Les réseaux ad hoc véhiculaires (VANETs) sont constitués par un ensemble de véhicules qui échangent des données de sécurité et de confort même s’ils ne sont pas toujours directement à portée radio.Les problèmes liés aux réseaux VANETs ne sont pas encore tous résolus. Dans ce contexte, et dans le but de maximiser la stabilité dans ce type de réseaux, nous proposons différentes contributions pour assurer le routage en combinant les métaheuristiques et la technique de clustérisation.Tout d’abord, nous présentons un modèle de routage utilisant l’algorithme de clustérisation le plus efficace k-medoids. Ensuite, nous proposons plusieurs améliorations en utilisant les métaheuristiques, plus précisément les algorithmes génétiques, la recherche tabou et la recherche par dispersion. Enfin, nous proposons une application réelle de communication entre trois robots mobiles dans les zones non couvertes par le réseau VANET.A l’aide de diverses métriques, des simulations extensives montrent que nos contributions donnent de bons résultats par rapport à d’autres modèles conçus dans le même but. / Vehicular ad hoc networks (VANETs) consist of a set of vehicles trying to exchange security and comfort data even if they are not directly within radio range of each other. The problems related to VANET networks are not yet solved. In this context, and in order to maximize the stability in the VANETs networks, we propose different contributions combining the metaheuristics and the clustering technique. First, we propose a routing model using the most efficient clustering algorithm K-medoids. Then, we propose several improvements using metaheuristics, more precisely the AGs, the RT and the Scatter Search. Finally, we propose a real application that uses the Arduino Uno platform to allow communication between three mobile robots in an areas not covered by the VANET network.Using various metrics, extensive simulations prove that our contributions show good results compared to other models designed for the same purpose.

This research devises a unified method for the distribution of pseudonyms in hybrid ephemeral vehicular networks (VNs), which are often referred to as vehicular ad hoc networks (VANETs), for the purposes of refill, intra-regional, and inter-regional movement. This work addresses a significant impediment to the use of pseudonyms, which has been almost universally accepted (and is on the verge of being standardized by the Institute for Electrical and Electronic Engineers (IEEE) and the Society for Automotive Engineers (SAE) as the best means to balance attribution and privacy to maximize the value of infrastructure deployment and citizen acceptability (i.e. use). The results include a pseudonym distribution protocol that maximizes ease of use while not compromising the security or privacy pseudonyms afford. These results contribute to the solution, in a scalable, adaptive, and bandwidth efficient manner, one of the remaining impediments to the adoption of VANETs. The new method shows improved performance compared to a baseline pseudonym distribution method that does not take these factors into consideration.

User desire for ubiquitous applications on-board a vehicle motivates the necessity for Network Mobility (NEMO) solutions for Vehicular Ad-Hoc Networks (VANETs). Due to the dynamic topology of VANETs, this approach incurs excessive infrastructure cost to maintain stable connectivity and support these applications. Our solution to this problem is focused on a novel NEMO-based Network Architecture where vehicles are the main network infrastructure. Within this Architecture, we present a Network Criticality-based clustering algorithm, which adapts to mobility changes to form stable self-organizing clusters of vehicles and dynamically builds on vehicle clusters to form more stable Mobile Networks. Simulation results show that the proposed method provides more stable clusters, lower handoffs and better connectivity compared to popular density-based vehicle clustering methods. In addition, they confirm the validity of the proposed Network Architecture. The proposed method is also robust to channel error and exhibits better performance when the heterogeneity of vehicles is exploited.

User desire for ubiquitous applications on-board a vehicle motivates the necessity for Network Mobility (NEMO) solutions for Vehicular Ad-Hoc Networks (VANETs). Due to the dynamic topology of VANETs, this approach incurs excessive infrastructure cost to maintain stable connectivity and support these applications. Our solution to this problem is focused on a novel NEMO-based Network Architecture where vehicles are the main network infrastructure. Within this Architecture, we present a Network Criticality-based clustering algorithm, which adapts to mobility changes to form stable self-organizing clusters of vehicles and dynamically builds on vehicle clusters to form more stable Mobile Networks. Simulation results show that the proposed method provides more stable clusters, lower handoffs and better connectivity compared to popular density-based vehicle clustering methods. In addition, they confirm the validity of the proposed Network Architecture. The proposed method is also robust to channel error and exhibits better performance when the heterogeneity of vehicles is exploited.

The safety-message dissemination problem for vehicular ad hoc networks (VANETs) was investigated. Four novel techniques were contributed for the efficient and reliable routing of safety messages in the vehicular ad hoc networks. The instant-broadcast technique was proposed to improve the end-to-end dissemination delay. The lane-based sectoring mechanism was presented for the collision mitigation in the dense-urban traffic scenario. The negative acknowledgment with smart neighborhood (NSN) technique was proposed to ensure the reliability of reception through recovering the packet loss caused by interference. Finally, the negative acknowledgment with smart neighborhood - hole recovery (NSN-H) technique was presented to provide guaranteed reception of the safety message at each individual node in the VANET. The investigation of the safety message routing in VANET conducted in this research also revealed the significance of hitherto-neglected factors that influence the vehicular network. Significance of the small payload size of the VANET safety message, the effect of road width on the multi-hop relay, and the attenuation caused by vehicles in the propagation path were among the important revealed factors.

As roadside and in-vehicle sensors are deployed under the Connected Vehicle Research program (formerly known as Vehicle Infrastructure Integration initiative and Intellidrive), an increasing variety of traffic data is becoming available in real time. This real time traffic data is shared among vehicles and between vehicles and traffic management centers through wireless communication. This course of events creates an opportunity for mobile computing and online traffic simulations. However, online traffic simulations require faster than real time running speed with high simulation resolution, since the purpose of the simulations is to provide immediate future traffic forecast based on real time traffic data. However, simulating at high resolution is often too computationally intensive to process a large scale network on a single processor in real time. To mitigate this limitation an online ad hoc distributed simulation with optimistic execution is proposed in this study. The objective of this study is to develop an online traffic simulation system based on an ad hoc distributed simulation with optimistic execution. In this system, data collection, processing, and simulations are performed in a distributed fashion. Each individual simulator models the current traffic conditions of its local vicinity focusing only on its area of interest, without modeling other less relevant areas. Collectively, a central server coordinates the overall simulations with an optimistic execution technique and provides a predictive model of traffic conditions in large areas by combining simulations geographically spread over large areas. This distributed approach increases computing capacity of the entire system and speed of execution. The proposed model manages the distributed network, synchronizes the predictions among simulators, and resolves simulation output conflicts. Proper feedback allows each simulator to have accurate input data and eventually produce predictions close to reality. Such a system could provide both more up-to-date and robust predictions than that offered by centralized simulations within a single transportation management center. As these systems evolve, the online traffic predictions can be used in surface transportation management and travelers will benefit from more accurate and reliable traffic forecast.

Importance of an alternative sensor system to an inertial measurement unit (IMU) is essential for intelligent land navigation systems when the vehicle travels in a GPS deprived environment. The sensor system that has to be used in updating the IMU for a reliable navigation solution has to be a passive sensor system which does not depend on any outside signal. This dissertation presents the results of an effort where position and orientation data from vision and inertial sensors are integrated. Information from a sequence of images captured by a monocular camera attached to a survey vehicle at a maximum frequency of 3 frames per second was used in upgrading the inertial system installed in the same vehicle for its inherent error accumulation. Specifically, the rotations and translations estimated from point correspondences tracked through a sequence of images were used in the integration. However, for such an effort, two types of tasks need to be performed. The first task is the calibration to estimate the intrinsic properties of the vision sensors (cameras), such as the focal length and lens distortion parameters and determination of the transformation between the camera and the inertial systems. Calibration of a two sensor system under indoor conditions does not provide an appropriate and practical transformation for use in outdoor maneuvers due to invariable differences between outdoor and indoor conditions. Also, use of custom calibration objects in outdoor operational conditions is not feasible due to larger field of view that requires relatively large calibration object sizes. Hence calibration becomes one of the critical issues particularly if the integrated system is used in Intelligent Transportation Systems applications. In order to successfully estimate the rotations and translations from vision system the calibration has to be performed prior to the integration process. The second task is the effective fusion of inertial and vision sensor systems. The automated algorithm that identifies point correspondences in images enables its use in real-time autonomous driving maneuvers. In order to verify the accuracy of the established correspondences, independent constraints such as epipolar lines and correspondence flow directions were used. Also a pre-filter was utilized to smoothen out the noise associated with the vision sensor (camera) measurements. A novel approach was used to obtain the geodetic coordinates, i.e. latitude, longitude and altitude, from the normalized translations determined from the vision sensor. Finally, the position locations based on the vision sensor was integrated with those of the inertial system in a decentralized format using a Kalman filter. The vision/inertial integrated position estimates are successfully compared with those from 1) inertial/GPS system output and 2) actual survey performed on the same roadway. This comparison demonstrates that vision can in fact be used successfully to supplement the inertial measurements during potential GPS outages. The derived intrinsic properties and the transformation between individual sensors are also verified during two separate test runs on an actual roadway section.

D. Tech. Electrical Engineering. / Discusses the protocol design in VANETs is very challenging due to their low latency and high data rate requirements in a high mobility environment. Hence, the central metrics of QoS such as throughput, reliability and delays are critical to the design of protocol in VANETs. Therefore, this project focuses on the scheduling and QoS enhancement algorithms. The QoS analytical model and multi-channel MAC protocol were completed; this was significant for the development of the VANETs.The anticipated benefits of this study may be described as: 1. The duty cycle adaptive MAC protocol could improve the QoS of VANET in the situation where the OBU is equipped with only one transceiver. 2. The results obtained from this model is significant for the designing and evaluation of the vehicular network. 3. Due to the characteristics of VANETs, the requirements of high throughput and low latency are critical in VANETs. An efficient multi-channel MAC protocol is a vital requirement in order to offer efficient, fair and stable channel access using the limited channel resources.

The topic of the research is granting privacy and authentication in Mobile Ad Hoc Networks (MANETs) that are under the authority of a certificate authority (CA) that is often not available. Privacy is implemented in the form of an anonymous identity or pseudonym, and ideally has no link to the real identity. Authentication and privacy are conflicting tenets of security as the former ensures a user's identity is always known and certified and the latter hides a user's identity. The goal was to determine if it is possible for a node to produce pseudonyms for itself that would carry the authority of the CA while being traceable by the CA, and would be completely anonymous. The first part of the dissertation places Vehicular Ad Hoc Networks (VANETs) into context, as this is the application of MANETs considered. This is followed by a detailed survey and analysis of the privacy aspects of VANETs. Thereafter, the solution is proposed, documented and analysed. Lastly, the dissertation is concluded and the contributions made are listed. The solution implements a novel approach for making proxies readily available to vehicles, and does indeed incorporate privacy and authentication in VANETs such that the pseudonyms produced are always authentic and traceable. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2012.

Le degré de pénétration du marché des appareils intelligents tels que les smartphones et les tablettes avec les technologies de communication embarquées comme le WiFi, 3G et LTE a explosé en moins d'une décennie. En complément de cette tendance technologique, les appli- cations des réseaux sociaux ont virtuellement connecté une grande partie de la population, en génèrant une demande de trafic de données croissant vers et depuis l'infrastructure de com- munication. Les communications pervasive ont aussi acquis une importance dans l'industrie automobile. L'émergence d' une gamme impressionnante d' appareils intelligents dans les véhicules permettant services tels que assistance au conducteur, infotainment, suivi à dis- tance du vehicule, et connectivité àux réseaux sociaux même en déplacement. La demande exponentielle de connectivité a encore défié les fournisseurs de services de télécommunications pour répondre aux attentes des utilisateurs du réseau à grande vitesse. L'objectif de cette thèse est de modéliser et comprendre la mobilité dynamique des utilisateurs à grande vitesse et leurs effets sur les architectures de réseau sans fil. Compte tenu de l' importance du développement de notre étude sur une représentation réal- iste de la mobilité des véhicules, nous étudions tout d'abord les approches les plus populaires pour la génération de trafic routier synthétique et discutons les caractéristiques des ensem- bles de données accessibles au public qui decrivent des mobilités véhiculaires. En utilisant l'information des déplacements de la population dans une région métropolitaine, les données du réseau routier détaillées et des modèles réalistes de conduite microscopiques, nous pro- posons un jeux de données de mobilité véhiculaire original qui redéfinit l'état de l'art et qui replie la circulation routière de facon realiste dans le temps et dans l'espace. Nous étudions ensuite l'impact des dynamiques de mobilité du point de vue de la couverture cellulaire en présence d'un déploiement réel des stations de base. En outre, en examinant les effets de la mobilité des véhicules sur les réseaux autonomes, nous voyons des possibilités pour les futurs paradigmes de réseaux hétérogènes. Motivés par l'évolution dynamique dans le temps de la mobilité des véhicules observée dans notre jeux de données, nous proposons également une approche en ligne pour prédire les flux de trafic macroscopiques. Nous analysons les paramètres affectant la prédiction de la mobilité en milieu urbain. Nous dévoilons quand et où la gestion des ressources réseau est plus crucial pour accueillir le trafic généré par les utilisateurs à bord. Ces études dévoilent des multiples opportunités de gestion intelligente des transports, soit pour construire de nouvelles routes, soit pour l'installation de bornes de recharge électriques, ou pour la conception de systèmes de feux de circulation intelligents, contribuant ainsi à la planification urbaine.