多径信道下OFDM系统的采样频率偏移盲估计方法

Blind estimation algorithm of sampling frequency offset for the OFDM system over multipath channels

为提高实际的非合作通信系统中正交频分复用系统的采样频率偏移估计性能,提出了一种多径衰落环境下、非合作通信系统中、时频同步之前的正交频分复用系统采样偏移估计的新方法.该方法先利用一种改进循环谱对谱相关点进行粗估计,再利用另一种改进的循环谱对谱相关点进行细估计,最后根据估计出的相关点上循环谱的相位值,经跳变转化、最小二乘直线拟合后计算出相位变化率,得到正交频分复用系统采样偏移的估计值.仿真结果表明,该方法在多径信道条件下,比现有的盲估计方法具有更高的估计精度与性能.

In order to improve the performance of sampling frequency offset（SFO） estimation for the Orthogonal Frequency Division Multiplexing（OFDM） system in practical non-cooperation communications, this paper proposes a new sampling frequency offset estimation for the OFDM system estimation algorithm in multipath fading channels and the non-cooperation communications system.The proposed algorithm first uses an improved cycle spectrum to make a coarse estimation of the relative point,and then estimates accurately the relative point through another improved cycle spectrum.Finally,the estimated values of sampling frequency offset are obtained by the rate of change of the phase of the cycle spectrum in the relative point after j umping phase change and least square fitting.Simulation results show that the proposed algorithm has not only higher estimation accuracy but also better performance over multipath channels.