基于对称相关谱和累积量切片的QAM信号识别

A Recognition Algorithm for QAM Signals Based on Symmetric Correlation Spectrum and Cumulant Slice Value

随着正交振幅调制信号(Quadrature Amplitude Modulation,QAM)的广泛应用,对其调制方式的识别显得至关重要。针对M-QAM的四次方谱谱线特征在低信噪比时对调制信号识别率低,且计算复杂度高等问题,提出了一种基于信号四次方的对称相关谱和四阶累积量的一维切片值的M-QAM调制方式的盲识别算法。该算法无需波特率和采样率等先验信息,没有复杂的迭代过程,可以应用于实际信号的调制识别,对NI USRP-2930无线接收平台接收的信号进行识别。实验结果表明,提出的算法在低信噪比下具有较高的识别率、实用性和有效性。

Blind recognition of high order Quadrature Amplitude Modulation（QAM） signals is crucial as it is widely applied in the wireless communication system.The features of M-QAM based on quartic spectrum suffer from computational complex and its performance is unsatisfactory in low Signal-Noise Ratio（SNR） environment.Aiming at this problem,a blind modulation recognition algorithm has been proposed based on quadratic symmetric correlation spectrum and one-dimensional slice value of fourth-order cumulant,which needs not complicated iterative process and requires no priori information such as baud rate and sampling rate.Thus it can be applied to the modulation recognition for practical signals.Experimental results indicate that the proposed algorithm which is to recognize signals transmitted and received by NI USRP-2930 is practical and feasible,and performs well at low SNR.