MIMO-OFDM系统Turbo接收机中的信道估计器

Channel Estimator for Turbo Receiver in MIMO-OFDM Systems

设计了一种新的MIMO-OFDM系统Turbo接收机中的信道估计器。考虑了信道估计误差对编码比特外信息计算的影响,利用软球形译码器的搜索列表和解码器反馈的先验信息对传统EM信道估计中的软信息近似处理进行了修正,获得了更为准确的软符号统计信息用于信道估计,提出了考虑软符号互相关性的Bayesian EM(BEM)信道估计算法。仿真结果表明,新算法较传统EM算法具有更低的误码率和更小的估计均方误差值。

A new channel estimator is proposed for Turbo receiver in MIMO-OFDM systems. The channel estimation error was taken into account in the evaluation of the extrinsic information for the coded bits. With the help of the candidates list of the list sphere decoder （LSD） and a prior information from the decoder, the approximation of the soft information in the conventional EM channel estimator was amended, and the statistic information of the soft symbols was improved for channel estimation. A new Bayesian EM channel estimation algorithm, which considers the autocorrelation of the soft symbols, was obtained. The simulation results show that the newly proposed algorithm has better performance in terms of both BER and mean square estimation error in comparison with the conventional EM algorithm.