稀疏信道下基于变换域的上行OFDMA信道估计方法

Channel estimation method for OFDMA systems based on transform-domain processing for sparse multipath channels

单用户正交频分复用(OFDM)系统通常使用插入的频域导频获得信道频域响应(CFR),将此CFR变换到时域进行滤波以获得更准确的信道估计。上行正交频分多址接入(OFDMA)系统中由于每个用户信号占用不同的子载波且经过的信道不同,使用上述方法会由于窗函数畸变产生能量泄漏。该文提出一种时域滤波频域补偿(TFFC)方法,使用补偿向量对时域滤波后的CFR进行补偿,降低变换域算法中由于畸变引起的能量泄漏,并给出在稀疏信道条件下该补偿向量的简化解。仿真表明:采用该方法,上行OFDMA信道估计的性能得到很大改善。

In orthogonal frequency division multiplexing（OFDM） systems,the inserted frequency domain pilots can be used to get the initial channel frequency response（CFR）,with transformation to the time domain and filtering to get a better CFR.In Orthogonal frequency division multiuser access（OFDMA） systems,users occupy different subcarriers and go through different channels.The original transform-domain method will lead to frequency leakage because of the frequency domain window.This paper presents a scheme that uses a selected vector to compensate the filtered CFR,as a time domain filter with frequency domain compensation（TFFC）.The vector compensates for the frequency leakage.Simulations show that this scheme improves the channel estimation performance.