Noise analysis in a communication system

• US 20030185176A1
• Filed: 10/18/2002
• Published: 10/02/2003
• Est. Priority Date: 02/28/2002
• Status: Active Grant

• Current Assignee: Maxlinear Incorporated
• Original Assignee: Texas Instruments, Inc.
• Inventors: Bitran, Yigal, Shalvi, Ofir, Sommer, Naftali, Reznic, Zvi, Lusky, Itay, Yagil, Ariel, Wajcer, Daniel, Haim, Eli, Bendel, Yosef, Senderovitz, Ran
• Granted Patent: US 7,492,703 B2
• Time in Patent Office: Days
• US Class Current: 370/335
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/20 using signal quality detector

Abstract

A system is provided to automatically estimate performance of a receiver for receiving input signals, the input signals having a carrier frequency and a baud rate, from a channel in a communication system and the effect of highly correlated noise cancellation on performance of the receiver, while no active transmission is occurring on the channel, comprising: a digital front end in the receiver for receiving samples of the input signals; a predictor coupled to the digital front end for predicting highly correlated noise in a second sample of the input signal; and a subtraction unit coupled to the predictor for subtracting the predictor output from the second sample to determine residual noise in the second sample. Other systems and methods are disclosed.

Claims

1. A method to automatically estimate performance of a receiver for receiving input signals, the input signals having a carrier frequency and a baud rate, from a channel in a communication system and to automatically estimate the effect of highly correlated noise cancellation on performance of the receiver, while no active transmission is occurring on the channel, comprising the steps of:

a. receiving a first sample of the input signal from the channel;

b. passing the first sample to a predictor for predicting highly correlated noise in a second sample of the input signal and outputting a prediction of highly correlated noise in the second sample as a predictor output;

c. receiving a second sample of the input signal from the channel;

d. subtracting the predictor output from the second sample to determine residual noise in the second sample;

e. passing the residual noise to a second energy detector unit to determine residual noise energy; and

f. outputting the residual noise energy.

2. The method of claim 1 further comprising the step of passing the first sample to a first energy detector unit to determine input signal energy.

3. The method of claim 2 further comprising the step of averaging the input signal energy.

4. The method of claim 2 further comprising the step of analyzing the input signal energy and residual noise energy to determine cancelled highly correlated noise energy.

5. The method of claim 1 further comprising the step of averaging the residual noise energy.

6. The method of claim 1 wherein the receiver comprises a digital front end for receiving the input signals.

7. The method of claim 1 wherein the method is repeated using a different carrier frequency.

8. The method of claim 1 wherein the method is repeated using a different baud rate.

9. The method of claim 1 further comprising the step of delaying the first sample prior to inputting the first sample to the predictor.

10. The method of claim 1 wherein the predictor comprises predictor coefficients further comprising the step of updating the predictor coefficients.

11. The method of claim 10 wherein a least mean square method is used to update the predictor coefficients.

12. The method of claim 1 wherein the highly correlated noise is ingress noise.

13. A system to automatically estimate performance of a receiver for receiving input signals, the input signals having a carrier frequency and a baud rate, from a channel in a communication system and the effect of highly correlated noise cancellation on performance of the receiver, while no active transmission is occurring on the channel, comprising:

a. a digital front end in the receiver for receiving samples of the input signals;

b. a predictor coupled to the digital front end for predicting highly correlated noise in a second sample of the input signal; and

c. a subtraction unit coupled to the predictor for subtracting the predictor output from the second sample to determine residual noise in the second sample.

14. The system of claim 13 wherein the digital front end is a dedicated digital front end.

15. The system of claim 13 further comprising a delay unit coupled to the digital front end for delaying the samples.

16. The system of claim 13 further comprising a first energy detector unit coupled to the digital front end to determine input signal energy from the first sample.

17. The system of claim 16 further comprising an average unit coupled to the digital front end for averaging the input signal energy.

18. The system of claim 17 wherein the average unit comprises an infinite impulse response filter.

19. The system of claim 13 further comprising a second energy detector unit coupled to the digital front end to determine residual noise energy from the residual noise.

20. The system of claim 19 further comprising an average unit coupled to the predictor for averaging the residual noise energy.

21. The system of claim 20 wherein the average unit comprises an infinite impulse response filter.

22. The system of claim 13, wherein the predictor comprises predictor coefficients, further comprising an update unit coupled to the predictor to update the predictor coefficients.

23. The system of claim 22 wherein a least mean square method is used to update the predictor coefficients.

24. The system of claim 13 wherein the highly correlated noise is ingress noise.