used to implement the function of the above-mentioned processing unit 1110, and the interface circuit 1220 is used to implement the function of the above-mentioned transceiver unit 1120.

[0283] When the above communication device is a chip applied to relay UE1, the relay UE1 chip implements the functions of the relay UE1 in the above method embodiment. The relay UE1 chip receives information from other modules (such as a radio frequency module or an antenna) in the relay UE1, and the information is sent to the relay UE1 by the source UE or the target UE; or, the relay UE1 chip sends information to other modules (such as a radio frequency module or an antenna) in the relay UE1, and the information is sent by the relay UE1 to the source UE or the target UE.

[0284] When the above communication device is a chip applied to the source UE, the terminal chip implements the function of the source UE in the above method embodiment. The chip of the source UE receives information from other modules (such as a radio frequency module or an antenna) in the source UE, and the information is sent to the source UE by the target UE or the relay UE1; or the chip of the source UE sends information to other modules (such as a radio frequency module or an antenna) in the base station, and the information is sent to the target UE or the relay UE1 by the source UE.

[0285] When the above communication device is a chip applied to the target UE, the terminal chip implements the function of the target UE in the above method embodiment. The chip of the target UE receives information from other modules (such as a radio frequency module or an antenna) in the target UE, and the information is sent to the target UE by the source UE or the relay UE1; or, the chip of the target UE sends information to other modules (such as a radio frequency module or an antenna) in the base station, and the information is sent to the source UE or the relay UE1 by the target UE.

[0286] It is understandable that the processor in the embodiments of the present application may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0287] The method steps in the embodiments of the present application can be implemented in hardware or in software instructions that can be executed by a processor. The software instructions can be composed of corresponding software modules, and the software modules can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, register, hard disk, mobile hard disk, CD-ROM or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. The storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC. In addition, the ASIC can be located in a base station or a terminal. The processor and the storage medium can also be present in a base station or a terminal as discrete components.

[0288] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instruction is loaded and executed on a computer, the process or function described in the embodiment of the present application is executed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device or other programmable device. The computer program or instruction may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer program or instruction may be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired or wireless means. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server, data center, etc. that integrates one or more available media. The available medium may be a magnetic medium, for example, a floppy disk, a hard disk, a tape; it may also be an optical medium, for example, a digital video disc; it may also be a semiconductor medium, for example, a solid-state hard disk. The computer-readable storage medium may be a volatile or nonvolatile storage medium, or may include both volatile and nonvolatile types of storage media.

[0289] In the various embodiments of the present application, unless otherwise specified or provided for in any logical conflict, the terms and / or descriptions between the different embodiments are consistent and may be referenced to each other, and the technical features in the different embodiments may be combined to form new embodiments according to their inherent logical relationships.

[0290] In the present application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In the text description of the present application, the character " / " generally indicates that the previous and next associated objects are in an "or" relationship; in the formula of the present application, the character " / " indicates that the previous and next associated objects are in a "division" relationship. "Including at least one of A, B and C" can mean: including A; including B; including C; including A and B; including A and C; including B and C; including A, B and C.

[0291] It is understood that the various numbers involved in the embodiments of the present application are only for the convenience of description and are not used to limit the scope of the embodiments of the present application. The size of the sequence number of the above-mentioned processes does not mean the order of execution, and the execution order of each process should be determined by its function and internal logic.

Claims

1. A relay communication method, executed by a relay terminal or a component of a relay terminal, characterized in that: include: receiving a first unicast connection establishment request message from a source terminal; Sending a second unicast connection establishment request message to the first target terminal; receiving a second unicast connection establishment accept message from the first target terminal, which is used to indicate that the first target terminal has established a unicast connection with the relay terminal according to the second unicast connection establishment request message; Allocating a first identifier to the first target terminal; receiving a third unicast connection establishment request message from the source terminal; Sending the third unicast connection establishment request message to the first target terminal; receiving a third unicast connection establishment accept message from the first target terminal, which is used to indicate that the first target terminal has established a unicast connection with the source terminal according to the third unicast connection establishment request message; Sending the third unicast connection establishment acceptance message to the source terminal; receiving a first data packet from the source terminal, where the first data packet includes the first identifier and first data; The first data is sent to the first target terminal according to the first identifier.

2. The method according to claim 1, characterized in that The method further comprises: Sending an association relationship between the first identifier and the first target terminal to the source terminal.

3. The method according to claim 1 or 2, characterized in that: The method further comprises: receiving a third security activation command message from the first target terminal; Sending the fourth security activation command message to the source terminal, where the fourth security activation command message includes the first identifier, which is used to indicate that the fourth security activation command message comes from the first target terminal; receiving a fourth security activation completion message from the source terminal, where the fourth security activation completion message includes the first identifier, which is used to indicate that the fourth security activation completion message is sent to the first target terminal; Send a third security activation completion message to the first target terminal.

4. The method according to any one of claims 1 to 3, characterized in that The method further comprises: A second data packet is received from the source terminal, wherein the second data packet includes a second identifier, second data, and a layer 2 address of the relay terminal, and the first data packet also includes the layer 2 address of the relay terminal.

5. The method according to any one of claims 1 to 4, characterized in that The sending the first data to the first target terminal according to the first identifier includes: The first data packet is sent to the first target terminal according to the first identifier.

6. The method according to any one of claims 1 to 5, characterized in that The method further comprises: Send a first identifier to the first target terminal.

7. The method according to any one of claims 1 to 6, characterized in that The method further comprises: receiving fourth data from the first target terminal; According to the association relationship, the first identifier is configured for the fourth data to obtain a fourth data packet; The fourth data packet is sent to the source terminal, where the fourth data packet includes the fourth data and the first identifier.

8. A relay communication method, executed by a source terminal or a component of a source terminal, characterized in that: include: Sending a first unicast connection establishment request message to the relay terminal; Sending a third unicast connection establishment request message to the relay terminal, requesting to establish a unicast connection between the source terminal and the first target terminal; receiving a third unicast connection establishment acceptance message from the relay terminal, which is used to indicate that the first target terminal has accepted the unicast connection establishment request between the source terminal and the first target terminal; receiving an association relationship between a first target terminal and a first identifier from the relay terminal; A first data packet is sent to the relay terminal according to the association relationship, where the first data packet includes the first identifier and first data.

9. The method according to claim 8, characterized in that The method further comprises: receiving a fourth security activation command message from the relay terminal, where the fourth security activation command message includes the first identifier, which is used to indicate that the fourth security activation command message comes from the first target terminal; A fourth security activation completion message is sent to the relay terminal, where the fourth security activation completion message includes the first identifier, which is used to instruct to send the fourth security activation completion message to the first target terminal.

10. The method according to claim 8 or 9, characterized in that: The method further comprises: A second data packet is sent to the relay terminal, where the second data packet includes a second identifier, second data, and a layer 2 address of the relay terminal, and the first data packet also includes the layer 2 address of the relay terminal.

11. A relay communication method, executed by a relay terminal or a component of a relay terminal, characterized in that: include: Receiving a first discovery request message from a source terminal for discovering a first target terminal; Sending a second discovery request message to the first target terminal to discover the first target terminal; receiving a second discovery response message from the first target terminal, used to instruct the first target terminal to reply the layer 2 address of the first target terminal to the relay terminal according to the second discovery request message; receiving a first discovery response message from the first target terminal, used to instruct the first target terminal to reply to the source terminal with a layer 2 address of the first target terminal device according to the first discovery request message and the second discovery request message; Allocating a first identifier to the first target terminal; Sending the first discovery response message to the source terminal; receiving a first data packet from the source terminal, where the first data packet includes the first identifier and first data; The first data is sent to the first target terminal according to the first identifier.

12. A communication device, comprising a module for executing the method according to any one of claims 1 to 11.

13. A communication device, characterized in that: The method comprises a processor and an interface circuit, wherein the interface circuit is used to receive signals from other communication devices and transmit them to the processor or send signals from the processor to other communication devices, and the processor is used to implement the method as described in any one of claims 1 to 11 through a logic circuit or by executing code instructions.

14. A computer-readable storage medium, characterized in that: The storage medium stores a computer program or an instruction, and when the computer program or the instruction is executed by the communication device, the method according to any one of claims 1 to 11 is implemented.

15. A computer program product, characterized in that The computer program product comprises a computer program or instructions, and when the computer program or instructions are executed by a communication device, the method according to any one of claims 1 to 11 is implemented.

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