Satellite-based cellular telecommunications system utilizing an earth station subsystem
First Claim
1. A subsystem in a satellite based telecommunications system of the type having at least one satellite which supports communications between user terminals and earth stations, said subsystem comprising:
- a first earth station for establishing a communications link through a satellite with a user terminal when said user terminal and said earth station are both covered by a satellite generated coverage area that moves with movement of said satellite;
a first MSC/VLR having a mobile services switching center (MSC) and a visitor locator register (VLR), said first MSC/VLR registering, in each instance independently of said satellite generated coverage area movement, terminal information for terminals located in a first geographically fixed location area assigned to said MSC/VLR;
an earth station network, interconnecting said first earth station and first MSC/VLR, for carrying communications data therebetween; and
a terrestrial network, connected to said first MSC/VLR, adapted to carry communications data to and from a public telephone system.
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Accused Products
Abstract
The present invention includes a satellite based telecommunications system having an earth station network which enables user terminals to remain registered with a single visitor location register independent of satellite movement so long as the terminal remains within a fixed geographic location area. The preferred embodiment includes multiple earth stations which communicate with user terminals via coverage satellites. Each user terminal is registered with a single visitor location register. As the user passes between location areas, the user terminal re-registers at a new associated visitor location register. Earth stations and mobile-services switching center/visitor location registers (MSC/VLRs) are interconnected along a dedicated earth station network link. Communications data is passed along the earth station network link between MSC/VLRs and earth stations in a compressed and/or encoded format. Each MSC/VLR is interconnected along a terrestrial network link with a gateway and the public switching telephone network. Communications data is passed along the terrestrial network link in a decompressed and/or decoded format. Optionally, MSC/VLRs may be located physically remote from earth stations. When MSC/VLRs and earth stations are provided at a common physical site, a modem switch is provided to selectively interconnect the earth station and MSC/VLR and the earth station network link. Earth stations and MSC/VLRs communicate along the earth station network through wide area network interfaces.
50 Citations
21 Claims
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1. A subsystem in a satellite based telecommunications system of the type having at least one satellite which supports communications between user terminals and earth stations, said subsystem comprising:
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a first earth station for establishing a communications link through a satellite with a user terminal when said user terminal and said earth station are both covered by a satellite generated coverage area that moves with movement of said satellite; a first MSC/VLR having a mobile services switching center (MSC) and a visitor locator register (VLR), said first MSC/VLR registering, in each instance independently of said satellite generated coverage area movement, terminal information for terminals located in a first geographically fixed location area assigned to said MSC/VLR; an earth station network, interconnecting said first earth station and first MSC/VLR, for carrying communications data therebetween; and a terrestrial network, connected to said first MSC/VLR, adapted to carry communications data to and from a public telephone system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 18, 19)
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13. A satellite based telecommunications system including earth stations and terminals, said system comprising:
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a plurality of satellites; a plurality of satellite generated coverage areas that move with movement of said plurality of satellites; a plurality of earth stations;
at least first and second visitor location registers having unique associated first and second geographically fixed location areas, said first and second visitor location registers registering, in each instance independently of said satellite generated coverage area movement, terminal information for at least first and second terminals therewith, respectively;a gateway having a home location register, said home location register storing routing information identifying a visitor location register at which each terminal is registered, said gateway directing communications data between a public telephone systems and one of said first and second visitor location registers based on said routing information stored in said home location register; and a direct communications link between said visitor location registers and said earth stations, wherein said first visitor location register directs communications data to and from any of said earth stations through said direct communications link.
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14. A method for routing calls in a satellite based cellular telecommunications system of the type having at least one satellite supporting communicating between user terminals and visitor location registers assigned to unique geographically fixed location areas, each of the visitor location registers containing terminal information for user terminals registered therewith, the method comprising the steps of:
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registering terminal identity and location information for a terminal located in a first geographically fixed location area with a first visitor location register; storing said terminal identity and location information from said first visitor location register in a home location register; receiving a call from a public switch telephone network directed to said terminal; routing the call to a visitor location register at which the terminal is registered based on a terminal identifier in the call and terminal identity and location information stored in the home location register; and rerouting the call from the first visitor location register to an earth station capable of establishing a communications link with the user terminal through a satellite generated coverage area that moves with movement of said satellite, said call being rerouted along an earth station network; and wherein said registering step comprises registering information for said terminals in each instance independently of said satellite generated coverage area movement. - View Dependent Claims (15, 16, 17, 20)
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21. A subsystem in a satellite based telecommunications system of the type having at least one satellite which supports communications between user terminals and earth stations, said subsystem comprising:
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a first earth station for establishing a communications link through a satellite with a user terminal when said user terminal and said earth station are both covered by a satellite generated coverage area that moves with movement of said satellite; and a first MSC/VLR having a mobile services switching center (MSC) and a visitor locator register (VLR) for registering a terminal therewith by storing terminal information in said first MSC/VLR, said first MSC/VLR registering, in each instance independently of said satellite generated coverage area movement, terminal information for terminals located in a first geographically fixed location area assigned to said MSC/VLR.
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Specification