ECC ADJUSTMENT BASED ON DYNAMIC ERROR INFORMATION

• US 20180159559A1
• Filed: 01/18/2017
• Published: 06/07/2018
• Est. Priority Date: 12/06/2016
• Status: Active Grant

• Current Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: BAZARSKY, ALEXANDER, SHARON, ERAN, NAVON, ARIEL
• Granted Patent: US 10,284,233 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 11/1012 using codes or arrangements adapted for a specific type of error G06F11/1048 takes precedence
• CPC Class Codes: G06F 11/1068 in sector programmable memories, e.g. flash disk G06F11/1072 takes precedence
• CPC Class Codes: G11C 2029/0411 Online error correction
• CPC Class Codes: G11C 29/028 with adaption or trimming of parameters
• CPC Class Codes: G11C 29/42 using error correcting codes [ECC] or parity check
• CPC Class Codes: G11C 29/52 Protection of memory contents; Detection of errors in memory contents
• 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 13/1154 Low-density parity-check convolutional codes [LDPC-CC]
• CPC Class Codes: H03M 13/2927 Decoding strategies
• CPC Class Codes: H03M 13/353 Adaptation to the channel
• CPC Class Codes: H03M 13/3715 Adaptation to the number of estimated errors or to the channel state

Abstract

A device includes a memory, an error correction code (ECC) decoder, and an ECC input adjuster. The ECC decoder is configured to perform a first decode operation to decode a first portion of a representation of data read from the memory based on one or more decode parameters and to perform a second decode operation to decode a second portion of the representation of data based on one or more adjusted decode parameters. The ECC input adjuster is configured to adjust one or more decode parameters to set the one or more adjusted decode parameters based on a count of bits of the first portion that are erroneous.

Claims

1. A device comprising:

a memory;

an error correction code (ECC) decoder configured to perform a first decode operation to decode a first portion of a representation of data read from the memory based on one or more decode parameters and to perform a second decode operation to decode a second portion of the representation of data based on one or more adjusted decode parameters; and

an ECC input adjuster configured to adjust the one or more decode parameters to set the one or more adjusted decode parameters based on a count of bits of the first portion that are erroneous.

2. The device of claim 1, wherein the one or more decode parameters comprises one or more log likelihood ratio (LLR) values.

3. The device of claim 1, wherein the count of bits includes at least one of a first count of bits that are erroneous and a second count of bits that are erroneous and that are indicated as reliable.

4. The device of claim 3, wherein the one or more decode parameters are adjusted further based on a third count of bits that are correct and that are indicated as unreliable.

5. The device of claim 1, wherein the ECC decoder is further configured to determine the count of bits.

6. The device of claim 5, wherein the ECC decoder is further configured to determine a second count of bits, the second count of bits representing at least bits of the second portion that are erroneous.

7. The device of claim 6, wherein the ECC input adjuster is further configured to further adjust the one or more adjusted decode parameters based on the second count of bits, and wherein the ECC decoder is further configured to decode a third portion of the representation of data based on the one or more adjusted decode parameters.

8. A method performed by a controller of a data storage device, the method comprising:

reading a representation of data from a memory;

decoding a first portion of the representation of data;

determining a first error count of bits of the first portion that are erroneous and a first bit count of bits of the first portion that are correct and indicated as unreliable;

adjusting one or more decode parameters based on the first error count and the first bit count to set one or more adjusted decode parameters; and

decoding a second portion of the representation of data based on the one or more adjusted decode parameters.

9. The method of claim 8, further comprising:

performing a second adjustment on the one or more adjusted decode parameters based on a second error count of bits of the second portion that are erroneous and a second bit count of bits of the second portion that are correct and indicated as unreliable; and

decoding a third portion of the representation of data based on the adjusted one or more decode parameters.

10. The method of claim 9, further comprising:

after decoding the third portion of the representation of data, reading a representation of second data from the memory responsive to receiving a second request for the second data; and

decoding a fourth portion of the representation of second data based on the adjusted one or more decode parameters.

11. The method of claim 10, wherein the data and the second data are stored in the same block of the memory.

12. The method of claim 8, further comprising:

performing a second adjustment on the one or more adjusted decode parameters based on a first value and a second value, the first value representing an average of the first error count and a second error count of bits of the second portion that are erroneous, the second value representing an average of the first bit count and a second bit count of bits of the second portion that are correct and indicated as unreliable; and

decoding a third portion of the representation of data based on the adjusted one or more decode parameters.

13. The method of claim 8, wherein the one or more decode parameters includes an expected decoding time to decode the representation of data.

14. The method of claim 8, wherein the one or more decode parameters comprises one or more log likelihood ratio (LLR) values.

15. The method of claim 8, wherein the representation of data includes a low-density parity check (LDPC) codeword that includes multiple sub-codes, and wherein the multiple sub-codes are independently decodable.

16. The method of claim 8, wherein the representation of data includes a convolutional low-density parity check (CLDPC) codeword, wherein the first portion corresponds to a first window associated with the CLDPC codeword, and wherein the second portion corresponds to a second window associated with the CLDPC codeword.

17. A data storage device comprising:

means for storing data;

means for reading a representation of data from the means for storing;

means for adjusting first log likelihood ratio (LLR) values based on at least a count of bits of a first portion of the representation of data that are erroneous to set second LLR values; and

means for decoding the first portion based on the first LLR values and for decoding a second portion of the representation of data based on the second LLR values.

18. The data storage device of claim 17, wherein the means for adjusting is configured to adjust the first LLR values based on a first count of bits of the first portion that are erroneous, a second count of bits of the first portion that are erroneous and are indicated as reliable, and a third count of bits of the first portion that are correct and that are indicated as unreliable.

19. The data storage device of claim 17, further comprising means for receiving a request for the data from an access device, the representation of data read from the means for storing responsive to the request.

20. The data storage device of claim 17, wherein the second LLR values are set based on stored LLR values that correspond to the count of bits.