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Performance analysis of QC-LDPC construction based on distance graph

According to the fact that the random construction method of LDPC(Low Density Parity Check) codes are lack of structure and are difficult to be implemented in hardware, two construction methods of QC-LDPC(Quasi-Cyclic LDPC) codes-sequential and random search method based on distance graph are proposed. The two algorithms can produce flexible QCLDPC codes by setting the parameters such as code length, rates and girth according to requirement. The simulation shows that: the random search method performs better than the sequential search method and the QC-LDPC codes constructed by random search method have equivalent BER performance with PEG construction method. Compared with the existing random construction method, the two methods proposed are faster, and can obtain quasi-cyclic codes which are easy to be implemented in hardware.