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Graph-Based Channel Detection for Multitrack Recording Channels


We propose a low complexity detection technique for multihead multitrack recording systems. By exploiting sparseness of two-dimensional partial response (PR) channels, we develop an algorithm which performs belief propagation (BP) over corresponding factor graphs. We consider the BP-based detector not only for partial response channels but also for more practical conventional media and bit-patterned media storage systems, with and without media noise. Compared to the maximum likelihood detector which has a prohibitively high complexity that is exponential with both the number of tracks and the number of intersymbol interference (ISI) taps, the proposed detector has a much lower complexity and a fast parallel structure. For the multitrack recording systems with PR equalization, the price is a small performance penalty (less than one dB if the intertrack interference (ITI) is not too high). Furthermore, since the algorithm is soft-input soft-output in nature, turbo equalization can be employed if there is an outer code. We show that a few turbo equalization iterations can provide significant performance improvement even when the ITI level is high.

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Correspondence to Tolga M. Duman.

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Hu, J., Duman, T.M. & Erden, M.F. Graph-Based Channel Detection for Multitrack Recording Channels. EURASIP J. Adv. Signal Process. 2008, 738281 (2009).

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  • Medium Storage
  • Factor Graph
  • Response Channel
  • Record Channel
  • Channel Detection