Location updating method and apparatus for mobile terminal in radio network

A location updating method for a mobile terminal, the method comprising:

• checking, when a location updating reject message is received from a visiting network, a cause of a rejection indicated by the location updating reject message;
• storing, when the cause of the rejection is “unknown International Mobile Station Identity (IMSI) in Home Location Register (HLR),” a network information of the visiting network;
• determining whether the visiting network information is identical with network information of a home network with which the mobile terminal is registered and a roaming network having a roaming contract with the home network;
• and
• maintaining, when the visiting network information is not identical with the home and roaming network information, a service state of the mobile terminal as a valid state by setting a Subscriber Identity Module (SIM) card of the mobile terminal as a valid state.

A mobile terminal comprising:

• a radio frequency unit for establishing a radio communication channel with a network to exchange location updating data;
• a memory unit for storing network information of at least one registered network with which the mobile terminal is registered and the network rejecting a location updating request of the mobile terminal;
• and
• a control unit for determining whether the network rejecting the location updating request is identical with the at least one registered network and for maintaining, when the network rejecting the location updating request is not identical with the at least one registered network, a service state of the mobile terminal by setting a Subscriber Identity Module (SIM) card of the mobile terminal as a valid state.