KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Author: search.filters.author.Timakul, SeksonSubject: search.filters.subject.LDPC codes

Search Results

Now showing 1 - 3 of 3
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    A simple parity check matrix LDPC code for perpendicular magnetic recording channels
    (2013-09-02)
    Timakul, Sekson
    ;
    Choochuay, Somsak
    In LDPC code design, the structure of code's parity check matrix can be very crucial to code performance. In this paper, we have investigated a simple designed parity check matrix when the code is applied to a PMR channel of a storage system. Belief propagation algorithm and min-sum algorithm are two major decoding algorithms used to benchmarked the code's merits. Additive white Gaussian noise channel (AWGN) and perpendicular magnetic recording (PMR) channel with SISO equalizer in PR2 target are the conditions of our investigation. The LDPC code itself is a modified array type. Its construction fairly simple compared to normal array and quasi-cyclic code. We used two decision variables to define the permutation matrix. A method proposed by Tanner's et.al had been adapted to the modified array code. The decoders have been tested for 5 and 20. iterations. SNR versus BER and BLER were measured. © 2013 IEEE.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    Construction of quasi-cyclic LDPC codes form SFT structure and cyclic shift
    (2011-12-01)
    Timakul, Sekson
    ;
    Choomchuay, Somsak
    This paper presents an alternative a method for designing a parity matrix of low density parity check codes. The proposed method can be viewed as a generalized version of Sridara-Fuja-Tanner (SFT) technique which is ideal for regular quasi cyclic code design. Upon the current investigation, the designed code has delivered a comparable BER-SNR performance when compared with that of more complicate designed matrix. The designed code offers similar performance when compared with Sridara-Fuja-Tanner code and Quadratic Congruences structure. In additions, the resulted matrix also has a desirable structure that it suits well the hardware implementation. © 2011 IEEE.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Item,
    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.