Structured LDPC Codes to Reduce Pseudo Cycles for Turbo Equalization in Perpendicular Magnetic Recording

Pornchai SUPNITHI; Watid PHAKPHISUT; Wicharn SINGHAUDOM

doi:10.1587/transfun.E94.A.1441

Structured LDPC Codes to Reduce Pseudo Cycles for Turbo Equalization in Perpendicular Magnetic Recording

Pornchai SUPNITHI, Watid PHAKPHISUT, Wicharn SINGHAUDOM

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Low-density parity-check (LDPC) codes are typically designed to avoid the length-4 cycles to ensure acceptable levels of performance. However, the turbo equalization, which relies on an interaction between an inner code such as an LDPC code and a soft-output Viterbi algorithm (SOVA) detector, exhibits a performance degradation due to the pseudo cycles. In this paper, we propose an interleaved modified array code (IMAC) that can reduce the number of pseudo cycles, hence, improving the gains from the iterative processing technique. The modification is made on the existing array-based LDPC codes named modified array codes (MAC) by introducing an additional interleaving matrix to the parity-check matrix. Simulation results on the perpendicular magnetic recording channels (PMRC) demonstrate that the IMAC outperforms both the MAC and the previously proposed random interleave array (RIA) codes for the partial-response targets under consideration. In addition, a subblock-based encoder design is proposed to reduce the encoding complexity of the IMAC and when compared with the RIA code, the IMAC exhibits a lower encoding complexity, and still maintains a comparable level of the decoding complexity.

Publication: IEICE TRANSACTIONS on Fundamentals Vol.E94-A No.6 pp.1441-1448

Publication Date: 2011/06/01

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Online ISSN: 1745-1337

DOI: 10.1587/transfun.E94.A.1441

Type of Manuscript: PAPER

Category: Coding Theory

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Pornchai SUPNITHI, Watid PHAKPHISUT, Wicharn SINGHAUDOM, "Structured LDPC Codes to Reduce Pseudo Cycles for Turbo Equalization in Perpendicular Magnetic Recording" in IEICE TRANSACTIONS on Fundamentals, vol. E94-A, no. 6, pp. 1441-1448, June 2011, doi: 10.1587/transfun.E94.A.1441.
Abstract: Low-density parity-check (LDPC) codes are typically designed to avoid the length-4 cycles to ensure acceptable levels of performance. However, the turbo equalization, which relies on an interaction between an inner code such as an LDPC code and a soft-output Viterbi algorithm (SOVA) detector, exhibits a performance degradation due to the pseudo cycles. In this paper, we propose an interleaved modified array code (IMAC) that can reduce the number of pseudo cycles, hence, improving the gains from the iterative processing technique. The modification is made on the existing array-based LDPC codes named modified array codes (MAC) by introducing an additional interleaving matrix to the parity-check matrix. Simulation results on the perpendicular magnetic recording channels (PMRC) demonstrate that the IMAC outperforms both the MAC and the previously proposed random interleave array (RIA) codes for the partial-response targets under consideration. In addition, a subblock-based encoder design is proposed to reduce the encoding complexity of the IMAC and when compared with the RIA code, the IMAC exhibits a lower encoding complexity, and still maintains a comparable level of the decoding complexity.
URL: https://global.ieice.org/en_transactions/fundamentals/10.1587/transfun.E94.A.1441/_p

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@ARTICLE{e94-a_6_1441,
author={Pornchai SUPNITHI, Watid PHAKPHISUT, Wicharn SINGHAUDOM, },
journal={IEICE TRANSACTIONS on Fundamentals},
title={Structured LDPC Codes to Reduce Pseudo Cycles for Turbo Equalization in Perpendicular Magnetic Recording},
year={2011},
volume={E94-A},
number={6},
pages={1441-1448},
abstract={Low-density parity-check (LDPC) codes are typically designed to avoid the length-4 cycles to ensure acceptable levels of performance. However, the turbo equalization, which relies on an interaction between an inner code such as an LDPC code and a soft-output Viterbi algorithm (SOVA) detector, exhibits a performance degradation due to the pseudo cycles. In this paper, we propose an interleaved modified array code (IMAC) that can reduce the number of pseudo cycles, hence, improving the gains from the iterative processing technique. The modification is made on the existing array-based LDPC codes named modified array codes (MAC) by introducing an additional interleaving matrix to the parity-check matrix. Simulation results on the perpendicular magnetic recording channels (PMRC) demonstrate that the IMAC outperforms both the MAC and the previously proposed random interleave array (RIA) codes for the partial-response targets under consideration. In addition, a subblock-based encoder design is proposed to reduce the encoding complexity of the IMAC and when compared with the RIA code, the IMAC exhibits a lower encoding complexity, and still maintains a comparable level of the decoding complexity.},
keywords={},
doi={10.1587/transfun.E94.A.1441},
ISSN={1745-1337},
month={June},}

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TY - JOUR
TI - Structured LDPC Codes to Reduce Pseudo Cycles for Turbo Equalization in Perpendicular Magnetic Recording
T2 - IEICE TRANSACTIONS on Fundamentals
SP - 1441
EP - 1448
AU - Pornchai SUPNITHI
AU - Watid PHAKPHISUT
AU - Wicharn SINGHAUDOM
PY - 2011
DO - 10.1587/transfun.E94.A.1441
JO - IEICE TRANSACTIONS on Fundamentals
SN - 1745-1337
VL - E94-A
IS - 6
JA - IEICE TRANSACTIONS on Fundamentals
Y1 - June 2011
AB - Low-density parity-check (LDPC) codes are typically designed to avoid the length-4 cycles to ensure acceptable levels of performance. However, the turbo equalization, which relies on an interaction between an inner code such as an LDPC code and a soft-output Viterbi algorithm (SOVA) detector, exhibits a performance degradation due to the pseudo cycles. In this paper, we propose an interleaved modified array code (IMAC) that can reduce the number of pseudo cycles, hence, improving the gains from the iterative processing technique. The modification is made on the existing array-based LDPC codes named modified array codes (MAC) by introducing an additional interleaving matrix to the parity-check matrix. Simulation results on the perpendicular magnetic recording channels (PMRC) demonstrate that the IMAC outperforms both the MAC and the previously proposed random interleave array (RIA) codes for the partial-response targets under consideration. In addition, a subblock-based encoder design is proposed to reduce the encoding complexity of the IMAC and when compared with the RIA code, the IMAC exhibits a lower encoding complexity, and still maintains a comparable level of the decoding complexity.
ER -