α稳定分布噪声下基于EM算法的多径时延估计算法

A multipath time delay estimation algorithm based on EM algorithm under α-stable distribution impulse noise environment

实际应用中大量非高斯信号和噪声具有显著的尖峰脉冲特性.这类信号带宽较窄,采用传统高斯模型下基于相关运算的多径时间延迟方法进行时延估计时,会因各个峰值的相互重叠而带来较大的估计误差.为此,根据信号噪声特性,在α稳定分布模型下,提出一种基于EM方法的高分辨率多径时延估计算法(P-EM算法).新算法基于分数低阶统计量理论,采用p阶相关思想,具有在脉冲噪声环境下,比较准确估计多径时间延迟的能力.理论分析和计算机仿真表明了该算法的韧性.

Bandwidth of non-Gaussian signals and noises in practical applications is narrow. If simply using correlation algorithm in traditional Gaussian model to estimate the multipath time delays, peak values will overlap each other. So it will bring on large estimate errors. To solve this problem, according to the characteristics of signal and noise and the theory of the fractional lower order statistics, a super resolution multipath time delay estimation algorithm referred to P-EM is proposed. It is based on the EM （expectation-maximization） algorithm using the pth-order correlation and can be applied under α-stable distribution noise. It is shown that the proposed approach is robust through the theoretical analysis and the computer simulations.