Adaptive interference suppression via subband power measurements of a phased-array antenna

• US 9,379,439 B2
• Filed: 02/14/2014
• Issued: 06/28/2016
• Est. Priority Date: 02/14/2014
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Turpin, Raenaurd D., Veysoglu, Murat E.
• Primary Examiner(s): Gregory, Bernarr
• Application Number:
  US14/180,402
• Publication Number:
  US 20150236413A1
• Time in Patent Office: 865 Days
• US Class Current: 1/1
• CPC Class Codes: G01S 7/36 Means for anti-jamming , e.g. ECCM, i.e. electronic counter-counter measures
• CPC Class Codes: H01Q 3/34 by electrical means active lenses or reflecting arrays H01Q3/46
• CPC Class Codes: H04B 17/318 Received signal strength
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 7/18508 with satellite system used as relay, i.e. aeronautical mobile satellite service
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system
• CPC Class Codes: H04B 7/2041 Spot beam multiple access
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

A phased-array antenna system includes an array of antenna feed elements that produces a radiation pattern to provide spot beams within which to receive a signal in a frequency band and carrying communication from a terminal at a known geographic location. A beamformer forms the spot beams; and a channelizer divides the frequency band into frequency subbands, and measures power levels of the signal over respective frequency subbands. And an antenna controller selects a frequency subband based on the measured power levels indicating that the signal includes an identifiable interference, and calculates a set of beam weights based on the measured power level over the selected frequency subband, and based on the known geographic location of the terminal. The beamformer, then, forms the spot beams based on the calculated set of beam weights to thereby suppress at least some of the identifiable interference from the signal.

Claims

1. A phased-array antenna system comprising:

a beamformer configured to form a plurality of spot beams;

an array of antenna feed elements coupled to the beamformer and configured to produce a radiation pattern to provide the spot beams within which the array of antenna feed elements is configured to receive a signal in a frequency band, the signal carrying communication from a terminal at a known geographic location;

a channelizer coupled to the beamformer and configured to divide the frequency band into a plurality of frequency subbands, and measure power levels of the signal over respective frequency subbands; and

an antenna controller coupled to the channelizer and beamformer, the antenna controller being configured to;

select a frequency subband of the frequency subbands based on the measured power levels indicating that the signal includes an identifiable interference; and

calculate a set of beam weights based on the measured power level over the selected frequency subband, and based on the known geographic location of the terminal,

wherein the beamformer being configured to form the spot beams includes being configured to form the spot beams based on the calculated set of beam weights to thereby suppress at least some of the identifiable interference from the signal.

2. The phased-array antenna system of claim 1, wherein the antenna controller being configured to calculate the set of beam weights includes being configured to calculate the set of beam weights that result in a reduction in the measured power level over the selected frequency subband, with no more than an allowable degradation in strength of the radiation pattern in a direction of the known geographic location of the terminal.

3. The phased-array antenna system of claim 1, wherein the signal carries communication from one or more terminals at respective geographic locations that define a known geographic area, and

wherein the antenna controller being configured to calculate the set of beam weights based on the known location of the terminal includes being configured to calculate the set of beam weights based on the known geographic area.

4. The phased-array antenna system of claim 1, wherein the antenna controller being configured to select the frequency subband includes being configured to select one or more of the frequency subbands over which respective, known nominal power levels are at or less than a threshold power level.

5. The phased-array antenna system of claim 1, wherein the antenna controller is further configured to identify one of the frequency subbands over which a respective measured power level indicates that the signal includes an identifiable interference, and

wherein the antenna controller being configured to select the frequency subband includes being configured to select the frequency subband at or above the identified frequency subband.

6. The phased-array antenna system of claim 5, wherein the antenna controller being configured to identify one of the frequency subbands includes being configured to:

compare at least some of the measured power levels to corresponding, known nominal power levels; and

identify one of the measured power levels having a difference from a corresponding one of the nominal power levels at or greater than a threshold power level, the identified one of the measured power levels being over the identified one of the frequency subbands.

7. The phased-array antenna system of claim 1, wherein the antenna controller being configured to calculate the set of beam weights includes being configured to apply a genetic algorithm including being configured to:

calculate and evaluate respective fitness values for a plurality of candidate sets of beam weights, the respective fitness values being calculated from a fitness function defined to include variables of the measured power level over the selected frequency subband, and strength of the radiation pattern in a direction of the known geographic location of the terminal; and

select the set of beam weights from the candidate sets of beam weights based on evaluation of the respective fitness values.

8. The phased-array antenna system of claim 7, wherein the antenna controller being configured to apply the genetic algorithm includes being configured to apply the genetic algorithm for a plurality of iterations,

wherein each of the iterations includes the antenna controller being configured to calculate and evaluate respective fitness values for a current generation of candidate sets of beam weights, the current generation of candidate sets of beam weights for each but a last of the iterations being received from a previous one of the iterations,

wherein each but the last of the iterations includes the antenna controller being configured to select candidate sets of beam weights from the current generation of candidate sets of beam weights based on evaluation of the respective fitness values, and modify one or more beam weights of each of the selected candidate sets of beam weights to generate a current generation of candidate sets of beam weights for a next one of the iterations, and

wherein the last of the iterations includes the antenna controller being configured to select the set of beam weights from the current generation of candidate sets of beam weights based on evaluation of the respective fitness values.

9. A method comprising:

forming a plurality of spot beams;

producing a radiation pattern by an array of antenna feed elements to provide the spot beams within which the array of antenna feed elements receives a signal in a frequency band, the signal carrying communication from a terminal at a known geographic location;

forming the spot beams provided by the radiation pattern produced by the array of antenna feed elements;

dividing the frequency band into a plurality of frequency subbands, and measuring power levels of the signal over respective frequency subbands;

selecting a frequency subband of the frequency subbands based on the measured power levels indicating that the signal includes an identifiable interference; and

calculating a set of beam weights based on the measured power level over the selected frequency subband, and based on the known geographic location of the terminal,

wherein forming the spot beams includes forming the spot beams based on the calculated set of beam weights to thereby suppress at least some of the identifiable interference from the signal.

10. The method of claim 9, wherein calculating the set of beam weights includes calculating the set of beam weights that result in a reduction in the measured power level over the selected frequency subband, with no more than an allowable degradation in strength of the radiation pattern in a direction of the known geographic location of the terminal.

11. The method of claim 9, wherein the signal carries communication from one or more terminals at respective geographic locations that define a known geographic area, and

wherein calculating the set of beam weights based on the known location of the terminal includes calculating the set of beam weights based on the known geographic area.

12. The method of claim 9, wherein selecting the frequency subband includes selecting one or more of the frequency subbands over which respective, known nominal power levels are at or less than a threshold power level.

13. The method of claim 9 further comprising identifying one of the frequency subbands over which a respective measured power level indicates that the signal includes an identifiable interference,

wherein selecting the frequency subband includes selecting the frequency subband at or above the identified frequency subband.

14. The method of claim 13, wherein identifying one of the frequency subbands comprises:

comparing at least some of the measured power levels to corresponding, known nominal power levels; and

identifying one of the measured power levels having a difference from a corresponding one of the nominal power levels at or greater than a threshold power level, the identified one of the measured power levels being over the identified one of the frequency subbands.

15. The method of claim 9, wherein calculating the set of beam weights comprises applying a genetic algorithm including:

calculating and evaluating respective fitness values for a plurality of candidate sets of beam weights, the respective fitness values being calculated from a fitness function defined to include variables of the measured power level over the selected frequency subband, and strength of the radiation pattern in a direction of the known geographic location of the terminal; and

selecting the set of beam weights from the candidate sets of beam weights based on evaluation of the respective fitness values.

16. The method of claim 15, wherein applying the genetic algorithm includes applying the genetic algorithm for a plurality of iterations,

wherein each of the iterations includes calculating and evaluating respective fitness values for a current generation of candidate sets of beam weights, the current generation of candidate sets of beam weights for each but a last of the iterations being received from a previous one of the iterations,

wherein each but the last of the iterations includes selecting candidate sets of beam weights from the current generation of candidate sets of beam weights based on evaluation of the respective fitness values, and modifying one or more beam weights of each of the selected candidate sets of beam weights to generate a current generation of candidate sets of beam weights for a next one of the iterations, and

wherein the last of the iterations includes selecting the set of beam weights from the current generation of candidate sets of beam weights based on evaluation of the respective fitness values.