Research On Security Rate Optimization Based On UAV Proactive Eavesdropping

Since the commercial deployment of The 5th Generation(5G)network,the wireless communication network has been further expanded,which extremely brings convenience to global communication.However,wireless communication networks may be misused by suspicious users to engage in illegal activities,which broughts public security huge challenges.Eavesdropping on suspicious commuciation is one of the effective ways to prevent and combat these malicious behaviors.It is a big challenge to improve the monitoring performance of monitors effectively with limited communication resources.The effective eavesdropping rate is an important index to evaluate the monitoring performance.Due to the advantages of high mobility and flexibility of unmanned aerial vehicle(UAV),the proposal of UAV proactive eavesdropping technology combines the interference strategy or spoof-relay strategy closely with UAV communication technology,which not only meets the monitoring requirements in different scenarios but also improves the effective eavesdropping rate.The allocation of power(jamming and spoof-relay)and trajectory planning are the two aspects mainly affect the effective eavesdropping rate of UAVs.This thesis research on the optimization of these two aspects to maximize the effective eavesdropping rate where a legitimate UAV eavesdrops on suspicious communication.The main contribution of this thesis are summarized as follows:1)Proactive eavesdropping in UAV systems via trajectory planning optimization:Aiming at the trajectory planning where a UAV proactively eavesdropping on the suspicious communication link,a system model was established.Based on interference strategy and under the consideration of the mobility constraints of the UAV,the expression of effective eavesdropping rate is derived and the problem of maximizing eavesdropping rate is concluded as a non-convex optimization problem.The problem was solved with piecewise processing and the interior point method.Then a successful algorithm for trajectory planning is developed.Numerical results validate that the maximum flight speed of the legitimate UAV has a great influence on the eavesdropping rate as well as trajectory.Compared with three conventional UAV trajectory schemes(sinusoidal,linear and circular),the proposed algorithm of trajectory planning can achieve significant gains in terms of the effective eavesdropping rate by about 104.5%,52.1%and 21.7%.2)Proactive eavesdropping in UAV systems via trajectory planning and jamming power optimization:Aiming at the trajectory planning and jamming power optimization where a UAV proactively eavesdropping on the suspicious communication between UAVs,a system model was established.Based on interference strategy and under consideration of the mobility constraints and limited jamming power of the UAV,the expression of effective eavesdropping rate is derived and the problem of maximizing eavesdropping rate is concluded as a non-convex and non-line optimization problem.The problem of jamming power optimization with the fixed trajectory is solved with 0-1 integer liner programming and trajectory planning with fixed jamming power is solved with convex approximation technology.Finally,an iterative optimization algorithm is proposed.Numerical results validate that the proposed algorithm reduces the total power of jamming signals by about 50%,and achieves significant gains in terms of the effective eavesdropping rate compared to the algorithm which only optimize the jamming power by at least 88.7%.3)Proactive eavesdropping in UAV systems via trajectory planning and power optimization based on spoofing-relay technology:Aiming at the trajectory planning and power(jamming and spoofing-relay)optimization where a UAV proactively eavesdropping on the suspicious communication between UAVs,a system model was established.Based on spoofing-relay strategy and under the constraints of mobility and limited power,the expression of effective eavesdropping rate is derived and the problem of maximizing eavesdropping rate is concluded as a non-convex and non-line optimization problem.The problem of power optimization with fixed trajectory is solved with convex approximation technology and 0-1 integer liner programming.Trajectory planning with fixed power allocation is solved with piecewise processing and the interior point method.A trajectory planning algorithm is firstly proposed,followed by an iterative optimization algorithm.Numerical results validate that the proposed trajectory planning algorithm achieves significant gains by at least 24.8%compared with the reference algorithm based on proactively jamming monitoring.The proposed iterative algorithm achieves significant gains by at least 156.1%in terms of the effective eavesdropping rate compared to the conventional UAV trajectory scheme based on spoofing-relay;the proposed iterative algorithm achieves significant gains by at least 31.2%in terms of the effective eavesdropping rate compared to the algorithm based on jamming strategy.The research studies on trajectory planning and power(jamming and spoofing-relay)optimization where a UAV proactively eavesdropping on the suspicious communication based on interference strategy or spoofing-relay strategy.In the theies four optimization algorithms are proposed to maximize the effective eavesdropping rate to improve the monitoring performance of wireless monitoring systems.