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Author: search.filters.author.Prasartkaew, Chutima

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    Combined coding algorithm of LDPC codes in bit-patterned media recording channels
    (2014-01-01)
    Prasartkaew, Chutima
    ;
    Kovintavewat, Piya
    ;
    Choomchuay, Somsak
    This paper presents a new coding algorithm of irregular low-density parity-check (LDPC) codes. This algorithm consists of two parts of block codes; parity bits was encoded using the magic square based algorithm (MSBA) which suitable for the short block (less than 500 bits) and the data bits, the rest part of all block codes, was encoded using the random number table. This proposed coding algorithm is called 'Combined Coding Algorithm LDPC codes (CCA-LDPC codes)' which can be used in bit-patterned media recording (BPMR) channels. The performance of the constructed codes was numerically simulated in BPMR channels model. The obtained performance of the proposed codes was compared with the comparable existing codes. The simulation results show that, at a block length of 4110 bit and code rate of 0.9, the proposed CCALDPC codes yields better performance than the existing ones, especially at high signal-to-noise ratio scenario. © (2014) Trans Tech Publications, Switzerland.
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    Parity check matrix construction of LDPC codes in bit-patterned media recording channels using Tippett's random number table
    (2013-12-01)
    Prasartkaew, Chutima
    ;
    Kovintavewat, Piya
    ;
    Choomchuay, Somsak
    This paper presents the application of a random number table for the parity check matrix construction of irregular low-density parity check (LDPC) codes. The performance of the constructed codes was tested in bit-patterned media recording channels. The obtained performance of the proposed codes was compared with that of the existing codes. The simulation results show that, at a block length of 4110 bit and code rate of 0.9, the proposed LDPC code yields better performance than the existing ones, especially at high signal-to-noise ratio scenario. © 2013 IEEE.
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    Parity check matrix construction via Magic Square Based Algorithm
    (2012-12-01)
    Prasartkaew, Chutima
    ;
    Choomchuay, Somsak
    This paper presents a construction algorithm for the short block irregular LDPC codes. By applying a magic square theorem as a part of the matrix construction, a newly developed algorithm, the so-called Magic Square Based Algorithm (MSBA), is obtained. The modified array codes are focused on in this study since the reduction of 1s can lead to simple encoding and decoding schemes. Simulation results based on AWGN channels show that with the code rate of 0.8 and SNR = 5 dB, the BER of 10<sup>-7</sup> can be obtained whilst the number of decoding iteration is relatively low. © 2012 IEEE.
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    A design of nonprime block irregular LDPC codes via CRT
    (2010-12-01)
    Chusin, Chalit
    ;
    Prasartkaew, Chutima
    ;
    Timakul, Sekson
    ;
    Choomchuay, Somsak
    This paper presents a new design of irregular LDPC codes that supports arbitrary block length. We propose the efficient construction method when nonprime size sub-matrices are used. The problem where GCD(L<inf>1</inf>,L <inf>2</inf>) that left unsolved has been tackled. We also consider the case GCD(L<inf>1</inf>,L<inf>2</inf>)=1 but L<inf>1</inf> or L<inf>2</inf> is a nonprime number. The results show that our designed codes have superior performance compared to MAC. The resulted codes still hold the attractive properties of LDPC codes. The performances of interleaved codes are higher than noninterleaved codes and it goes higher as SNR is increased. ©2010 IEEE.
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    A design of parity check matrix for irregular LDPC codes
    (2009-12-01)
    Prasartkaew, Chutima
    ;
    Choomchuay, Somsak
    This paper outlines a work on a design of parity check matrix for Irregular LDPC codes. The design is based on the adjustment of the modified array LDPC codes and interleave-modified array LDPC codes. The code rate of 0.930 is obtained. LDPC Codes based on this design suits the short and medium block length. ©2009 IEEE.
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    A parity check matrix design for irregular LDPC codes with 2K block length
    (2009-12-01)
    Prasartkaew, Chutima
    ;
    Choomchuay, Somsak
    This paper outlines the work on another design of a parity check matrix for Irregular LDPC codes. The design is based on the pattern of Modified Array and Interleaved Modified Array LDPC codes. The application of matrix transposition Quasi-cyclic shifting has resulted in the reduction of 1's. The designed matrix is suitable for codes with short and medium block lengths. The code rate of 0.56 at the BER of 10<sup>-4</sup> is obtained. ©2009 IEEE.