Method for reporting cell status information in wireless communication system and an apparatus therefor

1. A method for reporting cell activation status information for one or more cells to a network at a user equipment (UE) in a wireless communication system, the method comprising:

receiving, from the network, a message for reporting the cell activation status information,

wherein the message includes:

first information on a condition for reporting the cell activation status information, and

second information on a reporting type for reporting the cell activation status information, and

wherein the reporting type is one of a conditional reporting or an immediate reporting;

reporting the cell activation status information to the network based on the message,

wherein, if the reporting type is the conditional reporting, the cell activation status information is reported when the condition is met,

wherein, if the reporting type is the immediate reporting, the cell activation status information is reported immediately,

wherein the cell activation status information informs of whether each of the one or more cells is activated or deactivated, and

wherein the one or more cells are configured into a timing advance group (TAG); and

after the cell activation status information is reported to the network, reporting a bitmap information for time alignment timer (TAT) status of the TAG,

wherein, if the TAT of the TAG is running, a field of the bitmap information is set to 1, and

wherein, if the TAT of the TAG is not running, the field of the bitmap information is set to 0.

2. The method of claim 1 , wherein the one or more cells are not cells that are always activated.

3. The method of claim 1 , wherein, if the reporting type is the immediate reporting, the cell activation status information is reported to the network upon receipt of the message.

4. The method of claim 1 , wherein the condition comprises a deactivation of at least one cell among the one or more cells.

5. The method of claim 1 , wherein the condition comprises an activation of at least one cell among the one or more cells.

6. The method of claim 1 , wherein the condition comprises a predetermined time before a deactivation of at least one cell among the one or more cells.

7. The method of claim 1 , wherein the cell activation status information for the one or more cells comprises bitmap information for whether each of the one or more cells is activated or deactivated.

8. The method of claim 1 , wherein the reporting the cell activation status information comprises reporting the cell activation status information periodically.

9. The method of claim 1 , further comprising starting a deactivation timer when a command for activating at least one cell among the one or more cells is received.

10. The method of claim 9 , further comprising stopping the deactivation timer when a command for deactivating the at least one cell is received.

11. A user equipment (UE) for reporting cell activation status information for one or more cells to a network in a wireless communication system, the UE comprising:

a radio frequency (RF) module; and

a processor operably connected to the RF module, the processor being configured to:

control the RF module to receive, from the network, a message for reporting the cell activation status information,

wherein the message includes:

first information on a condition for reporting the cell activation status information, and

second information on a reporting type for reporting the cell activation status information, and

wherein the reporting type is one of a conditional reporting or an immediate reporting;

control the RF module to report the cell activation status information to the network based on the message,

wherein, if the reporting type is the conditional reporting, the cell activation status information is reported when the condition is met,

wherein, if the reporting type is the immediate reporting, the cell activation status information is reported immediately,

wherein the cell activation status information informs of whether each of the one or more cells is activated or deactivated, and

wherein the one or more cells are configured into a timing advance group (TAG); and

after the cell activation status information is reported to the network, control the RF module to report a bitmap information for time alignment timer (TAT) status of the TAG,

wherein, if the TAT of the TAG is running, a field of the bitmap information is set to 1, and

wherein, if the TAT of the TAG is not running, the field of the bitmap information is set to 0.