Method and system for initial procedure in a frequency overlay communication system

A method and a system for performing an initial operation in a frequency overlay communication system are provided to define an initial operation procedure of an NB-MS(Narrow Band-Mobile Station) and an EB(Extended Band)-MS in the frequency overlay communication system, thereby efficiently providing a high-speed multimedia service for the next generation mobile communication system. A method for performing an initial operation of a mobile station using the first frequency band comprises the following steps of: performing correlation on the entire frequency band by the first frequency band unit(506); receiving broadcast information through a frequency band having the maximum correlation value(510); and performing initial access to a base station through the frequency band having the maximum correlation value when a frequency bandwidth of the base station recognized by referring to the broadcast information is narrower than or equal to the first frequency bandwidth of the mobile station(512).