Vehicular networks are communication systems based on information exchange either between vehicles and roadside fixed infrastructure, which is called V2I (Vehicle-to-Infrastructure) mode, or from vehicle to vehicle V2V (Vehicle-to-Vehicle) mode also known as VANET (Vehicular Ad hoc Network). The objective of these networks is to provide drivers and transport authorities the most timely information on road traffic in order to improve the efficiency of transportation systems, users safety and comfort.Since their appearance, the VANET have been greatly developed; many standards, applications and routing mechanisms have been proposed to address the specifics of this new class of networks. The challenges arise mainly from the high vehicles mobility, the spatiotemporal diversity of traffic density and, the radio waves propagation in external environment unfavorable to wireless communications establishment.The difficulty, both economic and logistical, of a real implementation of vehicular networks makes the simulation widely used to conceive and assess the proposed solutions. The validity of simulation results depends strongly on the ability of the models to reproduce as faithfully as possible the real situations. Two aspects are mainly important in the VANET: the simulation of vehicles mobility and radio wave propagation.We propose in this thesis a new mobility model and a new radio propagation model for vehicular networks in urban and suburban environment. To be realistic, these two models are based on real static and dynamic data describing the topographic and socioeconomic characteristics of the environment. These data concern particularly the spatiotemporal vehicles distribution and the description of the infrastructures present in the environment. Three case studies are presented in the thesis to validate the models, a theoretical user-defined urban or suburban environment (the Manhattan case very often used) and two real environments from mean size cities.Another contribution of this thesis is the study of radio connectivity and performance of routing protocols in the VANET. From dynamic graphs representing the variation of the radio links between vehicles in motion, we have analyzed and determined the topology properties of vehicular networks. To study routing protocols, we used the mobility model and the radio propagation model in association with the network simulator ns-2. We have compared the performance of the widespread routing protocols and determined the most adapted routing mechanisms to vehicular networks.
