Research On Vertical Handoff Algorithm In Internet Of Vehicle

As the number of vehicles increases,so does the demand for in-vehicle applications and services.Vehicle terminal nodes obtain network services through the Internet of Vehicles.However,vehicles usually travel within different network coverage,which requires vehicles to effectively switch between networks during driving.Therefore,research on network handoff in the Internet of Vehicles is very necessary.Vertical handoff technology is an important research content in network handoff,and it is the key to obtaining seamless access technology for vehicles in the Internet of Vehicles.This paper studies the vertical handoff algorithm in the Internet of Vehicles.In the heterogeneous vehicle networking environment composed of LTE network and WLAN network,In orde to solve the problem of high handoff failure rate and network throughput degradation caused by uneven distribution of vehicle nodes,this paper is proposing the improvement of vertical handoff algorithm in high-speed moving scenes and vehicle aggregation scenarios.Aiming at the problem of high handoff delay in high-speed moving scenes of vehicles in the Internet of Vehicles,a vertical handoff algorithm based on fuzzy analytic hierarchy process and TOPSIS(PR-FA-T)is improved.Firstly,the candidate network is pre-filtered,and then the fuzzy analytic hierarchy process(FAHP)is used to be determined the weight of each attribute.The decision is made by TOPSIS algorithm and the best network is selected for switching.Simulation results show that the algorithm can reduce the handoff failure rate,reduce the handoff delay and improve the network throughput of the system.This algorithm is suitable for the vehicle networking scenario where the vehicle is moving at high speed.However,in the vehicle aggregation scenario,the algorithm’s handoff failure rate and network throughput still need to be further improved.In order to solve the above problems,the TOPSIS algorithm in the PR-FA-T algorithm is improved.The TOPSIS algorithm has the problem of not being able to consider the correlation between attribute indicators and the inability to evaluate the line where the positive and negative ideal solutions are equal.For these problems,this paper proposes a gray TOPSIS algorithm based on improved Mahalanobis distance(MG-TOPSIS).Applying MG-TOPSIS to the vertical handoff algorithm,a vertical handoff algorithm based on fuzzy analytic hierarchy process and MGTOPSIS(PR-FA-IT)is proposed.Firstly,the candidate network is pre-filtered,,then the attribute weight is determined by FAHP,and finally the best network decision is made by MG-TOPSIS.The simulation results show that compared with PR-FA-T,the improved algorithm PR-FA-IT can reduce the handoff failure rate and improve the network throughput,but increase the handoff delay.This method is suitable for vehicle aggregation scenarios and is not suitable for vehicles high-speed moving scene.