基于高阶累积量和循环谱的信号调制方式混合识别算法

Mixed Recognition Algorithm for Signal Modulation Schemes by High-order Cumulants and Cyclic Spectrum

为了识别当前通信系统所采用的主要调制方式,该文结合高阶累积量和循环谱的特点,采用混合识别算法,同时应用智能决策算法(神经网络)对信号进行识别。该算法基于四阶和六阶高阶累积量构造出一个新的特征参数,将数字调制信号分为{BPSK,2ASK},{QPSK},{2FSK,4FSK},{MSK}和{16QAM,64QAM}5类。然后利用高阶累积量的其它特征参数以及循环谱特征对{OFDM},{16QAM,64QAM},{2ASK,BPSK}及{2FSK,4FSK}进行识别。为便于工程实现,该文采用半实物仿真以及Lab VIEW和MATLAB混合编程来验证算法。仿真结果证明,该算法能够在较低信噪比下实现对{OFDM,BPSK,QPSK,2ASK,2FSK,4FSK,MSK,16QAM,64QAM}等多种信号的分类,在信噪比高于5 d B时,调制方式识别率可达94%以上,由此证明了该方法的有效性。

To recognize the major modulation schemes which are applied to concurrent communication systems, a joint method based on the high-order cumulants and cyclic spectrum with intelligent decision algorithm（neural network） is proposed to recognize the modulation schemes for digital signals. Firstly, a new featured parameter is extracted from the four-order and six-order cumulants of the digital signals to identify the modulation schemes of {BPSK, 2ASK}, {QPSK}, {2FSK, 4FSK}, {MSK}, and {16QAM, 64QAM}, then {OFDM}, {16QAM, 64QAM}, {2ASK, BPSK}, and {2FSK, 4FSK} are classified by the other featured parameters of the joint high-order cumulants and cyclic spectrum algorithms. In order to facilitate the engineering implementation, the semi-physical simulation and mixed programming of Lab VIEW and MATLAB are used to validate the proposed algorithms. Simulation results show that the algorithms can recognize modulations {OFDM, BPSK, QPSK, 2ASK, 2FSK, 4FSK, MSK, 16 QAM, 64QAM} with small Signal-to-Noise Ratio（SNR）. The average recognition rate is more than 94% with SNR greater or equal than 5 d B, which validates the effectiveness of the proposed algorithms.