Beam pair indication and beam reset after beam failure recovery

1. An apparatus for wireless communication at a user equipment (UE), comprising at least one processor coupled to memory and configured to:

detect a beam failure for a first beam pair for full duplex communication with a base station;

indicate a second beam pair for the full duplex communication to the base station; and

apply the second beam pair for the full duplex communication a period of time after indicating the second beam pair to the base station,

wherein the at least one processor is further configured to:

transmit a beam failure recovery request (BFRQ) for a primary cell (PCell) in a contention free random access (CFRA) message or in a contention based random access (CBRA) message;

receive a beam failure response (BFR) in a random access response (RAR) from the base station; and

transmit a medium access control-control element (MAC-CE) on a physical uplink shared channel (PUSCH) resource or in a second random access message, the MAC-CE including an indication of the second beam pair for the full duplex communication with the base station.

2. The apparatus of claim 1 , wherein the at least one processor is are further configured to:

transmit the beam failure recovery request (BFRQ) for the primary cell (PCell) in the contention free random access (CFRA) message;

receive the beam failure response (BFR) in the random access response (RAR) from the base station; and

transmit the medium access control-control element (MAC-CE) on the physical uplink shared channel (PUSCH) resource, the MAC-CE including the indication of the second beam pair for the full duplex communication with the base station.

3. The apparatus of claim 2 , wherein the RAR schedules the PUSCH resource for the UE to indicate the second beam pair, the at least one processor being further configured to:

receive, from the base station, a confirmation of the second beam pair in an acknowledgment (ACK) of the MAC-CE or in downlink control information (DCI).

4. The apparatus of claim 1 , wherein the at least one processor is are further configured to:

transmit the beam failure recovery request (BFRQ) for the primary cell (PCell) in the contention based random access (CBRA) message;

receive the beam failure response (BFR) in a third random access message including the random access response (RAR) from the base station; and

transmit the medium access control-control element (MAC-CE) in the second random access message, the MAC-CE including the indication of the second beam pair for the full duplex communication with the base station.

5. The apparatus of claim 4 , wherein the at least one processor is further configured to:

receive, from the base station, a confirmation of the second beam pair in a fourth random access message from the base station.

6. An apparatus for wireless communication at a user equipment (UE), comprising at least one processor, coupled to memory and configured to:

detect a beam failure for a first beam pair for full duplex communication with a base station;

indicate a second beam pair for the full duplex communication to the base station; and

apply the second beam pair for the full duplex communication a period of time after indicating the second beam pair to the base station,

wherein the at least one processor is further configured to:

begin measurement to select the second beam pair prior to transmission of a beam failure recovery request (BFRQ), the second beam pair for the full duplex communication being associated with the BFRQ; transmit the beam failure recovery request (BFRQ);

transmit a self-interference random access channel (RACH) preamble on each of a set of candidate beams; and measure self-interference from transmission of the RACH preamble for each beam pair from the set of candidate beams, wherein the second beam pair is selected based on the self-interference measured for each beam pair from the set of candidate beams; or

transmit the beam failure recovery request (BFRQ); transmit the self-interference random access channel (RACH) preamble on each of the set of candidate beams; and

measure, after transmission of the BFRQ, the self-interference from transmission of the RACH preamble for each beam pair from the set of candidate beams, wherein the second beam pair is selected based on the self-interference measured for each beam pair from the set of candidate beams.

7. The apparatus of claim 6 , wherein the at least one processor is further configured to transmit the beam failure recovery request (BFRQ) and to begin measurement to select the second beam pair prior to transmission of the beam failure recovery request (BFRQ), the second beam pair for the full duplex communication being associated with the BFRQ, and wherein to perform the measurement to select the second beam pair, the at least one processor is configured to:

transmit the self-interference random access channel (RACH) preamble on each of the set of candidate beams; and

measure the self-interference from transmission of the RACH preamble for each beam pair from the set of candidate beams, wherein the second beam pair is selected based on the self-interference measured for each beam pair from the set of candidate beams.

8. The apparatus of claim 6 , wherein the at least one processor is are further configured to:

transmit the beam failure recovery request (BFRQ);

transmit the self-interference random access channel (RACH) preamble on each of the set of candidate beams; and

measure, after the transmission of the BFRQ, the self-interference from transmission of the RACH preamble for each beam pair from the set of candidate beams, wherein the second beam pair is selected based on the self-interference measured for each beam pair from the set of candidate beams.

9. The apparatus of claim 8 , wherein the at least one processor is configured to:

receive a configuration of sounding reference signal (SRS) resources from the base station in response to the BFRQ, wherein the self-interference for a set of candidate beam pairs is measured based on transmissions in the SRS resources.

10. An apparatus for wireless communication at a user equipment (UE), comprising at least one processor, coupled to memory and configured to:

detect a beam failure for a first beam pair for full duplex communication with a base station;

indicate a second beam pair for the full duplex communication to the base station; and

apply the second beam pair for the full duplex communication a period of time after indicating the second beam pair to the base station,

wherein the at least one processor is further configured to:

transmit a first a contention based random access (CBRA) message to a primary cell (PCell);

receive a beam failure response (BFR) in a second random access message including a random access response (RAR) from the PCell;

transmit a beam failure recovery request (BFRQ) in a third random access message to the PCell;

receive a fourth random access message from the PCell; and

transmit a medium access control-control element (MAC-CE) including an indication of the second beam pair for the full duplex communication with the base station.

11. The apparatus of claim 10 , wherein the at least one processor is further configured to:

receiving, from the base station, a confirmation of the second beam pair in an acknowledgment (ACK) of the MAC-CE or in downlink control information (DCI).

12. An apparatus for wireless communication at a user equipment (UE), comprising at least one processor, coupled to memory and configured to:

detect a beam failure for a first beam pair for full duplex communication with a base station;

indicate a second beam pair for the full duplex communication to the base station; and

apply the second beam pair for the full duplex communication a period of time after indicating the second beam pair to the base station,

wherein the at least one processor is further configured to:

transmit a beam failure recovery request (BFRQ) for a primary cell (PCell) on an uplink beam of the first beam pair;

receive a beam failure response in downlink control information (DCI) with an uplink grant; and

transmit a medium access control-control element (MAC-CE) on a physical uplink shared channel (PUSCH) based on the uplink grant, the MAC-CE including an indication of the second beam pair for the full duplex communication with the base station.

13. The apparatus of claim 12 , wherein the at least one processor is further configured to:

receive, from the base station, a confirmation of the second beam pair in an acknowledgment (ACK) of the MAC-CE or in an additional DCI.

14. An apparatus for wireless communication at a user equipment (UE), comprising at least one processor, coupled to memory and configured to:

detect a beam failure for a first beam pair for full duplex communication with a base station;

indicate a second beam pair for the full duplex communication to the base station; and

apply the second beam pair for the full duplex communication a period of time after indicating the second beam pair to the base station,

wherein the at least one processor is further configured to:

transmit a beam failure recovery request (BFRQ) for a secondary cell (SCell) to the base station in a first medium access control-control element (MAC-CE) resource of a primary cell (PCell) or a different SCell;

receive a beam failure response in downlink control information (DCI) of the PCell or the different SCell; and

transmit a second MAC-CE on a physical uplink shared channel (PUSCH) of the PCell or the different SCell, the MAC-CE including an indication of the second beam pair for the full duplex communication for the SCell.

15. The apparatus of claim 14 , wherein the at least one processor is further configured to:

receive, from the base station, a confirmation of the second beam pair in an acknowledgment (ACK) of the MAC-CE or in an additional DCI of the PCell or the different SCell.