中文摘要：

现有的OFDM系统快时变信道估计方法均为时域估计方法,假定信道为整数倍采样信道,利用理想的等间隔均匀导频恢复信道时域响应函数,进而采用基扩展模型拟合并估计其时变特性。而实际的信道通常为非整数倍采样信道,频带内可用的导频也并非假定的理想模式。此时,恢复的信道时域响应出现能量泄漏,导致算法性能大大受限。本文提出一种频域快时变信道估计方法,利用信道频域时变传输函数辅助估计,从而估计得到信道频域响应矩阵。该方法在频域实现,性能不受信道时域响应能量泄露影响。仿真实验从误码率、均方误差两方面分别验证了该方法的有效性。

英文摘要：

Conventional fast Time-Varying （TV） Channel Estimation （CE） methods for Orthogonal Frequency Division Multiplexing （OFDM） systems are performed in the time-domain, which need optimal even-pilots to track the time-domain channel impulse response （CIR） variations over one symbol period by Basis Expansion Model （BEM）. And the multi-path channels are assmumed sample spaced. The required sample spaced channels and even-pilots are not satisfied in practical OFDM systems. As a result, the CIR leakage occurs and the estimation errors increase greatly. In this paper, a frequency- domain fast TV CE method for practical OFDM systems is proposed. The frequency-domain transmission function is used for estimation, and finally the frequency-domain channel matrix is obtained. The proposed method is performed in the frequec- ny-domain, so that it is immune to the time-domain CIR leakage. Simulation results demonstrate its validity in Symbol Error Rate （SER） and Mean Square Error （MSE）.