OFDM系统中多普勒频偏估计技术仿真研究

研究了移动信道中的最大多普勒频移估计技术。分析了一种基于循环前缀的多普勒频移估计算法,该算法通过计算正交频分复用（OFDM）符号已有的循环前缀的相关函数来获得最大多普勒频移。采用广义平稳非相关散射下的多径时变瑞利信道模型,对各个算法进行了仿真试验,比较了各个算法的性能。仿真结果表明,利用多普勒分集技术,可以显著降低误码率,提高系统在移动环境下的性能。

Simulation Study of Doppler Shift Estimation for OFDM Systems

The technology for maximum Doppler shift estimation in mobile channel is studied.A Doppler shift estimation algorithm based on the existing cyclic prefix of OFDM symbol is analyzed,and this algorithm,through calculating correlation function of the existing cyclic prefix of OFDM symbol,achieves the information of the maximum Doppler shift.In view of the contradiction between performance and computational complexity of traditional estimators,a simplified estimator for LS is proposed.With the multi-path time-varying Rayleigh channel model in the general-sense uncorrelated scattering,the BER curves for different channel estimation algorithms are compared.Simulation results show that the Doppler diversity technology could remarkably reduce the BER and improve the system performance in mobile environment.