Methods for the Soft-Decision Decoding of MTR Codes in Multiple-Head Magnetic Recording Systems

Two different methods for the soft-decision decoding of the maximum-transition-run (MTR) codes have been considered in this paper. The first one, the maximum a posteriori (MAP) algorithm, is based on the Bayesian algorithm, computing a posteriori log-likelihood ratios (LLR) using MTR codewords. The second one, the soft-decision implementation in Boolean logic circuits has been used to propagate the soft-values through the MTR decoder. The MTR code performs as an inner encoding code, in a simple concatenation of the low-density parity-check (LDPC) and the MTR. The special case of two-track two-head E2PR4 channel model was used, assuming the low level of inter-track interference (ITI) and the AWGN noise presence. The soft-decision decoding results with nearly 1.7dB coding gain, using the MAP algorithm, while nearly 1.9dB, using the second one approach.

[1]  L.C. Barbosa.  Simultaneous detection of readback signals from interfering magnetic recording tracks using array heads , 1990, International Conference on Magnetics.

[2]  Radford M. Neal,et al.  Near Shannon limit performance of low density parity check codes , 1996 .

[3]  Nikola Duric,et al.  MAP decoding of MTR codes in LDPC-MTR encoded magnetic recording systems , 2009, 2009 9th International Conference on Telecommunication in Modern Satellite, Cable, and Broadcasting Services.

[4]  Brian H. Marcus,et al.  Maximum transition run codes for generalized partial response channels , 2001, IEEE J. Sel. Areas Commun..

[5]  Nikola Duric,et al.  Soft-Output Decoding in Multiple-Head MTR Encoded Magnetic Recording Systems , 2006, 2006 IEEE International Conference on Communications.

[6]  Brendan J. Frey,et al.  Factor graphs and the sum-product algorithm , 2001, IEEE Trans. Inf. Theory.

[7]  Paul H. Siegel,et al.  Error-Event Characterization on Partial-Response Channels , 1999, IEEE Trans. Inf. Theory.

[8]  Jaekyun Moon,et al.  Maximum transition run codes for data storage systems , 1996 .

[9]  J. R. Cruz,et al.  Enforcing maximum-transition-run code constraints and low-density parity-check decoding , 2004, IEEE transactions on magnetics.

[10]  Evangelos S. Eleftheriou,et al.  Noise-predictive maximum likelihood (NPML) detection , 1998 .

[11]  H. Thapar,et al.  A class of partial response systems for increasing storage density in magnetic recording , 1987 .

[12]  Emina Soljanin,et al.  Multihead Detection for Multitrack Recording Channels , 1998, IEEE Trans. Inf. Theory.

[13]  Nikola Djuric,et al.  Application of MTR soft-decision decoding in multiple-head magnetic recording systems , 2009 .

[14]  Bane Vasic,et al.  Kirkman systems and their application in perpendicular magnetic recording , 2002 .

[15]  Zining Wu,et al.  Coding and Iterative Detection for Magnetic Recording Channels , 2000 .

[16]  John M. Cioffi,et al.  Achievable radial information densities in magnetic recording systems , 1992, [Conference Record] GLOBECOM '92 - Communications for Global Users: IEEE.

[17]  Paul H. Siegel,et al.  Constrained coding for binary channels with high intersymbol interference , 1999, IEEE Trans. Inf. Theory.

[18]  Joachim Hagenauer,et al.  Source-controlled channel decoding , 1994, Proceedings of 1994 IEEE International Symposium on Information Theory.