Patent ID: 7302259

Claim:
A mobile station for registering its location in a base station based on public land mobile network information included in system information which the base station transmits, the public land mobile network information including country and network identification codes, the mobile station comprising: a memory for storing a roaming public land mobile network table which has home public land mobile network information and information for a public land mobile network of a mobile communication business proprietor which supports a roaming function into the public land mobile network of a mobile communication business proprietor and a home public land mobile network; and a controller for determining whether acquired public land mobile network information exists in the roaming public land mobile network table stored in the memory using a frequency having a maximum receiving strength when international roaming occurs, registering the mobile station in a base station using the acquired public land mobile network information when the acquired public land mobile network information exists in the roaming public land mobile network table, acquiring new public land mobile network information using frequencies having a receiving strength less than the maximum receiving strength when the acquired public land mobile network information does not exist in the roaming public land mobile network table and determining whether the newly acquired public land mobile network information exists in the roaming public land mobile network table wherein roaming time is reduced by selectively registering a Public Land Mobile Network (PLMN) location only in a base station with a roaming function.