Satellite communication system for communicating packet data messages

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, a public switched telephone network (PSTN), or a data network, via the at least one satellite;

at least one gateway communicating with at least one user terminal over the at least one satellite wherein each of said user terminals within a given frequency band is distinguished from another of said user terminals employing orthogonal codes employed on forward channel transmissions; and

wherein said user terminals are equipped to initiate or receive or terminate packet data messages;

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

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

2. The satellite system of claim 1 wherein said satellite is in a low earth orbit (LEO) satellite constellation.

3. The satellite system as defined in claim 2 wherein said hand off is predicated on signal strength determined at the user terminal.

4. The satellite system of claim 1 wherein said satellite is in a geosynchronous earth orbit (GEO) satellite constellation.

5. The satellite system of claim 1 wherein said plurality of user terminals are equipped to receive global positioning system (GPS) signals.

6. The satellite system of claim 1 wherein said gateway is connected to a public switched telephone network (PSTN) and/or an Internet.

7. The satellite system of claim 1 wherein one of said plurality of user terminals is handed off from one beam of said satellite to another beam of said satellite.

8. The satellite system of claim 1 wherein said user terminal is handed off from one satellite to another satellite.

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

a low earth orbit (LEO) satellite constellation wherein each satellite of said constellation provides multiple beams;

a plurality of user terminals that communicate with each other, a public switched telephone network (PSTN), or a data network, via satellites of the constellation;

at least one gateway connected to an Internet and communicating with at least one user terminal over the constellation wherein each of said user terminals within a given frequency band is distinguished from another of said user terminals employing orthogonal codes employed on forward channel transmissions;

wherein said user terminal can either initiate or receive packet data messages;

wherein each of said plurality of 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.

10. The satellite communication system as defined in claim 9 wherein said satellite constellation comprises a geosynchronous earth orbit (GEO) satellite constellation.

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

a low earth orbit (LEO) satellite constellation wherein each satellite of said constellation provides multiple beams;

a plurality of user terminals that communicate with each other, a public switched telephone network (PSTN), or a data network, via satellites of the constellation;

at least one gateway connected to a PSTN and an Internet communicating with said at least one user terminal over the constellation wherein each of said user terminals within a given frequency band is distinguished from another of said user terminals employing orthogonal codes employed on forward channel transmissions;

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

wherein each of said plurality of 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.

12. The satellite communication system as defined in claim 11 wherein said satellite constellation comprises a geosynchronous earth orbit (GEO) satellite constellation.

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

a medium earth orbit (MEO) satellite constellation wherein each satellite of said constellation provides multiple beams;

a plurality of user terminals that communicate with each other, a public switched telephone network (PSTN), or a data network, via satellites of the constellation;

at least one gateway connected to an Internet and communicating with said at least one user terminal over the constellation wherein each of said user terminals within a given frequency band is distinguished from another of said user terminals employing orthogonal codes employed on forward channel transmissions;

wherein said user terminal can either initiate or receive packet data messages;

wherein each of said plurality of 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.

14. The satellite communication system as defined in claim 13 wherein said gateway is connected to a PSTN and an Internet.