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针对通信对抗和QAM信号解调的实际应用,建立多径和频率选择性衰落信道下的QAM信号模型,提出一种利用特定高阶循环累积量估计星形QAM载波的方法。通过理论分析可证明在平稳和非平稳高斯噪声背景和衰落信道特性下,星形8、16QAM信号的特定四阶循环累积量仅在载波位置处存在,因此可通过检测此循环频率实现载波的估计。该算法可推广到更高阶星形QAM信号。仿真实验验证了该算法的有效性。
Aiming at the practical applications of communication countermeasures and QAM signal demodulation, a QAM signal model under multipath and frequency selective fading channels is established. A method to estimate the star QAM carrier using a specific high order cyclic cumulant is proposed. Theoretical analysis shows that, under steady and non-stationary Gaussian noise background and fading channel characteristics, the specific fourth-order cyclic cumulants of star 8,16 QAM signal exist only at the position of the carrier, so the estimation of the carrier can be achieved by detecting this cycle frequency . The algorithm can be extended to higher order star QAM signals. Simulation results show the effectiveness of the algorithm.