METHOD FOR DECODING AN ECC BLOCK AND RELATED APPARATUS

• US 20070150798A1
• Filed: 12/12/2005
• Published: 06/28/2007
• Est. Priority Date: 12/12/2005
• Status: Abandoned Application

• Current Assignee: MediaTek, Inc.
• Original Assignee: MediaTek, Inc.
• Inventors: Liu, Pi-Hai, Shieh, Jia-Horng
• Application Number:
  US11/164,959
• Publication Number:
  US 20070150798A1
• Time in Patent Office: Days
• US Class Current: 714/785
• CPC Class Codes: G11B 20/1833 by adding special lists or symbols to the coded information G11B20/1806, G11B20/1866 take precedence
• CPC Class Codes: H03M 13/15 Cyclic codes, i.e. cyclic shifts of codewords produce other codewords, e.g. codes defined by a generator polynomial, Bose-Chaudhuri-Hocquenghem [BCH] codes H03M13/17 takes precedence
• CPC Class Codes: H03M 13/1515 Reed-Solomon codes
• CPC Class Codes: H03M 13/29 combining two or more codes or code structures, e.g. product codes, generalised product codes, concatenated codes, inner and outer codes
• CPC Class Codes: H03M 13/2909 Product codes
• CPC Class Codes: H03M 13/2927 Decoding strategies
• CPC Class Codes: H03M 13/6502 Reduction of hardware complexity or efficient processing

Abstract

A method for decoding an error correction code (ECC) block includes: providing a plurality of flags, wherein each flag is utilized to label at least one codeword of the ECC block as an error-free codeword; and detecting whether a flag corresponding to a specific codeword is asserted, and skipping calculating a syndrome of the specific codeword if the flag is asserted.

Claims

1. A method for decoding an error correction code (ECC) block comprising:

providing a plurality of flags, wherein each flag is utilized to label at least one data line of the ECC block as an error-free data line; and

detecting whether a flag corresponding to a specific data line is asserted, and skipping calculating a syndrome of the specific data line if the flag is asserted.

2. The method of claim 1, wherein each data line corresponds to a codeword.

3. The method of claim 1, wherein the step of detecting whether the flag is asserted further comprises:

if the flag is not asserted, calculating the syndrome of the specific data line, correcting data of at least one position of the specific data line if the syndrome of the specific data line is not equal to a predetermined value, and asserting the flag if the calculated syndrome is equal to the predetermined value or the data line is decodable.

4. The method of claim 3, wherein the step of correcting data of at least one position of the specific data line further comprises:

deasserting a flag of a second data line corresponding to the position.

5. The method of claim 4, wherein the specific data line is a PI codeword, and the second data line is a PO codeword corresponding to the position.

6. The method of claim 4, wherein the specific data line is a PO codeword, and the second data line is a PI codeword corresponding to the position.

7. The method of claim 1, wherein each flag is utilized to label a data line set having a plurality of data lines of the ECC block as an error-free data line set, and the step of detecting whether the flag is asserted further comprises:

if the flag is not asserted, calculating the syndrome of the specific data line in a specific data line set, correcting data of at least one position of the specific data line if the syndrome of the specific data line is not equal to a predetermined value, and asserting the flag if syndromes of the specific data line set are all equal to the predetermined value or if all the data lines of the specific data line are decodable.

8. The method of claim 7, wherein the step of correcting data of at least one position of the specific data line further comprises:

deasserting a flag of a second data line corresponding to the position.

9. The method of claim 8, wherein the specific data line is a PI codeword, and the second data line is a PO codeword corresponding to the position.

10. The method of claim 8, wherein the specific data line is a PO codeword, and the corresponding data line is a PI codeword corresponding to the position.

11. The method of claim 1, wherein the error correction code (ECC) block is used for optical storage system.

18. The decoding device of claim 10 further comprising:

an error corrector; and

a syndrome-flag circuit;

wherein each flag is utilized to label a data line set having a plurality of data lines of the ECC block as an error-free data line set, and the controller further controls the syndrome calculator to calculate the syndrome of the specific data line in a specific data line set if the flag is not asserted, controls the error corrector to correct data of at least one position of the specific data line if the syndrome of the specific data line is not equal to a predetermined value, and controls the syndrome-flag circuit to assert the flag if syndromes of the specific data line set are all equal to the predetermined value or if all data lines of the specific data line set are all decodable.

19. The decoding device of claim 18, wherein the controller further controls the syndrome-flag circuit to deassert a flag of a second data line corresponding to the position.

20. The decoding device of claim 19, wherein the specific data line is a PO codeword, and the second data line is a PI codeword corresponding to the position.

21. The decoding device of claim 19, wherein the specific data line is a PI codeword, and the second data line is a PO codeword corresponding to the position.

12. A decoding device for decoding an ECC block, the decoding device comprising:

a storage device for storing the ECC block and a plurality of flags, wherein each flag is utilized to label at least one data line of the ECC block as an error-free codeword;

a syndrome calculator; and

a controller for detecting whether a flag corresponding to a data line is asserted, and controlling the syndrome calculator to skip calculating a syndrome of the specific data line if the flag is asserted.

13. The decoding device of claim 12, wherein each data line corresponds to a codeword.

14. The decoding device of claim 12, further comprising:

an error corrector; and

a syndrome-flag circuit;

wherein the controller further controls the syndrome calculator to calculate the syndrome of the specific data line if the flag is not asserted, controls the error corrector to correct data of at least one position of the specific data line if the syndrome of the specific data line is not equal to a predetermined value, and controls the syndrome-flag circuit to assert the flag if the calculated syndrome is equal to the predetermined value or if the data line is decodable.

15. The decoding device of claim 14, wherein the controller further controls the syndrome-flag circuit to deassert a flag of a second data line corresponding to the position.

16. The decoding device of claim 15, wherein the specific data line is a PI codeword, and the second data line is a PO codeword corresponding to the position.

17. The decoding device of claim 15, wherein the specific data line is a PO codeword, and the second data line is a PI codeword corresponding to the position.

22. The decoding device of claim 12, wherein the error correction code (ECC) block is used for optical storage system.