为实现多输入多输出-正交频分复用（MIMO-OFDM）的盲信道估计,文中提出了斜投影子空间法,在满足算法识别系统的条件下,将接收信号空间划分为＂过去＂、＂现在＂、＂将来＂3个子空间,然后将＂现在＂子空间分别向＂过去＂、＂将来＂子空间进行斜投影,可以有效降低多径效应给接收系统带来的影响.文中给出了信道模糊矩阵的估计方法,采用了奇异值分解方法来提高算法的抗噪性能.通过与噪声子空间算法的比较,发现文中算法在牺牲少量估计精度的情况下可以大大降低计算复杂度.仿真结果表明该算法能有效地完成信道估计

Proposed in this paper is an oblique-projection subspace approach to the blind channel estimation of MIMO-OFDM system,which,under conditions of satisfying the identification system,divides the signal-receiving space into three subspaces including the ＂past subspace＂,the ＂present subspace＂ and the ＂future subspace＂.By obliquely projecting the ＂present subspace＂ respectively onto the ＂past subspace＂ and the ＂future subspace＂,the impact of multi-path effect on the receiving system can be effectively eliminated.In addition,a method to estimate the ambiguous matrix of channel is proposed,and the singular value decomposition is adopted to improve the anti-noise ability of the algorithm.It is found that,as compared with the noise subspace approach,the proposed approach is of lower computational complexity only with slight sacrifice of estimation accuracy.Simulated results show the proposed projection approach is efficient for identifying system channel.