Failure handling for secondary cell
A user equipment (UE) is connected to a wireless network and operates in a carrier aggregation (CA) state that includes a first connection to a primary cell and a second connection to a secondary cell. The UE determines a beam failure has occurred for one of the first connection or the second connection and initiates a beam failure recovery (BFR) operation. The BFR operation includes transmitting, to the primary cell, a BFR Medium Access Control (MAC) Control Element (CE).
1 . A method, performed by a network cell operating as a primary cell (PCell) for a user equipment (UE), the method comprising:
receiving, from the UE, a scheduling request;
transmitting, to the UE, an uplink grant in response to the scheduling request; and
receiving, from the UE in resources indicated by the uplink grant, a beam failure recovery (BFR) Medium Access Control (MAC) Control Element (CE) as part of a random access channel (RACH) procedure with the UE, wherein the UE triggers the RACH procedure for secondary cell (SCell) beam failure recovery (BFR).
2 . The method of claim 1 , wherein the BFR MAC-CE further comprises an identify of at least one other beam that is currently available for communication between the UE and a secondary cell (SCell).
3 . The method of claim 1 , wherein the scheduling request comprises a dedicated failure scheduling request.
4 . The method of claim 1 , wherein the scheduling request comprises a service transmission scheduling request.
5 . The method of claim 1 , further comprising:
transmitting, to the UE, an acknowledgement that the SCell BFR operation has been successfully completed.
6 . The method of claim 5 , wherein the acknowledgement comprises an uplink grant that schedules a new transmission for a same Hybrid Automatic Repeat Request (HARQ) process as a Physical Uplink Shared Channel (PUSCH) carrying the BFR MAC-CE.
7 . The method of claim 1 , wherein the BFR MAC-CE is transmitted in the uplink grant for the RACH procedure.
8 . A network cell operating as a primary cell, comprising:
a transceiver configured to communicate with a user equipment (UE); and
a processor configured to perform operations comprising:
receiving, from the UE, a scheduling request;
transmitting, to the UE, an uplink grant in response to the scheduling request; and
receiving, from the UE in resources indicated by the uplink grant, a beam failure recovery (BFR) Medium Access Control (MAC) Control Element (CE) as part of a random access channel (RACH) procedure with the UE, wherein the UE triggers the RACH procedure for secondary cell (SCell) beam failure recovery (BFR).
9 . The network cell of claim 8 , wherein the BFR MAC-CE further comprises an identify of at least one other beam that is currently available for communication between the UE and a secondary cell (SCell).
10 . The network cell of claim 8 , wherein the scheduling request comprises a dedicated failure scheduling request.
11 . The network cell of claim 8 , wherein the scheduling request comprises a service transmission scheduling request.
12 . The network cell of claim 8 , wherein the operations further comprise:
transmitting, to the UE, an acknowledgement that the SCell BFR has been successfully completed.
13 . The network cell of claim 12 , wherein the acknowledgement comprises an uplink grant that schedules a new transmission for a same Hybrid Automatic Repeat Request (HARQ) process as a Physical Uplink Shared Channel (PUSCH) carrying the BFR MAC-CE.
14 . The network cell of claim 8 , wherein the BFR MAC-CE is transmitted in the uplink grant for the RACH procedure.
15 . A processor of a network cell operating as a primary cell (PCell) for a user equipment (UE), the processor configured to:
receive, from the UE, a scheduling request;
transmit, to the UE, an uplink grant in response to the scheduling request; and
receive, from the UE in resources indicated by the uplink grant, a beam failure recovery (BFR) Medium Access Control (MAC) Control Element (CE) as part of a random access channel (RACH) procedure with the UE, wherein the UE triggers the RACH procedure for secondary cell (SCell) beam failure recovery (BFR).
16 . The processor of claim 15 , wherein the BFR MAC-CE further comprises an identity of at least one other beam that is currently available for communication between the UE and the SCell.
17 . The processor of claim 15 , wherein the scheduling request comprises a dedicated failure scheduling request or a service transmission scheduling request.
18 . The processor of claim 15 , wherein the processor is further configured to:
transmit, to the UE, an acknowledgement that the SCell BFR has been successfully completed.
19 . The processor of claim 18 , wherein the acknowledgement comprises an uplink grant that schedules a new transmission for a same Hybrid Automatic Repeat Request (HARQ) process as a Physical Uplink Shared Channel (PUSCH) carrying the BFR MAC-CE.
20 . The processor of claim 15 , wherein the BFR MAC-CE is transmitted in the uplink grant for the RACH procedure.