Cognitive Jamming Technology Based On Software Defined Radio Platform Research And Implementation

With the development of wireless communication technology,more and more communication technologies based on it have come out successively and are widely used.However,due to the inherent openness of wireless channels,communication signals are easily interfered during the channel transmission process.Therefore,electronic countermeasures for malicious interference are derived,which are manifested by artificially applying electronic interference to affect the normal reception or judgment of signals at the receiving end.In order to achieve accurate and efficient interference to target signals in complex electromagnetic environments,the concept of cognitive interference was subsequently proposed.In this thesis,based on the cognitive results of the electromagnetic environment,the cognitive interference decision-making research is carried out,and the generation of interference signals is realized,thereby constructing a cognitive interference system based on the cognitive results.As a new type of wireless communication architecture,software radio has outstanding performance in radar,electronic warfare,navigation,radio and television,measurement and control and other fields.The software radio has strong flexibility,it can complete the reconstruction of the same hardware through dynamic software programming,so as to realize different functions,and choose the selected software modules according to the required functions;Structure,software radio also has strong openness,its hardware can be updated or expanded with the development of devices and technologies,and the software can also be continuously upgraded as needed.Considering the above advantages,the design and implementation of the cognitive jamming system in this thesis will be completed based on the software radio platform.This study develops a theoretical foundation for an interference signal production system,starting with the background and importance of the research topic,and studies the key technologies in it,including channel coding,digital modulation,digital up-conversion,and polyphase filtering.The principles and characteristics of jamming,linear sweep jamming and comb-spectrum jamming are explored,which provides a theoretical basis and foreshadowing for the subsequent design of cognitive jamming systems,and provides a basis for system functional verification and performance testing.From the perspective of theoretical research,this thesis analyzes and explores cognitive interference decision-making based on cognitive results,and establishes the system bit error rate model of digital modulation signals such as ASK,PSK,FSK and QAM under correlated interference.Through simulation analysis and performance comparison,a set of matching templates for digital modulation signals and interference signals is developed.In addition,the above-mentioned system bit error rate model is improved,taking into account the time delay and phase shift of the interference relative to the communication signal,and analyzes the influence of the two factors on the interference performance.In the research of interference decision-making of direct sequence spread spectrum signal,the effects of the interference signal’s bandwidth and frequency on the interference effect are investigated,and the optimal interference pattern is studied by combining the characteristics of the two parameters.The frequency hopping signal’s interference decision analysis is similar to that of a direct spread signal.By studying the influence of the bandwidth of the interference signal and the number of interference frequency points on the interference effect,the calculation method of the optimal interference parameter is obtained.Finally,this thesis combines the research content of cognitive jamming decision with the framework of jamming signal generation system,designs a cognitive jamming system based on software radio platform and completes its FPGA implementation,and relies on the upper computer for functional verification and testing.The system can not only make jamming decisions autonomously and generate corresponding jamming signals according to the cognitive results,but also artificially control its jamming patterns and parameters through the upper computer platform.The available styles include ASK,PSK,FSK and QAM,a total of 10 modulations Interference and conventional interference such as white noise,audio,sweep and comb.