METHOD AND APPARATUS FOR MANAGING MULTIPLE TIMING ADVANCE GROUPS IN MOBILE COMMUNICATION SYSTEM SUPPORTING CARRIER AGGREGATION PRIORITY

摘要

A method by a terminal, wherein the method comprises the steps of: receiving, from a base station, radio resource control, RRC, connection reconfiguration information for configuring a secondary cell, SCell, wherein the RRC connection reconfiguration information includes an identifier of a timing advance group, TAG, to which the SCell belongs if the SCell does not belong to a primary TAG, PTAG, to which the PCell belongs and the RRC connection reconfiguration information does not include an identifier of a TAG for the SCell if the SCell belongs to the PTAG; receiving, from the base station, a medium access control, MAC, control element, CE, for activating the SCell; monitoring a physical downlink control channel, PDCCH, for the SCell based on the received MAC CE; receiving, from the base station, a PDCCH order for initiating a random access procedure on the SCell based on the monitoring; performing the random access procedure on the SCell based on the PDCCH order; and receiving, from the base station, a MAC CE including a timing advance command, TAC, for a TAG including the SCell based on the random access procedure.