基于多特征融合的卫星信号调制方式识别  

Satellite Signal Modulation Pattern Recognition Based on Multi-feature Fusion

作　　者：李云涛 边东明 张更新 LI Yuntao;BIAN Dongming;ZHANG Gengxin(School of Communications and Information Engineering,Nanjing University of Posts and Telecommunications,Nanjing,Jiangsu 210003,China;School of Communications Engineering,Army Engineering University of PLA,Nanjing,Jiangsu 210000,China)

机构地区：[1]南京邮电大学通信与信息工程学院,江苏南京210003 [2]陆军工程大学通信工程学院,江苏南京210000

出　　处：《信号处理》2024年第7期1298-1306,共9页Journal of Signal Processing

基　　金：国家自然科学基金(U21A20450);2021-JCJQ-LB-006重点实验室基金项目(6142411422118)。

摘　　要：面向卫星通信中常用的QPSK类调制方式识别问题,提出了一种联合了谱特征、瞬时统计特征、高阶累积量特征和幅度分布特征的调制识别算法。算法在信号预处理与频域检测的基础上,首先利用速率信号谱特征和二次方谱特征识别出OQPSK和BPSK,然后分别利用频谱重心法和速率信号法估计信号的载频、带宽和符号速率等参数,并从正交下变频及匹配滤波后的符号定时同步后的复信号中提取高阶累积量特征参数,将剩余信号分类为调相信号和幅相调制信号,最后联合四次方谱特征和幅度分布特征完成所有调制方式的识别。仿真结果表明算法对频偏不敏感,于16APSK和32QAM的识别性能也比传统的基于高阶谱的方法要好,且算法在信噪比为6 dB时除16QAM和64QAM外的调制方式识别率为100%。最后,用信号源和采集卡搭建测试平台,九种实采信号的分类结果验证了算法的有效性,由于经频谱重心法估计出的载频存在一定误差,再次证明了该算法对频偏不敏感。A modulation identification algorithm is proposed to address the problem of identifying QPSK-type modulation modes commonly used in satellite communications.The algorithm combines spectral,instantaneous statistical,higher-order cumulative,and amplitude distribution features.Based on signal pre-processing and frequency domain detection,the algorithm first uses rate signal and quadratic spectral features to identify the OQPSK and BPSK modulation modes.It then estimates parameters such as carrier frequency,bandwidth,and symbol rate using the spectral centroid and rate signal methods.It extracts higher-order cumulative feature parameters from the complex signal after orthogonal frequency down-conversion and matched filtering for symbol timing synchronization.The remaining signals are classified as either phase or amplitude shift keying signals.Finally,the algorithm uses fourth-order spectral and amplitude distribution features to identify all modulation modes.Simulation results showed that the algorithm is insensitive to frequency offsets and exhibits better identification performance for 16APSK and 32QAM than traditional methods based on higher-order spectra.Furthermore,at a signal-to-noise ratio of 6 dB,the algorithm achieved a 100%detection rate for modulation modes other than 16QAM and 64QAM.To validate the effectiveness of the algorithm,we constructed a test platform using a signal source and acquisition card.The classification results of nine actual acquisition signals confirmed the effectiveness of the algorithm.In addition,the presence of inherent errors in the carrier frequency estimation using the spectral centroid method highlighted the insensitivity of the algorithm to frequency offsets.In conclusion,the pro-posed algorithm combines multiple features and successfully identifies commonly used QPSK-type modulation modes in satellite communications.The algorithm exhibits robustness against frequency offsets and achieves high recognition rates for various modulation modes,making it a valuable solution for mod

关 键 词：卫星通信 谱特征 瞬时特征参数 高阶累积量 调制信号识别 

分 类 号：TN911.3[电子电信—通信与信息系统]