基于高阶累积量的同频16QAM信号的盲频偏估计算法

Blind frequency offset estimation algorithm of two co-frequency 16QAM signals based on high-order cumulants

在现代海事卫星通信中,广泛存在同频干扰问题,使得载波频率受到了干扰。在实际非合作通信研究中,针对两个同频率的16QAM调制的单通道信号的频偏估计,提出1种基于高阶循环累积量的盲频偏估计算法来解决。本文建立1个降维模型来证明2个同频16QAM信号的四阶循环累积量不受交叉项的干扰,当且仅当循环频率等于频偏时才成立。理论分析和仿真结果均验证了该算法的准确性和有效性,利用混合信号的Cramer-Rao界对该算法的性能进行了评价。与其他频偏估计算法相比,该方法不需要任何先验信息,对振幅、延迟、相位偏移等未知参数不敏感。

In modern maritime satellite communications,there is a widespread problem of co-frequency interference,which makes carrier frequency information interfered.In practical non-cooperative communication research,aimed at the frequency offset estimation(FOE)of two co-frequency 16 QAM signals in the single-channel,a blind FOE algorithm based on high-order cyclic cumulants is proposed.We build the reduced-order model to prove two co-frequency 16 QAM signals’fourth-order cyclic cumulants can’t be interfered by the cross-term and it only exists when the cyclic frequency equal to the frequency offset.Theoretical analysis and simultion results both verify that the algorithm is accurate and efficient.Cramer-Rao bound of mixed-signals’FOE is used to evaluate the performance of the proposed algorithm.Compared with other FOE algorithms,this method does not require any prior information and it is insensitive to unknown parameters,such as amplitude,delay and phase offset.