一种基于子空间的OFDM载频盲估计方法

利用正交频分信号自身的结构特性,提出了一种基于子空间的载波盲同步方法:利用OFDM信号子空间与噪声子空间的正交性进行小数倍频偏估计;对小数倍频偏进行补偿后,根据整数倍频偏会引起信号自相关矩阵对角线上的非零元素在子载波间平移的特点进行整数倍频偏估计。给出了理论分析过程和仿真实验结果。仿真结果表明,该算法具有较大的频偏估计范围以及良好的估计精度,算法性能几乎不受信道条件及系统子载波调制方式影响,且该算法只需要较小的数据量就能获得稳定的频偏估计性能。另外,该文还对仿真中存在的实验误差来源进行了分析。

A subspace-based algorithm for blind carrier frequency estimation in OFDM systems

Taking advantage of signal structure in OFDM systems,a blind carrier synchronization algorithm based on subspace was proposed: estimate decimal frequency offset according to the character that signal subspace is orthogonal with noise subspace.After decimal frequency offset was estimated and compensated,taking advantage the character that integral frequency offset would result in movement of non-zero elements in auto-correlation matrix,the integral frequency offset was estimated.Theoretical analysis and simulation results are provided.The simulation results show that the proposed algorithm can estimate frequency offset in large scale.Furthermore,it can achieve a high resolution.During simulation,it is showed that the algorithm was robust to modulation mode of subcarriers and channel.Besides,the algorithm only needs little data to converge.This paper also analyzed error source of simulation.