Research On Proactive Eavesdropping Strategy Based On UAV Communication

With the rapid development of wireless communication technology,the security of wireless network has attracted more and more public attention.However,based on the open characteristics of wireless network,malicious communication users can also access the wireless communication network for illegal information transmission.Therefore,active monitoring of suspicious communication links in wireless communication networks has become a important means to monitor and combat illegal and criminal activities.Thanks to the flexible deployment,high mobility and good line of sight(LOS)link of unmanned aerial vehicle(UAV),the active monitoring technology based on UAV Communication can provide an efficient solution for legal monitoring.This thesis studies two kinds of UAV active monitoring scenarios:cognitive network and relay network.In order to effectively improve the monitoring performance of legitimate listeners,interference and deception relay technology are used to improve the effective monitoring rate of legitimate monitoring UAVs.This thesis summarizes the main research contents into the following two points:(1)Research on active monitoring strategy of UAV for cognitive network.This thesis studies the problem of active monitoring in cognitive network,in which there are multiple primary users in cognitive network,and secondary users access the spectrum resources of primary users for communication.In order to ensure that secondary users do not use spectrum resources for illegal communication,this thesis uses UAV as a legal listener to conduct active monitoring in a full duplex way.While the UAV successfully monitors the suspicious link by means of active interference,it also needs to ensure the communication quality requirements of the main user.The problem is described as a joint optimization problem of UAV interference power and trajectory.On the premise of meeting the constraints of successful monitoring and energy limitation,the effective monitoring rate of UAV is maximized.Due to the coupling of multiple optimization variables,the problem can not be solved directly by convex optimization algorithm.Therefore,an alternating iterative optimization algorithm based on continuous convex approximation and block coordinate descent is proposed to obtain the local optimal solution of UAV interference power and trajectory.Finally,the numerical simulation results show that the monitoring performance of the optimized scheme is better than other benchmark schemes.(2)Research on active monitoring strategy of UAV Based on Spoofing relay.This thesis studies the problem of active monitoring in relay network.Suspicious ground transmitting nodes send suspicious signals to multiple suspicious ground receiving nodes at the same time.In order to effectively monitor the information transmission between suspicious ground nodes,UAV is used as spoofing relay to actively monitor.The UAV Spoofing relay can adaptively forward deception information or send interference information to the suspicious ground receiving node to change the transmission rate of the suspicious communication link and maximize the monitoring performance.The problem is described as a joint optimization problem of UAV interference power,relay power and three-dimensional(3D)trajectory.Under the constraints of UAV mobility and power,the effective monitoring rate of UAV is maximized.Because the problem is a non convex optimization problem,it is difficult to solve it directly by convex optimization algorithm.In this thesis,the non convex optimization problem is transformed into a convex optimization problem by introducing relaxation variables and continuous convex approximation.CVX tool is used to solve the problem,and the local optimal solutions of UAV interference power,relay power and its three-dimensional trajectory are obtained.Finally,the simulation results show the effectiveness of the proposed optimization algorithm.Compared with other benchmark schemes,the active monitoring strategy based on deception relay can more effectively improve the effective monitoring rate of UAV.