对分组码的chase2译码算法比较与硬判决，未编码情况下的提高了误码率增加了编码增益-right to a code decoding algorithm chase2 compared with the hard decision, no coding of the increased bit error rate increased coding gain

本人正在学习的图象处理的代ac_simple3.c是根据witten和neal的文章中所给算法（不包括模型建构）进行算术编码的.-I was learning image processing in lieu ac_simple3.c is witten and n Leveraging the article by the algorithm (not including the model building) arithmetic coding.

实现了2*2，2*1，1*2，4*4等多种时空编码和解码的算法，并能得到BER性能曲线-Achieve a 2* 2,2* 1,1* 2,4* 4, and other space-time coding and decoding algorithm, and BER performance curve can be obtained

LDPC基于生成矩阵的编码方法和和积译码算法,校验矩阵采用的是mackey的方法-LDPC coding method based on the generator matrix and decoding algorithm, check matrix is mackey methods