The Research And Improvement Of GPSR Routing Protocol In Vehicular Ad Hoc Network

VANET is an important part of intelligent transportation system which has a broad development prospects. Routing protocol is a key technology of VANETs which largely determines the performance of the network. In urban traffic scenes, the fast vehicle movement speed, frequent changes of network topology, the effects of buildings all lead the VANET’s link fracture frequently. Therefore the key of the research is designing a routing protocol that can solve the link broken problem.I researched a typical Greedy Perimeter Stateless Routing that was based on position, at the same time, identified the existing problems and propose an improved protocol that was a new stable greedy forwarding protocol RGFR(Reliable Greedy Forwarding Routing, RGFR).I completed the following work including:First, I studied a typical Greedy Perimeter Stateless Routing that was based on position GPSR.GPSR exist many problems, such as high overhead by using the right-hand rule to solving the empty problem, poor adaptability, poor fault tolerance, lacking of obstacles awareness and so on. Domestic and foreign scholars put forward a lot of improvement strategies based on the existing problems.Second, I designed a stable greedy forwarding routing protocol RGFR.I presented a stable greedy forwarding routing protocol RGFR based on the weakness of GPSR. This protocol is mainly divided into three parts: assessing the link survival time, identification the obstacles and scoring to find a balance between efficiency and stability value. It is in order to adapt to the actual urban traffic environment better.Third, I developed the simulation module of RGFR. I developed the protocol simulation module based on the designing process. I also designed the hello data structure and the key function.Fourth, I designed the scenario simulation which based on the Nanan distract of Chongqing city. I knew that the degree of crock was influence on the performance of the agreement according to the experiment. so I designed a city scenario simulation model according to the main road map in Nanan distract of Chongqing city based on the mobile node in the typical model and vehicle movement model. The establishment of the model made a good foundation for the research of routing protocol.Through making simulation experiments between the GPSR and RGFR routing protocol, I got that RGFR has higher delivery rate and lower delay than GPSR routing protocol in the actual topology vehicle model.