Worldwide telecommunications system using satellites

• US 5,655,005 A
• Filed: 07/24/1996
• Issued: 08/05/1997
• Est. Priority Date: 10/10/1991
• Status: Expired due to Term

• Current Assignee: Globalstar Incorporated
• Original Assignee: Space Systems/Loral Incorporated (Loral Space and Communications Incorporated)
• Inventors: Wiedeman, Robert A., Monte, Paul A.
• Primary Examiner(s): CUMMING, WILLIAM D
• Application Number:
  US08/685,640
• Time in Patent Office: 377 Days
• Field of Search: 379/59, 455/3.2, 455/13.1, 375/200
• US Class Current: 370/320
• CPC Class Codes: H04B 7/18541 for handover of resources
• CPC Class Codes: H04B 7/18556 using a location database

Abstract

A satellite telecommunications system that is operative in conjunction with an existing terrestrial telecommunications system. The satellite telecommunications system includes at least one satellite in earth orbit, at least one terrestrial communications gateway for coupling the at least one satellite to the terrestrial telecommunications system, a plurality of satellite telecommunications system subscriber transceivers operative for conducting communications through the at least one satellite with subscribers of the terrestrial telecommunications system, and a terrestrial network coordinating gateway (NCG) in communication with the at least one satellite. The NCG includes a satellite receiver for receiving access requests from individual ones of the plurality of subscriber transceivers and a controller for assigning satellite channels on behalf of the subscriber transceivers and for selecting terrestrial communications gateways to create call set-up links on behalf of the subscriber transceivers. The NCG further logs-in roaming subscriber transceivers.

Claims

1. In a satellite telecommunications system operative in conjunction with an existing terrestrial telecommunications system, said satellite telecommunications system comprising:

at least one satellite in earth orbit;

at least one terrestrial communications gateway for coupling said at least one satellite to said terrestrial telecommunications system;

a plurality of satellite telecommunications system subscriber transceivers each comprising means for conducting communications through said at least one satellite with subscribers of said terrestrial telecommunications system; and

a terrestrial network coordinating gateway in communication with said at least one satellite, said network coordinating gateway comprising

means for receiving, through said at least one satellite, access requests from individual ones of said plurality of subscriber transceivers;

means for assigning satellite channels on behalf of said subscriber transceivers;

means for selecting terrestrial communications gateways to create call set-up links on behalf of said subscriber transceivers; and

means for logging-in roaming subscriber transceivers;

said network coordinating gateway further comprising;

a satellite interface means;

coupled to the satellite interface means, a satellite antenna for communicating with said at least one satellite; and

coordination means coupled to said satellite interface means;

wherein

said satellite interface means is coupled to said existing terrestrial telecommunications system through terrestrial coupling means.

2. In a satellite telecommunications network operative in conjunction with an existing terrestrial telecommunications system, a method for operating said satellite telecommunications network comprising the steps of:

providing a plurality of satellites in earth orbit, at least one terrestrial communications gateway, at least one terrestrial network coordinating gateway, and a plurality of satellite telecommunications system subscriber transceivers;

bidirectionally coupling, through first channelized RF links, the at least one terrestrial communications gateway to at least one of the satellites;

bidirectionally coupling the at least one terrestrial communications gateway to the terrestrial telecommunications system;

bidirectionally coupling, through the first channelized RF links, the least one terrestrial network coordinating gateway to at least one of the satellites; and

bidirectionally coupling at least one of the plurality of satellite telecommunications system subscriber transceivers, that is requesting access to the network, to the at least one satellite through second channelized RF links and, through the at least one satellite, to the at least one terrestrial network coordinating gateway;

wherein the method further comprises steps, executed by the at least terrestrial network coordinating gateway, of,

receiving, through the at least one satellite, a request for access to the satellite telecommunications network from at least one of the plurality of subscriber transceivers, and in response to receiving the request for access;

verifying that the subscriber transceiver that is requesting access is acceptable to be authorized to use the satellite telecommunications network and, if the subscriber transceiver is not acceptable, ignoring the request, otherwise if the subscriber transceiver is acceptable;

assigning at least one satellite RF channel for the acceptable subscriber transceiver;

selecting a terrestrial communications gateway to create call set-up links, using the assigned at least one satellite RF channel, for the acceptable subscriber transceiver; and

updating a network database for the acceptable subscriber transceiver;

the method further comprising the steps of,

establishing a bidirectional communications link between the acceptable subscriber transceiver and the selected one of the terrestrial communications gateways; and

bidirectionally coupling, through the first and second channelized RF links, the acceptable subscriber transceiver to the terrestrial communications system through the at least one satellite and through the selected one of the terrestrial communications gateways.

3. A method as set forth in claim 2, wherein the step of updating further includes the steps of:

sending a message that includes an identification of the subscriber transceiver and a location of the subscriber transceiver to a home gateway of the acceptable subscriber transceiver; and

updating a database of the home gateway to indicate that the subscriber transceiver is roaming, and to indicate the location of the roaming subscriber transceiver.

4. A method as set forth in claim 3, wherein the step of sending a message includes a preliminary step of interrogating the network database to determine an identification of the acceptable subscriber transceiver'"'"'s home gateway.

5. A method as set forth in claim 2, wherein at least the second channelized RF links employ Code Division, Multiple Access, and further comprising a step of assigning at least one code to the acceptable subscriber transceiver.

6. A method as set forth in claim 2, and further comprising a step of updating a database of the selected terrestrial communications gateway to indicate that the acceptable subscriber transceiver has been assigned to the selected terrestrial communications gateway.

7. A method as set forth in claim 2, wherein the step of establishing includes the initial steps of:

determining at the selected terrestrial communications gateway if resources are available to accommodate the acceptable subscriber transceiver; and

if it is determined that resources are not available, signalling the network coordinating gateway to so indicate; and

selecting, at the network coordinating gateway, another terrestrial communications gateway.

8. A method as set forth in claim 2, and further comprising the steps of:

sensing, during a time that the subscriber transceiver is bidirectionally coupled to the terrestrial communications system, that a handoff is required from the at least one satellite to another one of the satellite;

selecting another one of the satellites; and

transmitting a message to the subscriber transceiver through the at least one satellite, the message including information for enabling the subscriber transceiver to establish a bidirectional RF communication link with the selected another one of the satellites.

9. A method as set forth in claim 8, wherein the message includes information for specifying at least one satellite RF channel.

10. A method as set forth in claim 8, wherein at least the second channelized RF links employ Code Division, Multiple Access, and wherein the message includes information for specifying at least one code.

11. A method as set forth in claim 2, wherein the at least one network coordinating gateway is provided so as to be co-located with at least one terrestrial communications gateway.

12. A method as set forth in claim 2, wherein at least one of the plurality of subscriber transceivers is provided to include a terrestrial cellular first RF transceiver unit, a satellite second RF transceiver unit, and a control unit coupled to the first and second RF transceiver units, the control unit storing an identification of the subscriber transceiver.

13. In a satellite telecommunications network operative in conjunction with an existing terrestrial telecommunications system, a method for operating said satellite telecommunications network comprising the steps of:

providing a plurality of satellites in low earth orbit, at least one terrestrial communications gateway, at least one terrestrial network coordinating gateway, and a plurality of satellite telecommunications system subscriber transceivers;

bidirectionally coupling, through first channelized RF links, the least one terrestrial communications gateway to at least one of the satellites;

bidirectionally coupling the at least one terrestrial communications gateway to the terrestrial telecommunications system;

bidirectionally coupling, through the first channelized RF links, the least one terrestrial network coordinating gateway to at least one of the satellites;

operating a subscriber transceiver to generate a service request, the service request indicating that the subscriber transceiver desires to gain access to the satellite telecommunications system, the subscriber transceiver being initially provided with a terrestrial cellular first RF transceiver unit, a satellite second RF transceiver unit, and a control unit coupled to the first and second RF transceiver units, the control unit storing an identification of the subscriber transceiver;

transmitting the service request from the subscriber transceiver to at least one satellite through second channelized RF links and, through the at least one satellite, to the at least one terrestrial network coordinating gateway;

wherein the method further comprises steps, executed by the terrestrial network coordinating gateway, of receiving the service request;

verifying that the subscriber transceiver that transmitted the service request can be authorized to use the satellite telecommunications network and, if the subscriber transceiver is authorized,

selecting a terrestrial communications gateway to create call set-up links for the authorized subscriber transceiver; and

updating a network database for the acceptable subscriber transceiver.

14. A method as set forth in claim 13, wherein the step of updating a network database further includes the steps of:

interrogating the network database to determine an identification of a home gateway of the authorized subscriber transceiver;

sending a message that includes an identification of the subscriber transceiver and a location of the subscriber transceiver to the home gateway of the authorized subscriber transceiver; and

updating a database associated with the home gateway to indicate that the subscriber transceiver is roaming, and to indicate the location of the roaming subscriber transceiver.

15. A method as set forth in claim 13, wherein the at least one network coordinating gateway is provided so as to be co-located with at least one terrestrial communications gateway.