针对在瑞利衰落信道下正交幅度调制(QAM)信号识别难的问题,利用多天线空间分集可以提高接收信号信噪比的特点,提出了一种基于多天线接收分集技术的识别方法.首先给出等增益分集用于调制分类的模型,然后使用非线性最小二乘估计器联合估计正交幅度调制信号的载波频偏和衰落相位,并推导合并器输出信号的四阶累积量和六阶累积量的理论值,最后使用四阶累积量和六阶累积量两个特征联合进行分类识别.仿真结果表明所述算法的有效性和正确性,且与已有的混合似似然比检测(qHLRT)方法相比,有较小的计算复杂度和较强的实用性. Aiming at the problem of quadrature amplitude modulation (QAM) signal identification under Rayleigh fading channel, the use of multi-antenna space diversity can improve the signal-to-noise ratio of the received signal and propose a method based on multi-antenna receiver diversity. The equal gain diversity is used to modulate the classification model. Then, the nonlinear least squares estimator is used to jointly estimate the carrier frequency offset and fading phase of the quadrature amplitude modulated signal, and the fourth cumulant and sixth order of the combiner output signal are derived. The theoretical value of the cumulant is calculated and finally the fourth-order cumulant and the sixth-order cumulant are combined to classify and recognize them.The simulation results show the effectiveness and correctness of the proposed algorithm and the hybrid likelihood ratio detection Compared with the qHLRT method, it has less computational complexity and strong practicability.