Research On QoS Routing Framework Based On Software Defined VANET

SDN(Software Defined Networking)is a new network architecture proposed in recent years.By separating the network control plane into remote controller,network administrators can centrally manage the network.SDN well solved the ossification problems of traditional network architectures.According to these outstanding characteristics of SDN,this thesis applied SDN to VANET and designed a new VANET architecture named SDVANET.SDVANET improves network management efficiency of VANET.In addition,this thesis analyzed the shortcomings of traditional Ad-hoc network deterministic routing protocol when applied in VANET environment,and designed a new opportunistic routing protocol for SDVANET.Link quality from vehicle to base station together with vehicle speed are taken into account to make a decision for selecting candidate forwarding nodes.Recently,the rapid development of self-driving technology significantly increased people's expectations of VANET.Vehicles are able to make decisions intelligently while driving according to big data computation from remote server.It is extremely important to ensure the quality of related data transmission in such scenario,because it strongly affects safety and security of passengers.Traditional network architecture cannot make full use of network resource to guarantee data transmission because of its design constraints.Although SDN architecture is able to schedule resources globally,current SDN QoS(Quality of Service)frameworks do not consider frequent change of network nodes,so they cannot be used in VANET,Based on this background,a new QoS framework for SDVANET is designed to solve problems mentioned above.It consists of two parts:1)OpenFlow network is well designed with resource management,data flow predication and routing scheduling in mind,and implemented using meter table and port queue in data plane;2)wireless network contains a complete QoS solution from MAC layer,network layer and application layer.SDVANET architecture and the QoS framework are implemented upon NS3 network simulator.By running simulation tests in different scenarios,it can be concluded that even in the case of network congestion,high-priority packets also can maintain a low average delay and packet loss rate,which shows feasibility andeffectiveness of SDVANET.