Receiver based saturation estimator

• US 20060227885A1
• Filed: 04/03/2006
• Published: 10/12/2006
• Est. Priority Date: 05/30/2003
• Status: Active Grant

• Current Assignee: ViaSat Incorporated
• Original Assignee: ViaSat Incorporated
• Inventors: Thesling, William H.
• Granted Patent: US 7,466,756 B2
• Time in Patent Office: Days
• US Class Current: 375/259
• CPC Class Codes: H04B 1/0475 with means for limiting noise, interference or distortion H04B1/0483 takes precedence
• CPC Class Codes: H04W 52/52 using AGC [Automatic Gain Control] circuits or amplifiers

Abstract

A processor-implemented method of estimating the saturation level of a transmitter from a transmitted communication signal received from the transmitter comprises generating a received data signal from the transmitted communication signal received from the transmitter, generating a transmitted data signal from the received data signal that corresponds to the actual data signal generated at the transmitter, comparing the transmitted data signal to the received data signal, and estimating the saturation level of the transmitter based on the comparison of the transmitted data signal to the received data signal.

Claims

1. A processor-implemented method of estimating a characteristic of a transmitter or transmission medium from a transmitted communication signal received from the transmitter, comprising:

filtering the transmitted communication signal to generate a received symbol sequence;

decoding the received symbol sequence to recover data;

analyzing the data for errors; and

based upon the analyzing step, then;

generating a transmitted symbol sequence;

comparing the transmitted symbol sequence to the received symbol sequence; and

estimating the characteristic of the transmitter or transmission medium based on the comparison of the transmitted symbol sequence to the received symbol sequence.

2. The method of claim 1, wherein comparing the transmitted symbol sequence to the received symbol sequence comprises:

generating a plurality of characteristic transfer functions, each characteristic transfer function corresponding to a particular characteristic;

filtering the transmitted symbol sequence to generate a communication signal;

inputting the communication signal into each characteristic transfer function to generate a plurality of estimated transmitted communication signals;

filtering the plurality of estimated transmitted communication signals to generate a plurality of estimated received symbol sequences; and

comparing each of the estimated received symbol sequences to the received symbol sequence.

3. The method of claim 2, wherein comparing each of the estimated received symbol sequences to the received symbol sequence comprises generating a correlation coefficient for each of the comparisons of the estimated received symbol sequences to the received symbol sequence.

4. The method of claim 3, further comprising:

determining if the characteristic of the transmitter crosses a threshold; and

transmitting an instruction to the transmitter to modify transmission if the characteristic of the transmitter is determined to cross the threshold.

5. The method of claim 4, further comprising transmitting an instruction to the transmitter to decrease a transmission data rate if the characteristic of the transmitter is determined to cross the threshold.

6. The method of claim 3, wherein estimating the characteristic of the transmitter or transmission medium based on the comparison of the transmitted symbol sequence to the received symbol sequence comprises:

determining the highest correlation coefficient generated; and

interpolating between at least the characteristic corresponding to the highest correlation coefficient generated at least one other characteristic.

7. The method of claim 3, wherein generating a correlation coefficient for each of the comparisons of the estimated received symbol sequences to the received symbol sequence comprises:

defining a characteristic trajectory;

defining a set equidistant points on the characteristic trajectory; and

setting each of the equidistant points to an interpolation index.

10. The method of claim 1, wherein comparing the transmitted symbol sequence to the received symbol sequence comprises generating a linear average of the transmitted symbol sequence to the received symbol sequence, and wherein estimating the characteristic of the transmitter based on the comparison of the transmitted symbol sequence to the received symbol sequence comprises estimating the characteristic of the transmitter based on the linear average.

11. The method of claim 1, further comprising:

determining if the characteristic of the transmitter crosses a threshold;

transmitting an instruction to the transmitter to increase transmission power if the characteristic of the transmitter is determined to cross the threshold; and

transmitting an instruction to the transmitter to decrease a transmission data rate if the characteristic of the transmitter is determined to cross the threshold.

12. The method of claim 1, wherein the transmitter is a block-up converter.

13. The method of claim 1, wherein generating the transmitted symbol sequence comprises generating a transmitted symbol sequence that is 180°

from an optimum symbol timing.

14. The method of claim 2, wherein generating a plurality of characteristic transfer functions, each characteristic transfer function corresponding to a particular characteristic comprises:

defining a characteristic trajectory;

defining a set equidistant points on the characteristic trajectory; and

generating the plurality of characteristic transfer functions at levels corresponding to the equidistant points on the characteristic trajectory.

15. The method of claim 2, wherein generating a plurality of characteristic transfer functions comprises:

interrogating one or more transmitters over a communication link to obtain characteristic transfer function data; and

generating the plurality of characteristic transfer functions based on the characteristic transfer function data obtained by the interrogation.

21. The method of claim 1, wherein the characteristic corresponds to saturation level.

8. (canceled)

9. (canceled)

16. A processor-implemented method of estimating a characteristic of a transmitter or transmission medium from a transmitted communication signal received from the transmitter, comprising:

generating a received data signal from the transmitted communication signal received from the transmitter;

generating a transmitted data signal from the received data signal that corresponds to the actual data signal generated at the transmitter;

comparing the transmitted data signal to the received data signal; and

estimating the characteristic of the transmitter or transmission medium based on the comparison of the transmitted data signal to the received data signal.

17. The method of claim 16, wherein comparing the transmitted data signal to the received data signal comprises:

generating a plurality of characteristic transfer functions, each characteristic transfer function corresponding to a saturation level;

inputting the transmitted data signal into each of the characteristic transfer functions to generate a plurality of estimated transmitted communication signals;

generating a plurality of estimated received data signals from the estimated transmitted communication signals; and

comparing each of the estimated received data signals to the received data signal.

18. The method of claim 16, wherein comparing each of the estimated received data signals to the received data signal comprises generating a correlation coefficient for each of the comparisons of the estimated received data signals to the received data signal.

19. The method of claim 16, further comprising:

determining if the characteristic of the transmitter crosses a threshold; and

transmitting an instruction to the transmitter to modify transmission if the characteristic of the transmitter is determined to cross the threshold.

20. The method of claim 18, wherein estimating the characteristic of the transmitter or transmission medium based on the comparison of the transmitted data signal to the received data signal comprises:

determining the highest correlation coefficient generated; and

interpolating between at least the characteristic corresponding to the highest correlation coefficient generated at least one other characteristic.

22. A method of estimating a characteristic of a transmitter or transmission medium, the method comprising steps of:

generating a received data signal from a transmitted communication signal received from the transmitter;

decoding the received data signal to recover data;

determining a transmitted data signal from the received data signal that corresponds to the actual data signal generated at the transmitter;

comparing the transmitted data signal to the received data signal; and

estimating the characteristic of the transmitter or transmission medium based on the comparing step.

23. The method of claim 22, further comprising a step of finding that no errors are detected in the data before performing the determining, comparing and estimating steps.