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, comprising:
at a user equipment (UE) connected to a wireless network and operating in a carrier aggregation (CA) state comprising a first connection to a primary cell and a second connection to a secondary cell:
determining a beam failure has occurred for the second connection; and
initiating a beam failure recovery (BFR) operation, wherein the BFR operation comprises:
transmitting, to the wireless network, a number of dedicated failure scheduling requests;
starting a timer when the transmission of the number of dedicated failure scheduling requests begins;
identifying that the timer expires before the BFR operation is successful;
releasing all sounding reference signals (SRS) in response to the identifying;
releasing configured uplink grants in response to the identifying;
initiating a random access channel (RACH) procedure with the primary cell in response to the identifying; and
transmitting, to the wireless network, a BFR Medium Access Control (MAC) Control Element (CE).
2. The method of claim 1 , wherein the BFR operation further comprises:
receiving an uplink grant, wherein the BFR MAC CE is transmitted in the uplink grant.
3. The method of claim 1 , wherein the BFR operation further comprises:
receiving, from the primary cell, an uplink grant for the RACH procedure, wherein the BFR MAC CE is transmitted in the uplink grant for the RACH procedure.
4. The method of claim 3 , wherein the network configures a maximum number of dedicated failure scheduling requests.
5. The method of claim 1 , wherein transmitting the BFR MAC CE comprises:
transmitting, to the wireless network, a first transmission comprising the BFR MAC CE, wherein the BFR MAC CE comprises a first set of data; and
when the first transmission is determined to have failed, transmitting, to the wireless network, a second transmission comprising the BFR MAC CE, wherein the BFR MAC CE comprises a second set of data.
6. The method of claim 5 , wherein the first set of data comprises an identification of the secondary cell and a first available beam and wherein the second set of data comprises the identification of the secondary cell and a second available beam, wherein the first available beam and the second available beam comprise one of the same beam or a different beam.
7. The method of claim 5 , wherein the first transmission is determined to have failed based on at least a timer that is initiated when the first transmission is sent.
8. A user equipment (UE), comprising:
a transceiver configured to establish a connection between the UE and a wireless network, the connection comprising a first connection to a primary cell and a second connection to a secondary cell; and
a processor configured to determine a beam failure has occurred for one of the first connection or the second connection and initiate a beam failure recovery (BFR) operation,
wherein the BFR operation comprises:
instructing the transceiver to transmit, to the wireless network a number of dedicated failure scheduling requests;
starting a timer when the transmission of the number of dedicated failure scheduling requests begins;
identifying that the timer expires before the BFR operation is successful;
releasing all sounding reference signals (SRS) in response to the identifying;
releasing configured uplink grants in response to the identifying;
initiating a random access channel (RACH) procedure with the primary cell in response to the identifying; and
instructing the transceiver to transmit, to the wireless network, a BFR Medium Access Control (MAC) Control Element (CE).
9. The UE of claim 8 , wherein the BFR operation further comprises the transceiver receiving the uplink grant, wherein the BFR MAC CE is transmitted in the uplink grant.
10. The UE of claim 8 , wherein the BFR operation further comprises receiving, from the primary cell, an uplink grant for the RACH procedure, wherein the BFR MAC CE is transmitted in the uplink grant for the RACH procedure.
11. The UE of claim 8 , wherein transmitting the BFR MAC CE comprises the transceiver transmitting, to the wireless network, a first transmission comprising the BFR MAC CE, wherein the BFR MAC CE comprises a first set of data and, when the first transmission is determined to have failed, transmitting, to the wireless network, a second transmission comprising the BFR MAC CE, wherein the BFR MAC CE comprises a second set of data.
12. The UE of claim 11 , wherein the first set of data comprises an identification of the primary cell or the secondary cell having the beam failure and a first available beam and wherein the second set of data comprises the identification of the primary cell or the secondary cell having the beam failure and a second available beam, wherein the first available beam and the second available beam comprise one of the same beam or a different beam.
13. An integrated circuit, comprising:
first circuitry configured to establish a connection between a user equipment (UE) and a wireless network, the connection comprising a first connection to a primary cell and a second connection to a secondary cell;
second circuitry configured to determine a beam failure has occurred for one of the first connection or the second connection; and
third circuitry configured to initiate a beam failure recovery (BFR) operation, wherein the BFR operation comprises:
transmitting, to the wireless network, a number of dedicated failure scheduling requests;
starting a timer when the transmission of the number of dedicated failure scheduling requests begins;
identifying that the timer expires before the BFR operation is successful;
releasing all sounding reference signals (SRS) in response to the identifying;
releasing configured uplink grants in response to the identifying;
initiating a random access channel (RACH) procedure with the primary cell in response to the identifying; and
transmitting, to the wireless network, a BFR Medium Access Control (MAC) Control Element (CE).
14. The integrated circuit of claim 13 , wherein the third circuitry is further configured to receive an uplink grant, wherein the BFR MAC CE is transmitted in the uplink grant.
15. The integrated circuit of claim 13 , wherein the third circuitry is further configured to receive, from the wireless network, an uplink grant for the RACH procedure, wherein the BFR MAC CE is transmitted in the uplink grant for the RACH procedure.
16. The integrated circuit of claim 13 , wherein the third circuitry is further configured to transmit, to the wireless network, a first transmission comprising the BFR MAC CE, wherein the BFR MAC CE comprises a first set of data and, when the first transmission is determined to have failed, transmit, to the wireless network, a second transmission comprising the BFR MAC CE, wherein the BFR MAC CE comprises a second set of data.