一种高阶QAM信号多普勒频率参数估计算法

A DOPPLER PARAMETERS ESTIMATION ALGORITHM FOR HIGH-ORDER QAM SIGNALS

为了解决高阶QAM信号载波同步中动态多普勒参数估计问题,提出一种基于调频信号相位多项式系数估计的方法。该方法针对QAM信号去调制后的信号表达式构造二次相位(QP)函数,通过估计二次项系数得到多普勒频率变化率的估计值。进一步依据最大似然准则估计一次项相位系数得到多普勒频率估计值。最后用取主值的方法进行相位估计。计算机仿真实验表明,该算法能有效应用于高阶QAM信号的动态多普勒参数估计。

To solve the problem of dynamic Doppler parameters estimation in the carrier synchronisation of high-order QAM signals,we propose a method which is based on phase polynomial coefficients estimation of frequency modulation signals. The method constructs a quadratic phase（ QP） function for the expression of QAM signals which have been wiped off the modulation information,and obtains the estimated value of Doppler frequency variation rate through the estimation of the quadratic term coefficient. In the next step,the algorithm gets the estimated Doppler frequency value by estimating the linear term coefficient of phase in compliance with the ML rule. Finally,the phase is obtained with principal value taken approach. Computer simulation experiments indicate that the proposed algorithm can be effectively applied in dynamic Doppler parameters estimation for high-order QAM signals.