中文摘要：

OFDM系统对载波频偏（CFO）非常敏感，CFO破坏了子载波正交性从而引起载波间干扰（ICI）导致系统性能下降。本文分析了CFO对解调数据二阶统计特性的影响，提出了一种适用于频率选择性衰落信道下的非数据辅助的频偏估计方法，利用解调数据二阶统计量矩阵的对角能量提取CFO信息，可实现CFO的精确估计。该方法不需要发送导频数据和信道响应先验知识，因而提高了系统传输效率。文中同时给出了估计的闭环求解方法，大大简化了实现复杂度。最后对算法在多径信道环境下进行了仿真，结果表明本文提出的估计方法在低SNR时仍具有较好的估计性能。

英文摘要：

One of the main drawbacks of OFDM is its high sensitivity to carrier frequency offsets （CFO）. This gives rise to intercarrier interference （ICI） for the orthogonality of subcarriers is destroyed. In this paper,by the analysis on second-order of output data, we propose a blind CFO estimator with high bandwidth efficiency in the case of frequency-selective channels. The proposed algorithm utilizes the diagonal energy of demodulate data＇ s second-order matrix to estimate CFO accurately without the priori knowledge of transmitted data and the channel. So the algorithm yields high efficient bandwidth utilization and high resolution. A closed-form solution is derived to reduce the computation complexity. Finally, simulation results on CFO estimation are reported in multi-path channel model, which shows that the proposed estimator is highly accurate and robust even in low SNR.