Research On Vertical Handoff Strategy In Heterogeneous Vehicular Networks On Expressway

At present,with the rapid development of intelligent transportation system,the demand for Internet of Vehicles communication technology is also increasing.The traditional single Internet of Vehicles has been unable to meet people’s growing needs of service,so heterogeneous vehicular networks technology emerges as the times require.Due to the different coverage of different access technologies and different network properties,how to ensure that users can choose the most suitable network in the case of multi network selection,and can switch between different networks seamlessly,so as to get high-quality user service is one of the fundamental problems.Therefore,this thesis selects three representative networks,LTE,Wi Fi and DSRC,to study the vertical handoff strategy in heterogeneous vehicular networks.The main contents of this thesis are as follows:(1)This thesis is going to analyze three network characteristics of LTE,Wi Fi,and DSRC,introduce the integration framework of heterogeneous vehicular networks,and expound the vertical handoff technology between the access networks.(2)This thesis proposes a vertical handoff strategy for single user handover in expressway scenario,which uses bandwidth,delay,jitter,packet loss ratio,safety factor and cost as handoff indicators,calculates the subjective and objective weights combined with the user feedback form constructed by user historical data,and then selects the most appropriate handoff network by using the calculation of network Chisquare distance.The vertical handoff decision is simulated by MATLAB,and the final experimental results prove the effectiveness of the proposed scheme.In addition,considering the safety factor in the Internet of Vehicles,a signcryption algorithm for single user handover in heterogeneous cryptosystem is proposed.(3)A vertical handoff strategy for fleet users in expressway scenario is put forward.First of all,obtaining the driving similarity of the vehicles by analyzing the relative distance,speed,direction and social relationship,which will be used as the measure of clustering algorithm.When the network is not congested,the user side constructs the evaluation model of machine learning,while,the network side divides the service types into dynamic priority.Considering these two aspects,the dynamic priority based handoff algorithm is used;when the network may be congested,the blocking rate constrained handoff algorithm is used.The simulation experiment is carried out by MATLAB,and the better performance of switching is obtained.In addition,a signcryption algorithm suitable for fleet users in heterogeneous cryptosystem is proposed.