Method and apparatus for selecting relay in device-to-device communication

1. A method for selecting a relay in device-to-device communication, comprising:

receiving, by a first user equipment (UE), information sent by a second UE, wherein the information is used to indicate that the second UE is capable of serving as a relay UE;

performing, by the first UE, demodulation processing on the received information sent by the second UE, to determine whether the information sent by the second UE is successfully received;

adding, by the first UE, the second UE to a candidate relay UE list when it is determined that the information sent by the second UE is successfully received;

measuring, by the first UE, a signal sent by each candidate relay UE in the candidate relay UE list, to obtain link quality of a radio link between each candidate relay UE and the first UE; and

determining, by the first UE, a target relay UE from the candidate relay UE list according to the link quality of the radio link between each candidate relay UE in the candidate relay UE list and the first UE,

wherein the target relay UE is used for relaying data transmitted between the first UE and a base station,

wherein the information is received by the first UE when a link quality of a wireless cellular link between the base station and the second UE is greater than a quality threshold, and

wherein the information is received by the first UE from the second UE by blind detection without first requesting the information from the second UE.

2. The method according to claim 1 , wherein the measuring the signal sent by each candidate relay UE in the candidate relay UE list comprises:

performing at least one of the following operations:

measuring a demodulation reference signal (DMRS) comprised in a data packet sent by second candidate relay UE in the candidate relay UE list; and

performing demodulation and decoding processing on a data packet sent by a third candidate relay UE in the candidate relay UE list, and when the data packet is successfully decoded, reconstructing at least one modulation symbol according to at least one information bit obtained through the decoding processing, and performing measurement according to the at least one modulation symbol.

3. The method according to claim 1 , wherein the determining the target relay UE from the candidate relay UE list according to the link quality of the radio link between each candidate relay UE in the candidate relay UE list and the first UE comprises:

sending first indication information to the base station, wherein the first indication information is used to indicate the link quality of the radio link between each candidate relay UE in the candidate relay UE list and the first UE;

receiving second indication information sent by the base station according to the first indication information, wherein the second indication information is used to indicate the target relay UE; and

determining the target relay UE according to the second indication information.

4. The method according to claim 1 , wherein the quality threshold is configured by the base station, or the quality threshold is indicated by the first UE by using indication information, or the quality threshold is predefined.

5. A non-transitory computer readable medium of a first user equipment (UE) configured for selecting a relay in device-to-device communication, the non-transitory computer readable medium storing instructions that when executed perform steps comprising:

receiving information sent by a second UE, wherein the information is used to indicate that the second UE is capable of serving as a relay UE;

performing demodulation processing on the received information sent by the second UE, to determine whether the information sent by the second UE is successfully received;

adding the second UE to a candidate relay UE list when it is determined that the information sent by the second UE is successfully received;

measuring a signal sent by each candidate relay UE in the candidate relay UE list, to obtain link quality of a radio link between each candidate relay UE and the first UE; and

determining a target relay UE from the candidate relay UE list according to the link quality of the radio link between each candidate relay UE in the candidate relay UE list and the first UE,

wherein the target relay UE is used for relaying data transmitted between the first UE and a base station,

wherein the information is received by the first UE when determining that link quality of a wireless cellular link between a base station and the second UE is greater than a quality threshold, and

wherein the information is received from the second UE by blind detection without first requesting the information from the second UE.

6. The non-transitory computer readable medium according to claim 5 , wherein the quality threshold is configured by the base station.

7. The non-transitory computer readable medium according to claim 5 , wherein the quality threshold is indicated by the first UE by using indication information.

8. The non-transitory computer readable medium according to claim 5 , wherein the quality threshold is predefined.

9. The non-transitory computer readable medium according to claim 5 , wherein the measuring the signal sent by each candidate relay UE in the candidate relay UE list comprises:

performing demodulation and decoding processing on a data packet sent by a third candidate relay UE in the candidate relay UE list, and when the data packet is successfully decoded, reconstructing at least one modulation symbol according to at least one information bit obtained through the decoding processing, and performing a measurement according to the at least one modulation symbol.

10. The non-transitory computer readable medium according to claim 5 , wherein the measuring the signal sent by each candidate relay UE in the candidate relay UE list comprises:

measuring a demodulation reference signal (DMRS) comprised in a data packet sent by second candidate relay UE in the candidate relay UE list.

11. The non-transitory computer readable medium according to claim 5 , wherein the determining the target relay UE from the candidate relay UE list according to the link quality of the radio link between each candidate relay UE in the candidate relay UE list and the first UE comprises:

sending first indication information to the base station, wherein the first indication information is used to indicate the link quality of the radio link between each candidate relay UE in the candidate relay UE list and the first UE;

receiving second indication information sent by the base station according to the first indication information, wherein the second indication information is used to indicate the target relay UE; and

determining the target relay UE according to the second indication information.

12. A user equipment (UE), comprising:

a processor; and

a memory storing instructions that when executed configure the processor to perform steps comprising:

receiving information sent by a second UE, wherein the information is used to indicate that the second UE is capable of serving as a relay UE;

performing demodulation processing on the received information sent by the second UE, to determine whether the information sent by the second UE is successfully received;

adding the second UE to a candidate relay UE list when it is determined that the information sent by the second UE is successfully received;

measuring a signal sent by each candidate relay UE in the candidate relay UE list, to obtain link quality of a radio link between each candidate relay UE and the UE; and

determining a target relay UE from the candidate relay UE list according to the link quality of the radio link between each candidate relay UE in the candidate relay UE list and the UE,

wherein the target relay UE is used for relaying data transmitted between the UE and a base station, and

wherein the information is received by the UE when determining that link quality of a wireless cellular link between a base station and the second UE is greater than a quality threshold, and

wherein the information is received from the second UE by blind detection without first requesting the information from the second UE.

13. The UE according to claim 12 , wherein the measuring the signal sent by each candidate relay UE in the candidate relay UE list comprises:

measuring a demodulation reference signal (DMRS) comprised in a data packet sent by second candidate relay UE in the candidate relay UE list.

14. The UE according to claim 12 , wherein the measuring the signal sent by each candidate relay UE in the candidate relay UE list comprises:

performing demodulation and decoding processing on a data packet sent by a third candidate relay UE in the candidate relay UE list, and when the data packet is successfully decoded, reconstructing at least one modulation symbol according to at least one information bit obtained through the decoding processing, and performing measurement according to the at least one modulation symbol.

15. The UE according to claim 12 , wherein the determining the target relay UE from the candidate relay UE list according to the link quality of the radio link between each candidate relay UE in the candidate relay UE list and the UE comprises:

sending first indication information to the base station, wherein the first indication information is used to indicate the link quality of the radio link between each candidate relay UE in the candidate relay UE list and the UE;

receiving second indication information sent by the base station according to the first indication information, wherein the second indication information is used to indicate the target relay UE; and

determining the target relay UE according to the second indication information.

16. The UE according to claim 12 , wherein the quality threshold is configured by the base station, or the quality threshold is indicated by the UE by using indication information, or the quality threshold is predefined.