Interworking between telecommunications networks

• US 6,256,497 B1
• Filed: 03/24/1998
• Issued: 07/03/2001
• Est. Priority Date: 04/01/1997
• Status: Expired due to Term

• Current Assignee: DBSD Services Ltd. (Dish Network Corporation)
• Original Assignee: ICO Services, Ltd. (Dish Network Corporation)
• Inventors: Chambers, Paul
• Primary Examiner(s): Trost, William G.
• Assistant Examiner(s): PEREZ GUTIERREZ, RAFAEL
• Application Number:
  US09/046,673
• Time in Patent Office: 1,197 Days
• Field of Search: 455/414, 455/435, 455/445, 455/561, 455/450, 455/454, 455/560, 455/432, 455/433
• US Class Current: 455/433
• CPC Class Codes: H04B 7/18563 Arrangements for interconnecting multiple systems data switching networks H04L12/00
• CPC Class Codes: H04W 84/06 Airborne or Satellite Networks space-based or airborne stations H04B7/185
• CPC Class Codes: H04W 92/02 Inter-networking arrangements

Abstract

A mobile telephone (UT 1) is configured for dual mode operation, so as to communicate either via an earth-orbiting satellite 3a with a satellite network (SAN 1) or through a conventional land-based cellular network (PLMN 9). In order to provide interworking between the satellite network and the land, cellular network 9, an interworking function (IWF 31) provides data to the cellular network 9 concerning the location of the user terminal (UT 1) in relation to the satellite network. The data is transmitted from the satellite visitor location register (VLR_SAT 1) to the home location register (HLR) of the cellular network 9. The IWF maintains a list of roaming subscribers provisioned with services which are specific to the visited network and not available in the home network. The (IWF 31) is configured to operate with local GSM, DAMPS, PHS or other local land-based networks, depending on the geographic location of the SAN.

Claims

1. 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; and

an 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, and

an 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.

2. The apparatus according to claim 1 wherein the first network is selected from the group comprising a GSM, DAMPS,PHS, PDC and a UMTS network.

3. Apparatus according to claim 1 wherein the second network includes a plurality of visitor location registers and the interworking home location register is operable to keep a record of which of the visitor location registers with which the user terminal is registered.

4. Apparatus according to claim 1 wherein the first network comprises a land based mobile network and the second network comprises a satellite telecommunications network.

5. Apparatus according to claim 1 wherein the service comprises a high power notification (HPN) service.

6. A method of interworking between first and second mobile telecommunications networks, for use with a mobile user terminal for a subscriber to the first network which can roam to the second network, the first network including a home location register for maintaining a record of the network with which the subscriber is currently registered, 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;

the method comprising;

maintaining in an interworking home location register 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, and

maintaining an 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.

7. An interworking function unit for providing interworking between first and second mobile telecommunications networks, for use with a mobile user terminal for a subscriber to the first network which can roam to the second network, the first network including a home location register for maintaining a record of the network with which the subscriber is currently registered, 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;

the interworking function unit comprising;

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 from the interworking function unit with data corresponding to said services to which access is permitted, and

an 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.