硬判决和和积译码的性能相差不大，而最大似然译码的性能较好。因为最大似然译码的方法是找出所有发送码字中可能性最大的发送码字作为译码估值，是一种通过经验与归纳，由接收值推测发送码字的方法。-Hard decisions and the performance of the sum-product decoding little difference, the maximum likelihood decoding performance is better. Because the maximum likelihood decoding method is to find all the most likely sent codeword as a codeword decoding sending valuation, is a type of experience and induction, the value suggested by the received code words to send method.