说明：  LDPC校验矩阵生成、高斯消去法编码、BP译码程序，可以作为自己编写LDPC编译码程序的参考。因为matlab代码效率不高，所以这个程序仿真起来比较慢.
(LDPC check matrix generation, Gaussian elimination coding, BP decoding procedure can be used as its own procedures for the preparation of LDPC codec reference. Because matlab code efficiency is not high, so this process is relatively slow simulation together.)