本文针对城市复杂信道环境下的最大多普勒频移估计需求,根据莱斯衰落信道中电平通过率(LCR)算法的理论推导,提出了一种基于噪声匹配的最大多普勒频移估计算法.所提算法通过对接收信号进行低通滤波处理,实现干扰噪声与多普勒检测器之间的匹配,从而有效提高最大多普勒频移的估计性能.而且基于莱斯衰落信道下最佳滤波比值的分析和推导,得到关于所提算法估计误差的两个重要推理.蒙特卡罗仿真结果表明:在低信噪比(SNR〈0dB)的典型城市环境下,相比于现有的对数包络(LE)算法和修正自相关函数(MCOV)算法,所提算法提高了估计性能2~5dB,从而保证了最大多普勒频移的准确估计和移动通信系统的接收性能.
According to the demand of maximum Doppler shift estimation under the urban complex channel environment,a novel maximum Doppler estimation is proposed based on noise matching.Through a low-pass filter designed(LPF) to filter the received signal,interference noise and the Doppler detector can be matched,thus the estimation performance of the maximum Doppler shift is increased effectively.Furthermore,by theoretical deduction of the best filtering ratio in Rice fading channel,two important deductions about the estimated error of proposed algorithm are presented.Monte-Carlo simulation results show that compared with the existing algorithms based on logarithmic envelope(LE) and modified covariance(MCOV),the proposed algorithm improves estimation performance by 2~5dB under the typical urban environment and low signal-noise-ratio(SNR0dB) conditions.Therefore,proposed algorithm can ensure an accurate estimation of maximum Doppler shift and the receiving performance of mobile communication systems.