Beam recovery method and apparatus

1. A method, comprising:

communicating, by a relay node, with a network device by using a serving beam;

after a serving beam failure of the serving beam is detected,

starting a beam recovery procedure by:

determining a new available beam from a candidate beam set while further monitoring the serving beam to determine whether the serving beam is recovered, and

sending a beam failure recovery request, by the relay node, to the network device in response to determining the new available beam; and

if the serving beam is recovered in response to the monitoring,

terminating the beam recovery procedure, by the relay node, and further communicating, by the relay node, with the network device by using the serving beam.

2. The method according to claim 1 , wherein the starting the beam failure recovery procedure comprises:

enabling at least one of a timer or a counter for the beam failure recovery procedure; and

the terminating, by the relay node, the beam failure recovery procedure comprises:

disabling or resetting the at least one of the timer or the counter for the beam failure recovery procedure.

3. The method according to claim 1 , wherein

the terminating, by the relay node, the beam failure recovery procedure comprises:

sending, by the relay node, a beam failure recovery rollback message to the network device; and

receiving a response of the network device to the beam failure recovery rollback message.

4. The method according to claim 3 , wherein the beam recovery rollback message is sent using the new available beam.

5. The method according to claim 1 , wherein the determining whether the serving beam is recovered comprises:

determining at least one of whether quality of the serving beam is better than a specified condition or whether the quality of the serving beam is better than quality of a new available beam.

6. The method according to claim 1 , wherein the candidate beam set, is a set including one or more reference signal resources or one or more synchronization signal block indices, wherein one beam corresponds to one CSI-RS (channel state information-reference signal) or SSB (synchronization signal block).

7. The method according to claim 1 , wherein:

the determining of the serving beam failure is determined by a physical layer of the relay node, and notified to a higher layer of the relay node;

the higher layer requests the candidate beam set from the physical layer; and

the higher layer selects the new available beam from the candidate beam set.

8. The method according to claim 1 , wherein:

the relay node sends the beam failure recovery request using a transmit beam corresponding to the new available beam, the beam failure recovery request being a RACH sequence, and

the relay node notifies, by using the RACH sequence, a base station of the new available beam in view of an association relationship between the preconfigured RACH and a candidate beam.

9. An apparatus, comprising:

a transceiver, configured to communicate with a network device by using a serving beam; and

a processor, configured to: after a serving beam failure of the servicing beam is detected,

start a beam recovery procedure by:

determining a new available beam from a candidate beam set while further monitoring the serving beam to determine whether the serving beam is recovered, and

sending a beam failure recovery request to the network device in response to determining the new available beam; wherein

the transceiver is further configured to: if the processor determines that the serving beam is recovered in response to the monitoring, terminate the beam recovery procedure, and further communicate with the network device by using the serving beam.

10. The apparatus according to claim 9 , wherein the processor is further configured to: enable at least one of a timer or a counter for the beam failure recovery procedure; and

disabling or resetting the at least one of the timer or the counter for the beam failure recovery procedure.

11. The apparatus according to claim 9 , wherein the transceiver is further configured to:

send a beam failure recovery rollback message to the network device if the serving beam is recovered; and

receive a response of the network device to the beam failure recovery rollback message.

12. The apparatus according to claim 9 , wherein the processor is further configured to perform one or more of the following:

determine whether quality of the serving beam is better than a specified condition; and determine whether the quality of the serving beam is better than quality of the new available beam.

13. A non-transitory computer-readable medium having processor-executable instructions stored thereon for saving power for a relay node, the processor-executable instructions when executed by a processor, causes the processor to implement operations including to:

communicate, by a relay node, with a network device by using a serving beam;

after a serving beam failure of the serving beam is detected,

start a beam recovery procedure by:

determining a new available beam from a candidate beam set while further monitor the serving beam to determine whether the serving beam is recovered; and

sending a beam failure recovery request to the network device in response to determining the new available beam; and

if the serving beam is recovered in response to the monitoring, terminate the beam recovery procedure, and further communicate, by the relay node, with the network device by using the serving beam.

14. The non-transitory computer-readable medium according to claim 13 , wherein the starting a beam failure recovery procedure comprises:

enabling at least one of a timer or a counter for the beam failure recovery procedure; and

the terminating, by the relay node, the beam failure recovery procedure comprises:

disabling or resetting at least one of the timer or the counter for the beam failure recovery procedure.

15. The non-transitory computer-readable medium according to claim 13 , wherein

the terminating, by the relay node, the beam failure recovery procedure comprises:

sending, by the relay node, a beam failure recovery rollback message to the network device; and

receiving a response of the network device to the beam failure recovery rollback message.

16. The non-transitory computer-readable medium according to claim 13 , wherein the determining whether the serving beam is recovered comprises:

determining at least one of whether quality of the serving beam is better than a specified condition or whether the quality of the serving beam is better than quality of a new available beam.