Methods and apparatuses for discontinuous reception operations for beam failure recovery procedure
A communication method performed by a User Equipment (UE) configured with a Discontinuous Reception (DRX) operation includes the UE initiating a Random Access (RA) procedure for Beam Failure Recovery (BFR) on a Special Cell (SpCell) after detecting a beam failure event on the SpCell, and transmitting a BFR Medium Access Control (MAC) Control Element (CE) on the SpCell. The BFR MAC CE indicates the beam failure event for the SpCell. The communication method further includes the UE determining a period of time as a DRX Active Time for the UE. The beginning of the period of time is determined by a first time at which the UE transmits the BFR MAC CE on the SpCell. The end of the period of time is determined by a second time at which the UE receives a BFR Response (BFRR) from the SpCell.
1. A communication method performed by a User Equipment (UE) configured with a Discontinuous Reception (DRX) operation, the communication method comprising:
initiating a Random Access (RA) procedure for a Beam Failure Recovery (BFR) on a Special Cell (SpCell) after detecting a beam failure event on the SpCell;
receiving, after initiating the RA procedure, a Random Access Response (RAR);
transmitting, on the SpCell, a BFR Medium Access Control (MAC) Control Element (CE) via a Physical Uplink Shared Channel (PUSCH) determined by an uplink grant indicated by the RAR, the BFR MAC CE indicating the beam failure event for the SpCell;
starting a timer after transmitting the BFR MAC CE via the PUSCH on the SpCell; and
stopping the timer after receiving a BFR Response (BFRR) from the SpCell, wherein the BFRR is received on a Physical Downlink Control Channel (PDCCH) that is addressed to a Cell Radio Network Temporary Identifier (C-RNTI).
2. The communication method of claim 1 , further comprising:
monitoring the PDCCH while the timer is running.
3. The communication method of claim 1 , further comprising:
monitoring the PDCCH until the timer expires, wherein stopping the timer comprises stopping the timer when the BFFR is received while the timer is running.
4. The communication method of claim 1 , further comprising:
restarting the timer in a first symbol after an end of a retransmission of the BFR MAC CE.
5. The communication method of claim 1 , further comprising:
monitoring the PDCCH while the timer is running during a measurement gap.
6. The communication method of claim 1 , wherein the BFR MAC CE includes at least one of a cell identity, a beam-presence indicator, or a candidate beam indicator.
7. The communication method of claim 1 , further comprising:
considering that the RA procedure is successfully completed when the UE receives the BFRR.
8. A User Equipment (UE) configured with a Discontinuous Reception (DRX) operation, the UE comprising:
at least one memory storing computer-readable instructions; and
at least one processor coupled to the at least one memory, the at least one processor configured to execute the computer-readable to cause the UE to:
initiate a Random Access (RA) procedure for a Beam Failure Recovery (BFR) on a Special Cell (SpCell) after detecting a beam failure event on the SpCell;
receive, after initiating the RA procedure, a Random Access Response (RAR);
transmit, on the SpCell, a BFR Medium Access Control (MAC) Control Element (CE) via a Physical Uplink Shared Channel (PUSCH) determined by an uplink grant indicated by the RAR, the BFR MAC CE indicating the beam failure event for the SpCell;
start a timer in after transmitting the BFR MAC CE via the PUSCH on the SpCell; and
stop the timer after receiving a BFR Response (BFRR) from the SpCell, wherein the BFRR is received on a Physical Downlink Control Channel (PDCCH) that is addressed to a Cell Radio Network Temporary Identifier (C-RNTI).
9. The UE of claim 8 , wherein the at least one processor is further configured to execute the computer-readable instructions to cause the UE to:
monitor the PDCCH while the timer is running.
10. The UE of claim 8 , wherein the at least one processor is further configured to execute the computer-readable instructions to cause the UE to:
monitor the PDCCH until the timer expires, wherein stopping the timer comprises stopping the timer when the BFFR is received while the timer is running.
11. The UE of claim 8 , wherein the at least one processor is further configured to execute the computer-readable instructions to cause the UE to:
restart the timer in a first symbol after an end of a retransmission of the BFR MAC CE.
12. The UE of claim 8 , wherein the at least one processor is further configured to execute the computer-readable instructions to cause the UE to:
monitor the PDCCH while the timer is running during a measurement gap.
13. The UE of claim 8 , wherein the BFR MAC CE includes at least one of a cell identity, a beam-presence indicator, or a candidate beam indicator.
14. The UE of claim 8 , wherein the at least one processor is further configured to execute the computer-readable instructions to cause the UE to:
consider that the RA procedure is successfully completed when the UE receives the BFRR.