有限字符集信号传输的互信息计算

针对目前有限字符集上衰落信道下的数字通信传输方法无法既简洁又准确地计算互信息值问题，提出了一种新的互信息值计算方法.通过分析对数似然比与互信息之间的关系，对高信噪比和低信噪比两种情况下的简化计算进行加权组合，实现了宽信噪比区间内的低复杂度和准确的互信息值计算.实验结果表明，该算法不仅能够准确地计算互信息值，而且能够简洁、准确地评估无线传输的差错概率.与目前常用算法相比，本文算法具有准确、简便和直观的优势，对数字通信系统性能的理论分析具有较好的指导意义.

Mutual information computation for signal transmission over finite alphabet

Aiming at the problem that the current digital communication transmission methods under fading channels over finite alphabet could not compute the mutual information value concisely and accurately,a new computation method for mutual information value was proposed.Through analyzing the relationship between log-likelihood ratio and mutual information as well as performing the weighted combination of simplified computation with both high and low signal to noise ratios,the mutual information computation with low complexity and high accuracy in a wide range of signal to noise ratio range was realized.The experimental results indicate that the poposed algorithm can not only compute the mutual information value precisely,but also evaluate the error probability for wireless transmission concisely and accurately.Compared with the commonly used algorithms,the proposed algorithm has such advantages as accuracy,convenience and intuition,and has good guiding significance for the theoretical analysis on the performance of digital communication systems.