迭代结构的信源信道联合解码及其简化算法

信源信道联合解码算法中的迭代信道解码需要进行比特似然值和概率值转换，以及联乘、累加运算，增加了信道解码的计算复杂度，该文针对这一问题，直接利用信道解码的比特硬判决值和参数的先验概率，估计比特的外信息，用于迭代信道解码。基于高斯-马尔可夫信源参数的仿真实验表明，该简化算法大大降低了迭代信道解码算法的计算复杂度。与独立解码算法相比，简化的联合解码算法明显改善了接收参数的信噪比，同时不会明显降低原迭代结构解码算法的性能。

Simplified Iterative Joint Source-Channel Decoding Algorithm

The iterative channel decoder of joint source-channel decode has the transform of log-likelihood and probability, also the multiplication and accumulation operation, which improves the computation complexity of channel decoder. In order to reduce the complexity, this paper proposes the simplified iterative channel decoding algorithm. The algorithm directly utilizes the hard decided value of channel decoder and parameter prior probability to estimate the extrinsic information for iterative channel decoder. Based on Gaussian-Markov source, simulation results show that the simplified iterative channel decoder significantly improves SNR of received parameters and reduces the computation compared with separation source channel decoder. Also, the simplified algorithm does not degrade the performance of joint source channel decoding algorithm obviously.