Satellite communications systems and methods using radiotelephone location-based beamforming

• US 20050260947A1
• Filed: 05/11/2005
• Published: 11/24/2005
• Est. Priority Date: 05/18/2004
• Status: Active Grant

• Current Assignee: ATC Technology Corporation (FedEx Corporation)
• Original Assignee: ATC Technology Corporation (FedEx Corporation)
• Inventors: Karabinis, Peter D., Dutta, Santanu, Churan, Gary G.
• Granted Patent: US 8,265,549 B2
• Time in Patent Office: Days
• US Class Current: 455/12.100
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04B 7/18515 Transmission equipment in satellites or space-based relays
• CPC Class Codes: H04B 7/2041 Spot beam multiple access

Abstract

A processor for use in a satellite communications system includes a selector that is configured to select a subset of a plurality of spatially diverse satellite signals based upon a location of a radioterminal. The processor further includes a signal processor that is configured to detect a return-link transmission from the radioterminal responsive to the selected subset of the spatially diverse satellite signals. The respective spatially diverse satellite signals may include respective signals corresponding to respective antenna elements of a satellite. The selector and the signal processor may be ground based.

Claims

1. A processor for use in a satellite communications system, the processor comprising:

a selector that is configured to select a subset of a plurality of satellite signals based upon a location of a radioterminal; and

a signal processor that is configured to detect a return-link transmission from the radioterminal responsive to the selected subset of satellite signals.

2. A processor according to claim 1, wherein the plurality of satellite signals correspond to antenna feed element signals of a satellite service link antenna.

3. A processor according to claim 1, wherein the selector and/or the signal processor are not located at a satellite of the satellite communications system.

4. A processor according to claim 1, wherein the selector is configured to select the subset of the plurality of satellite signals responsive to a forward and/or return link beam association of the terminal, a registration of the terminal and/or location information transmitted by the terminal.

5. A processor according to claim 4, wherein the selector is configured to select a first subset of the plurality of satellite signals responsive to a registration of the terminal, wherein the signal processor is configured to detect location information transmitted by the terminal responsive to the first subset of the plurality of satellite signals, wherein the selector is further configured to select a second subset of the plurality of satellite signals responsive to the detected location information, and wherein the signal processor is further configured to detect a subsequent transmission from the terminal responsive to the second subset of the plurality of satellite signals.

6. A processor according to claim 1, wherein the signal processor is operative to generate a plurality of frequency diverse signal sets from the selected subset of satellite signals, and to detect the return-link transmission from the radioterminal from at least one of the plurality of frequency diverse signal sets.

7. A processor according to claim 6, wherein the signal processor comprises:

a channelization and frequency translation unit configured to generate the plurality of frequency diverse signal sets; and

a performance-enhancing signal processor configured to detect the return-link transmission from the radioterminal from at least one of the plurality of frequency diverse signal sets.

8. A satellite communications system comprising:

a satellite configured to receive a radio signal from a radioterminal that is in a service region of the satellite;

means for generating a plurality of spatially diverse signals from the received radio signal; and

a return-link processor configured to select a subset of the plurality of spatially diverse signals based upon a location of the radioterminal and to detect a return-link transmission from the radioterminal responsive to the selected subset of the spatially diverse signals.

9. A system according to claim 8, wherein the means for generating a plurality of spatially diverse signals from the received radio signals comprises an antenna of the satellite.

10. A system according to claim 9, wherein respective ones of the spatially diverse signals comprise respective feed signals corresponding to respective elements of the antenna.

11. A system according to claim 9, wherein the return-link processor is ground based.

12. A system according to claim 11, wherein the means for generating a plurality of spatially diverse signals from the received radio signal further comprises a satellite-based return-link processor configured to receive first spatially diverse signals from a satellite antenna and to responsively generate a feeder link signal including second spatially-diverse signals, wherein the second spatially diverse signals correspond to selected frequency components of the first spatially diverse signals.

13. A system according to claim 8, wherein the return-link processor is configured to select the subset of the plurality of spatially diverse signals responsive to a forward and/or return link antenna pattern association of the terminal, a registration of the terminal and/or location information transmitted by the terminal.

14. A system according to claim 13, wherein the return-link processor is configured to select a first subset of the plurality of spatially diverse signals responsive to a registration of the terminal, to detect location information transmitted by the terminal responsive to the first subset of the plurality of spatially diverse signals, to select a second subset of the plurality of spatially diverse signals responsive to the detected location information, and to detect a subsequent transmission from the terminal responsive to the second subset of the plurality of spatially diverse signals.

15. A system according to claim 8, wherein the return-link processor is operative to generate respective sets of frequency diverse signals from the selected subset of spatially diverse signals, and to detect the return-link transmission from the radioterminal from at least one of the sets of frequency diverse signals.

16. A system according to claim 15, wherein the return-link processor comprises:

a selector configured to select the subset of spatially diverse signals;

a channelization and frequency translation unit configured to generate the sets of frequency diverse signals from the subset of spatially diverse signals; and

a performance-enhancing signal processor configured to detect the return-link transmission from the radioterminal from at least one of the sets of frequency diverse signals.

17. A satellite communications system comprising:

a satellite-based return-link processor configured to receive first spatially diverse signals from a satellite antenna and to responsively generate a feeder link signal, wherein the satellite-based return-link processor spectrally distributes second spatially diverse signals corresponding to selected frequency components of the first spatially diverse signals in the feeder link signal; and

a ground-based return-link processor configured to select a subset of the second spatially diverse signals based upon a location of a radioterminal and to detect a return-link transmission from the radioterminal responsive to the selected subset of the second spatially diverse signals.

18. A system according to claim 17, further comprising a satellite antenna that generates the first spatially diverse signals.

19. A system according to claim 17, wherein respective ones of the first spatially diverse signals comprise respective feed signals corresponding to respective elements of a satellite antenna.

20. A system according to claim 17, wherein the ground-based return-link processor is configured to select the subset of the plurality of spatially diverse signals responsive to a forward link association of the terminal, a registration of the terminal and/or location information transmitted by the terminal.

21. A system according to claim 20, wherein the ground-based return-link processor is configured to select a first subset of the plurality of spatially diverse signals responsive to a registration of the terminal, to detect location information transmitted by the terminal responsive to the first subset of the plurality of spatially diverse signals, to select a second subset of the plurality of spatially diverse signals responsive to the detected location information, and to detect a subsequent transmission from the terminal responsive to the second subset of the plurality of spatially diverse signals.

22. A system according to claim 17, wherein the ground-based return-link processor is operative to generate respective sets of frequency diverse signals from the selected subset of spatially diverse signals, and to detect the return-link transmission from the radioterminal from at least one of the sets of frequency diverse signals.

23. A system according to claim 22, wherein the ground-based return-link processor comprises:

a selector configured to select the subset of spatially diverse signals;

a channelization and frequency translation unit configured to generate the sets of frequency diverse signals from the subset of spatially diverse signals; and

a performance-enhancing signal processor configured to detect the return-link transmission from the radioterminal from at least one of the sets of frequency diverse signals.

24. A satellite communications method comprising:

generating a plurality of spatially diverse signals from radio transmissions from a service area served by a satellite;

selecting a subset of the plurality of spatially diverse signals based upon a location of a radioterminal; and

detecting a return-link transmission from the radioterminal responsive to the selected subset of the spatially diverse signals.

25. A method according to claim 24, wherein respective ones of the spatially diverse signals comprise respective feed signals corresponding to respective elements of an antenna at the satellite.

26. A method according to claim 24, wherein selecting a subset of the plurality of spatially diverse signals based upon a location of a radioterminal is preceded by transmitting the plurality of spatially diverse signals from the satellite to a ground station.

27. A method according to claim 24:

wherein generating a plurality of spatially diverse signals from radio transmissions from a service area served by a satellite comprises;

generating first spatially diverse signals from a satellite antenna; and

generating a feeder link signal including second spatially diverse signals responsive to the first spatially diverse signals, including spectrally distributing the second spatially diverse signals in the feeder link signal;

wherein selecting a subset of the plurality of spatially diverse signals based upon a location of a radioterminal comprises selecting a subset of the second spatially diverse signals based upon the location of the radioterminal; and

wherein detecting a return-link transmission from the radioterminal responsive to the selected subset of the spatially diverse signals comprises detecting the return-link transmission from the radioterminal responsive to the selected subset of the second spatially diverse signals.

28. A method according to claim 24, wherein selecting a subset of the plurality of spatially diverse signals based upon a location of a radioterminal comprises selecting the subset of the plurality of spatially diverse signals based on a forward link association of the radioterminal, a registration of the radioterminal and/or location information transmitted by the radioterminal.

29. A method according to claim 24:

wherein selecting a subset of the plurality of spatially diverse signals based upon a location of a radioterminal comprises selecting a first subset of the plurality of spatially diverse signals responsive to a registration of the terminal;

wherein detecting a return-link transmission from the radioterminal responsive to the selected subset of the spatially diverse signals comprises detecting location information transmitted by the terminal responsive to the first subset of the plurality of spatially diverse signals;

wherein selecting a subset of the plurality of spatially diverse signals based upon a location of a radioterminal further comprises selecting a second subset of the plurality of spatially diverse signals responsive to the detected location information; and

wherein detecting a return-link transmission from the radioterminal responsive to the selected subset of the spatially diverse signals further comprises detecting a subsequent transmission from the terminal responsive to the second subset of the plurality of spatially diverse signals.

30. A method according to claim 24, wherein detecting a return-link transmission from the radioterminal responsive to the selected subset of the spatially diverse signals comprises:

generating respective sets of frequency diverse signals from the selected subset of spatially diverse signals; and

detecting the return-link transmission from the radioterminal from at least one of the sets of frequency diverse signals.

31. A beam former for use in a wireless communications system in conjunction with an antenna comprising a plurality of antenna elements, the beam former configured to form an antenna pattern responsive to a set of antenna element signals provided to the beam former from a set of antenna elements, and wherein the beam former maintains the antenna pattern substantially invariant to any relative phase change between any two or more antenna element signals of the set of antenna element signals during transport of the any two or more antenna element signals from the antenna to the beam former.

32. A beam former according to claim 31 wherein the wireless communications system is a wireless satellite communications system and wherein the antenna comprises a satellite antenna of a satellite of the wireless satellite communications system.

33. A beam former according to claim 32 wherein the beam former is positioned at a location distant from the satellite.

34. A beam former according to claim 31 wherein the set of signals are transported from the set of antenna elements to the beam former using frequency division multiplexing.

35. A beam former for use in a wireless communications system in conjunction with an antenna comprising a plurality of antenna elements, the antenna configured to form an antenna pattern responsive to a set of antenna element signals transported from the beam former to a set of the antenna elements and wherein the beam former maintains the antenna pattern substantially invariant to any relative phase change introduced between any two or more antenna element signals of the set of antenna element signals during transport of the any two or more antenna element signals from the beam former to the antenna.

36. A beam former according to claim 35 wherein the wireless communications system is a wireless satellite communications system and wherein the antenna comprises a satellite antenna positioned at a satellite of the wireless satellite communications system.

37. A beam former according to claim 36 wherein the beam former is positioned at a location distant from the satellite.

38. A beam former according to claim 35 wherein the set of antenna element signals are transported from the beam former to the antenna using frequency division multiplexing.

39. A beam forming method comprising:

transporting a set of antenna element signals from a set of antenna elements to a beam former; and

forming an antenna pattern responsive to the set of antenna element signals, including maintaining the antenna pattern substantially invariant to any relative phase change between any two or more antenna element signals of the set of antenna element signals during transport of the two or more antenna element signals to the beam former.

40. A method according to claim 39 wherein the antenna elements comprise antenna elements of a satellite antenna positioned at a satellite of a wireless satellite communications system.

41. A method according to claim 40 wherein the beam former is positioned at a location distant to the satellite.

42. A method according to claim 39 wherein the set of antenna element signals are transported from the antenna to the beam former using frequency division multiplexing.

43. A beam forming method comprising:

transporting a set of antenna element signals from a beam former to a set of antenna elements of an antenna; and

forming an antenna pattern responsive to the set of antenna element signals, including maintaining the antenna pattern substantially invariant to any relative phase change introduced between any two or more antenna element signals of the set of antenna element signals during transporting of the any two or more antenna element signals from the beam former to the antenna.

44. A method according to claim 43 wherein the antenna comprises a satellite antenna positioned at a satellite of a wireless satellite communications system.

45. A method according to claim 44 wherein the beam former is positioned at a location distant from the satellite.

46. A method according to claim 43 wherein the set of antenna element signals are transported from the beam former to the antenna using frequency division multiplexing.