Intra- and/or inter-system interference reducing systems and methods for satellite communications systems

• US 7,340,213 B2
• Filed: 07/14/2004
• Issued: 03/04/2008
• Est. Priority Date: 07/30/2003
• 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., Zheng, Dunmin
• Primary Examiner(s): Anderson; Matthew
• Assistant Examiner(s): PEREZ, ANGELICA
• Application Number:
  US10/890,758
• Publication Number:
  US 20050037749A1
• Time in Patent Office: 1,329 Days
• Field of Search: 455527-531, 455/447, 455/12.1, 455/13.1, 455/13.2
• US Class Current: 455/12.1
• CPC Class Codes: H04B 7/1851 Systems using a satellite or space-based relay H04B7/18508, H04B7/18521 take precedence; providing specific services H04B7/18523 - H04B7/18576

Abstract

A first radio signal is received via a first satellite reception path, for example, an antenna or spot beam, which serves a satellite cell. The received first radio signal includes a desired satellite uplink signal transmitted from a first source using a frequency assigned to the satellite cell and an interfering signal transmitted from at least one second source using the frequency assigned to the satellite cell. A second radio signal is received via a second satellite reception path, for example, via another antenna or spot beam of the system and/or via a satellite antenna beam of another system. The second radio signal includes a measure of the interfering signal. The first and second radio signals are processed to recover the desired satellite uplink signal.

Claims

1. A method of operating a satellite radiotelephone communications system, the method comprising:

receiving a first radio signal via a first satellite reception path that serves a satellite cell, the received first radio signal including a desired satellite uplink signal transmitted from a first source using a frequency assigned to the satellite cell and an interfering signal transmitted from at least one second source using the frequency assigned to the satellite cell;

receiving a second radio signal via a second satellite reception path that is configured to receive radio transmissions from another communications system that uses the frequency assigned to the satellite cell, the second radio signal including a measure of the interfering signal; and

processing the first and second radio signals to recover the desired satellite uplink signal.

2. A method according to claim 1, wherein the second satellite reception path is configured to preferentially receive radio transmissions from an area outside of the satellite cell.

3. A method according to claim 2, wherein the area outside of the satellite cell comprises another satellite cell that uses the frequency assigned to the cell and/or a coverage area of another satellite communications system that uses the frequency assigned to the cell.

4. A method according to claim 2, wherein the satellite cell comprises a first satellite cell served by a first spot beam and wherein the second satellite reception path comprises a second spot beam that serves a second satellite cell of the satellite radiotelephone communications system.

5. A method according to claim 4, wherein at least one radiating source in a region of the second satellite cell uses a frequency assigned to the first satellite cell for satellite and/or terrestrial communications.

6. A method according to claim 4, wherein the second satellite cell is adjacent a third satellite cell that uses a frequency assigned to the first satellite cell.

7. A method according to claim 4, wherein the second satellite cell overlaps or is adjacent a terrestrial cell that uses a frequency assigned to the first satellite cell.

8. A method according to claim 4, wherein the satellite radiotelephone communications system comprises a first satellite radiotelephone communications system, and wherein the second satellite cell overlaps or is adjacent a coverage area of a second satellite radiotelephone communications system.

9. A method according to claim 2, wherein the first satellite reception path comprises a first satellite antenna positioned at a first satellite of the satellite radiotelephone communications system, and wherein the second satellite reception path comprises a second satellite antenna positioned at a second satellite of the satellite radiotelephone communications system.

10. A method according to claim 2, wherein the first satellite reception path comprises a first satellite antenna positioned at a satellite of the satellite radiotelephone communications system, and wherein the second satellite reception path is positioned at the same satellite.

11. A method according to claim 2, wherein the satellite radiotelephone communications system comprises a first satellite radiotelephone communications system, and wherein the second satellite reception path comprises a satellite of a second satellite radiotelephone communications system.

12. A method according to claim 11, wherein the second satellite reception path farther comprises an antenna configured to receive a feeder link transmission from the satellite of the second satellite radiotelephone communications system, and wherein the method further comprises conveying the feeder link transmission that is received by the antenna to the first satellite radiotelephone communications system.

13. A method according to claim 12, wherein the antenna is coupled to a gateway of the second satellite radiotelephone communications system, and wherein the method further comprises conveying the feeder link transmission that is received by to the first satellite radiotelephone communications system via the gateway of the second satellite radiotelephone communications system.

14. A method according to claim 12, wherein the antenna is coupled to a gateway of the first satellite radiotelephone communications system, and wherein the method further comprises conveying the feeder link transmission that is received by from the antenna to the gateway of the first satellite radiotelephone communications system.

15. A method according to claim 1, wherein processing the first and second radio signals to recover the desired satellite uplink signal comprises applying the first and second radio signals to an adaptive signal processor.

16. A method according to claim 1, wherein processing the first and second radio signals to recover the desired satellite uplink signal comprises:

applying the first and second radio signals to respective first and second transversal filters;

combining outputs of the first and second transversal filters; and

recovering the desired signal from the combined outputs.

17. A method according to claim 16, further comprising adjusting the first and second transversal filters responsive to the combined outputs.

18. A method according to claim 1, wherein receiving a second radio signal via a second satellite reception path comprises one or more of the following:

receiving the second radio signal via a satellite antenna spot beam other than a satellite antenna spot beam associated with reception of the first radio signal;

receiving the second radio signal via a satellite antenna other than a satellite antenna associated with reception of the first radio signal;

receiving the second radio signal via a satellite other than a satellite antenna spot beam associated with reception of the first radio signal; and

receiving the second radio signal via an antenna configured to receive feeder link transmissions from a satellite of a satellite radiotelephone communications system other than a satellite radiotelephone communications system associated with reception of the first radio signal.

19. A method according to claim 1, wherein the first and second satellite reception paths are configured to provide discrimination between the first and second sources based on a characteristic other than frequency.

20. A method of operating a satellite radiotelephone communications system, the method comprising:

receiving first and second radio signals via respective first and second spot beams that serve respective first and second satellite cells of the satellite radiotelephone communications system, the first radio signal including a desired satellite uplink signal transmitted from a first source in the first satellite cell using a frequency assigned to the first satellite cell and an interfering signal transmitted from at least one second source using the frequency assigned to the first satellite cell, the second radio signal including a measure of the interfering signal, the second spot beam configured to receive radio transmissions from another communications system that uses the frequency assigned to the first satellite cell; and

processing the first and second radio signals to recover the desired satellite uplink signal.

21. A method according to claim 20, wherein at least one radiating source in a region of the second satellite cell uses a frequency assigned to the first satellite cell for satellite and/or terrestrial communications.

22. A method according to claim 20, wherein the second satellite cell is adjacent a third satellite cell that uses a frequency assigned to the first satellite cell.

23. A method according to claim 20, wherein the second satellite cell overlaps or is adjacent a terrestrial cell that uses a frequency assigned to the first satellite cell.

24. A method according to claim 20, wherein the satellite radiotelephone communications system comprises a first satellite radiotelephone communications system, and wherein the second satellite cell overlaps or is adjacent a coverage area of a second satellite radiotelephone communications system.

25. A method according to claim 20, wherein the first and second spot beams are supported by respective first and second satellites of the satellite radiotelephone communications system.

26. A method according to claim 20, wherein the first and second spot beams are supported by one satellite of the satellite radiotelephone communications system.

27. A method according to claim 20, wherein processing the first and second radio signals to recover the desired satellite uplink signal comprises applying the first and second radio signals to an adaptive signal processor.

28. A method according to claim 20, wherein processing the first and second radio signals to recover the desired satellite uplink signal comprises:

applying the first and second radio signals to respective first and second transversal filters;

combining outputs of the first and second transversal filters; and

recovering the desired signal from the combined outputs.

29. A method according to claim 28, further comprising adjusting the first and second transversal filters responsive to the combined outputs.

30. A method of operating a first satellite radiotelephone communications system to reduce interference from a second satellite radiotelephone communications system, the method comprising:

receiving a first radio signal via a first satellite reception path that serves a satellite cell of the first satellite radiotelephone communications system, the received first radio signal including a desired satellite uplink signal transmitted from a first source using a frequency assigned to the satellite cell and an interfering signal transmitted from at least one second source communicating with the second satellite radiotelephone communications system using the frequency assigned to the satellite cell;

receiving a second radio signal via a second satellite reception path configured to preferentially receive transmissions from a coverage area of the second satellite radiotelephone communications system, the second radio signal including a measure of the interfering signal; and

processing the first and second radio signals to recover the desired satellite uplink signal.

31. A method according to claim 30, wherein the first and second satellite reception paths are positioned at a satellite of the first satellite radiotelephone communications system.

32. A method according to claim 31, wherein the first and second satellite reception paths comprise respective first and second antennas positioned at the satellite of the first satellite radiotelephone communications system and configured such that the first and second antennas preferentially receive transmissions from respective first and second coverage areas of the first satellite radiotelephone communications system and the second satellite communications systems.

33. A method according to claim 30, wherein the first satellite reception path comprises a first antenna positioned at a satellite of the first satellite radiotelephone communications system, and wherein the second satellite reception path comprises a second antenna positioned at a satellite of the second satellite radiotelephone communications system.

34. A method according to claim 30, wherein the second satellite reception path comprises an antenna configured to receive feeder link transmissions from a satellite of the second satellite radiotelephone communications system.

35. A method according to claim 30, wherein processing the first and second radio signals to recover the desired satellite up link signal comprises applying the first and second radio signals to an adaptive signal processor.

36. A method according to claim 30, wherein processing the first and second radio signals to recover the desired satellite uplink signal comprises:

applying the first and second radio signals to respective first and second transversal filters;

combining outputs of the first and second transversal filters; and

recovering the desired satellite uplink signal from the combined outputs.

37. A method according to claim 36, further comprising adjusting the first and second transversal filters responsive to the combined outputs.

38. A method of operating a first satellite radiotelephone communications system to reduce interference from a second satellite communications system, the method comprising:

receiving a first radio signal via a first satellite configured to preferentially receive transmissions from a coverage area of the first satellite radiotelephone communications system, the received first radio signal including a desired satellite uplink signal transmitted from a first source in the coverage area of the first satellite radiotelephone communications system and an interfering signal transmitted from at least one second source communicating with the second satellite communications system using at least one frequency of the desired satellite uplink signal;

receiving a second radio signal via a second satellite configured to preferentially receive transmissions from a coverage area of the second satellite communications system, the second radio signal including a measure of the interfering signal; and

processing the first and second radio signals to recover the desired satellite uplink signal.

39. A method according to claim 38, wherein receiving a second radio signal via a second satellite comprises receiving the second radio signal from the second satellite via an antenna configured to receive feeder link transmissions from the second satellite.

40. A method according to claim 39, wherein receiving the second radio signal from the second satellite via an antenna comprises receiving the second radio signal from the second satellite via the antenna and a gateway of the second satellite communications system.

41. A method according to claim 38, wherein processing the first and second radio signals to recover the desired satellite uplink signal comprises applying the first and second radio signals to an adaptive signal processor.

42. A method according to claim 38, wherein processing the first and second radio signals to recover the desired satellite uplink signal comprises:

applying the first and second radio signals to respective first and second transversal filters;

combining outputs of the first and second transversal filters; and

recovering the desired signal from the combined outputs.

43. A method according to claim 42, further comprising adjusting the first and second transversal filters responsive to the combined outputs.

44. A system comprising:

a first satellite reception path that serves a satellite cell and that receives a first radio signal including a desired satellite uplink signal transmitted from a first source using a frequency assigned to the satellite cell and an interfering signal transmitted from at least one second source using the frequency assigned to the satellite cell;

a second satellite reception path that is configured to receive radio transmissions from another communications system that uses the frequency assigned to the satellite cell, wherein the second satellite reception path is further configured to receive a second radio signal including a measure of the interfering signal; and

an interference-suppressing signal processor that processes the first and second radio signals to recover the desired satellite uplink signal.

45. A system according to claim 44, wherein the second satellite reception path is configured to preferentially receive radio transmissions from an area outside of the satellite cell.

46. A system according to claim 45, wherein the area outside of the satellite cell comprises another satellite cell that uses the frequency assigned to the satellite cell and/or a coverage area of another satellite communications system that uses the frequency assigned to the satellite cell.

47. A system according to claim 45, wherein the satellite cell comprises a first satellite cell served by a first Spot beam and wherein the second satellite reception path comprises a second spot beam that serves a second satellite cell of the satellite radiotelephone communications system.

48. A system according to claim 47, wherein the second satellite cell uses a frequency assigned to the first satellite cell.

49. A system according to claim 47, wherein the second satellite cell is adjacent a third satellite cell that uses a frequency assigned to the first satellite cell.

50. A system according to claim 47, wherein the second satellite cell overlaps or is adjacent a terrestrial cell that uses a frequency assigned to the first satellite cell.

51. A system according to claim 47, wherein the satellite radiotelephone communications system comprises a first satellite radiotelephone communications system, and wherein the second satellite cell overlaps or is adjacent a coverage area of a second satellite radiotelephone communications system.

52. A system according to claim 45, wherein the first satellite reception path comprises a first satellite antenna positioned at a first satellite of a satellite radiotelephone communications system, and wherein the second satellite reception path comprises a second satellite antenna positioned at a second satellite of the satellite radiotelephone communications system.

53. A system according to claim 45, wherein the first satellite reception path comprises a first satellite antenna positioned at a satellite of a satellite radiotelephone communications system, and wherein the second satellite reception path is positioned at the same satellite.

54. A system according to claim 45, wherein the satellite cell comprises a satellite cell of a first satellite radiotelephone communications system, and wherein the second satellite reception path comprises a satellite cell of a second satellite radiotelephone communications system.

55. A system according to claim 54, wherein the second satellite reception path further comprises an antenna configured to receive a feeder link transmission from the satellite of the second satellite radiotelephone communications system, and wherein the gateway is configured to convey the feeder link transmission via the antenna to the first satellite radiotelephone communications system.

56. A system according to claim 55, wherein the antenna is coupled to a gateway of the second satellite radiotelephone communications system, and wherein the gateway is configured to convey the feeder link transmission to the first satellite radiotelephone communications system.

57. A system according to claim 55, wherein the antenna is coupled to a gateway of the first satellite radiotelephone communications system, and wherein the interference-suppressing signal processor receives the feeder link transmission from the antenna and the gateway of the first satellite radiotelephone communications system.

58. A system according to claim 44, wherein the interference-suppressing signal processor comprises an adaptive interference reducer.

59. A system according to claim 44, wherein the interference-suppressing signal processor comprises:

first and second transversal filters that receive respective ones of the first and second radio signals;

a combiner that combines outputs of the first and second transversal filters; and

a detector that recovers the desired signal from the combined outputs.

60. A system according to claim 59, wherein the interference-suppressing signal processor further comprises a controller that adjusts the first and second transversal filters responsive to the combined outputs.

61. A system according to claim 44, wherein the first and second satellite reception paths are configured to provide discrimination between the first and second sources based on a characteristic other than frequency.

62. An apparatus comprising:

an interference-suppressing signal processor configured to receive a first radio signal from a first satellite reception path that serves a satellite cell, the first radio signal including a desired satellite uplink signal transmitted from a first source using a frequency assigned to the satellite cell and an interfering signal transmitted from at least one second source using the frequency assigned to the satellite cell, to receive a second radio signal from a second satellite reception path that is configured to receive radio transmissions from another communications system that uses the frequency assigned to the satellite cell and that receives a second radio signal including a measure of the interfering signal, and to process the first and second radio signals to recover the desired satellite uplink signal.

63. An apparatus according to claim 62, wherein the interference-suppressing signal processor comprises an adaptive signal processor.

64. An apparatus according to claim 62, wherein the interference-suppressing signal processor comprises:

first and second transversal filters that receive respective ones of the first and second radio signals;

a combiner that combines outputs of the first and second transversal filters; and

a detector that recovers the desired signal from the combined outputs.

65. An apparatus according to claim 64, wherein the interference-suppressing signal processor further comprises a controller that adjusts the first and second transversal filters responsive to the combined outputs.

66. A satellite radiotelephone communications system comprising:

first and second spot beams that serve respective first and second satellite cells of the satellite radiotelephone communications system and that receive respective first and second radio signals, the first radio signal including a desired satellite uplink signal transmitted from a first source in the first satellite cell using a frequency assigned to the first satellite cell and an interfering signal transmitted from at least one second source using the frequency assigned to the first satellite cell, the second radio signal including a measure of the interfering signal; and

an interference-suppressing signal, the second spot beam configured to receive radio transmissions from another communications system that uses the frequency assigned to the first satellite cell processor that processes the first and second radio signals to recover the desired satellite uplink signal.

67. A system according to claim 66, wherein at least one radiating source in an area of the second satellite cell uses a frequency assigned to the first satellite cell to communicate terrestrially and/or with a satellite.

68. A system according to claim 66, wherein the second satellite cell is adjacent a third satellite cell that uses a frequency assigned to the first satellite cell.

69. A system according to claim 66, wherein the second satellite cell overlaps or is adjacent a terrestrial cell that uses a frequency assigned to the first satellite cell.

70. A system according to claim 66, wherein the satellite radiotelephone communications system comprises a first satellite radiotelephone communications system, and wherein the second satellite cell overlaps or is adjacent a coverage area of a second satellite radiotelephone communications system.

71. A system according to claim 66, wherein the first and second spot beams are supported by respective first and second satellites of the satellite radiotelephone communications system.

72. A system according to claim 66, wherein the first and second spot beams are supported by the same satellite of the satellite radiotelephone communications system.

73. A system according to claim 66, wherein the interference-suppressing signal processor comprises an adaptive signal processor.

74. A system according to claim 66, wherein the interference-suppressing signal processor comprises:

first and second transversal filters that receive respective ones of the first and second radio signals;

a combiner that combines outputs of the first and second transversal filters; and

a detector that recovers the desired signal from the combined outputs.

75. A system according to claim 74, wherein the interference-suppressing signal processor further comprises a controller that adjusts the first and second transversal filters responsive to the combined outputs.

76. A system comprising:

a first satellite reception path that serves a satellite cell of a first satellite radiotelephone communications system and receives a first radio signal therefrom, the received first radio signal including a desired satellite uplink signal transmitted from a first source using a frequency assigned to the satellite cell and an interfering signal transmitted from at least one second source communicating with a second satellite radiotelephone communications system using the frequency assigned to the satellite cell;

a second satellite reception path that preferentially receives transmissions from a coverage area of the second satellite radiotelephone communications system and that receives a second radio signal including a measure of the interfering signal; and

an interference-suppressing signal processor that processes the first and second radio signals to recover the desired satellite uplink signal.

77. A system according to claim 76, wherein the first and second satellite reception paths are positioned at a satellite of the first satellite radiotelephone communications system.

78. A system according to claim 77, wherein the first and second satellite reception paths comprise respective first and second antennas positioned at a satellite of the first satellite radiotelephone communications system and configured such that the first and second antennas preferentially receive transmissions from respective first and second coverage areas of the first satellite radiotelephone communications system and the second satellite radiotelephone communications systems.

79. A system according to claim 76, wherein the first satellite reception path comprises a first antenna positioned at a satellite of the first satellite radiotelephone communications system, and wherein the second satellite reception path comprises a second antenna positioned at a satellite of the second satellite radiotelephone communications system.

80. A system according to claim 76, wherein the second satellite reception path comprises an antenna configured to receive feeder link transmissions from a satellite of the second satellite radiotelephone communications system.

81. A system according to claim 76, wherein the interference-suppressing signal processor comprises an adaptive signal processor.

82. A system according to claim 76, wherein the interference-suppressing signal processor comprises:

first and second transversal filters that receive respective ones of the first and second radio signals;

a combiner that combines outputs of the first and second transversal filters; and

a detector that recovers the desired signal from the combined outputs.

83. A system according to claim 82, wherein the interference-suppressing signal processor further comprises a controller that adjusts the first and second transversal filters responsive to the combined outputs.

84. A system comprising:

a first satellite configured to preferentially receive transmissions from a coverage area of a first satellite radiotelephone communications system and that receives a first radio signal including a desired satellite uplink signal transmitted from a first source in the coverage area of the first satellite radiotelephone communications system using a frequency and an interfering signal transmitted from at least one second source communicating with a second satellite communications system using the frequency;

an antenna configured to receive feeder link transmissions from a second satellite configured to preferentially receive transmissions from a coverage area of the second satellite communications system and that receives a second radio signal including a measure of the interfering signal; and

an interference-suppressing signal processor that processes the first and second radio signals to recover the desired satellite uplink signal.

85. A system according to claim 84, wherein the interference-suppressing signal processor receives the second radio signal from the antenna via a gateway of the second satellite communications system.

86. A system according to claim 84, wherein the interference-suppressing signal processor comprises an adaptive signal processor.

87. A system according to claim 84, wherein the interference-suppressing signal processor comprises:

first and second transversal filters that receive respective ones of the first and second radio signals;

a combiner that combines outputs of the first and second transversal filters; and

a detector that recovers the desired signal from the combined outputs.

88. A system according to claim 87, wherein the interference-suppressing signal processor further comprises a controller that adjusts the first and second transversal filters responsive to the combined outputs.