Link failure recovery procedure for a primary cell (PCell) and a secondary cell (SCell)

1. A method of wireless communication, comprising:

detecting, by a wireless communication device, a first link failure associated with a first cell;

detecting, by the wireless communication device, a second link failure associated with a second cell; and

performing, by the wireless communication device, a link failure recovery procedure by prioritizing a first link failure recovery for the first cell over a second link failure recovery for the second cell, wherein prioritizing the first link failure recovery for the first cell over the second link failure recovery for the second cell includes initiating the second link failure recovery after the first link failure recovery ends.

2. The method of claim 1 , wherein the first cell is one of a primary cell (PCell) or a secondary cell (SCell), and the second cell is the other one of the PCell or the SCell.

3. The method of claim 1 , wherein detecting the second link failure includes detecting the second link failure after detecting the first link failure or wherein detecting the first link failure includes detecting the first link failure after detecting the second link failure.

4. The method of claim 1 , comprising:

performing the first link failure recovery in response to detecting the first link failure, wherein the performing the first link failure recovery includes starting a first link failure recovery timer for the first cell and sending a first link failure recovery request to a base station (BS) via the first cell.

5. The method of claim 1 , wherein prioritizing the first link failure recovery for the first cell over the second link failure recovery for the second cell further includes completing the first link failure recovery before completing the second link failure recovery.

6. The method of claim 1 , comprising:

performing the second link failure recovery by sending a second link failure recovery request associated with the second cell to a BS via the second cell;

starting a link failure recovery timer for the second cell in response to detecting the second link failure, wherein detecting the first link failure includes detecting the first link failure after the starting a link failure recovery timer; and

adjusting the link failure recovery timer for the second cell to prioritize the first link failure for the first cell over the second link failure recovery for the second cell.

7. The method of claim 6 , wherein adjusting the link failure recovery timer for the second cell includes pausing the link failure recovery timer for the second cell in response to detecting the first link failure associated with the first cell.

8. The method of claim 7 , comprising:

performing the first link failure recovery after pausing the link failure recovery timer; and

resuming the second link failure recovery after completing the first link failure recovery.

9. The method of claim 8 , comprising:

measuring a reference signal;

selecting a new candidate beam associated with the second cell based on the reference signal;

sending an indication of the new candidate beam and the second link failure recovery request for the second cell; and

resending the indication of the new candidate beam based on a most recent measurement of the reference signal after the second link failure recovery resumes.

10. An apparatus comprising:

a processor configured to:

detect a first link failure associated with a first cell;

detect a second link failure associated with a second cell; and

perform a link failure recovery procedure, wherein, to perform the link failure recovery procedure, the processor is configured to prioritize a first link failure recovery for the first cell over a second link failure recovery for the second cell, and wherein, to prioritize the first link failure recovery for the first cell over the second link failure recovery for the second cell, the processor is configured to initiate the second link failure recovery after the first link failure recovery ends.

11. The apparatus of claim 10 , wherein:

the first cell is a primary cell (PCell), and the second cell is a secondary cell (SCell); or

the first cell is a SCell and the second cell is a PCell.

12. The apparatus of claim 10 , wherein the processor is configured to:

detect the second link failure after the first link failure; or

detect the first link failure after the second link failure.

13. The apparatus of claim 10 , further comprising:

a transceiver in communication with the processor, wherein the transceiver is configured to send a random access channel (RACH) preamble sequence via the first cell, wherein the RACH preamble sequence indicates the first link failure in the first cell and the second link failure in the second cell.

14. The apparatus of claim 10 , wherein, to perform the link failure recovery procedure, the processor is configured to perform the first link failure recovery in response to detecting the first link failure.

15. The apparatus of claim 10 , wherein, to perform the first link failure recovery procedure, the processor is configured to start a first link failure recovery timer for the first cell and send a first link failure recovery request in a contention-free RACH procedure or a contention-based RACH procedure to a base station (BS) via the first cell.

16. The apparatus of claim 10 , wherein, to perform the link failure recovery procedure, the processor is configured to start a second link failure recovery timer for the second cell and send a second link failure recovery request to a base station (BS) via the first cell or the second cell.

17. The apparatus of claim 10 , wherein, to prioritize the first link failure recovery for the first cell over the second link failure recovery for the second cell, the processor is configured to complete the first link failure recovery before completing the second link failure recovery.

18. The apparatus of claim 10 , wherein, to perform the second link failure recovery, the processor is configured to:

send a second link failure recovery request associated with the second cell to a base station (BS) via the second cell;

start a link failure recovery timer for the second cell in response to detecting the second link failure, wherein the detecting the first link failure includes detecting the first link failure after starting the link failure recovery timer; and

adjust the link failure recovery timer for the second cell to prioritize the first link failure recovery for the first cell over the second link failure recovery for the second cell.

19. The apparatus of claim 18 , wherein, to adjust the link failure recovery timer for the second cell, the processor is configured to pause the link failure recovery timer for the second cell in response to detecting the first link failure associated with the first cell.

20. The apparatus of claim 19 , wherein, to perform the first link failure recovery, the processor is configured to pause the link failure recovery timer; and

resume the second link failure recovery after completing the first link failure recovery.

21. The apparatus of claim 10 , wherein the processor is configured to:

measure a reference signal;

select a new candidate beam associated with the second cell based on the reference signal;

send an indication of the new candidate beam and the second link failure recovery request for the second cell; and

resend the indication of the new candidate beam based on a most recent measurement of the reference signal after the second link failure recovery resumes.

22. The apparatus of claim 10 , wherein the processor is configured to send, via a third cell, a message indicating the first link failure in the first cell and the second link failure in the second cell via at least one of a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), or a media access control-control element (MAC-CE) signal, wherein the third cell is different from the first cell and the second cell.

23. The apparatus of claim 10 , wherein the first link failure includes a first beam failure and the second link failure includes a second beam failure.

24. A method of wireless communication, comprising:

receiving, by a wireless communication device, a first link failure recovery request associated with a first link failure recovery for a first cell;

receiving, by the wireless communication device, a second link failure recovery request associated with a second link failure recovery for a second cell; and

performing, by the wireless communication device, a link failure recovery procedure by prioritizing the first link failure recovery for the first cell over the second link failure recovery for the second cell, wherein prioritizing the first link failure recovery for the first cell over the second link failure recovery for the second cell includes initiating the second link failure recovery after the first link failure recovery ends.

25. The method of claim 24 , wherein receiving the first link failure recovery request includes at least one of:

receiving the first link failure recovery request after receiving the second link failure recovery request; or

receiving the first link failure recovery request before receiving the second link failure recovery request.

26. The method of claim 24 , wherein receiving the first and second link failure recovery requests includes receiving via the first cell a RACH preamble sequence indicating that the first cell and the second cell have failed or receiving via a third cell a message in at least one of a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), or a media access control-control element (MAC-CE) signaling, wherein the message indicates that the first cell and the second cell have failed, and wherein the third cell is different from the first cell and the second cell.

27. An apparatus comprising:

a receiver configured to:

receive a first link failure recovery request associated with a first link failure recovery for a first cell;

receive a second link failure recovery request associated with a second link failure recovery for a second cell; and

a processor coupled to the receiver, wherein the processor is configured to perform a link failure recovery procedure, wherein, to perform the link failure recovery procedure, the processor is configured to prioritize the first link failure recovery for the first cell over the second link failure recovery for the second cell, and wherein, to prioritize the first link failure recovery for the first cell over the second link failure recovery for the second cell, the processor is configured to initiate the second link failure recovery after the first link failure recovery ends.

28. The apparatus of claim 27 , wherein the first cell is one of a primary cell (PCell) or the secondary cell (SCell), and the second cell is the other of the PCell or the secondary cell (SCell).

29. The apparatus of claim 27 , wherein:

the receiver is configured to receive the first link failure recovery request after receiving the second link failure recovery request; or

the receiver is configured to receive receives the first link failure recovery request before receiving the second link failure recovery request.

30. The apparatus of claim 27 , wherein the receiver is further configured to:

receive, via the first cell, a RACH preamble sequence indicating that the first cell and the second cell have failed; or

receive, via a third cell, a message in at least one of a physical uplink shared channel (PUSCH), a physical uplink control channel (PUCCH), or a media access control-control element (MAC-CE) signaling, wherein the message indicates that the first cell and the second cell have failed, and wherein the third cell is different from the first cell and the second cell.