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Author: search.filters.author.Warisam, ChanonHas files: No

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    Multilayer Perceptron-based Detector for a Coded Two-Dimensional Magnetic Recording
    (2022-01-01)
    Buajong, Chaiwat
    ;
    Warisam, Chanon
    Recently, magnetic recording technology is on the verge of reaching its recording density limit. Two-dimensional (2- D) magnetic recording (TDMR) becomes a candidate for next- generation magnetic recording because of its compatibility with the current technology and powerful 2-D signal processing tools. However, the degradation in signal quality due to 2-D interference is inevitable. In this paper, we introduce the multilayer perceptron (MLP)-based detector that can produce soft-output information in the form of a log-likelihood ratio (LLR). Such a detector can also execute turbo decoding by exchanging information with a low- density parity-check (LDPC) code. The simulation result shows that the proposed system outperforms the systems that use the conventional detector based on the Viterbi algorithm.
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    Simple Soft-Information Developers Based on Parallel Detection Scheme in Bit-Patterned Media Recording (BPMR) Systems
    (2021-06-27)
    Mattayakan, Mutita
    ;
    Sokjabok, Siwakon
    ;
    Warisam, Chanon
    Among the alternate ultra-high density data storage technologies, bit-patterned media recording (BPMR) is one of the mentioned technologies that was proposed to achieve a higher density. Due to the closeness between the magnetic islands, so the readback sequences are disrupted from the effect of two-dimensional (2D) interference, which includes both intersymbol interference (ISI) and intertrack interference (ITI). In this paper; therefore, we propose the simple and effective soft-information developers (SIDs) to improve the soft-information that are obtained from both vertical and horizontal detectors. An optimal weight was optimized under the BPMR channel before multiplying with the horizontal soft-information. The proposed SIDs and conventional 2D detector's performances were carefully compared in the terms of BER. The results show that our proposed methods achieve a gain of approximately 8 dB at a BER of 10-3.
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    A simple 2/3 modulation code and bit-flipping technique in bit-patterned media recording systems
    (2018-07-02)
    Busyatras, Wiparat
    ;
    Poompuang, Pitaya
    ;
    Myint, Lin M.M.
    ;
    Warisam, Chanon
    Two-dimensional (2-D) modulation code is considered as one of the key schemes to improve the areal density capability for next generation magnetic recording e.g., bit-patterned media recording (BPMR) technology, due to its advantages such as severe inter-track interference (ITI) suppression and user densities escalation. In this work, a rate-2/3 2-D modulation with a three-reader three-track (3R3T) system is studied where the positions of reader are accordingly optimized with the encoded criteria to obtain the highest bit-error rate (BER) performance. Moreover, we also propose a bit-flipping technique which is one way to extremely improve the overall system performance. Here, the soft-information that are obtained from soft-output Viterbit algorithm (SOVA) detectors will be improved according with the encoded criteria before sending to the proposed decoder. Simulation results demonstrate that significant performance gain can be achieved using these two proposed approaches.