OFDM系统中基于补零DFT信道插值算法的研究

针对OFDM系统中基于补零DFT实现信道插值的算法,对传统的时域方法和变换域方法进行了分析,并提出了一种新的补零方法。首先通过理论分析指出传统的基于补零DFT实现信道插值算法中,时域方法和变换域方法是等效的；通过对信道插值算法中冲激响应估计序列进行补零的分析,指出补零操作是为了重构出冲激响应的 点采样序列( 表示总子载波数),并针对传统补零方法在一定条件下产生的重构误差,提出了一种新的补零方法。仿真结果表明以上理论分析是正确的,新补零方法可以减小一定条件下的重构误差,增强信道插值算法对信道延迟分布的鲁棒性,有效提高系统的性能。

A Study of Channel Interpolation for OFDM Systems based on Zero-Padding DFT

Channel interpolation methods based on zero-padding DFT for OFDM systems are investigated. Two conventional interpolation schemes for channel estimation are analyzed. Analysis shows that those two methods are equivalent, and zero padding is to reconstruct the channel impulse response samples of length N, where N is the number of total subcarriers. The reconstruction error of conventional zero-padding methods is discussed, and a new zero-padding method is proposed. Simulation results show that the above analysis is correct, and the reconstruction error of channel impulse response is decreased by the proposed method in some channel conditions. Furthermore, the channel interpolation with the proposed zero-padding method is robust to the distribution of path delay, and the performance of system is enhanced.