Block linear equalization in a multicarrier communication system

• US 7,953,163 B2
• Filed: 05/16/2005
• Issued: 05/31/2011
• 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
• Primary Examiner(s): Payne; David C.
• Assistant Examiner(s): Guarino; Rahel
• Application Number:
  US11/131,392
• Publication Number:
  US 20060126747A1
• Time in Patent Office: 2,206 Days
• Field of Search: 375/260, 375/229, 375/222, 370/430, 708/323, 455/61
• 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, a second symbol, and a third symbol, each of the first, the second, and the third symbols being modulated onto a plurality of sub-carriers; and

reducing an error on at least one first sub-carrier from among the plurality of sub-carriers by adding at least one first weighted multiple of at least one second sub-carrier from among the plurality of sub-carriers and at least one second weighted multiple of at least one third sub-carrier from among the plurality of sub-carriers to the at least one first sub-carrier, the at least one second sub-carrier corresponding to at least one subcarrier of the second symbol and the at least one third sub-carrier corresponding to at least one subcarrier of the third symbol.

2. The method of claim 1, wherein the first symbol is a current symbol in time, the second symbol is a previous symbol in time, and the third symbol is a next symbol in time.

3. A multi-tone receiver for detecting data in a multi-tone signal, comprising:

a discrete Fourier transform module;

a block linear equalizer, coupled to the discrete Fourier transform module, configured to reduce an error on at least one sub-carrier of a first plurality of sub-carriers of a first symbol in a frequency domain by adding at least one weighted multiple of at least one other sub-carrier from among the first plurality of sub-carriers to the at least one sub-carrier and at least one weighted multiple of a second plurality of sub-carriers of a second symbol, wherein the first symbol and the second symbol are from different times; and

a frequency-domain equalization module, wherein the block linear equalizer is coupled to the discrete Fourier transform module through the frequency-domain equalization module.

4. The multi-tone receiver of claim 3, wherein the multi-tone receiver is implemented as part of a digital subscriber line modem.

5. The multi-tone receiver of claim 3, wherein the multi-tone receiver is implemented as part of a set top box.

6. The multi-tone receiver of claim 3, wherein the multi-tone receiver is coupled to a transmitter.

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

receiving, by a multi-carrier receiver implemented as part of the multi-carrier communication system, a first symbol having a first plurality of sub-carriers;

reducing, by the multi-carrier receiver, an error on at least one sub-carrier from among the first plurality of sub-carriers by adding at least one weighted multiple of at least one other sub-carrier from among the first plurality of sub-carriers to the at least one sub-carrier;

receiving, by the multi-carrier receiver, a second symbol having a second plurality of sub-carriers; and

reducing, by the multi-carrier receiver, the error on the at least one sub-carrier by adding at least one weighted multiple of the second plurality of sub-carriers.

8. The method of claim 7, further comprising:

forcing at least one of the at least one weighted multiple of the at least one other sub-carrier to zero.

9. The method of claim 8, further comprising:

allowing twenty of the at least one weighted multiples of the at least one other sub-carrier corresponding to lowest tones to be non-zero.

10. The method of claim 8, further comprising:

allowing ten to twenty of the at least one weighted multiples of the at least one other sub-carrier to be non-zero and others of the at least one weighted multiples of the at least one other sub-carrier to be substantially zero.

11. The method of claim 7, further comprising:

training the at least one weighted multiple of the at least one other sub-carrier.

12. The method of claim 11, further comprising:

training the at least one weighted multiple of the at least one other sub-carrier using a least-mean squares algorithm.

13. The method of claim 7, wherein the at least one sub-carrier comprises a lowest used sub-carrier.

14. The method of claim 7, wherein the multi-carrier communication system is a digital subscriber line system.

15. The method of claim 7, wherein the first symbol is a current symbol in time and the second symbol is a previous symbol in time.

16. The method of claim 7, wherein the first symbol is a current symbol in time and the second symbol is a next symbol in time.

17. The method of claim 7, further comprising:

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

reducing the error on the at least one sub-carrier by adding at least one weighted multiple of the third plurality of sub-carriers.

18. The method of claim 17, wherein the first symbol is a current symbol in time, the second symbol is a previous symbol in time, and the third symbol is a next symbol in time.

19. The method of claim 7, wherein the at least one weighted multiple of the at least one other sub-carrier is represented by a first matrix having non-zero diagonal values.

20. The method of claim 19, wherein the at least one weighted multiple of the second plurality of sub-carriers is represented by a second matrix having at least one non-diagonal element being zero.

21. The method of claim 20, wherein the second matrix is restricted to having approximately 15×

15 non-zero elements.

22. The method of claim 7, further comprising:

generating the first and the second plurality of sub-carriers using a discrete Fourier transform on a multi-tone signal of the communication system to convert data samples of the multi-tone signal from a time domain to a frequency domain.