Position-based Routing Protocols In Vehicular Ad Hoc Networks

Vehicular Ad Hoc Networks(VANET),which is built up between cars equipped with a wireless network interface devices,is a special Mobile Ad hoc Networks (MANET).It is one of the MANET applications with most future prospects.Due to the status of all nodes in the VANET being equality,self-organization,without infrastructure prior arranged or central control node,and high-speed mobile nodes of network that potentially leads to dynamic changes of network topology,routing protocol,as one of the key technologies,is important to determine the performance of VANET.Therefore,how to design an effective routing protocol to guarantee the information timely and reliable transmission is a hot and difficult problem in the research area of VANET.As its strong adaptability to the frequently changed network topology,location-based routing protocol is more suitable for VANET.In this paper, based on the OPNET network simulation platform,we study the location based routing protocols of VANET,develop the OPNET modules for GPSR protocols,which is a classic position based routing protocols,and present an improved EGPSR protocols.Firstly,we introduce the origin,characteristics,and applications of the VANET, and then summarize and conclude the classic routing protocols mentioned in literatures. Node movement model,as a result of the impact to simulation,is an important factor. Node movement model used in VANET simulation should be able to reflect the actual movement of vehicles,but can not simply use the traditional model of a random node. Based on the analysis of the characteristics of vehicle movement,we use the traffic simulation software to describe the trajectories of motor vehicles more truly and study how to use traffic simulation platform VanetMobiSim.Secondly,we investigate position-based routing protocols in VANET by OPNET platform.We develop a OPNET model for the classic GPSR protocols,based on the GRP model of OPNET. Then in order to improve the GPSR protocols,we present an EGPSR protocol and establish its OPNET model.Compared with the GPSR protocol,EGPSR is beneficial to improve the packet delivery rate,reduce redundancy generated by the perimeter transponder under specific urban environment.Finally,we combine the VanetMobiSim traffic simulation into OPNET simulation to evaluate and analyze the performances of EGPSR and GPSR.