Adaptive equalization and interference cancellation with time-varying noise and/or interference

• US 20090103669A1
• Filed: 04/08/2008
• Published: 04/23/2009
• Est. Priority Date: 10/17/2007
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Currivan, Bruce J., Kolze, Thomas Joseph
• Granted Patent: US 8,180,001 B2
• Time in Patent Office: Days
• US Class Current: 375/346
• CPC Class Codes: H04L 1/0056 Systems characterized by the type of code used H04L1/08 takes precedence
• CPC Class Codes: H04L 2025/03496 as a prediction filter
• CPC Class Codes: H04L 2025/03617 Time recursive algorithms H04L2025/03643 takes precedence
• CPC Class Codes: H04L 25/03019 adaptive, i.e. capable of adjustment during data reception
• CPC Class Codes: H04L 25/03038 with a non-recursive structure H04L25/03031 takes precedence
• CPC Class Codes: H04L 25/03057 with a recursive structure H04L25/03031 takes precedence
• CPC Class Codes: H04L 25/03286 with channel-decoding circuitry
• CPC Class Codes: H04L 25/067 providing soft decisions, i.e. decisions together with an estimate of reliability H04L25/068 and H04L25/069 take precedence; sequence estimation techniques H04L25/03178

Abstract

A method and apparatus is disclosed to compensate for interference and/or distortion impressed onto a transmitted communication signal in the presence of one or more time-varying noise and/or interference conditions. A communications receiver includes a noise analyzer to characterize the composition of the interference and/or the distortion impressed onto a transmitted communication signal in the presence of one or more time-varying noise and/or interference conditions. The noise analyzer produces a selection signal indicating the composition of the interference and/or the distortion impressed onto a transmitted communication signal in the presence of one or more time-varying noise and/or interference conditions to be used by the communications receiver. In an exemplary embodiment, the communications receiver selects at least one set of equalization coefficients and/or updates at least one parameter of a least-squares algorithm or the suitable equivalent algorithm to compensate for the interference and/or the distortion impressed onto a transmitted communication signal in the presence of a particular time-varying noise and/or interference condition. In another exemplary embodiment, the communications receiver selects a corresponding adaptive equalizer from an adaptive equalizer bank to compensate for the interference and/or the distortion impressed onto a transmitted communication signal in the presence of the particular time-varying noise and/or interference condition.

Claims

1. A communications receiver for compensating for effects of a communication channel resulting from one or more time-varying noise and/or interference conditions comprising:

a noise analyzer configured to characterize a composition of the one or more time-varying noise and/or interference conditions and to produce a coefficient selection signal based on the composition of the one or more time-varying noise and/or interference conditions;

a coefficient generator including a plurality of coefficient banks, wherein the coefficient generator selects at least one coefficient bank from the plurality of coefficient banks based on the coefficient selection signal; and

an adaptive equalizer to compensate for the effects of the communication channel using the at least one coefficient bank.

2. The communications receiver of claim 1, further comprising a slicer coupled to the adaptive equalizer, wherein the slicer produces a slicer information signal.

3. The communications receiver of claim 2, wherein the coefficient generator updates at least one coefficient bank based on the slicer information signal.

4. The communications receiver of claim 2, further comprising a forward error correction (FEC) decoder coupled to the slicer, wherein the FEC decoder produces a decoder information signal.

5. The communications receiver of claim 4, wherein the coefficient generator updates at least one coefficient bank based on at least one of the slicer information signal and the decoder information signal.

6. The communications receiver of claim 1, further comprising:

a buffer coupled to the adaptive equalizer configured to store a communication signal from the communication channel, wherein the buffer includes the one or more time-varying noise and/or interference conditions.

7. A method to compensate for effects of a communication channel resulting from one or more time-varying noise and/or interference conditions comprising:

characterizing a composition of the one or more time-varying noise and/or interference conditions and to produce a coefficient selection signal based on the composition of the one or more time-varying noise and/or interference conditions;

selecting at least one coefficient bank from a plurality of coefficient banks based on the coefficient selection signal; and

compensating for the effects of the communication channel using the at least one coefficient bank to produce an equalized communication signal.

8. The method of claim 7, further comprising:

providing symbol decisions based on the equalized communication signal to produce a digitized communication signal; and

generating a slicer information signal.

9. The method of claim 8, further comprising:

updating the at least one coefficient bank based on the slicer information signal.

10. The method of claim 8, further comprising:

correcting for errors in the digitized communication signal; and

generating a decoder information signal.

11. The method of claim 10, further comprising:

updating the at least one coefficient bank based on at least one of the slicer information signal and the decoder information signal.

12. The method of claim 7, further comprising:

buffering a communication signal including the one or more time-varying noise and/or interference conditions from the communication channel.

13. A communications receiver for compensating for effects of a communication channel resulting from one or more time-varying noise and/or interference conditions comprising:

a noise analyzer configured to characterize a composition of the one or more time-varying noise and/or interference conditions and to produce an equalizer selection signal based on the composition of the one or more time-varying noise and/or interference conditions;

an adaptive equalizer bank to compensate for the effects of the communication channel; and

an equalizer selector to select at least one adaptive equalizer from the adaptive equalizer bank based on the equalizer selection signal.

14. The communications receiver of claim 13, wherein the at least one adaptive equalizer further comprises:

a slicer coupled to the at least one adaptive equalizer, wherein the slicer produces a slicer information signal.

15. The communications receiver of claim 14, wherein the at least adaptive equalizer is updated based on the slicer information signal.

16. The communications receiver of claim 14, wherein the at least one adaptive equalizer further comprises:

a forward error correction (FEC) decoder coupled to the slicer, wherein the FEC decoder produces a decoder information signal.

17. The communications receiver of claim 16, wherein the at least adaptive equalizer is updated based on at least one of the slicer information signal and the decoder information signal.

18. A method to compensate for effects of a communication channel resulting from one or more time-varying noise and/or interference conditions comprising:

characterizing a composition of the one or more time-varying noise and/or interference conditions and to produce an equalizer selection signal based on the composition of the one or more time-varying noise and/or interference conditions;

selecting at least one adaptive equalizer from a plurality of adaptive equalizer banks based on the equalizer selection signal; and

compensating for the effects of the communication channel using the at least one adaptive equalizer to produce an equalized communication signal.

19. The method of claim 18, further comprising:

providing symbol decisions based on the equalized communication signal to produce a digitized communication signal; and

generating a slicer information signal.

20. The method of claim 19, further comprising:

updating the at least one coefficient bank based on the slicer information signal.

21. The method of claim 19, further comprising:

correcting for errors in the digitized communication signal; and

generating a decoder information signal.

22. The method of claim 21, further comprising:

updating the at least one coefficient bank based on at least one of the slicer information signal and the decoder information signal.

23. The method of claim 18, further comprising:

buffering a communication signal including the one or more time-varying noise and/or interference conditions from the communication channel.

24. A communications receiver for compensating for effects of a communication channel resulting from one or more time-varying noise and/or interference conditions comprising:

a noise analyzer configured to characterize a composition of the one or more time-varying noise and/or interference conditions and to produce a coefficient selection signal based on the composition of the one or more time-varying noise and/or interference conditions;

a coefficient generator including at least one coefficient bank, wherein the coefficient generator updates equalization coefficients using a least-squares algorithm, wherein the coefficient generator adapts at least one parameter of a least-squares algorithm based on the coefficient selection signal;

an adaptive equalizer to compensate for the effects of the communication channel by updating equalization coefficients using the at least one parameter of the least-squares algorithm.

25. The receiver of claim 24, wherein the least-squares algorithm comprises at least one of:

a Least Mean Squared (LMS);

a Minimum Mean Squared Error (MMSE) algorithm; and

/or

a Recursive Least Squares (RLS) algorithm.

26. The communications receiver of claim 24, further comprising a slicer coupled to the adaptive equalizer, wherein the slicer produces a slicer information signal, wherein the coefficient generator updates the at least one parameter of the least-squares algorithm based on the slicer information signal.

27. The communications receiver of claim 26, further comprising a forward error correction (FEC) decoder coupled to the slicer, wherein the FEC decoder produces a decoder information signal.

28. The communications receiver of claim 27, wherein the coefficient generator updates the at least one parameter of the least-squares algorithm based on at least one of the slicer information signal and the decoder information signal.

29. The communications receiver of claim 24, further comprising:

a buffer coupled to the adaptive equalizer configured to store a communication signal from the communication channel, wherein the buffer includes the one or more time-varying noise and/or interference conditions.