Patent ID: 7974619

Claim:
A method of coordinating communications of a mobile station with a satellite mobile communications system and a terrestrial mobile communications system, the method comprising: registering the mobile station for service at a terrestrial mobile communications system, wherein such registration for service includes registering location information about the mobile station at a home location register belonging to the terrestrial mobile communications system; authenticating the mobile station with an authentication center belonging to the terrestrial mobile communications system; concurrently registering the mobile station for service at the satellite mobile communications system, responsive to the registration of the mobile station for service with the terrestrial mobile communications system, wherein such registration also includes registering location information about the mobile station at a home location register belonging to the satellite mobile communications system; concurrently authenticating the mobile station with an authentication center belonging to the satellite mobile communications system; maintaining synchronization between location information about the mobile station at the location registers, as the location information changes due to movement of the mobile station so that the mobile station is concurrently enabled to communicate over each of the terrestrial mobile communications system and the satellite mobile communications system; and switching the mobile station from communicating with the terrestrial mobile communications system to being enabled to communicate with the satellite communications system using the location information at the home location register belonging to the satellite mobile communications system that was maintained synchronized with the location information at the home location register belonging to the terrestrial mobile communications system and without performing a location update of the home location register belonging to the satellite mobile communications system, and using the authentication of the mobile station with the authentication center belonging to the satellite mobile communications system that was concurrently authenticated, without retrieving additional authentication data.