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Author: search.filters.author.Kanjanakunchorn, Chavisa

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    Soft-Decision Algorithm of a Rate-5/6 2D Modulation Code for SHTR in Staggered BPMR Systems
    (2022-01-01)
    Kanjanakunchorn, Chavisa
    ;
    Warisarn, Chanon
    With an increasing demand for recording data storage, this paper is interested in magnetic recording in bit-patterned media recording (BPMR) systems. The main problem of BPMR system from track width and bit length decreasing is two-dimensional (2-D) interference, consisting of inter-symbol interference and inter-track interference. One thing that solved this problem is 2-D modulation code of a rate-5/6 for single-head/two-track reading with staggered bit islands. Moreover, we also improve the performance of system by soft decision algorithm and low-density parity-check code because it can do an iterative process. The soft information is created by log-likelihood ratio by using a look-up table of a rate-5/6 through the Boolean logic circuit equation. After that, this soft information is brought to modified one-dimensional (1-D) soft-output Viterbi algorithm detector. At the same code rate of 5/6 and with bit error rate of 10-4, the simulation results show that our proposed scheme at an areal density of 3 Terabit per square inch, is better than system that performs without 2-D modulation code for 2 dB. Moreover, it is also better than previously proposed system that uses hard decisions with 2-D modulation code for 4 dB.
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    Soft-Decision Output Encoding/Decoding Algorithms of a Rate-5/6 CITI Code in Bit-Patterned Magnetic Recording (BPMR) Systems
    (2019-06-01)
    Kanjanakunchorn, Chavisa
    ;
    Warisarn, Chanon
    Nowadays, the growing demand for recording storage is steadily increasing. At high areal densities in magnetic recording system major cause of small bit and track width as a way to overcome 2D interference, which consisting of inter-symbol interference (ISI) and intertrack interference (ITI). One way to improve performance of this problem, we need to be handled by using 2D modulation code with a simulation model in a bit-patterned media recording (BPMR). The previous research of modulation codes such as constructive ITI (CITI) code was created based on the hard decision. In this work; however, we propose a soft decision output decoding algorithm of a rate-5/6 constructive ITI (CITI) code to utilize it in an iterative decoding process. The proposed use the log-likelihood ratio (LLR) algebra in Boolean logic mappings with a modified 2D soft-output Viterbi algorithm (SOVA) detector. When we consider the BER=10{6}, simulation results show that the proposed encoding and decoding schemes offer approximately 1.5 and 3 dB gains over the conventional coded system at 2 and 3 Tera-bit per square inch (Tb/in<sup>2</sup>), respectively. In addition, the gains of approximately 0.2 and 1.5 dBs are obtained over that of a hard decision decoding of modulation code regarding with the same code rate and the same areal density, respectively.