Satellite communication system employing a combination of time slots and orthogonal codes

• US 9,143,361 B2
• Filed: 10/15/2012
• Issued: 09/22/2015
• Est. Priority Date: 01/04/2006
• Status: Active Grant

• Current Assignee: Globalstar Incorporated
• Original Assignee: Globalstar Incorporated
• Inventors: Monte, Paul A., Gallagher, Vijaya
• Primary Examiner(s): Patel, Ajit
• Application Number:
  US13/652,115
• Publication Number:
  US 20130051360A1
• Time in Patent Office: 1,072 Days
• Field of Search: 455/422.1, 455/427, 455/428, 370/310, 370315-326
• US Class Current: 1/1
• 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 with a plurality of user terminals comprising:

a satellite constellation comprising at least one satellite which provides multiple beams;

a plurality of user terminals that can communicate via said satellite constellation;

at least one gateway connected to a public switched telephone network and when communicating with at least a plurality of user terminals over the satellite communication system, distinguishing each of said user terminals within a given frequency band by 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 packet data messages;

wherein said satellite communication system is further configured to hand off a user terminal communication from one of said user terminals, from one beam of said at least one satellite having multiple beams to another beam of said at least one satellite having multiple beams based on signal strength determined from said user terminal communicating through said at least one satellite.

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 constellation comprises a LEO satellite constellation.

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

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

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

a satellite constellation comprising a plurality of satellites which provides multiple beams;

a plurality of user terminals that can communicate via said satellite constellation;

at least one gateway connected to a public switched telephone network and when communicating with a plurality of user terminals over the satellite communication system, distinguishing each of said user terminals within a given frequency band by employing a combination of time slots and orthogonal codes implemented in a forward and return link;

a ground operations center configured to provide, for each user terminal communication, (i) tracking information as to which satellites of the constellation to use for said user terminal communication and (ii) transmission parameters including and satellite antenna selection to use for said user terminal communication;

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

wherein said user terminal is configured to use tracking information provided by the ground operations control center for said user terminal communication.

7. The satellite communication system of claim 6 wherein said satellite constellation comprises 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.