# US 2022/0286147 A1 · One-shot state transition probability encoder and decoder

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- Number: US 2022/0286147 A1
- Document ID: US20220286147A1
- Status: Published application
- Kind: A1
- Application number: 17/825,905
- Filed: 2022-05-26
- Published: 2022-09-08
- Earliest claimed: 2020-08-21
- Assignees: Seagate Technology LLC
- Applicants: Seagate Technology LLC
- Inventors: Zheng Wang; Marcus Marrow; Jason Bellorado
- Web page: https://patentgrep.com/patent/US20220286147A1

## CPC

- G06F 3/0656: {Data buffering arrangements}
- H03M 5/145: {Conversion to or from block codes or representations thereof}
- H04L 1/0041: {Arrangements at the transmitter end}
- H04L 1/0045: {Arrangements at the receiver end}
- G06F 3/0604: {Improving or facilitating administration, e.g. storage management}
- G06F 3/0673: {Single storage device}
- G06F 18/295: {Markov models or related models, e.g. semi-Markov models; Markov random fields; Networks embedding Markov models}
- H03M 13/3961: {Arrangements of methods for branch or transition metric calculation}
- H03M 13/45: Soft decoding, i.e. using symbol reliability information (H03M13/41 takes precedence)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- H03M: CODING; DECODING; CODE CONVERSION IN GENERAL (using fluidic means F15C4/00; optical analogue/digital converters G02F7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G06T, G09G, G10L, G11B, G11C, H04B, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A one-shot state transition decoder receives a codeword having N-bits. The decoder reads a first D-bits of the codeword to determine a stitching location d within the codeword. The stitching location identifies a start bit of unencoded data in the codeword. The codeword is decoded into an output buffer for user data of L bits, where N>L. Parameters of the decoder are set before the decoding, including setting a length of the codeword to N−L+d and a number of expected decoded bits to d. The decoding including decoding the d bits based on a set of state transition probabilities and copying decoded bits into the output buffer, the unencoded data being copied to the end of the output buffer.

## Claims

### Claim 1

A method, comprising:
receiving an N-bit codeword at a modulation decoder;
reading a first D-bits of the codeword to determine a stitching location d within the codeword, the stitching location identifying a start bit of unencoded data in the codeword;
performing a decoding of the codeword into an output buffer for user data comprising L bits, L<N, wherein parameters of the modulation decoder are set before the decoding, the setting of the parameters including setting a number of expected decoded bits to d and a length of the codeword to N−L+d, the decoding including decoding the d bits based on a set of state transition probabilities and copying decoded bits into the output buffer;
copying the unencoded data to an end of the output buffer; and
sending the output buffer as recovered user data to a host.

### Claim 2 (depends on 1)

The method of claim 1, wherein based on the first D-bits being a predetermined pattern, there are no unencoded bits in the codeword and the decoding comprises decoding all N−D bits of the codeword excluding the first D-bits.

### Claim 3 (depends on 2)

The method of claim 2, wherein the predetermined pattern is all ones.

### Claim 4 (depends on 1)

The method of claim 1, wherein the set of state transition probabilities comprise a set of Markov state transition probabilities used in an encoding of the codeword.

### Claim 5 (depends on 4)

The method of claim 4, wherein the encoding implements probabilistic constraints that minimize certain patterns in generated codeword sequences without eliminating the certain patterns.

### Claim 6 (depends on 4)

The method of claim 4, wherein the encoding implements deterministic constraints that eliminate certain patterns in generated codeword sequences.

### Claim 7 (depends on 1)

The method of claim 1, wherein the codeword is received from a low-density parity check (LDPC) decoder.

### Claim 8 (depends on 1)

The method of claim 1, further comprising:
finding a first unencoded bit of the unencoded data; and
if the first unencoded bit is equal to a first value, perform a final bit carry operation when decoding the codeword, otherwise do not perform the final bit carry operation if the first unencoded bit is not equal to the first value.

### Claim 9

An apparatus, comprising a processing circuit, the processing circuit comprising:
an error correction decoder that decodes an N-bit codeword based on data read from a storage media; and
a modulation decoder operable to:
receive the codeword;
read a first D-bits of the codeword to determine a stitching location d within the codeword, the stitching location identifying a start bit of unencoded data in the codeword;
perform a decoding of the codeword into an output buffer for user data comprising L bits, L<N wherein parameters of the modulation decoder are set before the decoding, the setting of the parameters including setting a number of expected decoded bits to d and a length of the codeword to N−L+d, the decoding including decoding the d bits based on a set of state transition probabilities and copying decoded bits into the output buffer;
copy the unencoded data to an end of the output buffer; and
sending the output buffer as recovered user data to a host.

### Claim 10 (depends on 9)

The apparatus of claim 9, wherein based on the first D-bits being a predetermined pattern, there are no unencoded bits in the codeword and the decoding comprises decoding all N−D bits of the codeword excluding the first D-bits.

### Claim 11 (depends on 9)

The apparatus of claim 9, wherein the set of state transition probabilities comprise a set of Markov state transition probabilities used in an encoding of the codeword.

### Claim 12 (depends on 11)

The apparatus of claim 11, wherein the encoding implements probabilistic constraints that minimizes certain patterns in generated codeword sequences without eliminating the certain patterns.

### Claim 13 (depends on 11)

The apparatus of claim 11, wherein the encoding implements deterministic constraints that eliminates certain patterns in generated codeword sequences.

### Claim 14 (depends on 9)

The apparatus of claim 9, wherein the error correction decoder comprises a low-density parity check (LDPC) decoder.

### Claim 15

A method, comprising:
encoding user data into a codeword at a modulation encoder, the codeword having a length N ∈[Nmin, Nmax],
receiving the codeword at a low-density parity check (LDPC) encoder, the LDPC encoder having an LDPC graph with a maximum of K input nodes, K≥Nmax;
determining a minimum number of parity bits P for the LDPC graph, P≥Nmax−Nmin, the LDPC encoder producing an LDPC codeword of maximum length M, M≤Nmin+P;
determining N<K and in response thereto, zero-filling a remaining K−N information bits of the input nodes with zeros;
generating an intermediate LDPC codeword with length K+P;
puncturing out the K−N zero-filled information bits and N+P−M of the parity bits from the intermediate codeword to maintain a final LDPC codeword with length of M; and
storing the final LDPC codeword to a recording media.

### Claim 16 (depends on 15)

The method of claim 15, wherein the modulation encoder encodes the codeword based on a set of Markov state transition probabilities.

### Claim 17 (depends on 16)

The method of claim 16, wherein the encoding implements probabilistic constraints that minimizes certain patterns in generated codeword sequences without eliminating the certain patterns.

### Claim 18 (depends on 16)

The method of claim 16, wherein the encoding implements deterministic constraints that eliminates certain patterns in generated codeword sequences.

### Claim 19 (depends on 16)

The method of claim 16, wherein locations of the zero-filled information bits and punctured parity bits are made available at an LDPC decoder, so that missing bits are inserted back to right locations with properly set confidence levels for subsequent decoding of the final LDPC codeword.