Systems and Methods for Using Intrinsic Data for Regenerating Data from a Defective Medium

• US 20090235146A1
• Filed: 04/29/2008
• Published: 09/17/2009
• Est. Priority Date: 03/17/2008
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Inventors: Yang, Shaohua, Lee, Yuan Xing, Mathew, George, Zhong, Hao, Fitzpatrick, Kelly, Tan, Weijun
• Granted Patent: US 8,161,357 B2
• Time in Patent Office: Days
• US Class Current: 714/780
• CPC Class Codes: H03M 13/1102 Codes on graphs and decoding on graphs, e.g. low-density parity check [LDPC] codes
• CPC Class Codes: H03M 13/2957 Turbo codes and decoding
• CPC Class Codes: H03M 13/6331 Error control coding in combination with equalisation

Abstract

Various embodiments of the present invention provide systems and methods for data regeneration. For example, a system for data regeneration is disclosed that includes a data input derived from the medium. A data detector and a data recovery system receive the data input. The data detector provides a first soft output, and the data recovery system provides a second soft output. The first soft output and the second soft output are provided to a multiplexer. A media defect detector performs a media defect detection process, and provides a defect flag that indicates whether the data input is derived form a defective portion of the medium. The defect flag is provided to the multiplexer where it is used to select whether the first soft output or the second soft output is provides as an extrinsic output.

Claims

1. A method for regenerating data derived from a defective portion of a medium, the method comprising:

receiving a data input derived from a medium;

performing a data detection based at least in part on the data input, wherein a first soft output is generated;

determining a defect status of the medium;

based at least in part on the defect status;

decoding a regenerated signal in place of the first soft output, and wherein the decoding process produces a second soft output; and

producing the regenerated data signal, wherein the regenerated data signal includes the second soft output multiplied by a scalar.

2. The method of claim 1, wherein decoding the regenerated signal includes interleaving the regenerated signal to produce an interleaved first soft output, decoding the interleaved first soft output to created a decoded output, and de-interleaving the decoded output to produce the second soft output.

3. The method of claim 1, wherein determining the defect status includes providing a defect output, and wherein decoding the regenerated signal in place of the first soft output includes applying the defect output to an input control of a multiplexer.

4. The method of claim 1, wherein determining the defect status includes providing a defect output, wherein performing the data detection is done using a branch metric modified data detector;

wherein the branch metric modified data detector receives the data input and the defect output;

wherein the branch metric modified data detector utilizes a first branch metric whenever the defect output is indicates a non-defective portion of the medium associated with the data input; and

wherein the branch metric modified data detector utilizes a second branch metric whenever the defect output is indicates a non-defective portion of the medium associated with the data input.

5. The method of claim 4, wherein the second branch metric corresponds to the regenerated data signal.

6. The method of claim 5, wherein the second branch metric is mathematically (1+the scalar)*(the second soft output).

7. The method of claim 1, wherein the data input is a pre-coded data input.

8. The method of claim 7, wherein decoding the regenerated signal includes performing a two-state MAP depredecoding, and wherein the two-state MAP deprecoding utilizes the second soft output.

9. The method of claim 1, wherein the medium is selected from a group consisting of:

a magnetic storage medium, a wireless communication channel, and a wired communication channel.

10. A system for regenerating data derived from a defective portion of a medium, the system comprising:

a data input, wherein the data input is derived from a medium;

a data detector, wherein the data detector receives the data input and provides a first soft output;

a decoder, wherein the decoder decodes a second soft output and generates a third soft output;

a data regeneration system, wherein the data regeneration system multiplies the third soft output by a scalar to create a fourth soft output;

a media defect detector, wherein the media defect detector receives the data input and provides a defect flag indicative of a defect status of the medium; and

an input selector, wherein the input selector provides either the first soft output or the fourth soft output as the second soft output based at least in part on the defect flag.

11. The system of claim 10, wherein the decoder includes an interleaver that interleaves the second soft output to produce an interleaved second soft output;

a decoding circuit that receives the interleaved second soft output and creates a decoded output; and

a de-interleaver that de-interleaves the decoded output and provides the third soft output.

12. The system of claim 10, wherein the input selector is a multiplexer, and wherein the select control of the multiplexer is driven by the defect flag.

13. The system of claim 10, wherein the data detector, the data regeneration system and the input selector are implemented together as a branch metric modified data detector, wherein the branch metric modified data detector receives the data input and the defect flag;

and wherein the branch metric modified data detector utilizes the fourth soft output as a branch metric whenever the defect flag indicates a defective portion of the medium associated with the data input.

14. The system of claim 13, wherein the branch metric is mathematically (1+the scalar)*(the third soft output).

15. The system of claim 14, wherein the branch metric modified data detector utilizes the first soft output in place of the branch metric whenever the defect flag indicates a non-defective portion of the medium associated with the data input.

16. The system of claim 10, wherein the system further includes a precoder, and wherein the data input is precoded by the precoder.

17. The system of claim 16, wherein the system further includes a deprecoder, and wherein the deprecoder is operable to augment the fourth soft output.

18. The system of claim 17, wherein the deprecoder is a two state MAP deprecoder.

19. The system of claim 10, wherein the medium is selected from a group consisting of:

a magnetic storage medium, a wireless communication channel, and a wired communication channel.

20. A circuit for regenerating data derived from a defective portion of a medium, the system comprising:

a decoder circuit, wherein the decoder circuit decodes an intrinsic input and generates an extrinsic output;

a data input, wherein the data input is derived from a medium;

a data detector circuit operable to receive the data input and to generate a first soft output based at least in part on the data input;

a data recovery circuit operable to receive the data input and the intrinsic input;

wherein the data recovery circuit includes an equalizer circuit, a soft estimator circuit, and intrinsic scaling circuit;

wherein the equalizer circuit provides an equalized output indicating a polarity of the data input;

wherein the soft estimator circuit receives the equalized output and provides a second soft based at least in part on the equalized output; and

wherein the intrinsic scaling circuit includes a multiplier that multiplies the intrinsic input with a scalar value to create an output scalar, and an adder that sums the second soft output with the output scalar to generate a third soft output; and

a multiplexer, wherein the multiplexer provides either the first soft output or the third soft output as the extrinsic output based at least in part on an indication of a defect in the medium.