Research On Wireless Physical Layer Security Technology Based On Cooperative Interference

Based on the information theory,the physical layer security technology makes use of the inherent characteristics of wireless channel to realize the secure transmission of wireless communication system.Cooperative interference is an effective physical layer security technology,which reduces the quality of eavesdropping channel by interfering eavesdroppers with cooperative nodes,so as to improve the security performance.Mobile edge computing(MEC)extends computing and storage to the edge of the network,allowing users to offload computing tasks to the MEC server for processing,reducing the burden of network traffic,delay and energy consumption of devices.However,due to the broadcast characteristics of wireless channel,the offloading task of MEC device is easy to be eavesdropped,which leads to data security problems.The research on secure offloading of MEC system has important practical significance and needs to be solved urgently.Therefore,this paper utilizes cooperative interference technology to study the secure offloading and computation of MEC system.Firstly,based on the characteristics of non-orthogonal multiple access(NOMA)technology,the interference between NOMA users is appropriately used to fight against eavesdroppers.Considering the different delay requirements of two MEC users,a twoslot hybrid NOMA offloading system model for cooperative interference is established.In the first time slot,two users transmit their task signals by NOMA mode.In the second time slot,the user who has completed the task offloading will transmit jamming signal to secure the remaining signal of the other user.The weighted sum secrecy outage probability and the secrecy computation probability are used to measure the users’ security performance,and the performance analysis of the key parameters affecting the users’ security is carried out,and the proposed scheme is simulated and verified.Secondly,using full duplex base station(BS)to transmit artificial noise(AN)effectively reduces the quality of eavesdropping channel,and based on the advantages of intelligent reflecting surface(IRS)in improving physical layer security,this paper establishs a MEC system model assisted by IRS and AN,by adjusting IRS reflection phase shift matrix,the signal strength of eavesdropper is weakened.The AN transmitted by full-duplex BS is used to interfere with eavesdropper and improve the users’ secure offloading performance.Based on the proposed model,an iterative optimization algorithm is used to solve the proposed secure energy consumption minimization problem of the system,and the simulation results are verified.Finally,in order to improve the secure computing ability and energy sustainability of MEC wireless terminal,this paper uses wireless power transfer(WPT)technology to solve the problem of limited resource and battery life of wireless terminal and proposes an IRS-assisted WPT-MEC system model.In the WPT stage,IRS can improve the energy collection efficiency of the users.In the offloading stage,the assistance of IRS can reduce the strength of eavesdropping signal and improve the secure offloading performance.Based on the proposed model,an iterative optimization algorithm is developed to solve the proposed problem that maximize the secure computing task of the system and verify it by simulation.