中文摘要：

基于变分贝叶斯期望最大化（VBEM,variational Bayes expectation maximization）算法和Turbo原理,提出了时变信道条件下MIMO-OFDM系统中的联合符号检测与信道估计算法。设计的软入软出空时检测器在采用列表球形译码避免穷尽搜索的同时,考虑了信道估计误差方差矩阵的影响;利用空时检测获得的发送信号后验概率分布估计,推出了新的Kalman前向后向递归信道估计器。仿真结果表明,在时变多径信道条件下,提出的算法比传统EM算法和面向判决算法更加具有顽健性。

英文摘要：

A new joint symbol detection and channel estimation algorithm was proposed for MIMO-OFDM systems over the time-varying fading channel based on the variational Bayes expectation maximization algorithm and Turbo principle.The channel estimation error covariance matrix was considered in the soft-input soft-output detector which circumvented the undesirable exhaustive search via list sphere decoder（LSD）.In addition,a novel Kalman forward-backward channel estimator was derived based on the posterior distributions of the transmitted symbols which were obtained from the space-time detection.Simulation results show that the proposed algorithm has more robust performance than the conven-tional EM algorithm and decision-directed technique in the time varying multipath channel.