Enabling Physical Layer Security With D2D Spectrum Resource Sharing In Cellular V2X Networks

Vehicle-road cooperation technology is gradually emerging in promoting the development of networked autonomous driving and road traffic intelligence,attracting more and more attention from industry and academia.Vehicle-road cooperation technology uses widely distributed access nodes on the road side to complete the download tasks of HD map/video,driving path planning,pattern recognition and etc.,greatly reducing vehicle’ s power and computing time consumption,thus improving the endurance,driving stability and entertainment experience on the vehicle.Vehicle-road cooperation technology puts forward higher requirements for communication link capacity and security performance between vehicle and roadside infrastructure.In order to meet these special requirements of vehicle communication,C-V2X(Cellular Vehicle to Everything)technology has gradually matured and gained more and more industry recognition.C-V2X technology is based on the mature cellular mobile communication technology,which adapts to the high-speed mobile mode of vehicles,and realizes the efficient communication from vehicle to vehicle and from vehicle to roadside infrastructure.This access technology needs to realize ultra-low delay,ultra-high reliability and avoid the interference to the original cellular services.This thesis is committed to research a new vehicular wireless access mode,which could ensure the security of vehicular communication and improve the capacity of vehicular communication link,so as to meet the increasing demand of security services.In heterogeneous two-layer cell,macro cell is used to monitor the varying of vehicular traffic and allocate spectrum resources for small cell base stations in macro cell.The small cell base station is responsible for real-time transmitting power control and spectrum resource sharing between vehicular and traditional cellular user to realize safe and efficient transmission among vehicles.The cooperation between heterogeneous base stations can enhance the spectral efficiency and meet the security requirements.The main contents of this thesis are summarized as follows:1.We design the communication mechanism among vehicles in accordance with the existing deployment scheme of cellular infrastructure to improve the compatibility between vehicular and cellular communication.In heterogeneous cell,macro cell and small cell are respectively responsible for long-term spectrum resource scheduling and short-term transmission power and resource block allocation to meet multiple service requirements of vehicular communication.2.We design a power control scheme to meet the demand of safe transmission among vehicles.Based on the theory of physical layer security,using the special mechanism of spectrum resources sharing between vehicular users and cellular users,the cellular users are regarded as friendly jammers to reduce the wiretapping ability of potential eavesdroppers and improve the secrecy capacity of vehicular users.By obtaining the closed-form power control solution of vehicular and cellular user,the scheme realizes the secret transmission of key information among vehicles with low complexity,and improves the security performance of vehicular communication.3.We propose a graph-based resource allocation mechanism between cellular users and vehicular users to achieve efficient sharing of cellular spectrum.In this study,the resource sharing problem is modeled as a weighted bipartite graph matching problem.The maximum achievable data rate among vehicles is taking as the weight,and the global optimal resource block sharing scheme is obtained by using KM algorithm to maximize the overall achievable data rate among vehicles.The joint resource allocation mechanism can meet the minimum QoS requirements of cellular users and maximize the capacity of vehicular communication link.