A method for wireless communication supporting uplink and downlink multi carriers Includes performing initial access through one of at least two downlink component carriers among multiple downlink component carriers including the at least two downlink component carriers through which the user equipment is allowed to perform the initial access; and transmitting via an uplink component carrier allocated to the user equipment by using a carrier identifier, wherein the carrier identifier is applied to the uplink component carrier and is obtained from the downlink component carrier through which the initial access is performed, and wherein the system pre-defines one-to-one correspondence between multiple downlink component carriers and multiple uplink component carriers, and wherein the downlink component carrier through which the initial access is performed and the uplink component carriers allocated to the user equipment do not match the one-to-one correspondence pre-defined by the system.