OFDM系统中一种最大似然信道估计算法

A Novel Maximum Likelihood Channel Estimation for OFDM Systems

基于正交频分复用(OFDM)技术的无线通信系统为获得较佳的系统性能,接收端必须进行信道估计。OFDM系统中基于最大似然(ML)准则的信道估计技术需要已知有效信道长度,现有ML信道估计算法没有提供一种有效的信道有效长度获取方案。本文在分析ML信道估计算法的基础上,提出利用线性搜索策略来确定信道的有效长度,提高了ML信道估计器的精度。在多径瑞利衰落信道下的仿真结果显示,该算法可以有效地跟踪有效信道长度,提高ML信道估计器的性能。

To acquire a better performance,the receiver in orthogonal frequency division multiplexing（OFDM） systems must estimate the channel state information.Maximum likelihood（ML） channel estimation for OFDM systems needs to know the effective length of channel impulse response for achieving optimum performance. Existing ML channel estimation schemes do not offer an available scheme to track the variation in effective length of channel impulse response.Based on the analysis that the ML channel estimator performance depends on the assumed effective length of channel impulse response,a modified ML channel estimator which combines the ML estimation with a policy of line search was proposed to improve the precision of the ML channel estimator.The simulated results under the multi-path Rayleigh channel show that the improved algorithm in this paper can track effective length of channel impulse response effectively and improve performance of the ML channel estimator.