| 5G Internet of Vehicle(5G-Io V)is a self-organizing network the high dynamic characteristics of rapid movement of nodes,which brings great challenges to the transmission of end-to-end services.In order to obtain better assist for future road applications,5G-Io V technology must address various challenges such as network connectivity and resource optimization.Network connectivity mainly refers to the existence of wireless links and paths between vehicle nodes,vehicle nodes and roadside units.To enhance the performance of network connectivity can achieve more efficient and faster information transmission,so network connectivity has become an important performance index for the evaluation of communication quality in the Internet of vehicles.In the urban scene,in order to ensure the stability of vehicle communication,the optimization of resources in the Internet of vehicles is an important means to guarantee and realize network connectivity.As an important part of resource optimization,the problem of roadside unit selection and resource allocation has become an important research content of this paper.In order to get a more general conclusion,the network connectivity of the network is analyzed in one-way lane and two-way lane based on three methods,such as V2 I communication,V2 V assisted V2 I communication and cluster communication.In view of the above three scenarios,this paper analyzes and compares some key parameters,including single and double lanes,vehicle speed,distance between base stations,vehicle arrival rate,vehicle communication range,ratio of relay vehicles and safety distance between vehicles,and obtains the corresponding connectivity probability formula.Through the mathematical simulation,the correctness of the analysis conclusion is verified.After comparison,it is found that the network performance based on cluster communication mode is significantly better than that based on V2 I and assisted by V2 V.Based on the analysis of 5GInternet of vehicles connectivity,this paper first designs a roadside unit selection scheme.The central idea of this scheme is to grid the arrangement of roadside units and establish a joint evaluation model considering the network connectivity and load.According to the evaluation model,the most suitable roadside unit is selected.Then,a resource allocation method based on the improved greedy strategy is proposed according to the above model.Under the condition that the vehicle priority and total power limit are met,the total capacity of the system is maximized,and the most appropriate roadside unit is selected to ensure the data communication between the selected roadside unit and the vehicles in the cell.In this paper,a roadside unit selection scheme is first put forward,which mainly grids the arrangement of roadside units on the road.Based on the joint model of connectivity and load,the most appropriate roadside unit for the vehicle is selected.Then a resource allocation method is proposed to guarantee the normal communication between the selected roadside unit and the vehicles in the cell.This method optimizes subcarrier allocation by improving the greedy strategy,which meets the requirements of vehicle priority and total power constraints to reach the requirement of maximizing the total system capacity.The simulation shows that the roadside unit selection and resource allocation scheme proposed in this paper makes the total capacity of the system increase and the standardized capacity of each vehicle conforms to the vehicle priority compared with the existing method. |
