MIMO-OFDM系统自适应信道估计算法分析

Analysis of an Adaptive Channel Estimation Algorithm for MIMO-OFDM Systems

在MIMO—OFDM系统中,信道参数估计对相干检测至关重要。现有的信道估计算法大多需要对大矩阵做求逆运算,计算复杂度高,或者需要预知信道统计信息。提出一种MIMO—OFDM系统的自适应信道估计算法,无需任何先验信道统计信息,就能够通过导频辅助和迭代的方法对时变信道状态参数进行即时跟踪与估计。仿真结果表明在MIMO—OFDM系统中,提出的基于LMS或RLS的自适应信道估计算法相比于传统的不考虑噪声的LS信道估计算法,MSE和BER等性能均有大幅提高,能够很好地抵御无线信道引起的多径效应的影响,适宜应用于MIMO-OFDM系统。

The paper proposes an adaptive channel estimation algorithm. Although it doesn＇t require any prior knowledge of channel statistics, this algorithm can track and estimate time - varying channel parameters instantaneously with the help of pilot - aided and iterative methods in MIMO - OFDM systems. Simulation results have proved that the adaptive algorithm has better MSE and BER performances than LS algorithm which is without the effect of noise. Where the adaptive algorithm based on LMS has the characteristics including low computational complexity and BER performance which approximates the one of the adaptive algorithm based on RLS in fast mobile channel. However, the adaptive algorithm based RLS has better performance and faster convergence than that based on LMS.