APPARATUS AND METHOD FOR PERFORMING UPLINK SYNCHRONIZATION IN MULTI-COMPONENT CARRIER SYSTEM

摘要

The present invention relates to an apparatus and method for performing uplink synchronization in a multi-component carrier system. A method for performing uplink synchronization according to the present invention comprises the steps of: receiving, from a base station, a message that indicates a time alignment value for adjusting an uplink time of a sub-serving cell; adjusting the uplink time on the basis of the time alignment value; and driving a validity timer, which indicates the period of validity of the time alignment value when the sub-serving cell is deactivated. According to the present invention, with respect to a sub-serving cell, which performs a random access procedure to ensure and maintain a time alignment value, the validity of the time alignment value and whether or not uplink synchronization in the sub-serving cell is made can be quickly ascertained, and efficiency of uplink data transmission can increase.