METHOD AND APPARATUS FOR DISTRIBUTED SPECTRUM SENSING FOR WIRELESS COMMUNICATION

• US 20090143019A1
• Filed: 01/04/2008
• Published: 06/04/2009
• Est. Priority Date: 01/04/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Shellhammer, Stephen J.
• Granted Patent: US 10,069,591 B2
• Time in Patent Office: Days
• US Class Current: 455/67.110
• CPC Class Codes: H04B 17/24 with feedback of measurements to the transmitter
• CPC Class Codes: H04B 17/327 Received signal code power [RSCP]
• CPC Class Codes: H04K 3/226 Selection of non-jammed channel for communication spectrum sharing arrangements H04W16/14; selection of wireless resources by user or terminal H04W72/02
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 8/005 Discovery of network devices, e.g. terminals

Abstract

Methods and apparatus for determining if a signal of interest, for example, a licensed signal having or exceeding a predetermined field strength, is present in a wireless spectrum and/or which facilitates such a determination are described. The signal of interest maybe, e.g., a television signal or a wireless microphone signal using licensed television spectrum. The predetermined field strength may be specified or by a government regulation or rule.

Claims

1. A method for use in a system including wireless channel spectrum, the method comprising:

determining whether a signal of interest is present in a said wireless channel spectrum;

determining a confidence measure corresponding to the determination; and

transmitting the determination and confidence measure to another device.

2. The method of claim 1, wherein said signal of interest is a television signal;

where the determination is transmitted as a single bit value indicating whether or not the signal of interest was determined; and

where the confidence measure is transmitted as a confidence value including at least one bit.

3. The method of claim 1, wherein said signal of interest is a wireless microphone signal;

where the determination is transmitted as a single bit value indicating whether or not the signal of interest was determined; and

where the confidence measure is transmitted as a confidence value including at least one bit.

4. The method of claim 1, wherein said determination and confidence measure are communicated in a message, the method comprising:

generating said message prior to performing said transmitting step; and

wherein transmitting the determination and confidence measure includes;

transmitting said message over a wireless communications link.

5. The method of claim 1, wherein said determination is communicated in said message as a single bit value and said confidence measure is communicated as a multi-bit value.

6. The method of claim 1, further comprising:

measuring the field strength of said signal of interest;

generating a measured field strength value from the measured field strength of the signal of interest; and

transmitting the measured field strength value indicating the measured field strength of the signal of interest.

7. The method of claim 6, further comprising:

transmitting with said field strength value an indication of the reliability of the measured field strength value.

8. The method of claim 7,

wherein measuring the field strength of a signal of interest includes:

i) performing multiple field strength measurements of said signal of interest over a time period; and

ii) generating said measured field strength value from said multiple measurements.

9. The method of claim 7, wherein said indication of the reliability of the measured field strength includes:

one of;

a variance and a standard deviation of the field strength measurement.

10. The method of claim 1, further comprising:

receiving a control message; and

adjusting a detection threshold used in determining whether said signal is present in the wireless channel spectrum.

11. The method of claim 1, further comprising:

receiving a control message indicating a sensing method to be used in determining whether said signal is present in the given channel of said spectrum is present; and

using said indicated sensing technique to make a signal measurement used in said step of determining whether a signal in a given channel of a spectrum is present.

12. The method of claim 11, wherein said sensing technique is a sensing technique in the group of sensing techniques including:

energy detection, ATSC Pilot Power Detection, ATSC PN Sequence Detection, and ATSC Pilot Spectrum Analysis Detection.

13. The method of claim 1, wherein determining the confidence measure comprises determining a difference between a level detected in determining whether the signal is present and a threshold.

14. The method of claim 13, wherein the threshold comprises the threshold used for determining whether the signal is detected.

15. The method of claim 1, further comprising:

receiving a control message;

modifying one of;

i) a sensing technique used to generate a signal measurement used in determining the presence of said signal and ii) a threshold used in determining the presence of said signal; and

repeating said step of determining whether a signal in a given channel of a spectrum is present after said modifying step is performed.

16. An apparatus for use in a system including wireless channel spectrum, the apparatus comprising:

a presence determination module for determining whether a signal of interest is present in a said wireless channel spectrum;

a confidence measurement module for determining a confidence measure corresponding to the determination; and

a transmitter for transmitting the determination and confidence measure to another device.

17. The apparatus of claim 16, wherein said signal of interest is a television signal;

where the determination is transmitted as a single bit value indicating whether or not the signal of interest was determined; and

where the confidence measure is transmitted as a confidence value including at least one bit.

18. The apparatus of claim 16, wherein said determination and confidence measure are communicated in a message, the apparatus comprising:

a message generation module for generating said message prior to performing said transmitting step; and

wherein said transmitter is a wireless transmitter for transmitting over a wireless communications link.

19. The apparatus of claim 16, wherein said determination is communicated in said message as a single bit value and said confidence measure is communicated as a multi-bit value.

20. The apparatus of claim 16, further comprising:

a field strength measurement module for measuring the field strength of said signal of interest;

a measured field strength value generation module for generating a measured field strength value from the measured field strength of the signal of interest; and

a transmitter for transmitting the measured field strength value indicating the measured field strength of the signal of interest.

21. The apparatus of claim 20, further comprising:

a reliability indicator generation module for generating a reliability indicator value indicating the reliability of the generated field strength value.

22. The apparatus of claim 21,

wherein said field strength measurement module is configured to:

perform multiple field strength measurements of said signal of interest over a time period; and

generate said measured field strength value from said multiple measurements.

23. The apparatus of claim 22, wherein said reliability indicator generation module generates one of:

i) a variance and ii) a standard deviation from said multiple field strength measurements.

24. The apparatus of claim 16, further comprising:

a receiver for receiving a control message; and

a detection threshold adjusting module for adjusting a detection threshold used in determining whether said signal of interest is present in the wireless channel spectrum.

25. The apparatus of claim 16, further comprising:

a receiver for receiving a control message indicating a sensing method to be used in determining whether said signal is present in the given channel of said spectrum is present; and

a configuration module used to configure a sensor device included in said apparatus to use said indicated sensing technique to make a signal measurement used in determining whether a signal in a given channel of a spectrum is present.

26. The apparatus of claim 25, wherein said sensor device includes a sensor which implements one or more sensing techniques in the group of sensing techniques including:

energy detection, ATSC Pilot Power Detection, ATSC PN Sequence Detection, and ATSC Pilot Spectrum Analysis Detection.

27. The apparatus of claim 16, further comprising:

a receiver for receiving a control message;

a configuration control module for modifying one of;

i) a sensing technique used to generate a signal measurement used in determining the presence of said signal and ii) a threshold used in determining the presence of said signal; and

a processor for controlling the apparatus to determine whether a signal in a given channel of a spectrum is present after said modifying step is performed.

28. An apparatus for use in a system including wireless channel spectrum, the apparatus comprising:

means for determining whether a signal of interest is present in a said wireless channel spectrum;

confidence measurement means for determining a confidence measure corresponding to the determination; and

transmitter means for transmitting the determination and confidence measure to another device.

29. The apparatus of claim 28, wherein said signal of interest is a television signal;

where the determination is transmitted as a single bit value indicating whether or not the signal of interest was determined; and

where the confidence measure is transmitted as a confidence value including at least one bit.

30. The apparatus of claim 28, wherein said determination and confidence measure are communicated in a message, the apparatus comprising:

message generation means for generating said message prior to performing said transmitting step; and

wherein said transmitter means can transmit over a wireless communications link.

31. The apparatus of claim 28, wherein said determination is communicated in said message as a single bit value and said confidence measure is communicated as a multi-bit value.

32. A computer readable medium embodying computer executable instructions for controlling a device to implement a method for use in a system including wireless channel spectrum, the method comprising:

determining whether a signal of interest is present in said wireless channel spectrum;

determining a confidence measure corresponding to the determination; and

transmitting the determination and confidence measure to another device.

33. The computer readable medium of claim 32, wherein said signal of interest is a television signal;

where the determination is transmitted as a single bit value indicating whether or not the signal of interest was determined; and

where the confidence measure is transmitted as a confidence value including at least one bit.

34. The computer readable medium of claim 32, wherein said determination and confidence measure are communicated in a message, the method further comprising:

generating said message prior to performing said transmitting step; and

wherein transmitting the determination and confidence measure includes;

transmitting said message over a wireless communications link.

35. A device including a processor configured to control said device to implement a method for use in a system including wireless channel spectrum, the method comprising:

determining whether a signal of interest is present in said wireless channel spectrum;

determining a confidence measure corresponding to the determination; and

transmitting the determination and confidence measure to another device.

36. The device of claim 35, wherein said signal of interest is a television signal;

where the determination is transmitted as a single bit value indicating whether or not the signal of interest was determined; and

where the confidence measure is transmitted as a confidence value including at least one bit.

37. The device of claim 35, wherein said determination and confidence measure are communicated in a message, the method further comprising:

generating said message prior to performing said transmitting step; and

wherein transmitting the determination and confidence measure includes;

transmitting said message over a wireless communications link.

38. A method of providing information which can be used to determine if a wireless channel spectrum is available for use, the method comprising:

measuring the field strength of a signal of interest in said wireless channel spectrum;

generating a measured field strength value from the measured field strength of the signal of interest; and

transmitting the measured field strength value indicating the measured field strength of the signal of interest.

39. The method of claim 38, further comprising:

transmitting with said field strength value an indication of the reliability of the measured field strength value.

40. The method of claim 39,

wherein measuring the field strength of a signal of interest includes:

i) performing multiple field strength measurements of said signal of interest over a time period; and

ii) generating said measured field strength value from said multiple measurements.

41. The method of claim 40, wherein said indication of the reliability of the measured field strength includes:

one of;

a variance and a standard deviation of the field strength measurement.

42. An apparatus for providing information which can be used to determine if a wireless channel spectrum is available for use, the apparatus comprising:

a field strength measurement module for measuring the field strength of said signal of interest;

a measured field strength value generation module for generating a measured field strength value from the measured field strength of the signal of interest; and

a transmitter for transmitting the measured field strength value indicating the measured field strength of the signal of interest.

43. The apparatus of claim 42, further comprising:

a reliability indicator generation module for generating a reliability indicator value indicating the reliability of the generated field strength value.

44. The apparatus of claim 43,

wherein said field strength measurement module is configured to:

perform multiple field strength measurements of said signal of interest over a time period; and

generate said measured field strength value from said multiple measurements.

45. The apparatus of claim 44, wherein said reliability indicator generation module generates one of:

i) a variance and ii) a standard deviation from said multiple field strength measurements.

46. An apparatus for providing information which can be used to determine if a wireless channel spectrum is available for use, the apparatus comprising:

field strength measurement means for measuring the field strength of said signal of interest;

means for generating a measured field strength value from the measured field strength of the signal of interest; and

transmitter means for transmitting the measured field strength value indicating the measured field strength of the signal of interest.

47. The apparatus of claim 46, further comprising:

means for generating a reliability indicator value indicating the reliability of the generated field strength value.

48. The apparatus of claim 46, wherein said field strength measurement means is configured to:

perform multiple field strength measurements of said signal of interest over a time period; and

generate said measured field strength value from said multiple measurements.

49. A computer readable medium embodying computer executable instructions for controlling a device to implement a method of providing information which can be used to determine if a wireless channel spectrum is available for use, the method comprising:

measuring the field strength of a signal of interest in said wireless channel spectrum;

generating a measured field strength value from the measured field strength of the signal of interest; and

transmitting the measured field strength value indicating the measured field strength of the signal of interest.

50. The computer readable medium of claim 49, wherein the method further comprises:

transmitting with said field strength value an indication of the reliability of the measured field strength value.

51. The computer readable medium of claim 50, wherein measuring the field strength of a signal of interest includes:

i) performing multiple field strength measurements of said signal of interest over a time period; and

ii) generating said measured field strength value from said multiple measurements.

52. A device including a processor configured to control said device to implement a method of providing information which can be used to determine if a wireless channel spectrum is available for use, the method comprising:

measuring the field strength of a signal of interest in said wireless channel spectrum;

generating a measured field strength value from the measured field strength of the signal of interest; and

transmitting the measured field strength value indicating the measured field strength of the signal of interest.

53. The device of claim 52, wherein the method further comprises:

transmitting with said field strength value an indication of the reliability of the measured field strength value.

54. The device of claim 53, wherein measuring the field strength of a signal of interest includes:

i) performing multiple field strength measurements of said signal of interest over a time period; and

ii) generating said measured field strength value from said multiple measurements.

55. A method for use in a system including wireless channel spectrum, the method comprising:

receiving a control message;

modifying one or both of;

i) a sensing technique used to generate a signal measurement used in determining the presence of said signal and ii) a threshold used in determining the presence of said signal, in accordance with the received control message; and

determining whether a signal in said wireless channel spectrum is present after said modifying is performed.

56. The method of claim 55, further comprising:

using a sensing technique indicated in said message to make a signal measurement used in said step of determining whether a signal in a given channel of a spectrum is present.

57. The method of claim 56, wherein said sensing technique is a sensing technique in the group of sensing techniques including:

energy detection, ATSC Pilot Power Detection, ATSC PN Sequence Detection, and ATSC Pilot Spectrum Analysis Detection.

58. An apparatus for use in a system including wireless channel spectrum, the method comprising:

a receiver for receiving a control message;

a configuration module used to modify one or both of;

i) a sensing technique used to generate a signal measurement used in determining the presence of said signal and ii) a threshold used in determining the presence of said signal, in accordance with the received control message; and

a determination module for determining whether a signal in said wireless channel spectrum is present after said modifying is performed.

59. The apparatus of claim 58, wherein said configuration module modifies a sensing technique by controlling a sensor device included in said apparatus to implement a sensing technique indicated by said control message;

and

wherein said sensor device includes a sensor which implements one or more sensing techniques in the group of sensing techniques including;

energy detection, ATSC Pilot Power Detection, ATSC PN Sequence Detection, and ATSC Pilot Spectrum Analysis Detection.

60. An apparatus for use in a system including wireless channel spectrum, the method comprising:

receiver means for receiving a control message;

configuration means for modifying one or both of;

i) a sensing technique used to generate a signal measurement used in determining the presence of said signal and ii) a threshold used in determining the presence of said signal, in accordance with the received control message; and

determination means for determining whether a signal in said wireless channel spectrum is present after said modifying is performed.

61. The apparatus of claim 60, wherein said configuration means modify a sensing technique by controlling sensor means included in said apparatus to implement a sensing technique indicated by said control message;

and

wherein said sensor means includes a sensor which implements one or more sensing techniques in the group of sensing techniques including;

energy detection, ATSC Pilot Power Detection, ATSC PN Sequence Detection, and ATSC Pilot Spectrum Analysis Detection.

62. A computer readable medium embodying computer executable instructions for controlling a device to implement a method for use in a system including wireless channel spectrum, the method comprising:

receiving a control message;

modifying one or both of;

i) a sensing technique used to generate a signal measurement used in determining the presence of said signal and ii) a threshold used in determining the presence of said signal, in accordance with the received control message; and

determining whether a signal in said wireless channel spectrum is present after said modifying is performed.

63. The computer readable medium of claim 62, wherein the method further comprises:

using a sensing technique indicated in said message to make a signal measurement used in said step of determining whether a signal in a given channel of a spectrum is present.

64. The computer readable medium of claim 63, wherein said sensing technique is a sensing technique in the group of sensing techniques including:

energy detection, ATSC Pilot Power Detection, ATSC PN Sequence Detection, and ATSC Pilot Spectrum Analysis Detection.

65. A device including a processor configured to control said device to implement a method for use in a system including wireless channel spectrum, the method comprising:

receiving a control message;

modifying one or both of;

i) a sensing technique used to generate a signal measurement used in determining the presence of said signal and ii) a threshold used in determining the presence of said signal, in accordance with the received control message; and

determining whether a signal in said wireless channel spectrum is present after said modifying is performed.

66. The device of claim 65, wherein the method further comprises:

using a sensing technique indicated in said message to make a signal measurement used in said step of determining whether a signal in a given channel of a spectrum is present.

67. The device of claim 66, wherein said sensing technique is a sensing technique in the group of sensing techniques including:

energy detection, ATSC Pilot Power Detection, ATSC PN Sequence Detection, and ATSC Pilot Spectrum Analysis Detection.

68. A method of detecting the presence of a licensed transmission signal in wireless channel spectrum comprising:

receiving a plurality of decisions with respect to the presence of a signal of interest in a spectrum; and

processing the plurality of decisions to determine whether the wireless channel spectrum includes said licensed transmission.

69. The method of claim 68, where said processing includes combining said decisions using an ORing operation.

70. The method of claim 68, wherein processing comprises:

combining a plurality of one bit decisions and confidence information associated with each of the plurality of one bit decisions.

71. The method of claim 68, wherein processing comprises combining a plurality of field strength measurements.

72. The method of claim 71, wherein said processing comprises combining an estimation error associated with each of the field strength measurements to determine whether one or more channels of the spectrum including interfering licensed transmission.

73. The method of claim 68, further comprising determining whether to update local decision criteria for one or more transmitters of the plurality of decisions, and transmitting a control message to update the local decision criteria, when it is determined that it should be updated.

74. The method of claim 73, wherein determining whether to update local decision criteria for one or more transmitters comprises:

determining to update in response to an increase in the number of devices providing decisions over a number of devices previously providing decisions.

75. The method of claim 73, wherein determining whether to update local decision criteria for one or more transmitters comprises determining, on an individual basis, whether to update local decision criteria for each individual transmitter of a received decision.

76. The method of claim 68, further comprising:

transmitting a control message to control devices transmitting said decisions to change a threshold used to make said decisions.

77. The method of claim 68, further comprising:

transmitting a control message to control a device transmitting one of said decisions to signal to said device that it should use a sensing technique indicated in the control message.

78. An apparatus for detecting the presence of a licensed transmission signal in wireless channel spectrum comprising:

a receiver module for receiving a plurality of decisions with respect to the presence of a signal of interest in the wireless channel spectrum; and

a processing module for processing the plurality of decisions to determine whether the wireless channel spectrum includes said licensed transmission.

79. The apparatus of claim 78, wherein said processing module includes:

a decision combining module for combining a plurality of one bit decisions and confidence information associated with each of the plurality of one bit decisions.

80. The apparatus of claim 78, wherein said processing module includes:

a field strength combining module for combining a plurality of field strength measurements used to make said determination.

81. The apparatus of claim 80, wherein said processing comprises combining an estimation error associated with each of the field strength measurements to determine whether one or more channels of the spectrum including interfering licensed transmission.

82. The apparatus of claim 78, further comprising:

a sensing technique updating module for determining when to send a sensing technique control signal to at least one device providing a determination.

83. The apparatus of claim 82, further comprising:

a control message generation module for generating a control message including a sensing technique indicator indicating a sensing technique to be used.

84. The apparatus of claim 78, further comprising:

a threshold updating module for determining when to send a threshold update signal to at least one device providing a determination.

85. The apparatus of claim 84, further comprising:

a control message generation module for generating a control message including a threshold indicator providing information about a threshold to be used by the receiving device in making a decision with respect to the presence of a signal of interest in the wireless channel spectrum.

86. The apparatus of claim 85, further comprising:

a transmitter for transmitting generated control messages.

87. An apparatus for detecting the presence of a licensed transmission signal in wireless channel spectrum comprising:

receiver means for receiving a plurality of decisions with respect to the presence of a signal of interest in the wireless channel spectrum; and

processing means for processing the plurality of decisions to determine whether the wireless channel spectrum includes said licensed transmission.

88. The apparatus of claim 87, wherein said processing means includes:

decision combining means for combining a plurality of one bit decisions and confidence information associated with each of the plurality of one bit decisions.

89. The apparatus of claim 87, wherein said processing means includes:

field strength combining means for combining a plurality of field strength measurements used to make said determination.

90. A computer readable medium embodying computer executable instructions for controlling a device to implement a method of detecting the presence of a licensed transmission signal in wireless channel spectrum, the method comprising:

receiving a plurality of decisions with respect to the presence of a signal of interest in a spectrum; and

processing the plurality of decisions to determine whether the wireless channel spectrum includes said licensed transmission.

91. The computer readable medium of claim 90, where said processing includes combining said decisions using an ORing operation.

92. The computer readable medium of claim 90, wherein said processing comprises:

combining a plurality of one bit decisions and confidence information associated with each of the plurality of one bit decisions.

93. A device including a processor configured to control said device to implement a method of detecting the presence of a licensed transmission signal in wireless channel spectrum, the method comprising:

receiving a plurality of decisions with respect to the presence of a signal of interest in a spectrum; and

processing the plurality of decisions to determine whether the wireless channel spectrum includes said licensed transmission.

94. The device of claim 93, where said processing includes combining said decisions using an ORing operation.

95. The device of claim 93, wherein said processing comprises:

combining a plurality of one bit decisions and confidence information associated with each of the plurality of one bit decisions.