HANDLING MOBILITY FAILURE IN A RADIO CELL

1 . A user equipment (UE) for wireless communication, comprising:

at least one memory; and

at least one processor coupled with the at least one memory and configured to cause the UE to:

receive, from a serving cell, a conditional handover configuration comprising at least one candidate radio cell and a corresponding condition for handover execution;

start a first timer in response to initiating a handover execution to a first candidate radio cell;

determine that the handover execution has failed in response to expiry of the first timer;

start a second timer in response to determining that the handover execution has failed; and

transmit a reestablishment request to a second candidate radio cell based on the second timer being unexpired.

2 . The UE of claim 1 , wherein the first timer comprises a T 304 timer used for detecting handover failure, and wherein the second timer comprises a T 311 timer used for supervision of a cell selection procedure.

3 . The UE of claim 1 , wherein the at least one processor is configured to cause the UE to:

receive broadcast signaling comprising assistance information indicating a set of neighboring frequencies and at least one neighbor cell;

initiate a cell selection procedure on the set of neighboring frequencies in response to determining that the handover execution has failed; and

select the second candidate radio cell based on the cell selection procedure.

4 . The UE of claim 3 , wherein the at least one processor is configured to cause the UE to ignore a frequency layer associated with the serving cell during the cell selection procedure in response to determining that the handover execution has failed.

5 . The UE of claim 1 , wherein the at least one processor is configured to cause the UE to:

receive a downlink control information (DCI) triggering the handover execution; and

ignore a frequency layer associated with the serving cell during a cell selection procedure in response to the failure of the handover execution and based on the DCI triggering the handover execution.

6 . The UE of claim 1 , wherein the at least one processor is configured to cause the UE to:

determine that the serving cell is switched off after initiating the handover execution; and

ignore a frequency layer associated with the serving cell during a cell selection procedure in response to determining that the handover execution has failed and based on downlink control information (DCI) triggering the handover execution.

7 . The UE of claim 6 , wherein the at least one processor is configured to cause the UE to:

receive a switch-off indication from the serving cell; and

determine that the serving cell is switched off based on the switch-off indication.

8 . The UE of claim 6 , wherein the at least one processor is configured to cause the UE to:

receive a configuration indicating cell discontinuous transmission and cell discontinuation reception; and

determine that the serving cell is switched off based on the configuration.

9 . A method performed by a user equipment (UE), the method comprising:

receiving, from a serving cell, a conditional handover configuration comprising at least one candidate radio cell and a corresponding condition for handover execution;

starting a first timer in response to initiating the handover execution to a first candidate radio cell;

determining that the handover execution has failed in response to expiry of the first timer;

starting a second timer in response to determining that the handover execution has failed; and

transmitting a reestablishment request to a second candidate radio cell based on the second timer being unexpired.

10 . The method of claim 9 , wherein the first timer comprises a T 304 timer used for detecting handover failure, and wherein the second timer comprises a T 311 timer used for supervision of a cell selection procedure.

11 . A base station for wireless communication, comprising:

at least one memory; and

at least one processor coupled with the at least one memory and configured to cause the base station to:

transmit, to a user equipment (UE), a conditional handover configuration comprising at least one candidate radio cell and a corresponding condition for handover execution;

transmit a configuration for a first timer and a second timer associated with the handover execution; and

broadcast assistance information associated with a set of neighboring frequencies and at least one neighbor cell.

12 . The base station of claim 11 , wherein the first timer comprises a T 304 timer used for detecting handover failure, and wherein the second timer comprises a T 311 timer used for supervision of a cell selection procedure.

13 . The base station of claim 11 , wherein the at least one processor is configured to cause the base station to transmit a downlink control information (DCI) triggering the handover execution.

14 . The base station of claim 11 , wherein the at least one processor is configured to cause the base station to transmit a switch-off indication to the UE.

15 . The base station of claim 11 , wherein the at least one processor is configured to cause the base station to transmit a configuration indicating cell discontinuous transmission and cell discontinuation reception.

16 . A method performed by a base station, the method comprising:

transmitting, to a user equipment (UE), a conditional handover configuration comprising at least one candidate radio cell and a corresponding condition for handover execution;

transmitting a configuration for a first timer and a second timer associated with the handover execution; and

broadcasting assistance information that indicates a set of neighboring frequencies and at least one neighbor cell.

17 . The method of claim 16 , wherein the first timer comprises a T 304 timer used for detecting handover failure, and wherein the second timer comprises a T 311 timer used for supervision of a cell selection procedure.

18 . The method of claim 16 , further comprising transmitting a downlink control information (DCI) triggering the handover execution.

19 . The method of claim 16 , further comprising transmitting a switch-off indication to the UE.

20 . The method of claim 16 , further comprising transmitting a configuration indicating cell discontinuous transmission and cell discontinuation reception.