Patent ID: 6256497
Filing Date: 2001-07-03
Classification: H04B,H04W

Abstract:
Mobile telecommunications apparatus including:a first mobile telecommunications network for use with a mobile user terminal for a subscriber to the first network, the first network including a home location register for maintaining a record of the network with which the subscriber is currently registered;a second mobile telecommunications network to which the subscriber's user terminal can roam, the second network including at least one visitor location register with which the user terminal becomes registered when roaming to the second network, and the second network offering a service to the subscriber not available through the first network; andan interworking function unit has been for providing interworking between the first and second networks, including:an interworking home location register to maintain a record of when the subscriber's user terminal becomes registered with a visitor location register of the second network and those of the services of the second network to which the subscriber is permitted access, whereby when the user terminal has roamed to the second network and registered with a visitor location register of the second network, the visitor location register is provided with data corresponding to said services to which access is permitted from the interworking function unit, andan interworking visitor location register coupled to the interworking home location register, the interworking visitor location register being operable to communicate to the home location register of the first network that the subscriber's user terminal has become registered with the visitor location register of the second network whereby when the user terminal has roamed to the second network and registered with the visitor location register of the second network, a call may be routed to the user terminal through the second network by being directed to the home location register of the first network such that the home location register obtains routing information through the interworking function unit for routing the call to the user terminal through the second network.