Abstract: A method is provided for performing an authentication procedure according to location registration and update for a mobile subscriber station (MSS) in a broadband wireless access (BWA) communication system. The system includes the MSS operating in idle mode to minimize power consumption, paging groups each being formed by a plurality of adjacent cells in which a plurality of MSSs are paged, base stations (BSs) for paging the plurality of MSSs within each paging group, and a server for controlling location registration and authentication for the plurality of MSSs. The server determines whether to approve a request for transition to the idle mode received from the MSS through a BS. If the server approves the request for the transition to the idle mode, it allocates authentication information to the MSS through the BS and registers location of the MSS.