[1] Liang Yuan, Zhang Shulin, Gu Pinbiao, Wu Lenan, et al. Efficient construction and encoding of QC-LDPC codesby cyclic lifting of protographs [J]. Journal of Southeast University (English Edition), 2015, 31 (1): 25-30. [doi:10.3969/j.issn.1003-7985.2015.01.005]

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Efficient construction and encoding of QC-LDPC codesby cyclic lifting of protographs()

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Journal of Southeast University (English Edition)[ISSN:1003-7985/CN:32-1325/N]

Volumn:

31

Issue:

2015 1

Page:

25-30

Research Field:

Information and Communication Engineering

Publishing date:

2015-03-30

Info

Title:

Efficient construction and encoding of QC-LDPC codesby cyclic lifting of protographs

Author(s):

Liang Yuan;  Zhang Shulin;  Gu Pinbiao;  Wu Lenan

School of Information Science and Engineering, Southeast University, Nanjing 210096, China

Keywords:

low-density parity-check(LDPC)codes;  quasi-cyclic LDPC codes;  cyclic lifting;  protograph LDPC codes

PACS:

TN911.21

DOI:

10.3969/j.issn.1003-7985.2015.01.005

Abstract:

Quasi-cyclic low-density parity-check(QC-LDPC)codes can be constructed conveniently by cyclic lifting of protographs. For the purpose of eliminating short cycles in the Tanner graph to guarantee performance, first an algorithm to enumerate the harmful short cycles in the protograph is designed, and then a greedy algorithm is proposed to assign proper permutation shifts to the circulant permutation submatrices in the parity check matrix after lifting. Compared with the existing deterministic edge swapping(DES)algorithms, the proposed greedy algorithm adds more constraints in the assignment of permutation shifts to improve performance. Simulation results verify that it outperforms DES in reducing short cycles. In addition, it is proved that the parity check matrices of the cyclic lifted QC-LDPC codes can be transformed into block lower triangular ones when the lifting factor is a power of 2. Utilizing this property, the QC-LDPC codes can be encoded by preprocessing the base matrices, which reduces the encoding complexity to a large extent.

References:

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Memo

Memo:

Biographies: Liang Yuan(1990—), male, graduate; Zhang Shulin(corresponding author), male, master, associate professor, slzhang@seu.edu.cn.
Foundation item: The National Key Technology R& D Program of China during the 12th Five-Year Plan Period(No.2012BAH15B00).
Citation: Liang Yuan, Zhang Shulin, Gu Pinbiao, et al.Efficient construction and encoding of QC-LDPC codes by cyclic lifting of protographs[J].Journal of Southeast University(English Edition), 2015, 31(1):25-30.[doi:10.3969/j.issn.1003-7985.2015.01.005]

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