Sidelink communications method and apparatus

1. A communication method, wherein the method comprises:

sending, at a first protocol layer entity of a first terminal device, communication type information and a target side identifier to a second protocol layer entity of the first terminal device, wherein the communication type information identifies a unicast communication, and the target side identifier comprises an identifier of a second terminal device; and

establishing, at the second protocol layer entity of the first terminal device, at least one radio bearer for unicast communication, wherein the at least one radio bearer corresponds to the target side identifier.

2. The method according to claim 1 , wherein

configuration information of the at least one radio bearer is prestored in the first terminal device.

3. The method according to claim 1 , wherein the method further comprises:

sending, at the second protocol layer entity of the first terminal device, a first message to a second protocol layer entity of the second terminal device, wherein the first terminal device and the second terminal device are performing or are to perform the unicast communication, and the first message comprises configuration information of the at least one radio bearer; and

receiving, at the second protocol layer entity of the first terminal device, a second message in response to the first message from the second terminal device.

4. The method according to claim 3 , wherein the method further comprises:

when the second protocol layer entity of the first terminal device does not receive the second message in a duration greater than or equal to a specified duration, resending, at the second protocol layer entity of the first terminal device, the first message to the second protocol layer entity of the second terminal device.

5. The method according to claim 3 , wherein the method further comprises:

determining, at the second protocol layer entity of the first terminal device, a security mode configuration that is to be used by the first terminal device to perform confidentiality protection and integrity protection on the first message; and

wherein sending, at the second protocol layer entity of the first terminal device, the first message to the second protocol layer entity of the second terminal device comprises: sending, at the second protocol layer entity of the first terminal device, the first message and the security mode configuration to a packet data convergence protocol (PDCP) layer entity of the first terminal device, wherein after performing the confidentiality protection and the integrity protection on the first message based on the security mode configuration, the PDCP layer entity of the first terminal device sends the first message to the second protocol layer entity of the second terminal device.

6. The method according to claim 1 , wherein the method further comprises:

broadcasting, at the first protocol layer entity of the first terminal device, an establishment request, wherein the establishment request requests to establish the unicast communication; and

receiving, at the first protocol layer entity of the first terminal device, an establishment response, wherein the establishment response indicates to establish the unicast communication with the first terminal device.

7. A communication apparatus, comprising:

at least one processor, and a memory storing instructions that are executable by the at least one processor;

wherein, when executed, the instructions cause the apparatus to perform operations comprising:

sending, at a first protocol layer entity of the communication apparatus, communication type information and a target side identifier to a second protocol layer entity of the communication apparatus, wherein the communication type information identifies a unicast communication, and the target side identifier comprises an identifier of a second terminal device; and

establishing, at the second protocol layer entity of the communication apparatus, at least one radio bearer for unicast communication, wherein the at least one radio bearer corresponds to the target side identifier.

8. The communication apparatus according to claim 7 , wherein configuration information of the at least one radio bearer is prestored in the communication apparatus.

9. The communication apparatus according to claim 7 , wherein, when executed, the instructions cause the communication apparatus further to perform:

sending, at the second protocol layer entity of the communication apparatus, a first message to a second protocol layer entity of the second terminal device, wherein the communication apparatus and the second terminal device are performing or are to perform the unicast communication, and the first message comprises configuration information of the at least one radio bearer; and

receiving, at the second protocol layer entity of the communication apparatus, a second message in response to the first message from the second terminal device.

10. The communication apparatus according to claim 9 , wherein, when executed, the instructions cause the communication apparatus further to perform:

when the second protocol layer entity of the communication apparatus does not receive the second message in a duration greater than or equal to a specified duration, resending, at the second protocol layer entity of the communication apparatus, the first message to the second protocol layer entity of the second terminal device.

11. The communication apparatus according to claim 9 , wherein, when executed, the instructions cause the communication apparatus further to perform:

determining, at the second protocol layer entity of the communication apparatus, a security mode configuration that is to be used by the communication apparatus to perform confidentiality protection and integrity protection on the first message; and

wherein sending, by the second protocol layer entity of the communication apparatus, the first message to the second protocol layer entity of the second terminal device comprises: sending, at the second protocol layer entity of the communication apparatus, the first message and the security mode configuration to a packet data convergence protocol (PDCP) layer entity of the communication apparatus, wherein after performing the confidentiality protection and the integrity protection on the first message based on the security mode configuration, the PDCP layer entity of the communication apparatus sends the first message to the second protocol layer entity of the second terminal device.

12. The communication apparatus according to claim 7 , wherein, when executed, the instructions cause the communication apparatus further to perform:

broadcasting, at the first protocol layer entity of the communication apparatus, an establishment request, wherein the establishment request requests to establish the unicast communication; and

receiving, at the first protocol layer entity of the communication apparatus, an establishment response, wherein the establishment response indicates to establish the unicast communication with the communication apparatus.

13. A non-transitory memory storage medium comprising computer-executable instructions that, when executed, cause a first terminal device to perform:

sending, at a first protocol layer entity of the first terminal device, communication type information and a target side identifier to a second protocol layer entity of the first terminal device, wherein the communication type information identifies a unicast communication, and the target side identifier comprises an identifier of a second terminal device; and

establishing, at the second protocol layer entity of the first terminal device, at least one radio bearer for unicast communication, wherein the at least one radio bearer correspond to the target side identifier.

14. The non-transitory memory storage medium according to claim 13 ,

wherein configuration information of the at least one radio bearer is prestored in the first terminal device.

15. The non-transitory memory storage medium according to claim 13 , wherein the instructions, when executed, cause the first terminal device further to perform:

sending, at the second protocol layer entity of the first terminal device, a first message to a second protocol layer entity of the second terminal device, wherein the first terminal device and the second terminal device are performing or are to perform the unicast communication, and the first message comprises configuration information of the at least one radio bearer; and

receiving, at the second protocol layer entity of the first terminal device, a second message in response to the first message from the second terminal device.

16. The non-transitory memory storage medium according to claim 15 , wherein the instructions, when executed, cause the first terminal device further to perform:

when the second protocol layer entity of the first terminal device does not receive the second message in a duration greater than or equal to a specified duration, resending, at the second protocol layer entity of the first terminal device, the first message to the second protocol layer entity of the second terminal device.

17. The non-transitory memory storage medium according to claim 15 , wherein the instructions, when executed, cause the first terminal device further to perform:

determining, at the second protocol layer entity of the first terminal device, a security mode configuration that is to be used by the first terminal device to perform confidentiality protection and integrity protection on the first message; and

wherein sending, at the second protocol layer entity of the first terminal device, the first message to the second protocol layer entity of the second terminal device comprises: sending, at the second protocol layer entity of the first terminal device, the first message and the security mode configuration to a packet data convergence protocol (PDCP) layer entity of the first terminal device, wherein after performing the confidentiality protection and the integrity protection on the first message based on the security mode configuration, the PDCP layer entity of the first terminal device sends the first message to the second protocol layer entity of the second terminal device.

18. The non-transitory memory storage medium according to claim 13 , wherein the instructions, when executed, cause the first terminal device further to perform:

broadcasting, at the first protocol layer entity of the first terminal device, an establishment request, wherein the establishment request requests to establish the unicast communication; and

receiving, at the first protocol layer entity of the first terminal device, an establishment response, wherein the establishment response indicates to establish the unicast communication with the first terminal device.