中文摘要：

基于频域训练序列，深入地分析了MIMO—OFDM系统中基于多项式建模的频偏估计问题．设计训练序列使其结构满足适当的条件，根据相应矩阵的厄尔密特属性和实对称属性，分析出代价函数多项式方程根的成对性，进而提出整数频偏与小数频偏可同时通过直接多项式求根方法估计出来．分析了导数多项式求根方法与直接多项式求根方法，研究出代价函数多项式与其导数多项式具有公共的多项式因子，且代价函数多项式可以表示成该公共多项式因子的二次型，并进一步揭示出二者在估计上的等效性以及后者在实现上的优越性．计算机仿真结果验证了该理论分析结果．

英文摘要：

Based on the frequency domain training sequences, the polynomial-based carrier frequency offset （CFO） estimation in multiple-input multiple-output （ MIMO ） orthogonal frequency division multiplexing （ OFDM ） systems is extensively investigated. By designing the training sequences to meet certain conditions and exploiting the Hermitian and real symmetric properties of the corresponding matrices, it is found that the roots of the polynomials corresponding to the cost functions are pairwise and that both meger CFO and fractional CFO can be estimated by the direct polynomial rooting approach. By analyzing the polynomials corresponding to the cost functions and their derivatives, it is shown that they have a common polynomial factor and the former can be expressed in a quadratic form of the common polynomial factor. Analytical results further reveal that the derivative polynomial rooting approach is equivalent to the direct one in estimation at the same signal-to-noise ratio（SNR） value and that the latter is superior to the former in complexity. Simulation results agree well with analytical results.