A broadband wireless access (BWA) communication system including a serving BS for servicing an SS in at least one of a plurality of sub-carrier frequency bands, and a plurality of neighbor BSs adjacent to the serving BS. The SS measures CINRs of frequency band signals from the neighbor BSs, requests a handoff for a target BS having the highest CINR to the serving BS, transitions to the frequency band of the target BS, and acquires synchronization to the target BS. The SS transmits ranging information to the target BS in a ranging information region assigned by the target BS, receives from the target BS connection ID information between the target BS and the SS, transmits a handoff registration request message to the target BS according to the connection ID information, and receives a response message for the handoff registration request message from the target BS.