Wireless communication link quality forecasting

• US 6,308,043 B1
• Filed: 07/23/1998
• Issued: 10/23/2001
• Est. Priority Date: 07/23/1998
• Status: Expired due to Fees

• Current Assignee: United State Air Force
• Original Assignee: Radiometrics Corporation
• Inventors: Solheim, Fredrick S., Yager, Mark E.
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): WASHINGTON, ERIKA ALISE
• Application Number:
  US09/121,042
• Time in Patent Office: 1,188 Days
• Field of Search: 455/63, 455/67.1, 455/67.3, 455/67.4, 455/67.5, 455/226.1, 455/10, 455/12.1, 455/13.4, 455/427, 455/423, 455/424, 455/425, 375/224, 342/165, 342/351, 324/76.14
• US Class Current: 455/63.1
• CPC Class Codes: H04B 17/373 Predicting channel quality or other radio frequency [RF] parameters
• CPC Class Codes: H04B 17/3913 Predictive models, e.g. based on neural network models

Abstract

Apparatus and method for forecasting the quality of radio communication links on a short-term basis are disclosed, the apparatus including at least one, and preferably an ensemble of, sensors providing output indicia indicative of evolving atmospheric and/or ionospheric conditions in the vicinity of a monitored communication link. The sensors may include any device that provides data containing predictive information, such as a microwave radiometer for receiving atmospheric emissions that are related to atmospheric scattering and absorption of radio propagation, input for measurement of the signal-to-noise ratio of the radio link carrier, and sensors of surface meteorology including barometric pressure, temperature, and surface winds direction and velocity. Data provided is processed utilizing mathematical inversion (also referred to as function estimation) techniques to provide predictions of changing link quality in the short-term (e.g., down to and less than 15 minutes) requiring communication link adaptation. The apparatus and methods employed are completely automated and link-site based.

Claims

1. A method for short-term forecasting of quality changes of a wireless communication link comprising:

receiving indicia indicative of selected evolving vicinal atmospheric conditions;

processing said indicia to derive short-term link quality change prediction based at least in part on selected utilization of past communication link performance, processing including preprocessing said indicia to enhance data features of interest in said received indicia and processing said indicia utilizing a mathematical inversion method to derive said prediction of short-term link quality change from said enhanced data features, wherein preprocessing said indicia includes performing a wavelet transform on said received indicia, said wavelet transform selected to produce a scalar value utilized to discriminate atmospheric scintillations preceding changes in quality of a wireless communication link as said data features; and

utilizing said prediction remedially.

2. The method of claim 1 wherein utilizing said mathematical inversion method includes utilizing an artificial neural network.

3. The method of claim 1 wherein said mathematical inversion method includes training and adaptation by comparing said prediction, said indicia and/or wireless communication link performance data.

4. The method of claim 1 wherein the step of utilizing said prediction remedially includes adapting the communication link in view of said prediction.

5. The method of claim 1 further comprising measuring, at a base site of the communication link, selected atmospheric conditions at said base site and providing measurements as said indicia.

6. The method of claim 1 further comprising monitoring communication link carrier signal-to-noise ratio and providing monitoring data as said indicia.

7. The method of claim 1 further comprising gathering selected atmospheric data using a microwave radiometer at a base site of the communication link and providing said data as said indicia.

8. The method of claim 1 wherein said short-term link quality change includes events likely to evolve down to and less than 15 minutes from said prediction.

9. Apparatus for forecasting likely wireless communication link quality changes due to atmospheric conditions and responding to a predicted quality change in sufficient time to allow communication link adaptation, the atmospheric conditions including events likely to evolve in the vicinity of the communication link in the short-term down to and less than 15 minutes from forecasting, said apparatus comprising:

input means for providing data indicative of atmospheric conditions, said data including at least one of measured communication link attenuation, barometric measurements taken in the vicinity of the communication link, surface wind measurements taken in the vicinity of the communication link, air temperature measurements taken in the vicinity of the communication link, and atmospheric microwave power emission measurements taken in the vicinity of the communication link;

processing means for receiving said data and including a preprocessing stage enhancing data features of interest in said data received from said input means and a processing stage to extract prediction of short-term link quality change from said enhanced data; and

output means for receiving said prediction from said processing means to thereby accommodate initiation of communication link remediation measures when required.

10. The apparatus of claim 9 wherein said processing stage includes an artificial neural network utilizing a back propagation learning strategy.

11. The apparatus of claim 9 wherein said input means includes a plurality of inputs each providing data indicative of atmospheric or ionospheric conditions, said data at said inputs including at least measured communication link attenuation and atmospheric microwave power emission measurements taken in the vicinity of the communication link.

12. The apparatus of claim 11 wherein said preprocessing stage includes means for wavelet transform of said data to enhance said data features.

13. The apparatus of claim 9 wherein said input means includes a microwave radiometer for monitoring atmospheric propagation conditions in the vicinity of the communication link and providing atmospheric microwave emissions data as and output therefrom to said processing means.

14. The apparatus of claim 13 wherein said microwave radiometer is a waveguide-based microwave integrated circuit radiometer.

15. The apparatus of claim 13 wherein said radiometer is a monolithic microwave integrated circuit radiometer.

16. The apparatus of claim 15 wherein said monolithic microwave integrated circuit radiometer has a muted transmitter.

17. A method for short-term forecasting of quality changes of a wireless communication link comprising:

receiving indicia indicative of selected evolving vicinal atmospheric conditions;

processing said indicia to derive short-term link quality change prediction based at least in part on selected utilization of past communication link performance, wherein said short-term link quality change includes events likely to evolve down to and less than 15 minutes from said prediction; and

utilizing said prediction remedially.

18. The method of claim 17 further comprising monitoring selected ones of communication link attenuation, barometric pressure in the vicinity of the communication link, surface winds in the vicinity of the communication link, air temperature in the vicinity of the communication link, and atmospheric microwave power emissions in the vicinity of the communication link and providing monitoring data as said indicia.

19. The method of claim 17 wherein the step of processing includes preprocessing said indicia to enhance data features of interest in said received indicia and processing said indicia utilizing a mathematical inversion method to derive said prediction of short-term link quality change from said enhanced data features.

20. The method of claim 17 wherein said processing step includes deriving either impending signal degradation or impending signal improvement as said quality change prediction.

21. The method of claim 17 wherein said selected evolving vicinal atmospheric conditions include selected ones of observable meteorological conditions in the near vicinity of said communication link and evolving ionospheric effects in the near vicinity of said communication link.

22. The method of claim 17 wherein said selected utilization of past communication link performance includes one of data modeling, back propagation training, and linear regression training.

23. The method of claim 17 wherein said selected utilization of past communication link performance is ongoing to thereby provide continued adaptation to seasonal and sensory changes reflected by said indicia received and further refine said prediction.

24. The method of claim 17 wherein said processing step includes utilizing artificial neural network methods to provide a spectrum of temporal link quality change predictions.

25. The method of claim 17 wherein said indicia includes at least one of data trends and high frequency fluctuations in selected input data.

26. A monolithic microwave integrated (circuit radiometer receiver comprising:

an antenna;

a monolithic microwave integrated circuit transceiver connected with said antenna and configured with a muted transmitter, said transceiver having an intermediate frequency output;

a detector diode connected with said output of said transceiver; and

amplification means for signal amplification at selected stages between said antenna and said diode, said amplification means providing total amplification between said antenna and said diode selected so that, in response, output voltage changes at said diode are proportional to sky emission power changes received at said antenna.