Software-defined Networking(sdn)based VANET Architecture: Mitigation Of Traffic Congestion

With the increase in the number of vehicles in the urban traffic system,the traffic system is facing a series of problems,such as traffic congestion,longer travel times,and accidents.The intelligent transportation system(ITS)based on VANET technology has alleviated these problems.However,with the continuous and rapid increase in the number of vehicles,the operation efficiency of traditional ITS is decreasing.New technical support is urgently needed to improve the efficiency of solving traffic problems.In this context,the SDN-based VANET(VANET based software-defined network)framework emerge as the times require.SDN-based VANET combines SDN(Software Defined Network)advantages,decouples the control layer and data layer,and introduces an independent logic controller to make VANET more intelligent,which can significantly improve the efficiency of VANET in helping to solve traffic problems.Based on the SDN-based VANET framework,this thesis proposes a new heuristic algorithm called Congestion Free Path(CFP).The proposed CFP proactively computes the congestion-free path for a vehicle based on the traffic density parameter.Since CFP will calculate all paths in the case of less congestion,this paper proposes an optimization algorithm called OCFP.OCFP will limit the upper limit of the number of single-vehicle when calculating the congestion-free path and improve the efficiency of the algorithm by reducing the amount of low-income calculation.In order to evaluate the performance of the two algorithms,the test module uses NS3 simulator,Open Street Map and Urban Traffic Simulation module to simulate the traffic situation of Dalian under traffic congestion,and compares CFP and OCFP with SDNbased Shortest Path(SP)and existing Distributed Road Traffic Congestion(DRTC).The experimental results show that CFP and OCFP are more efficient in reducing the congestion ratio and underutilized roads rate in the case of congestion.Compared with the existing two algorithms,the efficiency of CFP is improved by 20%,and the efficiency of OCFP is improved by 30%.