光纖通訊使用低密度檢查碼(LDPC)之快速編解碼法;Quick Encoding and Decoding Methods for Optical Communication Systems Using LDPC Codes

許恭睿, Kung-jui Hsu

Yong Wang

A novel construction method with the advantages of simple construction and easy implementation encoding for quasi-cyclic low-density parity-check(QC-LDPC) codes based on Galois field(GF(q)) multiplicative group is proposed.This algorithm can flexibly adjust code length and code rate Furthermore,the complexity of the encoding and decoding is low.An irregular QC-LDPC(3843,3603) code suitable for optical communication systems is constructed by applying the proposed construction method.The simulation results show that the error-correction performance of the QC-LDPC(3843,3603) code is better than that of the classic RS(255,239) code,the LDPC code constructed by the SCG construction method,and the regular QC-LDPC(4221,3956) code.So the QC-LDPC(3843,3603) code is suitable for the high-speed long-haul optical communication systems.

Yuan Jiangu

A construction method of Quasi-Cyclic Low-Density Parity-Check(QC-LDPC) codes based on cyclic subgroups of finite field is proposed.The method owns the advantages such as easier construction,more flexible adjustment on code-length and code-rate and lower encoding/ decoding complexity.Moreover,a regular QC-LDPC(5334,4955)code suitable for optical communication systems is constructed by this construction method.The simulation results show that the code can gain good performance under the condition of additive white Gaussian noise(AWGN)channel with iterative decoding sum-product algorithm(SPA).The error-correction performance of the QC-LDPC(5334,4955)code is better than that of the classic RS(255,239) code which is widely used in optical communication system.Therefore,the constructed QC-LDPC(5334,4955)code can be better suitable for the long-haul and high-speed optical communication systems.

Ho-Il Kim, 김호일

楊旭弘, Hsu-Hung Yang

Zhongxun Wang, Baojun Liu, Min Zhang +1 more

Low density parity check (LDPC) code is a kind of linear block code with excellent performance which is proposed by Dr. Gallager. It overcomes the shortcomings of other error correcting codes and it is the nearest channel code from Shannon limit at the present discover. The decoding algorithms of L DPC code can reduce the decoding delay by the parallel decoding structure, so this has caused great concern in many fields. In recent years more and more scholars begin to study LDPC code, this makes the coding and decoding algorithms of LDPC code improved continuously. LDPC code has been widely used in many fields such as optical fiber communication, digital watermarking, underwater communication and deep space communication because of its excellent performance. Non-binary LDPC code has better performance compared with binary LDPC code. In this paper, FFT-BP decoding algorithm of non-binary LDPC code is studied, and on this basis, we proposed an improved FFT-BP algorithm. The improved decoding algorithm can effectively reduce the average iteration number. Finally, we achieved encode and decode algorithm of non-binary LDPC code with FPGA.