Apparatus and method for performing uplink synchronization in wireless communication system

摘要

This specification relates to an apparatus and method for performing random access in a wireless communication system. This specification discloses a mobile station, including a reception unit for receiving TAG configuration information on which at least one serving cell configured in the mobile station is classified as a Timing Alignment Group (TAG) from a base station and a transmission unit for transmitting a random access preamble to the base station on one representative serving cell within the TAG. In accordance with this specification, a procedure of obtaining a TAV for a serving cell in order to secure and maintain uplink timing synchronization becomes clear, the time taken to obtain uplink synchronization for a serving cell may be reduced, and overhead due to excessive random access attempts may be reduced by obtaining a TAV for a plurality of serving cells through one random access procedure.

主权项

1. A user equipment (UE) performing an uplink synchronization in a wireless communication system, the UE comprising:
a receiving unit configured for receiving a medium access control (MAC) protocol data unit (PDU) from a base station (BS); and a MAC processing unit configured for:
identifying that the MAC PDU includes a MAC header and a MAC control element (CE);obtaining, from the MAC header, a subheader;obtaining, from the subheader, a logical channel identifier (LCID) indicating an index to identify whether the MAC CE is for timing advance command (TAC);obtaining, from the MAC CE, a TAC field with 6 bits indicating a timing alignment value (TAV) and a timing alignment group (TAG) index field with 2 bits identifying a TAG to control uplink timing adjustment identically with the TAV;identifying the TAG to which the TAV is applied based on the TAG index field; andcontrolling the uplink timing adjustment for at least one serving cell in the identified TAG.