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Effects of base matrices on iterative decoding performance of irregular QC-LDPC codes

Conference Paper


Abstract


  • The edge connections in factor graphs of quasicyclic

    (QC) LDPC codes, which affect their iterative decoding

    performance, are determined by their base matrices. In this

    paper, the effects of base matrices on the iterative decoding

    performance of QC-LDPC codes are investigated by using the recently

    proposed EXIT chart tool for protograph LDPC codes. Extensive

    experiments have been carried out and iterative decoding

    thresholds of QC-LDPC codes with the same degree distribution

    pair but base matrices having different structures and different

    dimensions have been obtained and compared. Experimental

    results show that 1) the base matrix structure affects not only the

    waterfall performance but also the error floor performance; base

    matrices having good waterfall performance may exhibit rather

    poor error floor performance. 2) by increasing the dimensions

    of base matrices for a given degree distribution, the threshold

    means are reduced while the ranges of threshold distributions

    are increased. 3) similar to the case of detailed represented

    LDPC codes, base matrices with sufficiently large dimensions may

    have thresholds surpassing the conventional ensemble threshold

    with the same degree distribution pair. Moreover, as a concrete

    example, an improved base matrix is designed for a rate-1/2

    WiMax LDPC code.

Publication Date


  • 2013

Citation


  • S. Tong, Q. Guo, J. Xi & Y. Yu, "Effects of base matrices on iterative decoding performance of irregular QC-LDPC codes," in 7th International Conference on Signal Processing and Communication Systems, 2013, pp. 1-4.

Scopus Eid


  • 2-s2.0-84903847641

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/1980

Start Page


  • 1

End Page


  • 4

Place Of Publication


  • United States

Abstract


  • The edge connections in factor graphs of quasicyclic

    (QC) LDPC codes, which affect their iterative decoding

    performance, are determined by their base matrices. In this

    paper, the effects of base matrices on the iterative decoding

    performance of QC-LDPC codes are investigated by using the recently

    proposed EXIT chart tool for protograph LDPC codes. Extensive

    experiments have been carried out and iterative decoding

    thresholds of QC-LDPC codes with the same degree distribution

    pair but base matrices having different structures and different

    dimensions have been obtained and compared. Experimental

    results show that 1) the base matrix structure affects not only the

    waterfall performance but also the error floor performance; base

    matrices having good waterfall performance may exhibit rather

    poor error floor performance. 2) by increasing the dimensions

    of base matrices for a given degree distribution, the threshold

    means are reduced while the ranges of threshold distributions

    are increased. 3) similar to the case of detailed represented

    LDPC codes, base matrices with sufficiently large dimensions may

    have thresholds surpassing the conventional ensemble threshold

    with the same degree distribution pair. Moreover, as a concrete

    example, an improved base matrix is designed for a rate-1/2

    WiMax LDPC code.

Publication Date


  • 2013

Citation


  • S. Tong, Q. Guo, J. Xi & Y. Yu, "Effects of base matrices on iterative decoding performance of irregular QC-LDPC codes," in 7th International Conference on Signal Processing and Communication Systems, 2013, pp. 1-4.

Scopus Eid


  • 2-s2.0-84903847641

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/1980

Start Page


  • 1

End Page


  • 4

Place Of Publication


  • United States