A method for an evolved Node-B, eNB, to establish an uplink, UL, synchronization in a wireless communication system, the method comprising: setting (S410; S508; S610; S710) a CC set to be used by a user equipment, UE; configuring (S508; S624; S726) a UL timing group including at least one UL CC used in devices in the same radio network, from among CCs included in the CC set; transmitting information associated with the UL timing group and information associated with the CC set to the UE through the same message through a primary serving cell or a primary DL CC; receiving (S440; S540; S640; S740) the synchronization request message from the UE through a delegate UL CC in the UL timing group, wherein the delegate UL CC is selected by the UE or the eNB based on a state of the UL timing group and characteristics of the plurality of CCs forming the UL timing group, so as to establish the UL synchronization; calculating (S450; S550; S650; S750) a time advance, TA, value that adjusts a UL transmission time for the delegate UL CC corresponding to the UL timing group, in response to the received synchronization request message; and transmitting (S450; S550; S650; S750), to the UE, UL synchronization information corresponding to the UL timing group including the calculated TA value together with UL grant information for the UE through a random access response message through a predetermined DL CC so as to establish the UL synchronization, wherein the delegate UL CC corresponds to at least one of i) a UL CC having a lowest center frequency value, ii) a UL CC having a center frequency value that is closest to a mean value, iii) a UL CC having a highest center frequency value, iv) a UL CC having a broadest frequency band, and v) a UL CC that is set to be used for monitoring DL quality, from among the plurality of UL CCs forming the UL timing group; and the delegate UL CC is included in one or more serving cells. setting (S410; S508; S610; S710) a CC set to be used by a user equipment, UE; configuring (S508; S624; S726) a UL timing group including at least one UL CC used in devices in the same radio network, from among CCs included in the CC set; transmitting information associated with the UL timing group and information associated with the CC set to the UE through the same message through a primary serving cell or a primary DL CC; receiving (S440; S540; S640; S740) the synchronization request message from the UE through a delegate UL CC in the UL timing group, wherein the delegate UL CC is selected by the UE or the eNB based on a state of the UL timing group and characteristics of the plurality of CCs forming the UL timing group, so as to establish the UL synchronization; calculating (S450; S550; S650; S750) a time advance, TA, value that adjusts a UL transmission time for the delegate UL CC corresponding to the UL timing group, in response to the received synchronization request message; and transmitting (S450; S550; S650; S750), to the UE, UL synchronization information corresponding to the UL timing group including the calculated TA value together with UL grant information for the UE through a random access response message through a predetermined DL CC so as to establish the UL synchronization, wherein the delegate UL CC corresponds to at least one of i) a UL CC having a lowest center frequency value, ii) a UL CC having a center frequency value that is closest to a mean value, iii) a UL CC having a highest center frequency value, iv) a UL CC having a broadest frequency band, and v) a UL CC that is set to be used for monitoring DL quality, from among the plurality of UL CCs forming the UL timing group; and the delegate UL CC is included in one or more serving cells.