SATELLITE COMMUNICATION SYSTEM EMPLOYING A COMBINATION OF TIME SLOTS AND ORTHOGONAL CODES

• US 20130051360A1
• Filed: 10/15/2012
• Published: 02/28/2013
• Est. Priority Date: 01/04/2006
• Status: Active Grant

• Current Assignee: Globalstar Incorporated
• Original Assignee: Globalstar Incorporated
• Inventors: Monte, Paul A., Gallagher, Vijaya
• Granted Patent: US 9,143,361 B2
• Time in Patent Office: Days
• US Class Current: 370/330
• CPC Class Codes: H04B 7/195 Non-synchronous stations
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways
• CPC Class Codes: H04W 88/16 Gateway arrangements

Abstract

A satellite communication system for communicating between a plurality of user terminals is disclosed having at least one satellite which provides multiple beams, a plurality of user terminals that communicate with each other via satellites of said constellation, at least one gateway connected to a public switched telephone network and communicating with at least one user terminal over the satellite communication system wherein each of said user terminals within a given frequency band is distinguished from another of the user terminals employing a combination of time slots and orthogonal codes implemented in a forward and return link. Each of the user terminals is equipped to initiate or receive or terminate packet data messages. Each of said user terminals is handed off from one beam of a satellite to another beam of said satellite. The hand off is predicated on signal strength determined at said plurality of user terminals.

Claims

1. A satellite communication system for communicating between a plurality of user terminals comprising:

at least one satellite which provides multiple beams;

a plurality of user terminals that communicate with each other via satellites of said constellation;

at least one gateway connected to a public switched telephone network and communicating with at least one user terminal over the satellite communication system wherein each of said user terminals within a given frequency band is distinguished from another of said user terminals employing a combination of time slots and orthogonal codes implemented in a forward and return link;

wherein each of said user terminals is equipped to initiate or receive or terminate packet data messages;

wherein each of said user terminals is handed off from one beam of a satellite to another beam of said satellite; and

wherein said hand off is predicated on signal strength determined at said plurality of user terminals.

2. A satellite communication system as defined in claim 1 wherein said forward link comprises orthogonal codes and said return link comprises a combination of time slots and phase shift of one or more pseudo-random codes.

3. A satellite communication system as defined in claim 1 wherein said satellite communication system comprises a LEO satellite constellation.

4. A satellite communication system as defined in claim 1 wherein said satellite communication system comprises a MEO satellite constellation.

5. A satellite communication system as defined in claim 1 wherein said satellite communication system comprises a GEO satellite constellation

6. A satellite communication system for communicating between a plurality of user terminals comprising:

a plurality of satellites which provides multiple beams;

a plurality of user terminals that communicate with each other via satellites of said constellation;

at least one gateway connected to a public switched telephone network and communicating with at least one user terminal over the satellite communication system wherein each of said user terminals within a given frequency band is distinguished from another of said user terminals employing a combination of time slots and orthogonal codes implemented in a forward and return link;

a ground operations control center which provides tracking information over a ground data network as to which satellites of the constellation to use and transmission parameters including transmit power, frequencies to use for communication between the plurality of user terminals, and which antenna to use;

wherein said user terminal is equipped to initiate or receive or terminate packet data messages; and

wherein said user terminal uses tracking information provided by the ground operations control center to optimize its signal transmission and reception parameters.

7. The satellite communication system of claim 6 wherein said satellites are in a LEO satellite constellation.

8. A satellite communication system as defined in claim 6 wherein said forward link comprises orthogonal codes and said return link comprises a combination of time slots and phase shift of one or more pseudo-random codes.