METHOD AND APPARATUS FOR LAYER 1/LAYER 2 TRIGGERED MOBILITY IN WIRELESS NETWORKS

1 . A method performed by a User Equipment (UE) for Layer 1/Layer 2 Triggered Mobility (LTM), the method comprising:

receiving, from a source cell, a Cell Switch Command (CSC) Medium Access Control (MAC) Control Element (CE), the CSC MAC CE indicating a target cell, Timing Advance (TA) information, and a Transmission Configuration Indicator (TCI) state;

determining whether the TA information is valid;

determining a pathloss based on a pathloss reference signal associated with the TCI state in a case that the TA information is valid;

determining whether the CSC MAC CE comprises Contention-Free Random Access (CFRA) information in a case that the TA information is not valid; and

determining the pathloss based on a Synchronized Signal Block (SSB) indicated in the CFRA information in a case that the CSC MAC CE comprises the CFRA information.

2 . The method of claim 1 , further comprising:

determining to perform a Random-Access Channel-less (RACH-less) cell switch procedure in a case that the TA information is valid,

wherein determining the pathloss based on the pathloss reference signal associated with the TCI state comprises determining the pathloss during the RACH-less cell switch procedure.

3 . The method of claim 2 , wherein the pathloss determined based on the pathloss reference signal associated with the TCI state during the RACH-less cell switch procedure is associated with a transmission power of a Physical Uplink Shared Channel (PUSCH) transmission to the target cell.

4 . The method of claim 3 , wherein the PUSCH transmission is a first uplink transmission to the target cell after receiving the CSC MAC CE from the source cell.

5 . The method of claim 2 , wherein the pathloss reference signal is provided by a pathlossReferenceRS field.

6 . The method of claim 1 , wherein the pathloss determined based on the SSB indicated in the CFRA information is associated with a transmission power of a Physical Random-Access Channel (PRACH) triggered by the CSC MAC CE.

7 . The method of claim 6 , further comprising:

performing a Random-Access procedure with the target cell based on the transmission power of the PRACH.

8 . A User Equipment (UE) for Layer 1/Layer 2 Triggered Mobility (LTM), 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 Cell Switch Command (CSC) Medium Access Control (MAC) Control Element (CE), the CSC MAC CE indicating a target cell, Timing Advance (TA) information, and a Transmission Configuration Indicator (TCI) state;

determine whether the TA information is valid;

determine a pathloss based on a pathloss reference signal associated with the TCI state in a case that the TA information is valid;

determine whether the CSC MAC CE comprises Contention-Free Random Access (CFRA) information in a case that the TA information is not valid; and

determine the pathloss based on a Synchronized Signal Block (SSB) indicated in the CFRA information in a case that the CSC MAC CE comprises the CFRA information.

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:

determine to perform a Random-Access Channel-less (RACH-less) cell switch procedure in a case that the TA information is valid,

wherein determining the pathloss based on the pathloss reference signal associated with the TCI state comprises determining the pathloss during the RACH-less cell switch procedure.

10 . The UE of claim 9 , wherein the pathloss determined based on the pathloss reference signal associated with the TCI state during the RACH-less cell switch procedure is associated with a transmission power of a Physical Uplink Shared Channel (PUSCH) transmission to the target cell.

11 . The UE of claim 10 , wherein the PUSCH transmission is a first uplink transmission to the target cell after receiving the CSC MAC CE from the source cell.

12 . The UE of claim 9 , wherein the pathloss reference signal is provided by a pathlossReferenceRS field.

13 . The UE of claim 8 , wherein the pathloss determined based on the SSB indicated in the CFRA information is associated with a transmission power of a Physical Random-Access Channel (PRACH) triggered by the CSC MAC CE.

14 . The UE of claim 6 , wherein the one or more computer-executable instructions, when executed by the at least one processor, further cause the UE to:

perform a Random-Access procedure with the target cell based on the transmission power of the PRACH.