摘要 |
Operation of a terminal for determining which time alignment timer is applied to a certain condition when specific timers operate for each carrier-wave group in the event a wireless communication system using carrier aggregation techniques. A terminal performs communication without malfunctions using a timer suitable for a certain condition. The terminal operates the timer by receiving, from a base station, a message including a timing advance command and an index on a timing advance group (TAG), operating the timer for the TAG, the index has a value of 00 when the TAG includes a first cell. A terminal operates a timer by operating a first timer for a TAG including a first cell, operating a second timer upon receipt of a timing advance command for a second TAG that does not include the first cell, and, if the first timer has expired, deeming the second timer to also be expired. |