There is provided a system for judging validity of a radio terminal according to identification information on the radio terminal and providing a service. A radio network is divided into a plurality of zones. For each of the zones, there is arranged a server for storing in a particular zone, the position...http://www.google.fr/patents/US20070149190?utm_source=gb-gplus-shareBrevet US20070149190 - Roaming system, mobile communication system, and mobile communication control method
Roaming system, mobile communication system, and mobile communication ...
