Research On The Physical Layer Security Technology Of UAV Communication System

In recent years,traditional communications networks which use fixed infrastructure have been unable to meet the service requirements of the 5th generation mobile communications(5G).This situation is caused by the huge volumes of data and the variety of applications.At the same time,UAV communication has brought new opportunities for the development of wireless communication systems.UAV communication has many advantages compared with traditional terrestrial wireless communication,such as high mobility,low cost and on-demand deployment.This makes UAV communication widely used in both military and civilian fields.However,it is challenging to realize secure transmission due to the openness of air-ground channel.Therefore,UAV communication system needs us to consider the system security performance roundly,and design the system transmission scheme elaborately.This thesis mainly studies the physical layer security(PLS)transmission problem in UAV communication system.The research carries out theoretical analysis and simulation verification on the system security performance to provide guidence for the design of secure UAV communication system.Our work in this thesis can be summarized as follows:1.In the multi-antenna untrusted UAV relay system,the secure transmission scheme is designed and the system security performance is analyzed.Considering the uplink untrusted UAV relay communication scenario,the terminal node uses multiple antennas to transmit artificial noise(AN)signals to interfere with the relay cooperatively.In this thesis,the security outage probability(SOP)and ergodic security rate(ESR)of the system are derived and simulated.The influence of relevant parameters on the safety performance of the system is analyzed and summarized.Then,considering a downlink untrusted UAV multi-relay scenario,the terminal node interferes with the untrusted UAV relay cooperatively.This thesis designs a joint power allocation and relay selection scheme.The simulation results show that the designed scheme can effectively improve the system security performance compared with the traditional scheme.2.In the energy-constrained UAV relay system,the secure transmission scheme is designed and the security performance of the system is analyzed.Considering the single user communication scenario of uplink UAV relay based on simultaneous wireless information and power transfer(SWIPT),the UAV relay collects energy from the radio frequency signal of the source node,and the source node superimposes the user information and AN signal to interfere with the ground eavesdropping users,The positive influence of source node cooperative interference on system security performance is clarified,and the influence of relevant parameters on the safety performance of the system is analyzed and summarized.Then the thesis considers the downlink untrusted UAV relay multi-user scenario based on SWIPT and non orthogonal multiple access(NOMA).The source node sends AN signal to interfere with the relay cooperatively.The relay obtains information and energy from the source node signal.The performance advantages of the proposed scheme are described compared with the traditional orthogonal multiple access(OMA)scheme,and the influence of relevant parameters on the safety performance of the system is analyzed and summarized.