相关分块衰落信道下基于因子图EM算法的解码方法  

Joint estimation-decoding approach based on factor graph expectation maximization algorithm over correlated block fading channels

作　　者：颜斌[1] 贾霞[1] 王小明[2] 郭银景[1] 郝建军[1] 

机构地区：[1]山东科技大学信息与电气工程学院,山东青岛266590 [2]移动通信国家重点实验室(东南大学),南京210096

出　　处：《计算机应用》2013年第3期607-610,共4页journal of Computer Applications

基　　金：国家自然科学基金资助项目(61272432);山东省自然科学基金资助项目(ZR2011FM018);青岛市科技计划项目(12-1-4-6-(10)-jch)

摘　　要：针对相关分块衰落信道模型,提出一种基于因子图期望最大化(FGEM)算法的联合估计解码方法。在接收机中,采用因子图消息传递方法进行信道估计和迭代解码,并引入期望最大化(EM)算法来消除因子图模型中存在环路对消息传递的影响,同时解决了消息传递中的混合高斯消息计算的问题。采用卡尔曼前后向算法代替最大化步消息更新过程,简化了消息的迭代计算,降低了联合解码和估计的复杂性。实验结果表明,与只有导频辅助方法和判决方法相比,该算法进一步提高了信道估计的准确度和接收机的解码性能。To deal with the channel uncertainty of the correlated block fading channels, a joint estimation-decoding approach based on Factor Graph Expectation Maximization （FGEM） algorithms was proposed. In the receiver, a message passing method on factor graph was adopted to jointly estimate the channel and decode the message. EM algorithm was used to remove the effect of loops on the convergence of message passing. It also solved the calculation problem of Gaussian mixture message. The calculation of message passing was simplified by the Kalman forward-backward algorithm, which resulted in reduced complexity in joint estimation-decoding. The simulation results show that the proposed algorithm can improve the accuracy of the channel estimation and improve the decoding performance.

关 键 词：信道估计 相关分块衰落信道 因子图 期望最大化算法 

分 类 号：TN921[电子电信—通信与信息系统]