A method for transmitting, by a base station, signals in a communication system. Control information for a subsidiary carrier band is transmitted to a mobile station via a primary carrier band. Data is transmitted to the mobile station via the subsidiary carrier band based on the control information and via the primary carrier band. Furthermore, the primary carrier band is a carrier frequency band which the mobile station initially attempts to access or via which information of a carrier aggregation configuration is transmitted. Additionally, the control information includes a logical index assigned to the subsidiary carrier band for the mobile station and a physical index of a frequency allocation band used as the subsidiary carrier band. The physical index corresponds to one of plural absolute frequency band indexes assigned to frequency allocation bands available in the communication system.