基于直接判决和导频跟踪的OFDM系统快时变信道估计

Channel estimation for time varying channel based on decision directed technique in OFDM mobile systems

提出了一种基于直接判决的OFDM系统的快时变信道估计方法。采用了直接判决算法进行信道估计,并从中选择有效的估计结果,联合导频信号进行信道跟踪。将基于训练序列的信道估计结果作为直接判决算法的初始值,利用传输信号直接判决的统计特性进行了信道估计,并利用改进的导频算法进一步地跟踪信道在时间上的变化。Simulink仿真结果表明,该估计算法适用于时变信道,比基于导频的信道估计方法和基于训练序列的信道估计方法效果都要好。

A channel estimation method was proposed based on decision directed technique and pilot tracking for OFDM WLANS with mobile terminals. The result of training sequence based estimation was used as the initialization of decision directed technique. With the help of the decision symbols, the statistical characteristics of the transmitted data via the fading channel were applied for the channel estimation. Some reliable estimated results combined with pilot were used to track the change of the fading channel. The simulation results show that the proposed method has better performance than training sequence based or pilots based channel estimation method.