Research On Computation Offloading In Software-Defined VANET

As a research hotspot of intelligent transportation system,Vehicular Ad hoc Networks(VANETs)plays an important role in the development of the transportation industry.They not only improve operational efficiency of the transportation system,but also provide the driver with a convenient,safe and comfortable experience.VANETs require the performance of low latency,high reliability,and large-scale terminal interconnection in the future,which bring challenges to the traditional network architecture.In this paper,we analyze the relation between software-defined network(SDN)and traditional network architecture by researching,then propose the division and allocation method of computational tasks and the fault tolerant method.The research contents are as follows:A computation offloading scheme assisted by surrounding vehicles is proposed to solve the problem that the computing ability of current vehicles can not match with the computing requirements.In this scheme,computation offloading considers vehicles’ computing ability,storage space,task transmission and execution time which ensure that the two vehicles maintain communication during the transmission of the subtasks,and the amount of subtasks does not exceed the executing vehicles’ remaining storage space.After the subtasks calculation by the executing vehicles,considering the disconnection between the executing vehicle and the requesting vehicle,the controller calculates the forwarding path of the data packet and return the calculation results to requesting vehicle.The controller agent module is designed for the single controller may not respond when the requests are frequent.This module is used to complete the vehicles’ requests by receiving the policies of the controller.Finally,the distance priority strategy and the computing ability priority strategy are simulated on the Mininet-WiFi network simulator.The experimental results show that the task completion rate with distance prioritization is high when the number of surrounding vehicles is small,on the contrary,the task completion rate with the priority of computing ability is high.Taking the vehicle uploading data to the base station as an example,the feasibility of the controller proxy module is verified.