System and method to monitor broadband radio frequency transport systems

• US 20070135056A1
• Filed: 12/14/2005
• Published: 06/14/2007
• Est. Priority Date: 12/14/2005
• Status: Active Grant

• Current Assignee: Procomm International Pte. Ltd. (Transpacific IP Group Limited)
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Schatz, Paul, Mitchell, William, Zavadsky, Dean, Kremer, Michael, Toms, Jerry, Wala, Philip, Wiwel, Bernard
• Granted Patent: US 7,603,093 B2
• Time in Patent Office: Days
• US Class Current: 455/67.110
• CPC Class Codes: H04B 17/327 Received signal code power [RSCP]

Abstract

A system to monitor gain in a broadband radio frequency transport system that includes a radio frequency antenna, a remote unit, and a host unit adapted to receive a signal from the remote unit over a transmission link. The remote unit includes a pilot tone generator adapted to generate at least one single-frequency tone having a known power level, a summing circuit operably associated with the pilot tone generator adapted to sum the single-frequency tone with the respective received radio frequency signal. Each host unit includes a pilot tone receiver circuit to receive the transmitted signal and detect the single-frequency tone transmitted over the transmission link. The host unit includes a controller to determine a gain within the transmission link and to determine if the gain is in a preset range of gains based on the power level of the received pilot tone.

Claims

1. A system to monitor gain in a broadband radio frequency transport system, the system comprising:

a least one radio frequency antenna that receives a radio frequency signal;

at least one remote unit, each remote unit communicable with a respective one of the radio frequency antennae, each remote unit comprising,

a pilot tone generator adapted to generate at least one single-frequency tone having a known power level,

a summing circuit operably associated with the pilot tone generator adapted to sum the single-frequency tone with the respective received radio frequency signal, and

at least one amplifier in communication with the summing circuit, wherein the at least one amplifier amplifies the summed signal and transmits the signal over a respective transmission link; and

at least one host unit adapted to receive the signal from over the transmission link from a respective one of the remote units, each host unit comprising;

a pilot tone receiver circuit adapted to receive the transmitted signal and detect the single-frequency tone transmitted over the transmission link from the received signal; and

a controller adapted to determine a gain within the transmission link and adapted to determine if the gain is in a preset range of gains based on the power level of the received pilot tone.

2. The system of claim 1, the system further comprising:

the transmission link between the remote unit and the host unit; and

a connection to a receiving station.

3. The system of claim 2, wherein the transmission link is selected from a group that comprises an optical fiber link, a free-space optical link, a millimeter wave link, a coaxial cable link, a twisted-pair cable link, a broadband transmission link, a wireless transmission link, a physical medium transmission link, and combinations thereof.

4. The system of claim 2, wherein the radio frequency antenna is a first radio frequency antenna, and wherein the connection to the receiving station is established via at least one second radio frequency antenna.

5. The system of claim 2, wherein the connection to the receiving station is established via a physical media.

6. The system of claim 2, wherein the connection to the receiving station is established via a free-space optical link.

7. The system of claim 2, wherein the system is a simulcast transmission system.

8. The system of claim 1, wherein the host unit further comprises:

a radio frequency up-converter to up-convert the received signal; and

an alarm adapted to generate a warning based on a determination that the gain is not in a preset range of gains.

9. The system of claim 8, wherein the warning is transmitted to a receiver station.

10. The system of claim 1, wherein the received radio frequency signal is within a defined frequency spectrum, and wherein the at least one single-frequency tone is at a frequency above the defined frequency spectrum.

11. The system of claim 1, wherein the received radio frequency signal is within a defined frequency spectrum, and wherein the at least one single-frequency tone is at a frequency below the defined frequency spectrum.

12. The system of claim 1, wherein the received radio frequency signal is within a defined frequency spectrum, and wherein the at least one single-frequency tone includes a first frequency below the defined frequency spectrum and a second frequency above the defined frequency spectrum.

13. The system of claim 1, wherein the at least one single-frequency tone is positioned at a frequency to minimize interference with received radio frequency signals including frequencies above and below the frequency of the single-frequency tone.

14. The system of claim 1, wherein the signal transmitted over the transmission link is a digitized signal, and wherein the host unit further comprises:

a digital to analog converter circuit.

15. The system of claim 1, wherein the pilot tone generator periodically generates the at least one single-frequency tone.

16. The system of claim 15, wherein the controller is adapted to determine a difference in gain between the periodically generated single-frequency tones.

17. The system of claim 16, wherein the controller is adapted to trigger an alarm to generate a warning based on a determination that the difference in gain between the periodically generated single-frequency tones is greater than a selected threshold.

18. The system of claim 17, wherein the selected threshold is −

6 dB.

19. The system of claim 1, wherein the remote unit further includes:

a remote pilot tone receiver adapted to detect the single-frequency tone to determine a gain within the remote unit.

20. The system of claim 19, wherein the host unit further includes:

a host pilot tone generator adapted to generate at least one single-frequency tone having a known power level, wherein the controller is adapted to determine a gain within the host unit.

21. The system of claim 1, wherein the host unit further includes:

a host pilot tone generator adapted to generate at least one single-frequency tone having a known power level, wherein the controller is adapted to determine a gain within the host unit.

22. A method to monitor gain in a broadband transport system, the method comprising:

receiving a broadband radio frequency signal;

adding at least one single-frequency tone to the broadband signal to form a summed signal;

transmitting the summed signal through a transmission link;

receiving the transmitted summed signal;

determining a gain in the single-frequency tone transmitted through the transmission link; and

determining when the gain is an acceptable gain.

23. The method of claim 22, wherein receiving the transmitted summed signal comprises:

up-converting the received signal; and

receiving the up-converted signal at a pilot tone receiver.

24. The method of claim 22, wherein adding at least one single-frequency tone to the broadband signal comprises:

generating the at least one single-frequency tone at a pilot tone generator.

25. The method of claim 24, wherein the generating is a periodic generating.

26. The method of claim 25, wherein determining a gain in the single-frequency tone comprises:

determining a ratio of a power level of a current single-frequency tone to a power level of a last-measured single-frequency tone.

27. The method of claim 26, wherein determining the gain in the single-frequency tone further comprises:

determining a ratio of the power level of the current single-frequency tone to a power level of a previously measured single-frequency tone.

28. The method of claim 25, wherein determining a gain in the single-frequency tone comprises:

determining a ratio of the power level of the current single-frequency tone to a power level of a previously measured single-frequency tone.

29. The method of claim 25, further comprising:

calibrating a power level of the at least one single-frequency tone, wherein the determining a gain in the single-frequency tone comprises,

determining a ratio of the power level of a current single-frequency tone to the power level of the calibrated single-frequency tone.

30. The method of claim 25, the method further comprising:

sequentially generating a plurality of single-frequency tones in a preset time; and

comparing a peak-hold power level for the sequentially generated plurality of single-frequency tones to a power level of a calibrated single-frequency tone.

31. The method of claim 25, the method further comprising:

sequentially generating a plurality of single-frequency tones in a preset time; and

comparing an average power level for the sequentially generated plurality of single-frequency tones to a power level of a calibrated single-frequency tone.

32. A system to monitor repeater links in a broadband transport system, the system comprising:

means for summing a plurality of broadband radio frequency signals received at a respective plurality of remote antennae with at least one respective single-frequency signal at a respective plurality of remote units;

means for amplifying the plurality of signals;

means for transmitting the plurality of amplified signals to a respective host unit; and

means for determining a gain for each transmitted single-frequency signal at the respective host unit.

33. The system of claim 32, further comprising:

means for indicating when the gain is below an acceptable gain.

34. A system to monitor a broadband radio frequency transport system, the system comprising:

at least one remote unit, each remote unit communicable with a respective radio frequency antenna, and each remote unit comprising,

at least one amplifier in communication with the antenna, wherein the at least one amplifier amplifies in-band radio frequency signals associated with a radio frequency signal received at the radio frequency antenna;

a double down-converter adapted to down-convert in frequency the in-band radio frequency signals; and

at least one host unit adapted to receive the signal transmitted over a transmission link from a respective one of the remote units, each host unit comprising,

a double up-converter circuit adapted to up-convert in frequency the in-band radio frequency signals;

a noise floor detector circuit adapted to determine the power level of the noise outside the frequency of the in-band radio frequency signals; and

a controller adapted to determine if a noise level is within an acceptable noise level.

35. The system of claim 34, the system further comprising:

the transmission link between the remote unit and the respective host unit; and

a connection to a receiving station.

36. The system of claim 35, wherein the transmission link is selected from a group that comprises an optical fiber link, a free-space optical link, a millimeter wave link, a coaxial cable link, a twisted-pair cable link, a broadband transmission link, a wireless transmission link, a physical medium transmission link, and combinations thereof.

37. The system of claim 35, wherein the radio frequency antenna is a first radio frequency antenna, and wherein the connection to the receiving station is established via at least one second radio frequency antenna.

38. The system of claim 35, wherein the connection to the receiving station is established via a physical media.

39. The system of claim 35, wherein the connection to the receiving station is established via a free-space optical link.

40. The system of claim 35, wherein the system is a simulcast transmission system.

41. The system of claim 34 wherein the received radio frequency signal is within a defined frequency spectrum.

42. The system of claim 34, wherein the double down-converter comprises:

a first down-converter to downshift the in-band signal;

a first filter to transmit the in-band signal and to reject out-of-band signals;

a second down-converter to downshift the in-band radio frequency signal; and

a second filter to transmit the in-band signal and to reject out-of-band signals.

43. The system of claim 34, the host unit further comprising:

an alarm, wherein the controller is adapted to trigger the alarm to generate a warning based on a determination that the power level of the noise outside the frequency of the in-band signals changes by more than a specified threshold within a preset time.

44. The system of claim 43, wherein the selected threshold is 6 dB.

45. The system of claim 34, wherein the signal transmitted over the transmission link is a digitized signal, and wherein the host unit further comprises:

a digital to analog converter circuit.

46. A method to monitor a broadband radio frequency transport system, the method comprising:

receiving a broadband radio frequency signal;

amplifying the broadband radio frequency signal;

double down-converting the broadband signal; and

transmitting the double down-converted broadband signal through a transmission link.

47. The method of claim 46, further comprising:

receiving the transmitted double down-converted broadband signal;

determining a noise level in the double down-converted broadband signal transmitted through the transmission link; and

determining when the noise level is within an acceptable noise level.

48. The method of claim 47, wherein determining when the noise level is within an acceptable noise level comprises:

comparing a current noise level to a last-measured noise level.

49. The method of claim 48, wherein determining when the noise level is within an acceptable noise level further comprises:

comparing the current noise level to a previously measured noise level.

50. The method of claim 47, wherein determining when the noise level is within an acceptable noise level comprises:

comparing a current noise level to a previously measured noise level.

51. The method of claim 46, wherein double down-converting the broadband signal to form a double down-converted broadband signal comprises:

down-converting the broadband signal to a first down-converted broadband signal;

filtering the first down-converted broadband signal;

down-converting the first down-converted signal to a double down-converted broadband signal; and

filtering the double down-converted broadband signal.

52. A system to monitor gain in repeater links in a broadband transport system, the system comprising:

means for double down-converting a plurality of signals received at remote antennae;

means for amplifying the plurality of signals; and

means for transmitting the plurality of amplified signals to a respective host unit.

53. The system of claim 52, further comprising:

means for determining a noise for each transmitted single-frequency signal at the respective host unit; and

means for indicating when the noise is below an acceptable noise level.

54. A system to monitor gain in repeater links in a broadband transport system, the system comprising:

means for direct down-converting a plurality of signals received at remote antennae;

means for amplifying the plurality of signals; and

means for transmitting the plurality of amplified signals to a respective host unit.

55. The system of claim 54, further comprising:

means for determining a noise for each transmitted single-frequency signal at the respective host unit; and

means for indicating when the noise is below an acceptable noise level.

56. A remote unit communicable with a radio frequency antenna, the remote comprising:

a pilot tone generator adapted to generate at least one single-frequency tone having a known power level;

a summing circuit operably associated with the pilot tone generator adapted to sum the single-frequency tone with a radio frequency signal received from the radio frequency antenna; and

at least one amplifier in communication with the summing circuit, wherein the at least one amplifier is adapted to amplify the summed signal, wherein the remote unit is operable to transmit the amplified signals over a transmission link to a host unit so that the host unit can determine a gain in a system that includes the remote unit, the host unit and the transmission link.

57. A host unit operable to receive a signal transmitted over a transmission link, the host unit comprising:

a pilot tone receiver adapted to receive the signal transmitted from a remote unit, wherein the signal includes a broadband signal and a single-frequency tone signal, the pilot tone receiver further adapted to strip the single-frequency tone signal from the received signal, the pilot tone receiver further adapted to detect an amplitude of the single-frequency tone signal, determine a gain within the transmission link, so that the host unit can determine the gain in a system that includes the remote unit, the host unit and the transmission link.

58. A remote unit communicable with a radio frequency antenna, the remote unit comprising:

at least one amplifier, wherein the at least one amplifier is adapted to amplify a radio frequency signal received from the radio frequency antenna;

a double down-converter including filters, wherein the double down-converter is adapted to generate a double down-converted broadband signal from the signal received from the at least one amplifier; and

a data transport circuit to transmit the double down-converted signal over a transmission link to a host unit so that the host unit can determine a noise-level in a system that includes the remote unit, the host unit and the transmission link.

59. A host unit operable to receive a signal transmitted over a transmission link, the host unit comprising:

a data transport circuit adapted to receive a double-down converted broadband signal that was transmitted from a remote unit;

a noise floor detector circuit adapted to detect a noise-level of the signal at a narrow band frequency range outside the frequency range of the double-down converted broadband signal; and

a controller adapted to determine if the detected noise level is within an acceptable noise level for a system that includes the remote unit, the host unit and the transmission link.

60. A system to monitor gain in a remote unit, the remote unit in communication with a radio frequency antenna and a host unit of broadband radio frequency transport system, the system comprising:

a pilot tone generator adapted to generate at least one single-frequency tone having a known power level,

a summing circuit operably associated with the pilot tone generator adapted to sum the single-frequency tone with the respective received radio frequency signal,

at least one amplifier in communication with the summing circuit, wherein the at least one amplifier amplifies the summed signal and transmits the signal over a respective transmission link to a host unit,

a remote pilot tone receiver adapted to receive the amplified summed signal and detect the at least one single-frequency tone, and

a controller adapted to determine a gain within the remote unit and adapted to determine if the gain is in a preset range of gains based on the power level of the received pilot tone.

61. A system to monitor gain in a host unit of a broadband radio frequency transport system, the system comprising:

a host unit adapted to receive a signal transmitted over a transmission link from a remote unit, each host unit comprising;

a host pilot tone generator adapted to generate at least one single-frequency tone having a known power level;

a pilot tone receiver circuit adapted to receive the at least one single-frequency tone; and

a controller adapted to determine a gain within the host unit and adapted to determine if the gain is in a preset range of gains based on the power level of the received pilot tone.