Communication method and apparatus

1 . A communication method performed by a first terminal device or a chip in the first terminal device, comprising:

determining a candidate relay device set, wherein the candidate relay device set comprises at least one candidate relay device, and a status of a signal between the at least one candidate relay device and the first terminal device satisfies a first preset condition; and

sending a first message to a second terminal device, wherein the first terminal device and the second terminal device perform relay communication via a first relay device, wherein the first message comprises an identifier of the at least one candidate relay device, a relay reselection indication indicating to change a relay device, and an address of the at least one candidate relay device, wherein the address of the at least one candidate relay device is for obtaining a status of a communication link between the second terminal device and the at least one candidate relay device, and the address of the at least one candidate relay device is a layer 2 identifier; and

receiving indication information from the second terminal device based on the first message, wherein the indication information indicates to change a relay device between the second terminal device and the first terminal device to a second relay device, wherein the at least one candidate relay device comprises the second relay device, the indication information comprises an identifier of the second relay device, and the indication information is carried by a link modification request message.

2 . The method according to claim 1 , wherein the sending a first message to the second terminal device comprises:

sending the first message to the second terminal device via the first relay device.

3 . The method according to claim 1 , wherein the determining the candidate relay device set comprises:

determining, based on a status of a signal between a third terminal device and the first terminal device, that the candidate relay device set comprises the third terminal device, wherein the status of the signal comprises at least one of signal quality or signal strength.

4 . The method according to claim 3 , wherein determining, based on the status of the signal between the third terminal device and the first terminal device, that the at least one candidate relay device comprises the third terminal device comprises:

determining, based on the status of the signal between the third terminal device and the first terminal device and based on a status of a signal between the first relay device and the first terminal device, that the at least one candidate relay device comprises the third terminal device; or

determining, based on the status of the signal between the third terminal device and the first terminal device, a status of a signal between the first relay device and the first terminal device, and a status of a communication link between the third terminal device and the second terminal device, that the at least one candidate relay device comprises the third terminal device, wherein the communication link status comprises either the communication link exists or communication link does not exist.

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

obtaining the status of the signal between the third terminal device and the first terminal device.

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

obtaining the status of the communication link between the third terminal device and the second terminal device.

7 . The method according to claim 1 , wherein the status of the signal comprises at least one of signal quality or signal strength of an announcement message received from the at least one candidate relay device.

8 . The method according to claim 1 , wherein the status of the signal comprises at least one of signal quality or signal strength of a response message to a discovery message received from the at least one candidate relay device.

9 . A communication method performed by a second terminal device or a chip in the second terminal device, comprising:

receiving a first message from a first terminal device, wherein the second terminal device and the first terminal device perform relay communication via a first relay device, wherein the first message comprises an identifier of at least one candidate relay device, a relay reselection indication indicating to change a relay device, and an address of the at least one candidate relay device, and the address of the at least one candidate relay device is a layer 2 identifier, wherein a status of a signal between the at least one candidate relay device and the first terminal device satisfies a first preset condition;

obtaining, based on the address of the at least one candidate relay device, a status of a signal between the at least one candidate relay device and the second terminal device;

determining, based on the status of the signal between each of the at least one candidate relay device and the second terminal device, a second relay device from the at least one candidate relay device; and

sending indication information to the first terminal device, wherein the indication information indicates to change a relay device between the second terminal device and the first terminal device to the second relay device, the indication information comprises an identifier of the second relay device, and the indication information is carried by a link modification request message.

10 . The method according to claim 9 , wherein the obtaining, based on the address of the at least one candidate relay device, a status of a signal between the at least one candidate relay device and the second terminal device comprises:

sending a request message to a second candidate relay device based on an address of the second candidate relay device, wherein the second candidate relay device is any relay device in the at least one candidate relay device;

receiving a response message from the second candidate relay device; and

determining a status of a signal between the second candidate relay device and the second terminal device based on the response message.

11 . The method according to claim 9 , wherein the sending indication information to the first terminal device comprises sending the indication information to the second terminal device via the first relay device.

12 . A communication apparatus, comprising:

at least one processor; and

a non-transitory computer-readable storage medium storing a program to be executed by the at least one processor, the program including instructions for:

determining a candidate relay device set, wherein the candidate relay device set comprises at least one candidate relay device, and a status of a signal between the at least one relay device and the communication apparatus satisfies a first preset condition; and

sending a first message to a second terminal device, wherein the second terminal device and the communication apparatus perform relay communication via a first relay device, wherein the first message comprises an identifier of the at least one candidate relay device, a relay reselection indication indicating to change a relay device, and an address of the at least one candidate relay device, wherein the address of the at least one candidate relay device is for obtaining a status of a communication link between the second terminal device and the at least one candidate relay device, and the address of the at least one candidate relay device is a layer 2 identifier; and

receiving indication information from the second terminal device based on the first message, wherein the indication information indicates to change a relay device between the second terminal device and the communication apparatus to a second relay device, wherein the at least one candidate relay device comprises the second relay device, the indication information comprises an identifier of the second relay device, and the indication information is carried by a link modification request message.

13 . The communication apparatus according to claim 12 , wherein the instructions further include instructions to:

send the first message to the second terminal device via the first relay device.

14 . The communication apparatus according to claim 12 , wherein the first message further comprises at least one of a status of a signal between the at least one candidate relay device and the communication apparatus or an address of the at least one candidate relay device.

15 . The communication apparatus according to claim 12 , wherein the instructions further include instructions to:

determine, based on a status of a signal between a third terminal device and the apparatus, that the candidate relay device set comprises the third terminal device, wherein the status of the signal comprises at least one of signal quality or signal strength.

16 . A communication apparatus, comprising:

at least one processor; and

a non-transitory computer-readable storage medium storing a program to be executed by the at least one processor, the program including instructions for:

receiving a first message from a first terminal device, wherein the first terminal device and the communication apparatus perform relay communication via a first relay device, wherein the first message comprises an identifier of at least one candidate relay device, a relay reselection indication indicating to change a relay device, and an address of the at least one candidate relay device, and the address of the at least one candidate relay device is a layer 2 identifier, wherein a status of a signal between the at least one candidate relay device and the first terminal device satisfies a first preset condition;

obtaining, based on the address of the at least one candidate relay device, a status of a signal between the at least one candidate relay device and a second terminal device;

determining, based on the status of the signal between each of the at least one candidate relay device and the second terminal device, a second relay device from the at least one candidate relay device; and

sending indication information to the first terminal device, wherein the indication information indicates to change a relay device between the communication apparatus and the first terminal device to the second relay device, the indication information comprises an identifier of the second relay device, the indication information is carried by a link modification request message.

17 . The communication apparatus according to claim 16 , wherein the at least one candidate relay device comprises at least two relay devices, and the instructions further include instructions to:

determine the second relay device based on statuses of signals between the at least two relay devices and the communication apparatus.

18 . The communication apparatus according to claim 17 , wherein the instructions further include instructions to:

send the indication information to the first terminal device based on a status of a signal between the second relay device and the communication apparatus and based on a status of a signal between the first relay device and the communication apparatus.

19 . The communication apparatus according to claim 16 , wherein the at least one candidate relay device comprises at least two relay devices, the first message further comprises a status of a signal between the at least one candidate relay device and the first terminal device, and the instructions further include instructions to:

determine the second relay device based on the status of the signal between the at least one candidate relay device and the first terminal device and based on a status of a signal between the at least one candidate relay device and the communication apparatus.

20 . The communication apparatus according to claim 16 , wherein the instructions further include instructions to:

send a request message to a second candidate relay device based on an address of the second candidate relay device, wherein the second candidate relay device is any relay device in the at least one candidate relay device;

receive a response message from the second candidate relay device; and

determine a status of a signal between the second candidate relay device and the second terminal device based on the response message.

21 . The communication apparatus according to claim 16 , wherein the instructions further include instructions to send the indication information to the second terminal device via the first relay device.