Research On Task Offloading And Secure Communication Technology Based On Physical Layer Security In Edge Computing

With the rapid popularization of 5G communication and Internet of Things(Io T)technology,the appearance of mobile network system has changed greatly.As a new computing paradigm in 5G standard,Mobile Edge Computing(MEC)has become a hot spot of academic research in recent years.MEC is suitable for portable devices and applications with complex computing and delay sensitive.It has many advantages,such as local deployment,low delay and proximity.However,most of the existing research contents focus on offloading strategy,optimization algorithm and reducing delay and energy consumption,while the research on secure communication of confidential data is very limited.Different from the traditional cryptography methods,this thesis adopts the physical layer security technology more suitable for MEC system to ensure the secure communication,and analyzes the security performance in detail.This thesis focuses on the offloading strategy,energy consumption optimization,channel model,vehicle networking,diversity signal correlation mode and security performance index.The main work of this thesis is as follows:(1)Aiming at the problem of confidentiality and energy saving in MEC scenario based on physical layer security technology,the Device to Device(D2D)offloading strategy and physical layer security technology are introduced into the traditional MEC system,and the confidential MEC-D2 D system architecture is constructed to minimize the user energy consumption in the system and ensure the confidentiality of confidential data in the offloading process.In this system,users can choose the best one of the three computing modes to perform computing tasks.The problem of minimizing energy consumption is proposed,which is solved by the joint optimization strategy of computing task allocation,channel resource allocation and transmission power resource allocation.The optimization problem is decomposed into three subproblems and transformed into a convex problem by Lagrange dual method.Simulation results verify the accuracy of the formula derivation and the performance superiority of the proposed offloading strategy.(2)Aiming at the problem of secure communication in the scene of Internet of vehicles based on physical layer security technology,a Vehicle to Infrastructure(V2I)system architecture with illegally stolen vehicles is constructed to analyze the channel security performance in a reasonable scene of Internet of vehicles.Nakagami-m channel model with imperfect Channel State Information(CSI)is adopted.The channel outage probability and security outage probability under different correlation types of diversity signals at the receiving end of legal and illegal vehicles are analyzed,and their exact closed form expressions are derived.Simulation experiments verify the accuracy of the closed expression,and evaluate the effects of vehicle speed,signal-to-noise ratio,data transmission rate,correlation type and correlation coefficient on the security performance.