# US 8,786,968 B2 · Data storage device including a recording channel, a detector, and a noise prediction circuit, and method of processing a signal in a data storage device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,968 B2 - Document ID: US8786968B2 - Status: Granted - Kind: B2 - Application number: 13/684,104 - Filed: 2012-11-21 - Published: 2013-05-23 - Granted: 2014-07-22 - Earliest claimed: 2011-11-21 - Assignees: Agency for Science, Technology and Research - Applicants: Agency for Science, Technology and Research - Inventors: Zhi Liang Qin; Moulay Rachid Elidrissi; Kheong Sann Chan - Web page: https://patentgrep.com/patent/US8786968B2 ## CPC - G11B 5/59688: {Servo signal format patterns or signal processing thereof, e.g. dual, tri, quad, burst signal patterns} - G11B 20/10009: {Improvement or modification of read or write signals} - G11B 20/10268: {bit detection or demodulation methods} - G11B 20/1217: {on discs} - G11B 27/36: Monitoring, i.e. supervising the progress of recording or reproducing {(for digital recording G11B20/00 and s.gr.; for monitoring, testing or measuring of TV recorders of the type covered by H04N5/76 and subgroups, see H04N17/06)} - H03M 13/1111: {Soft-decision decoding, e.g. by means of message passing or belief propagation algorithms} - H03M 13/6331: {Error control coding in combination with equalisation} - H03M 13/6343: {Error control coding in combination with techniques for partial response channels, e.g. recording} - G11B 20/1037: {based on hard decisions, e.g. by evaluating bit error rates before or after ECC decoding} - G11B 2020/185: {using an low density parity check [LDPC] code} - G11B 2220/2516: Hard disks - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) - 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) ## Abstract According to embodiments of the present invention, a data storage device is provided. The data storage device includes a recording channel configured to carry a signal; a detector configured to detect the signal from the recording channel; and a noise prediction circuit configured to predict noise affecting the recording channel and the detected signal based on a noisy channel model. According to further embodiments of the present invention, a method of processing a signal in a data storage device is also provided. ## Claims ### Claim 1 A data storage device comprising: a recording channel configured to carry a signal; a detector configured to detect the signal from the recording channel; a noise prediction circuit configured to predict noise affecting the recording channel and the detected signal based on a noisy channel model; and a decoder configured to decode the detected signal based on the predicted noise; wherein the detector and the decoder form a joint detector/decoder circuit; and wherein the noisy channel model comprises at least one of: a single channel graph model, wherein the joint detector/decoder circuit has a layered structure comprising check nodes of low-density parity-check codes, low-density parity-check bit nodes, and channel check nodes; or a concatenated channel graph model, wherein the joint detector/decoder circuit has a layered structure comprising a serial concatenation of a rowwise binary channel graph, a columnwise non-binary channel graph, and a low-density parity-check code graph. ### Claim 2 (depends on 1) The data storage device of claim 1, wherein the joint detector/decoder circuit is a low density parity check joint detector/decoder circuit. ### Claim 3 (depends on 1) The data storage device of claim 1, wherein the noise prediction circuit comprises a data dependent noise prediction circuit. ### Claim 4 (depends on 1) The data storage device of claim 1, wherein the noisy channel model comprises an equalized channel model. ### Claim 5 (depends on 1) The data storage device of claim 1, further comprising a quantizer arranged to quantize the signal from the recording channel. ### Claim 6 (depends on 1) The data storage device of claim 1, further comprising an encoder arranged to encode user data for storing in the recording medium. ### Claim 7 A method of processing a signal in a data storage device, the method comprising: providing a recording channel; detecting a signal from the recording channel; predicting noise affecting the recording channel and the detected signal based on a noisy channel model; and decoding the detected signal based on the predicted noise; wherein detecting a signal from the recording channel and decoding the detected signal comprise jointly detecting and decoding the signal; wherein detecting and decoding the signal is based on at least one of: a message-passing algorithm operating on a layered structure comprising low-density parity-check check nodes, low-density parity-check bit nodes, and channel check nodes; or a message-passing algorithm operating on a layered structure comprising a serial concatenation of a rowwise binary channel graph, a columnwise non-binary channel graph, and a low-density parity-check code graph. ### Claim 8 (depends on 7) The method of claim 7, wherein predicting noise comprises predicting data dependent noise. ### Claim 9 (depends on 7) The method of claim 7, further comprising quantizing the signal from the recording channel. ### Claim 10 (depends on 7) The method of claim 7, further comprising encoding user data for storing in the recording medium.