基于IEEE802.11ad的OFDM线性拟合频偏估计

Frequency offset estimation algorithm for OFDM based on IEEE802.11ad

提出了一种基于IEEE802.11ad的正交频分复用(OFDM)频偏估计算法,该算法将接收到的训练序列与本地保存的训练序列共轭相乘,对其相位角进行线性拟合,得到的斜率经过简单计算即得归一化频偏.通过数据消噪和分组对算法进一步改进,使得低信噪比下的估计性能得到改善.Matlab仿真表明:在高斯(加性高斯白噪声)信道和60GHz多径信道下,改进的线性拟合方法性能稳定,频偏估计精度比传统的时频域估计高1个数量级,当信噪比为0dB时,频偏估计的均方差达到10-4数量级,从而满足了OFDM系统的技术要求.

A frequency offset estimation algorithm for orthogonal frequency division multiplexing(OFDM)based on IEEE802.11 ad was presented.The algorithm multiplied the locally conjugate training sequence stored by the training sequence received and extraction its phase angle.Then linear regression for phase angle fitting was made,and the normalized frequency offset was obtained by simple calculation.In order to further improve the performance of algorithm in low signal noise ratio(SNR)environment,the receiver would process data by reducing noise and grouping data.Simulations show that the improved algorithm has stable performance and the estimation accuracy beyond the traditional algorithm one order of magnitude over additive white Gaussian noise(AWGN)channel and multipath channel,which meets the requirements of OFDM system.