基于频域导频时域处理的OFDM系统信道估计算法

针对正交频分复用(OFDM)系统，提出了一种适用于时变信道的信道估计算法。该方法利用频域导频，经离散傅立叶变换(DFT)，获得的信道冲击响应等效于利用频域导频对应的时域序列和接收信号进行循环相关获得的信道冲击响应。因此，避免了在时域采用复杂的循环相关运算。同时，通过消除频域导频时域序列的自相关误差，能有效降低由DFT谱泄漏导致的信道估计误差。仿真和分析表明，在时变多径衰落信道下，提出的信道估计方法的性能比传统的基于DFT的算法和频域维纳滤波算法有明显提高。

A Channel Estimation Method Based on Frequency-domain Pilots and Time-domain Processing for OFDM Systems

A channel estimation method is proposed for OFDM systems in time-varying channels. Through Discrete Fourier Transform (DFT), the channel impulse response is estimated by using the frequency-domain pilots, which is equivalent to channel estimation achieved by cyclic correlating time-domain sequence of frequency-domain pilots with received signals. Hence, the complicated cyclic correlation in time-domain is evitable. At the same time, the channel estimation error, caused by the spectral leakage of DFT, can be reduced by canceling the auto-correlation error of the time-domain sequence of frequency-domain pilots. The theoretical analysis and simulation results show that the proposed method outperforms the traditional DFT based method and frequency-domain Wiener filter algorithm in time-varying multi-path fading channels.