Methods and apparatus for accessing subscriber information in interconnected wireless telecommunications networks

A method of obtaining subscriber data for a mobile terminal roaming into a service area of a visited wireless network, the method comprising:

• receiving a registration request from the mobile terminal at the visited wireless network, the registration request comprising an identifier;
• searching a Home Location Register (HLR) of the visited wireless network for subscriber data corresponding to the identifier;
• upon failure to find subscriber data corresponding to the identifier at the HLR, searching a Visitor Location Register (VLR) of the visited wireless network for subscriber data corresponding to the identifier;
• upon failure to find subscriber data corresponding to the identifier at the VLR, searching an Intersystem Roaming (ISR) database for an address corresponding to the identifier;
• upon finding an address corresponding to the identifier in the ISR database, transmitting a subscriber data request comprising the identifier to the address;
• and
• upon failure to find an address corresponding to the identifier in the ISR database, broadcasting a subscriber data request to plural wireless networks connected to the visited wireless network.

A wireless system for providing service to a mobile terminal roaming into a service area of the wireless system, the wireless system comprising:

• a Home Location Register (HLR) for storing subscriber data for mobile terminals provisioned on the wireless network;
• a Visitor Location Register (VLR) for temporarily storing subscriber data for mobile terminals provisioned on other wireless networks;
• an Intersystem Roaming (ISR) database for storing addresses in association with identifiers;
• search means responsive to a registration request specifying a particular identifier for searching the HLR for subscriber data associated with the particular identifier, the search means being responsive to failure to find subscriber data associated with the particular identifier in the HLR to search the VLR for subscriber data associated with the particular identifier, and the search means being responsive to failure to find subscriber data associated with the particular identifier in the VLR to search the ISR database for an address associated with the particular identifier;
• and
• transmission means responsive to location of an address associated with the particular identifier in the ISR database to transmit a subscriber data request comprising the particular identifier to the address.

A wireless system for providing service to a mobile terminal roaming into a service area of the wireless system, the wireless system comprising:

• a Home Location Register (HLR) for storing subscriber data for mobile terminals provisioned on the wireless network;
• a Visitor Location Register (VLR) for temporarily storing subscriber data for mobile terminals provisioned on other wireless networks;
• an Intersystem Roaming (ISR) database for storing addresses in association with identifiers;
• search means responsive to a registration request specifying a particular identifier for searching the HLR for subscriber data associated with the particular identifier, the search means being responsive to failure to find subscriber data associated with the particular identifier in the HLR to search the VLR for subscriber data associated with the particular identifier, and the search means being responsive to failure to find subscriber data associated with the Particular identifier in the VLR to search the ISR database for an address associated with the particular identifier;
• and
• transmission means responsive to location of an address associated with the particular identifier in the ISR database to transmit a subscriber data request comprising the particular identifier to the address;
• wherein the transmission means is responsive to failure to locate an address associated with the particular identifier in the ISR database to broadcast a subscriber data request to plural other wireless systems.

A system for supporting roaming of mobile terminals into a service area of a wireless network, the system comprising:

• a Visitor Location Register (VLR) for temporarily storing subscriber data for mobile terminals provisioned on other wireless networks;
• an Intersystem Roaming (ISR) database for storing addresses in association with identifiers;
• search means responsive to a failure to find subscriber data associated with a particular identifier specified in a registration request in the HLR to search the VLR for subscriber data associated with the particular identifier, and the search means being responsive to failure to find subscriber data associated with the particular identifier in the VLR to search the ISR database for an address associated with the particular identifier;
• and
• transmission means responsive to location of an address associated with the particular identifier in the ISR database to transmit a subscriber data request comprising the particular identifier to the address.

A system for supporting roaming of mobile terminals into a service area of a wireless network, the system comprising:

• a Visitor Location Register (VLR) for temporarily storing subscriber data for mobile terminals provisioned on other wireless networks;
• an Intersystem Roaming (ISR) database for storing addresses in association with identifiers;
• search means responsive to a failure to find subscriber data associated with a particular identifier specified in a registration request in the HLR to search the VLR for subscriber data associated with the particular identifier, and the search means being responsive to failure to find subscriber data associated with the particular identifier in the VLR to search the ISR database for an address associated with the particular identifier;
• and
• transmission means responsive to location of an address associated with the particular identifier in the ISR database to transmit a subscriber data request comprising the particular identifier to the address;
• wherein the transmission means is responsive to failure to locate an address associated with the particular identifier in the ISR database to broadcast a subscriber data request to plural other wireless systems.