Author: David Marín SánchezPublisher:
ISBN:
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Languages : en
Pages :
Book Description
[ANGLÈS] VANETs (Vehicular Ad-hoc Networks) are an emerging new technology which integrates the capabilities of new generation wireless networks to vehicles. It includes a variety of applications such as co-operative traffic monitoring, control of traffic flows, blind crossing, prevention of collisions, nearby information services and real-time detour routes computation. Another important application for VANETs is providing Internet connectivity to vehicular nodes while on the move, so that passengers can download music, send emails, book a restaurant or play games. Because of the high nodes mobility and unreliable channel conditions, VANETs have unique characteristics which pose many challenging research issues. This work is mainly focused on a key networking problem: routing protocol for VANETs. The main requirement of routing protocols is to achieve minimal communication time with minimum consumption of network resources. Many routing protocols have been developed for MANETs (Mobile Ad-hoc Networks), such as AODV (Ad-hoc On demand Distance Vector) and DSR (Dynamic Source Routing). However, VANETs differ from MANETs by their highly dynamic topology. A number of studies have been done to simulate and compare the performance of those routing protocols in various traffic conditions in VANETs. Simulation results showed that MANET routing protocols suffer from poor performances because of the characteristics of fast vehicle's movement, dynamic information exchange and relative high speed of mobile nodes. This text aims to continue the work of Roger Calzada in his final degree thesis. In that thesis, AODV was the routing protocol used during the simulation process to evaluate its performance over VANETs. The conclusion of the thesis was that AODV is not the best routing protocol to handle high mobility of nodes and short duration of routes. He proposed as future work the evaluation of existing routing protocol which considers car position, trajectories or speeds gathered via GPS (Global Positioning System) that could lead to better results. To consider the vehicle network, people can intuitively think to use the geographical position information to decide the route. Most position based routing algorithms base forwarding decision on location information. GSR (Geographical Source Routing) is a promising routing technique for VANETs and recently several routing protocols have been proposed based on it. For example, GPSR (Greedy Perimeter Stateless Routing) is one of the best known position-based protocols in literature. Basically, our project is divided in two parts: first, we make a state of the art related to the VANETs in order to find the most appropriate and recommended mobility generator and network simulator reported in literature. We also include at the end of this part the description of GPSR routing protocol. Second, from the research done in the previous part, we use VanetMobiSim as a mobility generator due to its variety models that could be tested; and NS2 as a network simulator for being one of the most used by many authors and also due to its compatibility with VanetMobiSim. Using these tools, VanetMobiSim and NS2, we carry out a performance evaluation of two routing protocols (AODV and GPSR) over VANETs. We give different values to parameters such as the number of nodes, speed, transmission range and different propagation models. Finally, we analyze and discuss the benefits of GPSR compared to AODV in vehicular scenarios.