Method and apparatus for managing time alignment timer for small data transmission in wireless communication system
The present disclosure relates to a method managing a time alignment timer (TAT) for small data transmission (SDT) in a wireless communication system. In particular, the method includes the steps of: starting a configured grant based small data transmission (CG-SDT) time alignment timer (TAT) upon receiving CG-SDT configuration; transmitting at least one data unit based on the CG-SDT configuration in 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 a 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.
1 . A method comprising:
receiving, by a user equipment (UE) from a network, configuration information related to a configured grant based small data transmission (CG-SDT);
starting, by the UE, a CG-SDT time alignment timer (TAT) based on the configuration information; and
performing, by the UE, a CG-SDT procedure in radio resource control (RRC) INACTIVE state while during the CG-SDT TAT is running,
wherein, based on a timing advance command (TAC) being received and based on the CG-SDT procedure being ongoing, the CG-SDT TAT is restarted, and
wherein, based on the TAC being received and based on the CG-SDT procedure not being ongoing, a legacy TAT is started or restarted without restarting the CG-SDT TAT.
2 . The method of claim 1 , wherein, based on the CG-SDT procedure being initiated, the CG-SDT procedure is considered to be ongoing until a reception of at least one of a radio resource control (RRC) release message, a RRC resume message, a RRC reject message or a RRC setup message.
3 . The method of claim 1 , wherein the configuration information related to the CG-SDT is received via a radio resource control (RRC) release message.
4 . The method of claim 1 , wherein, based on the CG-SDT TAT being expired, the configuration information related to the CG-SDT is released.
5 . The method of claim 1 , wherein, during the CG-SDT TAT is running, CG resources for the CG-SDT is considered to be valid.
6 . A user equipment (UE) comprising:
at least one processor; and
at least one computer memory storing instructions that, when executed by the at least one processor, cause the UE to perform operations comprising:
receiving configuration information related to a configured grant based small data transmission (CG-SDT);
starting a CG-SDT time alignment timer (TAT) based on the configuration information; and
performing a CG-SDT procedure in radio resource control (RRC) INACTIVE state while the CG-SDT TAT is running,
wherein, based on a timing advance command (TAC) being received and based on the CG-SDT procedure being ongoing, the CG-SDT TAT is restarted, and
wherein, based on the TAC being received and based on the CG-SDT procedure not being ongoing, a legacy TAT is started or restarted without restarting the CG-SDT TAT.
7 . The UE of claim 6 , wherein, based on the CG-SDT procedure being initiated, the CG-SDT procedure is considered to be ongoing until a reception of at least one of a radio resource control (RRC) release message, a RRC resume message, a RRC reject message or a RRC setup message.
8 . The UE of claim 6 , wherein the configuration information related to the CG-SDT is received via a radio resource control (RRC) release message.
9 . The UE of claim 6 , wherein, based on the CG-SDT TAT being expired, the configuration information related to the CG-SDT is released.
10 . The UE of claim 6 , wherein, during the CG-SDT TAT is running, CG resources for the CG-SDT is considered to be valid.
11 . An apparatus for a user equipment (UE), the apparatus comprising:
at least one processor; and
at least one computer memory storing instructions that, when executed by the at least one processor, cause the UE to perform operations comprising:
receiving configuration information related to a configured grant based small data transmission (CG-SDT);
starting a CG-SDT time alignment timer (TAT) based on the configuration information; and
performing a CG-SDT procedure in radio resource control (RRC) INACTIVE state while the CG-SDT TAT is running,
wherein, based on a timing advance command (TAC) being received and based on the CG-SDT procedure being ongoing, the CG-SDT TAT is restarted, and
wherein, based on the TAC being received and based on the CG-SDT procedure not being ongoing, a legacy TAT is started or restarted without restarting the CG-SDT TAT.
12 . A non-transitory computer readable storage medium storing at least one computer program comprising program instructions that, when executed by at least one processor, cause a user equipment (UE) to perform operations comprising:
receiving configuration information related to a configured grant based small data transmission (CG-SDT);
starting a CG-SDT time alignment timer (TAT) based on the configuration information; and
performing a CG-SDT procedure in radio resource control (RRC) INACTIVE state while the CG-SDT TAT is running,
wherein, based on a timing advance command (TAC) being received and based on the CG-SDT procedure being ongoing, the CG-SDT TAT is restarted, and
wherein, based on the TAC being received and based on the CG-SDT procedure not being ongoing, a legacy TAT is started or restarted without restarting the CG-SDT TAT.