基于波达方向矩阵的MIMO-OFDM系统载频偏移估计

MIMO-OFDM系统中设置虚拟子载波后,时域接收符号向量与经频域信道系数加权的频域发射符号向量之间通过一个范德蒙矩阵相互联系,且该矩阵的列向量的结构决定于载频偏移量。基于此,提出了一种采用波达矩阵方法、利用范德蒙矩阵的移不变结构完成载频偏移估计的闭式频偏估计方法。该方法综合地利用了多收发天线的空域分集效应,降低了信道零点对频偏估计性能的影响,有效地提高了估计的均方误差性能。仿真结果验证了不同天线配置情况下所提出算法的性能。

Carrier frequency offset estimation in MIMO-OFDM systems based on DOA-matrix

When virtual carriers are applied in MIMO-OFDM,the time-domain received symbols can be represented as product of a Vandermonde matrix and frequency-domain symbols vector weighted by frequency-domain channel coefficients,and the structure of each column of such Vandermonde matrix is determined by CFO.Therefore,a DOA-matrix based closed-form CFO estimation algorithm is proposed based on the shift invariance structure of Vandermonde matrix.The proposed algorithm can combat channel null by exploiting spatial diversity introduced by multiple transmit and receive antennas,improves the performance of CFO estimation.Simulation results verify the performance of the proposed method for systems with different array configurations.