基于EM算法的MIMO OFDM系统信道估计

EM-based Channel Estimation for MIMO OFDM Systemy

针对慢时变频率选择性MI MO OFDM(Multiple Input Multiple Output Orthogonal Frequency Division Multi-plexing)系统,提出一种低复杂度的信道估计算法。文中所用方法是STBC(space-ti me block coded)MI MO OFDM系统中一种基于EM(Expectation Maxi mization)的自适应信道估计技术。仿真结果显示在慢衰落环境下,随着用户数的增加,最小均方误差性能没有损失。与RLS(Recursive Least-Squares)算法比较,本文所提出的方法利用了Alamouti STBC编码结构,从而降低了计算复杂度。

We propose a low complexity algorithm for channel estimation of Multiple Input Multi ple Output Orthogonal Frequency Division Multiplexing systems in slow time-varying frequency selective environment. The proposed algorithm was an adaptive channel estimation technique based on an expectation maximization algorithm for space-time block coded MIMO OFDM systems. Simulation results show that in slow fading environment there was no degradation in normalized mean square error as we increased the number of users. Comparing the Recursive LeastSquares algorithm, the proposed algorithm exploits the structure of Alamouti STBC codes to reduce computational complexity.