Method and apparatus for managing time alignment timer for small data transmission in wireless communication system

A user equipment (UE) in a wireless communication system, the UE comprising:

• at least one transceiver;
• at least one processor;
• and
• at least one computer memory operably connectable to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations comprising:
• starting a configured grant based small data transmission (CG-SDT) time alignment timer (TAT) upon receiving CG-SDT configuration;
• performing a CG-SDT procedure in radio resource control (RRC) INACTIVE state during the CG-SDT TAT is running;
• and
• restarting the CG-SDT TAT based on a timing advance command (TAC) being received and based on the CG-SDT procedure being ongoing,
• wherein, based on the TAC being received and based on the CG-SDT procedure not being ongoing, the CG-SDT TAT is not restarted.

An apparatus for a user equipment (UE), the apparatus comprising:

• at least one processor;
• and
• at least one computer memory operably connectable to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations comprising:
• starting a configured grant based small data transmission (CG-SDT) time alignment timer (TAT) upon receiving CG-SDT configuration;
• performing a CG-SDT procedure in radio resource control (RRC) INACTIVE state during the CG-SDT TAT is running;
• and
• restarting the CG-SDT TAT based on a timing advance command (TAC) being received and based on the CG-SDT procedure being ongoing,
• wherein, based on the TAC being received and based on the CG-SDT procedure not being ongoing, the CG-SDT TAT is not restarted.

A computer readable storage medium storing at least one computer program comprising instructions that, when executed by at least one processor, cause the at least one processor to perform operations for a user equipment (UE), the operations comprising:

• starting a configured grant based small data transmission (CG-SDT) time alignment timer (TAT) upon receiving CG-SDT configuration;
• performing a CG-SDT procedure in radio resource control (RRC) INACTIVE state during the CG-SDT TAT is running;
• and
• restarting the CG-SDT TAT based on a timing advance command (TAC) being received and based on the CG-SDT procedure being ongoing,
• wherein, based on the TAC being received and based on the CG-SDT procedure not being ongoing, the CG-SDT TAT is not restarted.