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Author: search.filters.author.Kovintavewat, PiyaSubject: search.filters.subject.BPMR

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    Neural Networks Input Techniques to Maintain a Small Skew Angle in Bit-Patterned Magnetic Recording with a V-Shaped Read-Head Array
    (2023-01-01)
    Fatika, Kirana Alif
    ;
    Koonkarnkhai, Santi
    ;
    Kovintavewat, Piya
    ;
    Warisarn, Chanon
    The demand for enormous storage devices has kept increasing, leading to the development of various advanced technologies with a vast storage capacity. Extensive numbers of related research studies have been aiming at optimizing code design and algorithms analytically; however, enacting them on practical devices has been scarce. Achieving this demand might bring some obstacles called two-dimensional interference and skew angle (SA). To meet the challenge of the obstacle, we propose a SA detection method for bit-patterned magnetic recording systems by computing a specific target by three readback sequences before estimating the SA value and detecting the SA amount happening in the system using an application of neural network namely multilayer perceptron. An error correction code, low-density parity-check, is applied, and its decoder outputs a log-likelihood ratio whose probability density distribution is examined. The simulation results show that the sliding window technique can significantly provide a better bit error rate performance.
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    An Intertrack Interference (ITI) subtraction scheme for bit-patterned media recording
    (2021-05-19)
    Buajong, Chaiwat
    ;
    Warisarn, Chanon
    ;
    Koonkarnkhai, Santi
    ;
    Kovintavewat, Piya
    Currently, hard disk drive has been struggled to overcome the super-paramagnetic limit that restricts the density increment. Bit-patterned magnetic recording (BPMR) is a candidate that can increase an areal density (AD) up to 4 Tb/in2. However, inter-track interference (ITI) arising from a narrow track width at high AD severely degrades the system performance. This study proposes the ITI subtraction technique with turbo iteration in a coded BPMR system. This method refines the equalized sequence by subtracting the ITI using an imitated ITI sequence that is generated by the soft information obtained from turbo iteration and ITI coefficients. The refined sequence that contains the partial ITI is sent to the turbo iteration as many rounds as needed. Simulation results indicate that the proposed system outperforms the conventional system whether or not media noise is considered.
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    A simple recorded-bit patterning scheme for bit-patterned media recording
    (2013-09-02)
    Arrayangkool, Autthasith
    ;
    Warisarn, Chanon
    ;
    Myint, Lin M.M.
    ;
    Kovintavewat, Piya
    In bit-patterned magnetic recording (BPMR), inter-symbol interference (ISI) and inter-track interference (ITI) become a major impairment due to small bit and track pitches. One way to alleviate ISI and ITI is to encode the data sequence before recording. In general, two-dimensional (2D) coding scheme requires many redundant bits, thus lowering the code rate. This paper proposes a novel 2D coding scheme (referred to as a simple recorded-bit patterning (RBP) scheme) with high code rate to combat both ISI and ITI effects. Specifically, the data bits will first be patterned by finding the best data pattern based on a look-up table that can avoid severe ISI and ITI effects before recording. Simulation results indicate that the proposed scheme can provide a significant performance improvement if compared to the system without coding. © 2013 IEEE.