한국통신학회논문지

Quasi-Cyclic LDPC Codes using Superposition Matrices and Their Layered Decoders for Wibro Systems

Beomkyu Shin, Hosung Park, Jong‐Seon No, Sang‐Hyo Kim

Published Jan 1, 2010• 1 citation

Abstract

Most communication systems including Wibro use quasi-cyclic LDPC codes composed of circulants. However, it is very difficult to design quasi-cyclic(QC) LDPC codes with optimal degree distribution satisfying conditions on layered decoding and girth due to the restriction of the size of its base matrix. In this paper, we propose a good solution by introducing superposition matrices to QC LDPC codes. We derive the conditions on checking girth of QC LDPC codes with superposition matrices, and propose new decoder to support layered decoding both for original QC LDPC codes and their modifications with superposition matrices. Simulation results show considerable improvements to convergence speed and error-correcting performance of proposed scheme which adopts QC LDPC codes with superposition matrices.

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