Block linear equalization in a multicarrier communication system

• US 20060126747A1
• Filed: 05/16/2005
• Published: 06/15/2006
• Est. Priority Date: 11/30/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Wiese, Brian
• Granted Patent: US 7,953,163 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 2025/03414 Multicarrier
• CPC Class Codes: H04L 2025/03445 Time domain
• CPC Class Codes: H04L 2025/03522 Frequency domain
• CPC Class Codes: H04L 25/03159 operating in the frequency domain H04L25/03165, H04L25/03178 take precedence
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01

Abstract

A method and apparatus for channel equalization in a multi-carrier communication system. The method may include receiving a symbol having multiple sub-carriers and reducing an error on at least one of the sub-carriers of the symbol by adding to it, one or more weighted multiples of other sub-carriers. The added weighted multiples may be from neighboring sub-carriers in the same symbol and/or from other symbols in a tone, for example, a previous or next symbol. The apparatus may include a reduced-complexity block linear equalizer.

Claims

1. A method of channel equalization in a multi-carrier communication system, comprising:

receiving a first symbol having a first plurality of sub-carriers; and

reducing an error on at least one sub-carrier of the first plurality of sub-carriers by adding one or more weighted multiples of one or more other sub-carriers to the at least one sub-carrier.

2. The method of claim 1, wherein the one or more other sub-carriers are neighboring sub-carriers of the at least one sub-carrier of the first symbol.

3. The method of claim 2, further comprising:

receiving a second symbol having a second plurality of sub-carriers; and

reducing the error on the at least one sub-carrier of the first plurality of sub-carriers by adding one or more weighted multiples of the second plurality of sub-carriers of the second symbol.

4. The method of claim 2, further comprising forcing at least one of the one or more weighted multiples to zero.

5. The method of claim 4, further comprising allowing approximately twenty of the weighted multiples corresponding to lowest tones to be non-zero.

6. The method of claim 4, further comprising allowing approximately ten to twenty of the weighted multiples to be non-zero and others of the weighted multiples being substantially zero.

7. The method of claim 2, further comprising training the one or more weighted multiples.

8. The method of claim 7, further comprising training the one or more weighted multiples using a least-mean squares algorithm.

9. The method of claim 2, wherein the at least one sub-carrier comprises a lowest used sub-carrier.

10. The method of claim 2, wherein the multi-carrier communication system is a digital subscriber line system.

11. The method of claim 1, further comprising receiving a second symbol having a second plurality of sub-carriers, and wherein the one or more other sub-carriers are from the second plurality of sub-carriers of the second symbol.

12. The method of claim 11, wherein the first symbol is a current symbol in time and the second symbol is a previous symbol in time.

13. The method of claim 11, wherein the first symbol is a current symbol in time and the second symbol is a next symbol in time.

14. The method of claim 11, further comprising:

receiving a third symbol having a third plurality of sub-carriers; and

reducing the error on the one sub-carrier of the first plurality of sub-carriers by adding one or more weighted multiples corresponding to respective one or more sub-carriers of the third plurality of sub-carriers of the third symbol.

15. The method of claim 14, wherein the first symbol is a current symbol in time, the second symbol is a previous symbol in time, and the third symbol is next symbol in time.

16. The method of claim 11, further comprising forcing at least one of the one or more weighted multiple to zero.

17. The method of claim 11, further comprising allowing approximately twenty of the one or more weighted multiples corresponding to lowest tones to be non-zero and other ones of the weighted multiples to be substantially zero.

18. The method of claim 11, further comprising allowing approximately ten to twenty of the one or more weight multiples to be non-zero.

19. The method of claim 11, wherein the at least one sub-carrier comprises a lowest used sub-carrier.

20. The method of claim 11, wherein the lowest used sub-carrier is 33.

21. The method of claim 11, wherein the multi-carrier communication system is a digital subscriber line system.

22. The method of claim 3, wherein weights of the weighted multipliers from the first plurality of sub-carriers of the first symbol are represented by a first matrix having non-zero diagonal values.

23. The method of claim 22, wherein weights of the weighted multipliers from the second plurality of sub-carriers of the second symbol are represented by a second matrix having one or more non-diagonal elements being zero.

24. The method of claim 23, wherein the second matrix is restricted to having approximately 15×

15 non-zero elements.

25. An apparatus, comprising:

a multi-tone receiver to detect data in a multi-tone signal, the receiver comprising;

a discrete Fourier transform module; and

a block linear equalizer coupled to the discrete Fourier transform module, the block linear equalizer to reduce an error on at least one sub-carrier of a first plurality of sub-carriers by adding one or more weighted multiples of one or more other sub-carriers to the at least one sub-carrier.

26. The apparatus of claim 25, further comprising a frequency-domain equalization module, wherein the block linear equalizer is coupled to the discrete Fourier transform module through the frequency-domain equalization module.

27. A set top box employing a digital subscriber line modem comprising the apparatus of claim 25.

28. A set top box employing a digital subscriber line modem comprising the apparatus of claim 26.

29. The apparatus of claim 25, further comprising a transmitter coupled to the receiver.

30. An article of manufacture, comprising:

a machine-accessible medium including data that, when accessed by a machine, cause the machine to perform operations comprising;

receiving a first symbol having a first plurality of sub-carriers; and

reducing an error on at least one sub-carrier of the first plurality of sub-carriers by adding one or more weighted multiples of one or more other sub-carriers to the at least one sub-carrier.

31. The article of manufacture of claim 30, wherein the one or more other sub-carriers are neighboring sub-carriers of the at least one sub-carrier of the first symbol.

32. The article of manufacture of claim 30, wherein the one or more other sub-carriers are from the first plurality of sub-carriers of the first symbol, and wherein the data, when accessed by the machine, cause the machine to perform operations further comprising:

receiving a second symbol having a second plurality of sub-carriers; and

reducing the error on the at least one sub-carrier of the first plurality of sub-carriers by adding one or more weighted multiples of the second plurality of sub-carriers of the second symbol.

33. The article of manufacture of claim 30, wherein the data, when accessed by the machine, cause the machine to perform operations further comprising receiving a second symbol having a second plurality of sub-carriers, and wherein the one or more other sub-carriers are from the second plurality of sub-carriers of the second symbol.