高阶QAM信号多普勒参数联合估计算法

New Joint Algorithm of Doppler Parameter Estimation for High-Order QAM Signals

针对动中通卫星通信系统中QAM信号多普勒参数盲估计难的问题,提出了一种基于高阶循环累积量和相位差分的多普勒频率和变化率联合估计算法。无需定时同步和匹配滤波等预处理,通过检测QAM信号四倍频率处的循环频率来估计多普勒频率,并利用基于数据辅助的相位差分方法计算变化率。详尽的Monte Carlo仿真分析了不同信噪比、数据量的多普勒参数估计性能,结果表明,算法能有效实现高斯白噪声信道下QAM多普勒参数的联合估计。

Aiming at the difficulties of blind doppler parameter estimation for QAM signals in SCOTM（Satellite Communication on-the-move）,a new joint algorithm of blind doppler frequency and doppler-rate estimation are proposed based on cyclic-statistical tests and phase difference.The algorithm obviates the need for preprocessing tasks,such as symbol timing recovery and match filtering.By detecting the cyclic frequency of QAM signals,located at the quartic frequency,doppler frequency is effectively estimated,meanwhile,the data-aided phase difference method is exploited to calculate the doppler-rate.All-sided Monte Carlo simulations are employed to analyze the relationship between estimation performance and different SNRs,symbols.Experimental results indicate that the novel algorithm can accomplish blind doppler parameter estimation effectively under the condition of low SNRs and fading channels.