Multiple satellite mobile communications method and apparatus for hand-held terminals

• US 6,337,980 B1
• Filed: 03/18/1999
• Issued: 01/08/2002
• Est. Priority Date: 03/18/1999
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Original Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Inventors: Mayfield, William, Chang, Donald C. D., Chang, Ming U., Novak, John I. III, Hagen, Frank A., Yung, Kar
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): PEREZ GUTIERREZ, RAFAEL
• Application Number:
  US09/271,997
• Time in Patent Office: 1,027 Days
• Field of Search: 455/13.1, 455/13.2, 455/12.1, 455/67.6, 455/427, 455/428, 455/429, 455/430, 455/447, 455/502, 455/503, 375/211, 370/316, 370/326
• US Class Current: 455/430
• CPC Class Codes: H04B 7/18504 Aircraft used as relay or high altitude atmospheric platform
• CPC Class Codes: H04B 7/18506 Communications with or from aircraft, i.e. aeronautical mobile service
• CPC Class Codes: H04B 7/18532 Arrangements for managing transmission, i.e. for transporting data or a signalling message
• CPC Class Codes: H04B 7/18534 for enhancing link reliablility, e.g. satellites diversity
• CPC Class Codes: H04B 7/212 Time-division multiple access [TDMA]

Abstract

A novel mobile satellite communications technique for hand-held terminals includes a satellite system having a plurality of individual satellites all in communication with a ground telecommunications hub. A signal processed by the ground telecommunications hub is radiated through multiple paths to a plurality of the individual satellites in the satellite constellation simultaneously. The radiated signal is then re-radiated by the plurality of individual satellites to a mobile satellite terminal that receives the re-radiated signal from the plurality of individual satellites simultaneously such that the same frequency spectrum may be re-used by another mobile user.

Claims

1. A mobile satellite communications system for mobile users, comprising:

a satellite constellation having a plurality of individual satellites which act as a sparse radiating array;

a ground telecommunications hub in communication with each of said plurality of individual satellites, such that a signal processed by said ground telecommunications hub is radiated through a plurality of paths to a plurality of said individual satellites in said satellite constellation, wherein said ground telecommunications hub includes a processing center for receiving a plurality of signals and processing the signals to be transmitted to said plurality of individual satellites and wherein said processing center includes;

apparatus for combining said plurality of received signals for transmission to said plurality of individual satellites;

apparatus for amplifying said combined signals;

apparatus for filtering said combined signals;

apparatus for up-converting said combined signals;

a beam former for forming multiple beams for transmitting signals to said plurality of satellites, and

apparatus for predicting any time variant differential among various paths between said hub and said mobile terminal, and

a mobile terminal for receiving said signal radiated from said plurality of individual satellites simultaneously,

wherein said signal is processed by said ground telecommunications hub to be transmitted through said plurality of individual satellites such that said signal is received simultaneously at said mobile terminal.

2. The mobile satellite communications system of claim 1, wherein said apparatus for predicting said time variant utilizes two-way ranging navigation.

3. A method for transmitting a communications signal to a mobile hand-held terminal, comprising the steps of:

providing a ground telecommunications hub;

processing a signal at said ground telecommunications hub in order to focus signal strength at the mobile hand-held terminal from a plurality of satellites;

radiating said signal through multiple paths to said plurality of satellites in a satellite constellation;

re-radiating said signal from said plurality of satellites to the mobile hand-held terminal; and

combining said re-radiated signal received from said plurality of satellites simultaneously at the mobile hand-held terminal,

wherein said signal processing is such that said signal is transmitted through said plurality of individual satellites and received simultaneously at said mobile terminal.

4. The method of claim 3, further comprising:

processing a plurality of received user signals at said ground telecommunications hub.

5. The method of claim 4, wherein said step of processing said plurality of received user signals further comprises:

combining said plurality of received signals for transmission to said plurality of individual satellites.

6. The method of claim 5, wherein said step of processing said plurality of received user signals further comprises:

filtering said combined signals; and

up-converting said combined signals.

7. The method of claim 6, wherein said step of processing said plurality of received user signals further comprises:

forming multiple beams for transmitting signals to said plurality of satellites.

8. A method for transmitting a communications signal to a mobile hand-held terminal, comprising the steps of:

providing a ground telecommunications hub;

processing a signal at said ground telecommunications hub;

predicting any time variant differential among multiple paths between said hub and said mobile terminal;

radiating said signal through said multiple paths to a plurality of satellites in a satellite constellation which are configured to act as a sparse radiating array; and

re-radiating said signal from said plurality of satellites through multiple paths to the mobile hand-held terminal such that the multiple paths are received at the mobile hand-held terminal simultaneously, wherein processing said signal is performed such that said signal is received at the mobile hand-held terminal simultaneously.

9. The method of claim 8, further comprising:

processing a plurality of received user signals at said ground telecommunications hub.

10. The method of claim 9, wherein said step of processing said plurality of received user signals further comprises:

forming multiple beams for transmission to said plurality of satellites.

11. The method of claim 9, wherein said step of processing said plurality of received user signals further comprises:

combining said plurality of received signals for transmission to said plurality of satellites.

12. The method of claim 8, wherein said step of processing a signal at said ground telecommunications hub further comprises:

filtering said signal prior to said step of radiating.

13. The method of claim 12, wherein said step of processing a signal at said ground telecommunications hub further comprises:

up-converting said signal prior to said step of radiating.