Journal of Nanjing University of Science and Technology

Code Optimization and Iterative Decoding of QC-LDPC Coded OFDM System

Shunliang Mei

Published Jan 1, 2009• 0 citations

Abstract

In the multi-paths environment,since the performance of orthogonal frequency division multiplexing(OFDM) system may be severely degraded by the sub-carriers in deep fading,powerful error-correcting codes have to be applied to OFDM.This paper presents a novel quasi-cyclic low density parity check(QC-LDPC) coded OFDM system.In this system,the redundant bits of codeword are mapped to higher-order constellation,and a group shuffled message passing scheduling is used in the iterative decoding.According to the mapping scheme,the QC-LDPC code is optimized by density evolution based on group shuffled message passing with Gaussian approximation.Simulation results show that the proposed system can achieve better error rate performance and faster decoding convergence than conventional approaches on both additive white Gaussian noise(AWGN) and Rayleigh fading channels.

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