【作者】 黄玉春；

【导师】 黄载禄；

【作者基本信息】 华中科技大学 ， 信息与通信工程， 2007， 博士

【摘要】 通信信号辐射源个体识别针对同型号、同批次、相同工作方式的不同辐射源,从接收信号中提取出最能反映辐射源个体差异的细微特征矢量,结合高效实时分类识别策略实现在线的个体识别,在未来电子侦察、无线网络安全及通信资源管理等应用领域将发挥巨大作用。不同于传统的通信领域研究信息传输的高效可靠性,通信信号辐射源个体识别研究重点转向了调制信息背后隐藏的、由于辐射源器件性能参数、非线性差异在接收信号中留下的、可全面刻画信号辐射源的细微特征集合。本文首次系统地基于通信信号辐射源稳态工作时采样到的信号,深入研究了辐射源个体的细微特征产生机理及提取方法,以极致学习机为基础,提出了自适应在线序贯式极致学习机SLFN网络训练算法用于辐射源个体的在线分类识别,取得了很好的识别效果。论文主要工作包括:1、从理论和工程应用的角度出发,提出了以离散HT变换为基础的通信信号测量特征提取理论与方法,包括:基于解绕相位信息的载频线性拟合估计方法和基于绝对包络信息的数字通信信号的码元速率估计方法等,大量仿真和实测结果显示了本文所提方法精确有效且易于实现。2、为提取包括FM信号调频指数和数字通信信号调制参数在内的调制特征信息,提出了基于FFT迭代插值和CZT的两种通用且易于DSP实现的高性能单音信号参数估计方法,前者通过动态对称频率偏差估计器的不断迭代过程,自适应地调整估计精度,不仅测量精度较传统FFT插值方法高,而且信噪比门限要求低、速度快、全频率范围内性能表现均很接近CRLB下限;后者借助一定的先验知识,提高了频率分辨率,对短时平稳和存在近邻分量干扰时的单音信号参数估计,结果准确且稳定一致,十分接近CRLB下限,具有更强的抵抗近邻分量干扰和噪声的能力。3、基于通信信号非线性寄生幅度调制杂散输出特征和欠采样技术提出的特征双谱,有效地将信号固有自发频率分量与因非线性QPC所致的频率分量区分开来,保留了高阶谱分析的所有优点同时又大大减少了分析时间,基于积分围线的特征双谱选择结合了积分双谱和选择双谱的优点,抗噪性强、无交叉项干扰、计算简单高效,有效完成了2-D特征双谱向1-D矢量特征的转化,表现出较强的区分能力。4、针对辐射源个体的时频特性,提出了基于EMD时频谱熵的杂散特征提取方法。EMD时频谱熵从自适应时频分布的角度分析了杂散输出的非线性、非平稳特征,基于相关程度的分解结束标准加快了EMD分解的速度,熵的概念的引入有效刻画了EMD时频分布谱图的能量分布均匀程度,以标量形式简单刻画了辐射源个体识别的时频能量分布,具备一定的区分能力。5、在极致学习机算法的基础之上,利用回归拟合、正交化等相关技术,提出了SLFN网络中随选隐点对网络学习精度的贡献度指标,实现了网络模型的自适应逐一或成块递增式确定方式,结合序贯式学习的需要,提出了自适应在线序贯式极致学习机算法,实现了SLFN网络的自适应在线序贯式学习,全过程无需人工参与、对训练样本的到达方式和次序无任何要求,提升了算法的通用性,减少了对硬件设备计算存储能力的要求,大量仿真和实测结果说明了其简单有效性,对于FM、FSK实测通信信号辐射源个体的识别率均可达到85%以上。此外,结合论文研究的需要,本文基于COM组件技术和数据库技术建立了通信信号辐射源个体识别的软件系统,该系统可根据评价辐射源细微特征的衡量标准,从载频、调制参数和杂散输出差异等对辐射源个体进行识别。更多还原

【Abstract】 Communication signal transmitter recognition includes not only characteristicfine feature extraction from the sampled sequence generated by di?erent transmitterswith the same expected performance parameters and modulation mode, which actsas a comprehensive representation of the transmitters , but a highly e?cient andreal-time classification strategy to implement the online transmitter recognition. Itis of great significance and role in future electronic warfare, wireless network securityand communication resource management.Unlike usual e?ciency- and reliance- oriented communication theory, communi-cation signal transmitter recognition focuses on the hidden fine feature set associatedwith the variances in actually working performance parameters and nonlinear prop-erty of the device and cares no details about modulated information. This papersystematically and thoroughly discusses the generating mechanism and extractionmethods of fine features from the sampled signal observations of di?erent steady-working transmitters for the first time, proposes an adaptive online sequential learn-ing extreme learning machine to train the Single hidden-Layer Feedforward Neuralnetwork (SLFN) to fulfill the classification and identification of transmitter basedon the extreme learning machine, which attains good recognition rate. The maincontributions are as follows:1. From the theoretical and engineering point of view, the discrete HT-based theoryand method for communication signal measured feature (carrier and modulationparameters) extraction are presented, which includes unwrapped instantaneousphase based linear fitting carrier estimation and absolute envelope based symbolrate estimation for digital communication signal, etc. Lots of simulations andexperiments show the proposed methods are e?ective and simple to implement.2. To extract such modulation-relative features as FM modulation index and dig-ital modulation parameters, two generalized, DSP implementable FFT-basediteratively interpolated and CZT-based high performance single tone parameterestimator are proposed. The FFT-based one adaptively adjusts the estima- tion accuracy by the constant iteration of dynamic symmetric frequency o?setestimation to attain not only more accurate estimation but lower SNR thresh-old, higher speed and much more CRLB-approximating performance over thefull frequency range compared to traditional Rife-Jane’s and Quinn’s one. TheCZT-based one enhances the frequency resolution by means of certain priori toobtain an accurate, stable, consistent, closely CRLB-approximating single-toneparameter estimation as well as more robustness to noise in the case of short-timestationarity and adjacent single-tone interference3. Based on nonlinear parasitic amplitude modulation miscellaneous output and sub-sampling, featured bispectra e?ectively distinguish the spontaneous intrinsic fre-quency from that caused by nonlinear QPC, retain all property of HOS butgreatly reduce the computation e?ort meanwhile. Surrounding line Integration-based featured bispectra selection incorporates advantages of both integrated bis-pectra and selected bispectra: strong noise robustness, no cross interference andsimple, e?cient computation, accomplishes the translation from 2-D featuredbispectra into 1-D vectored feature which shows great individual transmitterdiscriminant ability.4. Based on the time-frequency property of individual transmitters, EMD time-frequency spectrum entropy- based miscellaneous feature extraction is proposed,which characterizes the nonlinear, nonstationary miscellaneous output by adap-tive time-frequency distribution. Correlation degree- based decomposition fin-ished criterion speeds up the EMD process and the concept of entropy e?ectivelydepicts the degree of uniform distribution of the energy in EMD time-frequencyspectrum as a simple scalar of some individual transimitter discriminant ability.5. Based on the extreme learning machine, contribution of randomly generated hid-den node in SLFN to network learning accuracy is proposed by regressive fittingand orthogonalization to realize the adaptability of network model one-by-oneor chunk-by-chunk and adaptive online sequential learning of SLFN which notonly runs automatically without manual parameter setting and special require-ment on the arriving mode and order of training samples but greatly reduces therequirements on storage and computation ability of hardware. Lots of simula- tions and experiments show that the proposed algorithm is e?ective and simpleto attain a recognition rate of above 85% for the collected both FM and FSKindividual transimitter observations.Moreover, based on COM and Database techniques, a communication signaltransmitter recognition software system is established to implement our proposedalgorithms, which identifies individual transmitters by carrier, modulation parametersand miscellaneous feature variance according to conditions and criteria of these finefeatures.更多还原