Research On Energy-Efficient Robust Secure Transmission Technology Of UAV Communication Systems

UAV has been widely used in various fields because of its advantages of light weight,small volume,strong operability and low cost.However,in wireless communication,due to the broadcast and openness of wireless communication channel,and UAV is limited by volume and load,security and energy efficiency have always been hot issues in UAV communication research.In order to solve the security problems in wireless communication,it is a new research hotspot to combine the UAV communication technology with physical layer security technology(PLS),which has attracted extensive attention in recent years,At the same time,considering the energy limitation of UAV,it is difficult to carry high-precision positioning devices and obtain the accurate location information of eavesdroppers,which will lead to a significant decline in security or energy efficiency.Therefore,when the physical layer security of UAV communication system is designed,it is also necessary to consider the energy efficiency of UAV and the impact of ground node position error on secrecy energy efficiency.This paper mainly studies the problem of maximizing the robust secrecy energy efficiency of UAV communication system,and considers two UAV communication system models,as follows:(1)Two UAVs are considered to assist in communication.While one is used to receive the confidential signal sent by the ground user,and another transmits artificial noise to interfere with the ground eavesdropper,in order to ensure the communication security of the uplink of the ground user.For this scenario,the signal transmission model between the nodes of the system is derived,and based on the definition of secrecy capacity and the energy consumption model of fixed wing UAV,the worst secrecy energy efficiency optimization model in the case of ground user position error is proposed.Due to the nonconvex characteristics of the optimization model,by combining auxiliary variables,successive convex approximation and semidefinite programming,the nonconvex optimization problem can be transformed into a solvable convex optimization problem,and an iterative algorithm is designed to obtain the optimal solution of the original optimization problem.Finally,simulation results show that the proposed algorithm will significantly improve the robust security energy efficiency of the system compared with the benchmark scheme.(2)In order to further reduce the cost and energy consumption,the full duplex technology is combined with the UAV communication technology,and the communication scenario of a single full duplex UAV is considered.The full duplex UAV is not only used to receive the confidential signal sent by the ground user,but also transmit artificial noise to interfere with the ground eavesdropper,so as to ensure the communication security of the uplink of the ground user.Under this scenario,the signal transmission model between the nodes of the system is derived,and based on the definition of safety capacity and the energy consumption model of fixed wing UAV,the worst secrecy energy efficiency optimization model in the case of ground user position error is proposed.Similarly,due to the nonconvex characteristics of the optimization model,it is first transformed into subtractive form by Dinkelbach algorithm,and then combined auxiliary variables,successive convex approximation and semidefinite programming,the nonconvex optimization problem can be transformed into a solvable convex optimization problem,and an iterative algorithm is designed to obtain the optimal solution of the original optimization problem.Simulation results show that the algorithm can significantly improve the robust security energy efficiency of this system.