Turbo编码OFDM系统中一种判决反馈的WLMS信道跟踪算法

在Turbo译码时对信息位和校验位都进行MAP译码,避免了传统基于译码再编码判决反馈信道估计和跟踪算法中反馈信号重构时的错误传播问题,降低了反馈信号的错误概率,提高了信道估计和跟踪的性能,解决了在信道变化较快条件下文献8]提出的维纳LMS(WLMS)算法信噪比门限过高的问题。仿真结果表明,算法性能接近理想判决反馈时的性能限,与直接判决反馈的维纳LMS算法相比,在系统误比特率为10~(-4)条件下系统性能约提高2dB。

A Wiener LMS Decision Feedback Channel Tracking Algorithm for Turbo Coded OFDM Systems

Not only the information bit but also the parity bit is decoded using MAP algorithm in the Turbo decoding,which a- voids the error propagation in the reconstruction of feedback signal in the decision-directed feedback channel estimation and tracking al- gorithm.The proposed method decreases the error rate of the feedback signal,improves the performance of channel estimation and tracking,and solves the high SNR threshold of8]under fast varying channel.The simulation results have shown that the performance of the proposed method is near the performance of ideal feedback,and compared with decision-direct feedback WLMS algorithm,the performance is 2dB better at a system BER of 10~(-4).