用于超宽带认知跳频系统的抗干扰检测与分类技术研究

发布时间：2018-11-01 16:46

【摘要】：跳频通信(Frequency Hopping Communications,FH)作为典型的隐蔽通信方式,因其具有抗干扰、抗截获、抗远近效应、抗衰落能力强,且易于多址组网以及与窄带系统兼容等优点,成为了战术无线通信的首要技术手段。由于战场频谱资源的日渐紧张以及电磁对抗与复杂干扰的不断升级,传统的跳频通信技术已经无法适应快速可靠传输的要求,成为制约战术无线通信技术发展的瓶颈。认知无线电(Cognitive Radio,CR)是一种能与外部环境交互并智能变换自身参数配置的无线电系统,该系统可以根据环境的变换调整自身参数,以达到预期通信目标。因此,在复杂的电磁环境中,将基于认知无线电的自适应技术与传统跳频通信技术相结合是提升跳频通信系统的抗干扰能力与通信性能和改变跳频通信困境的有效途径之一。鉴于此,本课题针对用于认知自适应跳频通信系统的频谱感知抗干扰技术进行了研究,给出了一种具有现实意义的干扰检测和分类方案,最后给出了超宽带频谱接收机的可行实现方法。本文的主要工作包括以下几个方面:首先,对现有扩频通信理论基础及跳频通信系统原理进行了研究,在此基础上,分析了传统跳频系统的几个主要关键技术即跳频序列、跳频同步和频率合成器。在分析了现有跳频通信系统无法满足现代战场复杂需求的基础上,把认知技术应用到了跳频系统的设计中。其次,针对跳频通信系统常见的不同种类干扰信号进行了建模、分析及仿真,并针对系统需求,设计了对跳频频段上未知干扰进行检测的系统流程。该流程涉及的算法包括:干扰的盲检测算法、干扰类型的盲识别算法、干扰信号参数提取算法以及基于小波奇异性检测的确定窄带、宽带干扰信号的参数确定方法。论文对该流程进行了仿真验证。最后,对比了现存的超宽带数据采集平台设计方案,包括数字下变频接收机、宽带数字测频接收机、宽带引导式数字带宽匹配接收机、以及宽带数字信道化接收机,设计了基于FPGA和高速ADC的多通道超宽带频谱感知接收机,实现了超宽带频谱数据的采集,并利用多相数字处理机制,实现了超宽带频谱数据的产生。该平台可为之前给出的干扰信号检测方法提供了物理平台与数据支持。
[Abstract]:As a typical covert communication mode, FH (Frequency hopping Communication (Frequency Hopping Communications,FH) has the advantages of anti-jamming, anti-interception, anti-far-near effect, strong anti-fading ability, easy to set up multiple access networks and compatible with narrowband system, etc. It has become the primary technical means of tactical wireless communication. Due to the increasing shortage of spectrum resources and the upgrading of electromagnetic countermeasures and complex interference, the traditional frequency-hopping communication technology has been unable to adapt to the requirements of fast and reliable transmission, and has become the bottleneck of the development of tactical wireless communication technology. Cognitive radio (Cognitive Radio,CR) is a kind of radio system which can interact with external environment and intelligently change its parameters. The system can adjust its parameters according to the change of environment to achieve the desired communication goal. Therefore, in the complex electromagnetic environment, the combination of adaptive technology based on cognitive radio and traditional frequency-hopping communication technology is one of the effective ways to improve the anti-jamming ability and communication performance of frequency-hopping communication system and to change the dilemma of frequency-hopping communication. In view of this, this paper studies the spectrum sensing and anti-jamming technology used in cognitive adaptive frequency-hopping communication system, and presents a practical interference detection and classification scheme. Finally, the feasible implementation method of UWB spectrum receiver is given. The main work of this paper includes the following aspects: firstly, the basic theory of spread spectrum communication and the principle of frequency hopping communication system are studied. On this basis, several key technologies of the traditional frequency hopping system, namely frequency hopping sequence, are analyzed. Frequency hopping synchronization and frequency synthesizer. Based on the analysis that the existing FH communication system can not meet the complex requirements of modern battlefield, the cognitive technology is applied to the design of FH system. Secondly, the model, analysis and simulation of different kinds of interference signals in frequency-hopping communication system are presented. According to the system requirements, the system flow of detecting unknown interference in frequency hopping band is designed. The algorithms involved include: blind detection algorithm of interference, blind identification algorithm of interference type, parameter extraction algorithm of interference signal and parameter determination method of narrowband and wideband interference signal based on wavelet singularity detection. The process is verified by simulation in this paper. Finally, the design schemes of UWB data acquisition platform are compared, including digital downconversion receiver, wideband digital frequency measurement receiver, wideband guided digital bandwidth matching receiver and wideband digital channelized receiver. A multi-channel UWB spectrum sensing receiver based on FPGA and high-speed ADC is designed. The acquisition of UWB spectrum data is realized, and the generation of UWB spectrum data is realized by using polyphase digital processing mechanism. The platform can provide the physical platform and data support for the interference signal detection method.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN914.41

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