Universal modulation coding for a data channel

• US 8,976,474 B1
• Filed: 10/03/2013
• Issued: 03/10/2015
• Est. Priority Date: 10/03/2013
• Status: Active Grant

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Patapoutian, Ara, Wang, Zheng, Venkataramani, Raman C., Shamir, Gil I.
• Primary Examiner(s): HOLDER, REGINA NEAL
• Application Number:
  US14/045,584
• Time in Patent Office: 523 Days
• Field of Search: None
• US Class Current: 360/40
• CPC Class Codes: G11B 20/1403 characterised by the use of two levels
• CPC Class Codes: G11B 20/1426 conversion to or from block codes or representations thereof

Abstract

Technologies are described herein for implementing a universal modulation coding mechanism for a data channel. A user data sequence comprising a first number of bits is received. The user data sequence is encoded into a codeword sequence comprising a second number of bits utilizing a modulation encoder. The modulation encoder may encode the user data sequence based on a set of Markov state transition probabilities. The modulation encoder may implement a data de-compressor algorithm from a lossless data compression scheme. The codeword sequence is output to the data channel. The codeword sequence is subsequently received from the data channel, and the user data sequence is decoded from the codeword sequence utilizing a modulation decoder. The modulation decoder may decode the user data sequence based on the same set of Markov states transition probabilities. The modulation de-coder may implement the data compressor algorithm from the lossless data compression scheme.

Claims

1. An apparatus for implementing a universal modulation coding mechanism, the apparatus comprising:

a storage area containing a set of state transition probabilities;

a modulation encoder configured to perform the steps of

receiving a data sequence comprising a first number of bits,

encoding the data sequence into a codeword sequence comprising a second number of bits based on the set of state transition probabilities, the second number of bits is greater than the first number of bits, and

providing the codeword sequence to a recording channel of a storage device; and

a modulation decoder configured to perform the steps of

receiving the codeword sequence from the recording channel, and

decoding the data sequence from the codeword sequence based on the set of state transition probabilities.

2. The apparatus of claim 1, wherein the modulation encoder comprises a data de-compressor based on a lossless data compression scheme, and wherein the modulation decoder comprises a data compressor based on the lossless data compression scheme.

3. The apparatus of claim 1, wherein the modulation encoder comprises an arithmetic decoder based on the set of state transition probabilities, and wherein the modulation decoder comprises an arithmetic encoder based on the set of state transition probabilities.

4. The apparatus of claim 1, wherein the set of state transition probabilities comprise Markov state transition probabilities and the set is programmable.

5. The apparatus of claim 1, wherein the set of state transition probabilities is configured based on channel characteristics of the recording channel of the storage device.

6. The apparatus of claim 1, wherein the set of state transition probabilities are configured such that the codeword sequence satisfies both a deterministic constraint and a probabilistic constraint.

7. The apparatus of claim 1, wherein the set of state transition probabilities are configured such that the codeword sequence satisfies one or more of a maximum transition run (“

MTR”

) constraint, a running digital sum (“

RDS”

) constraint, a K-constraint, and a Nyquist constraint.

8. A method comprising steps of:

receiving a user data sequence comprising a first number of bits at a controller,

encoding the user data sequence by the controller into a codeword sequence comprising a second number of bits utilizing a data de-compressor based on a lossless data compression scheme;

outputting the codeword sequence to a data channel;

receiving the codeword sequence from the data channel; and

decoding the user data sequence by the controller from the codeword sequence utilizing a data compressor based on the lossless data compression scheme.

9. The method of claim 8, wherein the first number of bits is less than the second number of bits.

10. The method of claim 8, wherein the data de-compressor and the data compressor implement an entropy coding scheme associated with predetermined Markov state transition probabilities.

11. The method of claim 10, wherein the entropy coding scheme comprises an arithmetic coding scheme.

12. The method of claim 10, wherein the predetermined Markov state transition probabilities are configured such that the codeword sequence satisfies both a deterministic constraint and a probabilistic constraint.

13. The method of claim 10, wherein the predetermined Markov state transition probabilities are configured such that the codeword sequence satisfies one or more of a maximum transition run (“

MTR”

) constraint, a running digital sum (“

RDS”

) constraint, a K-constraint, and a Nyquist constraint.

14. The method of claim 8, further comprising steps of:

determining by the controller whether the codeword sequence may be decoded by the data compressor;

upon determining that the coded sequence may not be decoded by the data compressor, mapping the user data sequence by the controller to a new data sequence; and

encoding the new data sequence by the controller into a new codeword sequence utilizing the data de-compressor.

15. The method of claim 8, wherein encoding the user data sequence into the codeword sequence comprises:

mapping the user data sequence to a plurality of new, distinct data sequences;

encoding each of the new, distinct data sequences by the controller into codeword sequences in parallel data de-compressors based on the lossless data compression scheme;

determining one or more of the parallel data de-compressors by the controller wherein the encoding was successful; and

selecting the codeword sequence by the controller from one of the one or more parallel data de-compressors.

16. The method of claim 15, further comprising steps of:

upon determining that the encoding was not successful in at least one of the parallel data de-compressors, encoding the user data sequence by the controller into a new codeword sequence utilizing a conventional modulation encoder.

17. A system comprising:

a hard disk drive comprising a magnetic recording channel; and

a universal modulation encoder/decoder comprising a storage area containing a set of Markov state transition probabilities, the universal modulation encoder/decoder configured to

receive a user data sequence,

encode the user data sequence into a codeword sequence utilizing an arithmetic decoder based on the set of Markov state transition probabilities,

provide the codeword sequence to the magnetic recording channel,

receive the codeword sequence from the magnetic recording channel, and

decode a recovered user data sequence from the codeword sequence utilizing an arithmetic encoder based on the set of Markov state transition probabilities.

18. The system of claim 17, wherein the set of Markov state transition probabilities is configured based on channel characteristics of the magnetic recording channel of the hard disk drive.

19. The system of claim 17, wherein the set of Markov state transition probabilities are configured such that the codeword sequence satisfies both a deterministic constraint and a probabilistic constraint.

20. The system of claim 17, wherein the set of Markov state transition probabilities are configured such that the codeword sequence satisfies one or more of a maximum transition run (“

MTR”

) constraint, a running digital sum (“

RDS”

) constraint, a K-constraint, and a Nyquist constraint.