SYSTEMS AND METHODS FOR REDUCING POWER ROBBING IMPACT OF INTERFERENCE TO A SATELLITE

• US 20090011704A1
• Filed: 06/24/2008
• Published: 01/08/2009
• Est. Priority Date: 07/03/2007
• Status: Active Grant

• Current Assignee: ATC Technology Corporation (FedEx Corporation)
• Original Assignee: Mobile Satellite Venture LP
• Inventors: Karabinis, Peter D.
• Granted Patent: US 8,064,824 B2
• Time in Patent Office: Days
• US Class Current: 455/13.400
• CPC Class Codes: H04B 7/18534 for enhancing link reliablility, e.g. satellites diversity
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Processing return feeder link signals at a satellite gateway including a first and second receive antennas includes receiving first and second return feeder link signals at the first and second receive antennas, respectively, modulating a phase of the first return feeder link signal to form an adjusted first feeder link signal, combining the adjusted first feeder link signal with the second return feeder link signal to form a combined feeder link signal, detecting periodic amplitude variation in the combined feeder link signal, and shifting a phase of the first return feeder link signal to reduce periodic amplitude variation in the combined feeder link signal.

Claims

1. A method of processing return feeder link signals at a satellite gateway including a plurality of spatially diverse receive antennas, the method comprising:

receiving respective return feeder link signals at each of the plurality of receive antennas;

selectively adjusting amplitudes and/or phases of a plurality of the return feeder link signals received at the plurality of receive antennas in response to amplitude/phase adjustment settings to provide a plurality of adjusted return feeder link signals;

combining the plurality of adjusted feeder link signals to generate a combined return feeder link signal;

detecting periodic amplitude variation in the combined return feeder link signal; and

configuring the amplitude/phase adjustment settings in response to the combined return feeder link signal to reduce the periodic amplitude variation in the combined return feeder link signal.

2. The method of claim 1, wherein configuring the amplitude/phase adjustment settings comprises providing non-periodic phase adjustment signals to a plurality of amplitude/phase adjustors that process the plurality of return feeder link signals.

3. The method of claim 1, wherein selectively adjusting amplitudes and/or phases of the return feeder link signals comprises adjusting the amplitude/phase of a first one of the return feeder link signals at a first adjustment frequency and adjusting the amplitude/phase of a second one of the return feeder link signals at a second adjustment frequency that is different from the first adjustment frequency.

4. The method of claim 3, wherein the first adjustment frequency is 10 Hz and the second adjustment frequency is 50 Hz.

5. The method of claim 3, further comprising adjusting amplitudes/phases of the first and second return feeder link signals using respective first and second periodic functions that are in phase quadrature therebetween.

6. The method of claim 5, wherein the first and second periodic functions comprise sinusoidal functions.

7. The method of claim 1, wherein the plurality of receive antennas comprises four antennas, the method further comprising:

receiving first, second, third and fourth return feeder link signal at respective ones of the plurality of receive antennas;

selectively adjusting amplitudes and/or phases of the first and second return feeder link signals received at the first and second receive antennas to generate respective first and second adjusted feeder link signals;

combining the first adjusted feeder link signal and the third return feeder link signal to generate a first intermediate combined signal;

combining the second adjusted feeder link signal and the fourth return feeder link signal to generate a second intermediate combined signal; and

combining the first intermediate combined signal and the second intermediate combined signal to generate the combined return feeder link signal.

8. The method of claim 7, further comprising:

adjusting an amplitude and/or phase of the first intermediate combined signal to generate an adjusted intermediate combined signal;

wherein combining the first intermediate combined signal and the second intermediate combined signal comprises combining the adjusted intermediate combined signal and the second intermediate combined signal.

9. The method of claim 1, wherein the plurality of receive antennas comprises four antennas, the method further comprising:

receiving first, second, third and fourth return feeder link signal at respective ones of the plurality of receive antennas;

selectively adjusting amplitudes and/or phases of the first, second and third return feeder link signals received at the first, second and third receive antennas to generate respective first, second and third adjusted feeder link signals; and

combining the first, second and third adjusted feeder link signals and the fourth return feeder link signal to generate the combined return feeder link signal.

10. The method of claim 1, wherein combining the plurality of adjusted feeder link signals to generate a combined return feeder link signal comprises RF combining the signals.

11. The method of claim 1, further comprising converting the feeder link signals to an intermediate frequency, wherein combining the plurality of adjusted feeder link signals to generate a combined return feeder link signal comprises combining intermediate frequency signals.

12. The method of claim 1, further comprising:

converting the combined return feeder link signal to baseband; and

combining the baseband combined return feeder link signal with another baseband signal.

13. A satellite gateway comprising:

a plurality of receive antennas; and

a processor coupled to the plurality of receive antennas and configured to receive respective return feeder link signals from each of the plurality of receive antennas, configured to selectively adjust amplitudes and/or phases of a plurality of the return feeder link signals received at the plurality of receive antennas in response to amplitude/phase adjustment settings to provide a plurality of adjusted return feeder link signals, and configured to combine the plurality of adjusted feeder link signals to generate a combined return feeder link signal;

wherein the processor comprises a control circuit configured to detect periodic amplitude variation in the combined return feeder link signal, and to configure the amplitude/phase adjustment settings in response to periodic amplitude variation in the combined return feeder link signal to reduce periodic amplitude variation in the combined return feeder link signal.

14. The satellite gateway of claim 13, wherein the control circuit is configured to provide non-periodic phase adjustment signals to a plurality of amplitude/phase adjustors that process the plurality of return feeder link signals.

15. The satellite gateway of claim 13, wherein the processor comprises a first amplitude/phase adjustor that is configured to selectively adjust the amplitude/phase of a first one of the return feeder link signals at a first adjustment frequency and a second amplitude/phase adjustor that is configured to selectively adjust the amplitude/phase of a second one of the return feeder link signals at a second adjustment frequency that is different from the first adjustment frequency.

16. The satellite gateway of claim 15, wherein the first adjustment frequency is 10 Hz and the second adjustment frequency is 50 Hz.

17. The satellite gateway of claim 15, wherein the first amplitude/phase adjustor and the second amplitude/phase adjustor adjust amplitudes/phases of the first and second return feeder link signals using respective first and second periodic functions that are in phase quadrature therebetween.

18. The satellite gateway of claim 17, wherein the first and second periodic functions comprise sinusoidal functions.

19. The satellite gateway of claim 13, wherein the plurality of receive antennas comprises four antennas, and wherein the processor further comprises:

a first amplitude/phase adjustor configured to selectively adjust amplitude/phase of a first return feeder link signal;

a second amplitude/phase adjustor configured to selectively adjust amplitude/phase of a second return feeder link signal;

a first combiner configured to combine the first return feeder link signal and a third return feeder link signal to form a first intermediate combined signal;

a second combiner configured to combine the second return feeder link signal and a fourth return feeder link signal to form a second intermediate combined signal; and

a third combiner configured to combine the first intermediate combined signal and the second intermediate combined signal to generate a combined return feeder link signal.

20. The satellite gateway of claim 19, wherein the processor further comprises:

a third amplitude/phase adjustor configured to selectively adjust amplitude/phase of the first intermediate combined signal to generate an adjusted intermediate combined signal;

wherein the third combiner is configured to combine the adjusted intermediate combined signal and the second intermediate combined signal.

21. The satellite gateway of claim 13, wherein the plurality of receive antennas comprises four antennas, and wherein the processor further comprises:

a first amplitude/phase adjustor configured to selectively adjust amplitude/phase of a first return feeder link signal;

a second amplitude/phase adjustor configured to selectively adjust amplitude/phase of a second return feeder link signal;

a third amplitude/phase adjustor configured to selectively adjust amplitude/phase of a third return feeder link signal; and

a combiner configured to combine the first return feeder link signal, the second return feeder link signal, the third return feeder link signal and a fourth return feeder link signal to form the combined return feeder link signal.

22. A method of processing return feeder link signals at a satellite gateway including a first and second receive antennas, the method comprising:

receiving first and second return feeder link signals at the first and second receive antennas, respectively;

modulating a phase of the first return feeder link signal to form an adjusted first feeder link signal;

combining the adjusted first feeder link signal with the second return feeder link signal to form a combined feeder link signal;

detecting periodic amplitude variation in the combined feeder link signal; and

shifting a phase of the first return feeder link signal to reduce the periodic amplitude variation in the combined feeder link signal.

23. The method of claim 22, further comprising:

receiving third and fourth return feeder link signals at respective third and fourth receive antennas;

modulating a phase of the third return feeder link signal to form an adjusted third feeder link signal;

combining the adjusted third feeder link signal with the fourth return feeder link signal to form a second combined feeder link signal;

detecting periodic amplitude variation in the second combined feeder link signal; and

shifting a phase of the third return feeder link signal to reduce periodic amplitude variation in the second combined feeder link signal.

24. The method of claim 23, further comprising:

modulating a phase of the combined feeder link signal to form an adjusted combined feeder link signal;

combining the adjusted combined feeder link signal with the second combined feeder link signal to form a third combined feeder link signal;

detecting periodic amplitude variation in the third combined feeder link signal; and

shifting a phase of the combined feeder link signal to reduce periodic amplitude variation in the third combined feeder link signal.

25. The method of claim 22, further comprising:

receiving third and fourth return feeder link signals at respective third and fourth receive antennas; and

modulating phases of the third and fourth return feeder link signals to form an adjusted third feeder link signal and an adjusted third feeder link signal;

wherein combining the adjusted first feeder link signal with the second return feeder link signal to form the combined feeder link signal comprises combining the adjusted first feeder link signal, the second return feeder link signal, the adjusted third feeder link signal and the adjusted fourth feeder link signal to form the combined feeder link signal.

26. A satellite gateway, comprising:

a processor configured to receive first and second return feeder link signals from first and second receive antennas, respectively;

a phase modulator configured to modulate a phase of the first return feeder link signal;

a phase shifter configured to shift a phase of the first return feeder link signal by a phase delay;

a combiner configured to combine the first return feeder link signal with the second return feeder link signal to form a combined feeder link signal;

a power detector configured to detect periodic amplitude variation in the combined feeder link signal; and

a feedback loop from the power detector to the phase shifter configured to adjust the phase delay to reduce periodic amplitude variation in the combined feeder link signal.

27. The satellite gateway of claim 26, wherein the processor is further configured to receive third and fourth return feeder link signals from respective third and fourth receive antennas, and wherein the processor further comprises:

a second phase modulator configured to modulate a phase of the third return feeder link signal;

a second phase shifter configured to shift a phase of the third return feeder link signal by a second phase delay;

a second combiner configured to combine the third return feeder link signal with the fourth return feeder link signal to form a second combined feeder link signal;

a second power detector configured to detect periodic amplitude variation in the second combined feeder link signal; and

a second feedback loop from the second power detector to the second phase shifter configured to adjust the second phase delay to reduce periodic amplitude variation in the second combined feeder link signal.

28. The satellite gateway of claim 27, further comprising:

a third phase modulator configured to modulate a phase of the combined feeder link signal;

a third phase shifter configured to shift a phase of the third combined feeder link signal by a third phase delay;

a third combiner configured to combine the combined feeder link signal with the second combined feeder link signal to form a third combined feeder link signal;

a third power detector configured to detect periodic amplitude variation in the third combined feeder link signal; and

a third feedback loop from the third power detector to the third phase shifter configured to adjust the third phase delay to reduce periodic amplitude variation in the third combined feeder link signal.

29. The satellite gateway of claim 26, wherein the processor is further configured to receive third and fourth return feeder link signals from respective third and fourth receive antennas, and wherein the processor further comprises:

a second phase modulator configured to modulate a phase of the third return feeder link signal;

a second phase shifter configured to shift a phase of the third return feeder link signal by a second phase delay;

a third phase modulator configured to modulate a phase of the fourth return feeder link signal; and

a third phase shifter configured to shift a phase of the fourth return feeder link signal by a third phase delay;

wherein the combiner is configured to combine the first, second, third and fourth return feeder link signals to form the combined feeder link signal.