一种改进的OFDM定时同步算法

摘要

Orthogonal Frequency Division Multiplexing (OFDM) is a special muti-carrier communication system, which is extremely sensitive to synchronization errors which can lead to severe system degradation.An improved training-sequence-based OFDM synchronization algorithm is proposed on the basis of the study of SC, Minn and Park algorithms.The training symbols of SC algorithm are used in the frequency domain in the new algorithm.The plateau in timing synchronization is eliminated by multiplying the special pseudo-random sequence in time domain.The frequency synchronization is finished by utilizing the good autocorrelation of the training sequence in the frequency domain.The simulation results show that the proposed scheme is more efficient in comparison with the conventional algorithm, the improved algorithm has a very sharp peak in synchronization position and a better performance in synchronization, and it is more accurate in symbol timing.The carrier frequency offset estimation is also improved.%OFDM系统是一种多载波通信系统,对同步误差非常敏感,同步不准确在很大程度上降低了系统性能.在SC算法、Minn和Park算法的基础上,提出一种基于训练序列的改进的OFDM同步算法.新算法在频域上使用SC算法的训练符号,并通过对训练符号在时域乘以特殊的伪随机序列来消除定时同步中的峰值平台问题,利用训练序列在频域良好的自相关性估计整数倍频偏.仿真结果表明,与传统算法相比,改进算法在同步位置具有很尖锐的峰值.同步性能更好,符号定时更精确,载波频偏估计也有所提高.