Integrated or autonomous system and method of satellite-terrestrial frequency reuse using signal attenuation and/or blockage, dynamic assignment of frequencies and/or hysteresis

• US 20050265273A1
• Filed: 07/11/2005
• Published: 12/01/2005
• Est. Priority Date: 08/02/2000
• Status: Active Grant

• Current Assignee: ATC Technology Corporation (FedEx Corporation)
• Original Assignee: ATC Technology Corporation (FedEx Corporation)
• Inventors: Karabinis, Peter D., Singh, Rajendra
• Granted Patent: US 7,706,746 B2
• Time in Patent Office: Days
• US Class Current: 370/316
• CPC Class Codes: H04B 7/18563 Arrangements for interconnecting multiple systems data switching networks H04L12/00
• CPC Class Codes: H04B 7/2041 Spot beam multiple access
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks

Abstract

A cellular communications system comprising a space based system comprising a first set of cells, and a ground based system comprising a second set of cells. The space and ground systems can optionally function substantially autonomously, with each using spectrum from at least one predetermined frequency band.

Claims

1. A cellular communications system, comprising:

a space based system comprising at least one satellite, each satellite comprising at least one antenna and establishing a first set of cells that selectively use and/or reuse frequencies of at least one predetermined frequency band geographically and transmitting and receiving waveforms using at least a first portion of the at least one predetermined frequency band used by the first set of cells; and

a ground based system comprising at least one base transceiver station (BTS), each BTS establishing at least one second cell and transmitting and receiving waveforms utilizing at least a second portion of the at least one predetermined frequency band, said space based and ground based systems functioning substantially independently and/or autonomously.

2. The system according to claim 1, wherein the spaced based system and the ground based system are configured to support at least one subscriber terminal communicating preferentially with the at least one BTS when the at least one subscriber terminal is located in the first set of cells and in the at least one second cell.

3. The system according to claim 1, further comprising at least one radio resource manager (RRM) determining available communication links between said at least one subscriber terminal and at least one of said space based system and said ground based system.

4. The system according to claim 1, wherein said at least one predetermined frequency band comprises at least one discrete space based system uplink portion and at least one discrete space based system downlink portion, wherein said ground based system uses and/or reuses at least a portion of at least one of the uplink and downlink portions.

5. The system according to claim 4, wherein each of the discrete portions is associated with at least one of a satellite cell and a BTS cell.

6. The system according to claim 1, wherein the at least one predetermined frequency band comprises at least one space based system portion and at least one ground based system portion that are substantially mutually exclusive and do not overlap.

7. The system according to claim 1, wherein at least two cells of the first set of cells in said space based system use substantially mutually exclusive portions of the at least one predetermined frequency band.

8. The system according to claim 1, wherein one or more frequencies in the first and/or second portions of the at least one predetermined frequency band used by said space based system and said ground based system are substantially the same, substantially different or closely spaced.

9. The system according to claim 1, wherein a subscriber terminal uses a first vocoder rate when said subscriber terminal is communicating with said space based system, and wherein said subscriber terminal uses a second vocoder rate when said subscriber terminal is communicating with said ground based system.

10. The system according to claim 9, further comprising at least one radio resource manager (RRM) determining available communication links between at least one subscriber terminal and at least one of said space based system and said ground based system, wherein said RRM at least one of assigns and activates at least one of the first and second vocoders in response to predetermined criteria.

11. The system according to claim 10, wherein the predetermined criteria comprise at least one of capacity demand, voice quality, and/or a received signal level.

12. The system according to claim 10, further comprising at least one mobile switching center operatively connected to said space based system and said ground based system that assigns and/or activates a vocoder in response to predetermined criteria comprising capacity demand, voice quality, and/or a received signal level.

13. The system according to claim 10, wherein said RRM further assigns and/or activates a different vocoder to a voice communications circuit in response to the predetermined criteria.

14. The system according to claim 13, wherein the predetermined criteria comprise at least one of capacity demand, voice quality, a signal content, and a received signal level having changed substantially since assignment and/or activation of the at least first and second vocoder being utilized.

15. The system according to claim 1, wherein the at least one predetermined frequency band comprises first and second frequency bands, and wherein a subscriber terminal communicates with said ground based system by transmitting at frequencies within the first frequency band used as an uplink of said space based system, and receives at frequencies within the second frequency band used as a downlink of said space based system.

16. The system according to claim 15, wherein the frequencies used by a cell of said space based system are substantially mutually exclusive to frequencies used by a cell of said ground based system within the cell of said space based system.

17. The system according to claim 1, wherein the at least one predetermined frequency band comprises first and second frequency bands, and wherein a subscriber terminal communicates with said ground based system by transmitting at frequencies within the first frequency band used as a downlink of said space based system, and receiving at frequencies within the second frequency band used as an uplink of said space based system.

18. The system according to claim 17, wherein the frequencies used by a cell of said space based system are substantially mutually exclusive to frequencies used by a cell of said ground based system within the cell of said space based system.

19. The system according to claim 1, wherein the at least one predetermined frequency band comprises first and second frequency bands, and wherein a subscriber terminal communicates with said at least one ground based system by transmitting at frequencies within the first frequency band used as an uplink of said space based system, and receives at frequencies within the first frequency band used as the uplink of said space based system.

20. The system according to claim 19, wherein the frequencies used by a cell of said space based system are substantially mutually exclusive to frequencies used by a cell of said ground based system within the cell of said space based system.

21. The system according to claim 1, wherein the at least one predetermined frequency band comprises first and second frequency bands, and wherein a subscriber terminal communicates with said at least one ground based system by transmitting at frequencies within the first frequency band used as a downlink of said space based system, and receives at frequencies within the first frequency band used as the downlink of said space based system.

22. The system according to claim 21, wherein the frequencies used by a cell of said space based system are substantially mutually exclusive to frequencies used by a cell of said ground based system within the cell of said space based system.

23. The system according to claim 1, further comprising at least one radio resource manager (RRM) determining available communication links between at least one subscriber terminal and at least one of said space based system and said ground based system, wherein each of said at least one RRM monitors which channels are currently being utilized by said at least one subscriber terminal.

24. The system according to claim 23, further comprising a mobile switching center (MSC) operatively connected to one or more of said at least one RRM, wherein one or more of said at least one RRM indicates to said MSC which channels are currently being utilized by each of one or more subscriber terminals.

25. The system according to claim 24, wherein each of said at least one RRM is operatively configured to receive waveforms and to determine a frequency content thereof.

26. The system according to claim 1, further comprising first and second RRMs determining available communication links between at least one subscriber terminal and respective ones of said space based system and said ground based system.

27. The system according to claim 26, wherein said first and second RRMs monitor inband interference and avoid using and/or reusing channels that would cause levels of interference exceeding a predetermined threshold.

28. The system according to claim 27, wherein said first and second RRMs further monitor at least one of received signal quality and available link margin from said at least one subscriber terminal.

29. The system according to claim 28, wherein said first RRM and/or said second RRM executes utilization of a different communications channel when a quality measure of the existing communications channel has fallen below a predetermined level and/or has fallen below a predetermined link margin.

30. The system according to claim 1, wherein said ground based system and/or said space based system are configured to communicate with a subscriber terminal having a variable vocoder rate.

31. The system according to claim 30, wherein the subscriber terminal uses a vocoder data rate as determined by predetermined criteria.

32. The system according to claim 31, wherein the predetermined criteria comprises at least one of capacity demand, voice quality, a signal content, and a received signal level.

33. The system according to claim 1, further comprising at least one RRM determining available communication links between at least one subscriber terminal and at least one of said space based system and said ground based system, wherein said RRM further monitors inband interference and avoids using channels containing levels of interference exceeding a predetermined threshold.

34. The system according to claim 33, wherein said RRM further monitors received signal quality from subscriber terminals communicating with at least one of said space based system and said ground based system.

35. The system according to claim 33, wherein said RRM further monitors available link margin from subscriber terminals communicating with at least one of said space based system and said ground based system.

36. The system according to claim 33, wherein said RRM executes utilization of a different communications channel when a quality measure of the existing communications channel has fallen below a predetermined level and/or has fallen below a predetermined link margin.

37. The system according to claim 1, further comprising a network operations controller (NOC) operatively connected to at least a mobile switching center that assigns a channel to subscriber units, said NOC maintaining cognizance of the availability of at least one of satellite and terrestrial resources and administering at least one of reconfiguration, assignment and reuse of frequencies within said predetermined frequency band to meet changed traffic patterns or other predetermined conditions.

38. The system according to claim 37, wherein said NOC is commonly shared between and operatively connected to said space based system and said ground based system.

39. The system according to claim 37, wherein said NOC utilizes past system traffic patterns in the reconfiguration, assignment and reuse of the frequencies.

40. The system according to claim 37, wherein said NOC utilizes at least one of hysteresis and negative hysteresis in the reconfiguration, assignment and/or reuse of the frequencies.

41. The system according to claim 37, wherein said space based system further comprises a satellite having a geostationary orbit, and wherein said NOC dynamically assigns a channel to a subscriber unit communicating with said space based system.

42. The system according to claim 41, wherein the dynamic assignment is performed on a call-by-call basis.

43. The system according to claim 41, wherein the dynamic assignment is performed based on past and/or present usage.

44. The system according to claim 41, wherein the dynamic assignment is performed by one or more base station controllers operationally connected to said NOC.

45. The system according to claim 37, wherein said space based system further comprises a satellite having a geostationary orbit, and wherein said NOC assigns channels to a subscriber unit communicating with said space based system in accordance with a predetermined channel assignment scheme.

46. The system according to claim 37, wherein said space based system further comprises a satellite having a geostationary orbit, and wherein one or more base station controllers assign channels to a subscriber unit communicating with said space based system in accordance with a predetermined channel assignment scheme.

47. The system according to claim 1, wherein the space based system uses a Frequency Division Duplex (FDD) and/or a Time Division Duplex (TDD) air interface and the ground based system uses a TDD and/or FDD air interface.

48. The system according to claim 1, wherein the space based system uses a first air interface, and the ground based system uses a second air interface.

49. The system according to claim 48, wherein the first air interface is at least one of a Global System for Mobile Communications (GSM) based air interface and a derivative thereof, and the second air interface is at least one of a GSM based air interface and a derivative thereof.

50. The system according to claim 48, wherein the first air interface is at least one of a Global System for Mobile Communications (GSM) based air interface and a derivative thereof, and the second air interface is at least one of a Code Division Multiple Access (CDMA) based air interface and a derivative thereof.

51. The system according to claim 48, wherein the first air interface is at least one of a Code Division Multiple Access (CDMA) based air interface and a derivative thereof, and the second air interface is at least one of a Global System for Mobile Communications (GSM) based air interface and a derivative thereof.

52. The system according to claim 48, wherein the first air interface is at least one of a Code Division Multiple Access (CDMA) based air interface and a derivative thereof, and the second air interface is at least one of a CDMA based air interface and a derivative thereof.

53. The system according to claim 1, wherein the space based system and/or the ground based system is configured to cause an increase in the output power of a subscriber terminal utilizing the space based system as an aggregate signal strength of the subscriber terminals utilizing the ground based system reaches a predetermined threshold.

54. The system according to claim 53, wherein the space based system and/or the ground based system is configured to cause a decrease in a number of subscriber terminals utilizing the ground based system as at least one of bit error rate, received signal strength, available link margin, and voice quality reach respective predetermined thresholds.

55. The system according to claim 1, wherein the space based system and/or the ground based system is configured to enable a subscriber terminal to communicate at one of a plurality of data rates and to select a data rate as determined by at least one of capacity demand, a received signal level a received signal quality and a Bit Error Rate (BER).

56. The system according to claim 55, wherein the space based system and/or the ground based system is configured to communicate with the subscriber terminal using a different data rate as determined by at least one of capacity demand, a received signal level, a received signal quality, and received signal level and a BER having changed substantially since assignment or activation of a current channel.

57. A method of assigning to a requesting subscriber terminal a communications channel of a satellite band whose frequencies are selectively used and/or reused geographically by a space based communications system, the communications channel commonly shared or commonly not shared between the space based communications system and a ground based communications system, comprising:

configuring a plurality of satellite spot beams, associated with the space based system, having a plurality of communication channels associated therewith;

configuring at least one terrestrial cell, associated with the ground based system, that at least partially geographically overlaps at least one of the plurality of satellite spot beams;

requesting by the subscriber terminal a communications channel;

at least one of the ground based system and the space based system substantially independently and/or autonomously determining channel availability; and

assigning to the requesting subscriber terminal a channel that is not used and/or a used channel having a sufficiently weak signal strength.

58. The method according to claim 57, wherein the space based system uses a Frequency Division Duplex (FDD) and/or a Time Division Duplex (TDD) air interface and the ground based system uses a TDD and/or a FDD air interface.

59. The method according to claim 57, wherein the space based system uses a first air interface, and the ground based system uses a second air interface.

60. The method according to claim 59, wherein the first air interface is a Global System for Mobile Communications (GSM) based air interface and/or a derivative thereof, and the second air interface is a GSM based air interface and/or a derivative thereof.

61. The method according to claim 59, wherein the first air interface is a Global System for Mobile Communications (GSM) based air interface and/or a derivative thereof, and the second air interface is a Code Division Multiple Access (CDMA) based air interface and/or a derivative thereof.

62. The method according to claim 59, wherein the first air interface is a Code Division Multiple Access (CDMA) based air interface and/or a derivative thereof, and the second air interface is a Global System for Mobile Communications (GSM) based air interface and/or a derivative thereof.

63. The method according to claim 59, wherein the first air interface is a Code Division Multiple Access (CDMA) based air interface and/or a derivative thereof, and the second air interface is a CDMA based air interface and/or a derivative thereof.

64. The method according to claim 59, further comprising increasing the output power of a subscriber terminal utilizing the space based system as an aggregate signal strength of the subscriber terminals utilizing the ground based system reaches a predetermined threshold.

65. The method according to claim 64, further comprising decreasing a number of subscriber terminal connections with the ground based system as at least one of a bit error rate, received signal strength, available link margin, and voice quality reach respective predetermined thresholds.

66. The method according to claim 57, further comprising:

enabling a subscriber terminal to communicate at a plurality of data rates; and

selecting a data rate as determined by at least one of a capacity demand, received signal quality, received signal level and received bit error rate.

67. The method according to claim 66, further comprising communicating, by the subscriber terminal, with the space based system or the ground based system using a different data rate as determined by at least one of a capacity demand, received signal level, received signal quality and received bit error rate having changed substantially since assignment and/or activation of a current channel.

68. The method according to claim 57, wherein the channel comprises first and second frequency bands, and wherein the subscriber terminal communicates with the ground based system by transmitting at frequencies within a first frequency band used as an uplink of the space based system, and receiving at frequencies within a second frequency band used as a downlink of the space based system.

69. The method according to claim 57, wherein the channel comprises first and second frequency bands, and wherein the subscriber terminal communicates with the ground based system by transmitting at frequencies within a first frequency band used as an downlink of the space based system, and receiving at frequencies within a second frequency band used as a uplink of the space based system.

70. The method according to claim 57, wherein the channel comprises first and second frequency bands, and wherein the subscriber terminal communicates with the ground based system by transmitting at frequencies within a first frequency band used as an uplink of the space based system, and receiving at frequencies within the first frequency band used as the uplink of the space based system.

71. The method according to claim 57, wherein the channel comprises first and second frequency bands, and wherein the subscriber terminal communicates with the ground based system by transmitting at frequencies within a first frequency band used as a downlink of the space based system, and receiving at frequencies within the first frequency band used as the downlink of the space based system.

72. The method according to claim 57, wherein a communications channel associated with a spot beam of the space based system comprises a first frequency band used for uplink communications and a second frequency band used for downlink communication, and wherein the ground based system shares at least a portion of the first and second frequency bands in a terrestrial cell positioned substantially outside of and non-overlapping with the satellite spot beam.

73. The method according to claim 57, further comprising the ground based system and/or the space based system independently and/or autonomously monitoring interference and avoiding use and/or reuse of channels that would cause levels of interference exceeding a predetermined threshold.

74. The method according to claim 73, further comprising utilizing a different communications channel when a quality measure of an existing communications channel has fallen below a predetermined level.

75. The method according to claim 57, further comprising the space based system and/or the ground based system independently and/or autonomously monitoring at least one of received signal quality and available link margin from/to a subscriber terminal.

76. The method according to claim 75, further comprising utilizing a different communications channel when received signal quality and/or available link margin has fallen below a predetermined link margin.

77. The method according to claim 57, further comprising arranging for channel reconfiguration and/or reuse of frequencies to meet changed traffic patterns.

78. The method according to claim 77, wherein past system traffic patterns are utilized in the reconfiguration and reuse of frequencies.

79. The method according to claim 77, wherein hysteresis and/or negative hysteresis are utilized in determining the reconfiguration and reuse of frequencies.

80. The method according to claim 57, wherein the communications channel is assigned to the subscriber terminal in accordance with a predetermined channel assignment scheme.

81. In a cellular communications system comprising a space based system comprising a first set of cells that selectively use and/or reuse geographically frequencies of a satellite frequency band, and a ground based system comprising a second set of cells, in which at least a portion of the second set of cells have at least a portion of overlapping geographic coverage with the first set of cells, the space based and ground based systems functioning substantially independently and/or autonomously and each using one or more mutually exclusive predetermined frequency sub-bands of the satellite frequency band, a method for initiating communications between a dual mode subscriber terminal and at least one of the space based system and the ground based system, comprising preferentially initiating communications between the dual mode subscriber terminal and the ground based system by assigning to the ground based system for use with the dual mode subscriber terminal at least one of an unused space based system channel, using in the ground based system an unused ground based system channel to establish communications between the ground based system and the dual mode subscriber terminal, reusing in the ground based system to establish communication between the ground based system and the dual mode subscriber terminal a channel used by the space based system having a substantially weak signal relative to the dual mode subscriber terminal and reusing in the ground based system a channel used by the ground based system having a substantially weak signal relative to the subscriber terminal to establish communications between the ground based system and the dual mode subscriber terminal, and using in the space based system a channel assigned to the space based system.

82. In a cellular communications system comprising a space based system comprising a first set of cells that selectively use and/or reuse geographically frequencies of a satellite frequency band, and a ground based system comprising a second set of cells, in which at least a portion of the second set of cells have at least a portion of overlapping geographic coverage with the first set of cells, the space based system and the ground based system share and commonly use at least a portion of a predetermined frequency sub-band of the satellite frequency band, and in which the space based and ground based systems function substantially independently and/or autonomously, a method for initiating communications between a dual mode subscriber terminal and at least one of the space based system and the ground based system, comprising preferentially initiating communications between the dual mode subscriber terminal and the ground based system by using at least one of an unused channel to establish communications between the ground based system and the dual mode subscriber terminal, reusing in the ground based system a channel used by the space based system having a substantially weak signal relative to the subscriber terminal to establish communications between the ground based system and the dual mode subscriber terminal, and reusing in the ground based system a channel used by the ground based system having a substantially weak signal relative to the subscriber terminal to establish communications between the ground based system and the dual mode subscriber terminal, and using in the space based system an available channel having an acceptable signal strength.