首先分析了虚载波对基于离散傅里叶变换(DFT)信道估计的影响,结果表明,对于边缘子载波,由于虚载波部分导频信道信息缺失所引起的估计误差远大于噪声带来的估计误差,严重影响边缘子载波的信道估计性能.基于此分析,提出了一种低复杂度的正交频分复用(OFDM)信道估计方法,在边缘子载波,利用频域最小平方(LS)估计结果代替DFT估计结果,并给出了边缘子载波替换准则及此信道估计方法的均方误差下界.仿真结果表明,所提方法均方误差(MSE)及误码率(BER)性能优于频域LS估计和单纯基于DFT的估计.
Based on discrete Fourier transform(DFT) estimator, the effect of virtual subcarriers is analyzed. It is shown that, on edge subcarriers, the estimation errors caused by channel information missing are much larger than that caused by noise. Therefore the estimation errors of edge subcarriers are getting worse. A low complexity channel estimator is proposed. The proposed estimator takes the least square (ES) estimation instead of the DFT estimation on edge subcarriers. Then replacement criteria and the bound of mean square error(MSE) are presented. The simulation shows that the MSE and BER performances of the proposed method are better than that of LS estimator or DFT-based estimator.