METHOD AND APPARATUS FOR LAYER1/LAYER2 TRIGGERED MOBILITY (LTM) OPERATIONS

1 . A method for a User Equipment (UE) for performing a Layer1/Layer2 Triggered Mobility (LTM) operation, the method comprising:

receiving, from a source cell, a target Transmission Configuration Indicator (TCI) state configuration corresponding to a target cell;

receiving, from the source cell, an LTM cell switch command via a first Medium Access Control (MAC) Control Element (CE), the LTM cell switch command indicating the target cell;

switching from the source cell to the target cell; and

applying a TCI state in the target cell, wherein:

the TCI state is associated with the target TCI state configuration,

the LTM cell switch command indicates the TCI state among a first set of TCI states in a case that the UE receives an LTM TCI state activation command,

the LTM cell switch command indicates the TCI state among a second set of TCI states and activates the TCI state in a case that the UE does not receive the LTM TCI state activation command, and

the first set of TCI states is a subset of the second set of TCI states.

2 . The method of claim 1 , further comprising receiving, from the source cell, a plurality of candidate cell configurations, wherein:

each of the plurality of candidate cell configurations comprises a candidate TCI state configuration, and

the target cell corresponds to one of the plurality of candidate cell configurations.

3 . The method of claim 1 , wherein:

the TCI state is applied no later than a time duration after the last symbol of a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH) with Hybrid Automatic Repeat Request-Acknowledgement (HARQ-ACK) information of a Physical Downlink Shared Channel (PDSCH) providing the LTM cell switch command.

4 . The method of claim 1 , wherein:

the second set of TCI states comprises all TCI states configured in the target TCI state configuration.

5 . The method of claim 1 , wherein:

the LTM TCI state activation command is received via a second MAC CE, and

the LTM TCI state activation command activates the first set of TCI states among all TCI states configured in the target TCI state configuration.

6 . The method of claim 1 , wherein:

the LTM TCI state activation command is received before the LTM cell switch command is received.

7 . The method of claim 1 , wherein the target TCI state configuration comprises a parameter for indicating a separate TCI mode or a joint TCI mode.

8 . A User Equipment (UE) for performing a Layer1/Layer2 Triggered Mobility (LTM) operation, the UE comprising:

at least one processor; and

at least one non-transitory computer-readable medium coupled to the at least one processor and storing one or more computer-executable instructions that, when executed by the at least one processor, cause the UE to:

receive, from a source cell, a target Transmission Configuration Indicator (TCI) state configuration corresponding to a target cell;

receive, from the source cell, an LTM cell switch command via a first Medium Access Control (MAC) Control Element (CE), the LTM cell switch command indicating the target cell;

switch from the source cell to the target cell; and

apply a TCI state in the target cell, wherein:

the TCI state is associated with the target TCI state configuration,

the LTM cell switch command indicates the TCI state among a first set of TCI states in a case that the UE receives an LTM TCI state activation command,

the LTM cell switch command indicates the TCI state among a second set of TCI states and activates the TCI state in a case that the UE does not receive the LTM TCI state activation command, and

the first set of TCI states is a subset of the second set of TCI states.

9 . The UE of claim 8 , wherein the one or more computer-executable instructions, when executed by the at least one processor, further cause the UE to:

receive, from the source cell, a plurality of candidate cell configurations, wherein:

each of the plurality of candidate cell configurations comprises a candidate TCI state configuration, and

the target cell corresponds to one of the plurality of candidate cell configurations.

10 . The UE of claim 8 , wherein:

the TCI state is applied no later than a time duration after the last symbol of a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH) with Hybrid Automatic Repeat Request-Acknowledgement (HARQ-ACK) information of a Physical Downlink Shared Channel (PDSCH) providing the LTM cell switch command.

11 . The UE of claim 8 , wherein:

the second set of TCI states comprises all TCI states configured in the target TCI state configuration.

12 . The UE of claim 8 , wherein:

the LTM TCI state activation command is received via a second MAC CE, and

the LTM TCI state activation command activates the first set of TCI states among all TCI states configured in the target TCI state configuration.

13 . The UE of claim 8 , wherein:

the LTM TCI state activation command is received before the LTM cell switch command is received.

14 . The UE of claim 8 , wherein the target TCI state configuration comprises a parameter for indicating a separate TCI mode or a joint TCI mode.

15 . A Base Station (BS) for configuring a Layer1/Layer2 Triggered Mobility (LTM) operation, the BS comprising:

at least one processor; and

at least one non-transitory computer-readable medium coupled to the at least one processor and storing one or more computer-executable instructions that, when executed by the at least one processor, cause the BS to:

transmit, via a source cell, to a user equipment (UE), a target Transmission Configuration Indicator (TCI) state configuration corresponding to a target cell; and

transmit, via the source cell, to the UE, an LTM cell switch command via a first Medium Access Control (MAC) Control Element (CE), the LTM cell switch command indicating the target cell and enabling the UE to switch from the source cell to the target cell and to apply a TCI state in the target cell, wherein:

the TCI state is associated with the target TCI state configuration,

the LTM cell switch command indicates the TCI state among a first set of TCI states in a case that the UE receives an LTM TCI state activation command,

the LTM cell switch command indicates the TCI state among a second set of TCI states and activates the TCI state in a case that the UE does not receive the LTM TCI state activation command, and

the first set of TCI states is a subset of the second set of TCI states.

16 . The BS of claim 15 , wherein the one or more computer-executable instructions, when executed by the at least one processor, further cause the BS to:

transmit, via the source cell, to the UE, a plurality of candidate cell configurations, wherein:

each of the plurality of candidate cell configurations comprises a candidate TCI state configuration, and

the target cell corresponds to one of the plurality of candidate cell configurations.

17 . The BS of claim 15 , wherein:

the UE applies the TCI state no later than a time duration after the last symbol of a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH) with Hybrid Automatic Repeat Request-Acknowledgement (HARQ-ACK) information of a Physical Downlink Shared Channel (PDSCH) providing the LTM cell switch command.

18 . The BS of claim 15 , wherein:

the second set of TCI states comprises all TCI states configured in the target TCI state configuration.

19 . The BS of claim 15 , wherein:

the LTM TCI state activation command is transmitted via a second MAC CE, and

the LTM TCI state activation command activates the first set of TCI states among all TCI states configured in the target TCI state configuration.

20 . The BS of claim 15 , wherein the target TCI state configuration comprises a parameter for indicating a separate TCI mode or a joint TCI mode.