The present invention relates to a wireless communication system. Specifically, the invention relates to a method for configuring a component carrier at a base station in a wireless communication system, comprising the steps of determining whether initial access is permitted to a user equipment with respect to a downlink component carrier; and transmitting a synchronization channel signal and a broadcast channel signal to at least one user equipment via the downlink component carrier, wherein the initial access permission is applied to said at least one user equipment by modifying at least one of the synchronization channel signal and the broadcast channel signal.