This work presents the development of the Context-Aware Hybrid Data Dissemination protocol for vehicular networks. The importance of developing vehicular networking data dissemination protocols is exemplified by the recent announcement by the U.S. Department of Transportation (DOT) National Highway Traffic Safety Administration (NHTSA) to enable vehicle-to-vehicle (V2V) communication technology. With emphasis on safety, other useful applications of V2V communication include but are not limited to traffic and routing, weather, construction and road hazard alerts, as well as advertisement and entertainment. The core of V2V communication relies on the efficient dispersion of relevant data through wireless broadcast protocols for these varied applications. The challenges of vehicular networks demand an adaptive broadcast protocol capable of handling diverse applications. This research work illustrates the design of a wireless broadcast protocol that is context-aware and adaptive to vehicular environments taking into consideration vehicle density, road topology, and type of data to be disseminated. The context-aware hybrid data dissemination scheme combines store-and-forward and multi-hop broadcasts, capitalizing on the strengths of both these categories and mitigates the weaknesses to deliver data with maximum efficiency to a widest possible reach. This protocol is designed to work in both urban and highway mobility models. The behavior and performance of the hybrid data dissemination scheme is studied by varying the broadcast zone radius, aggregation ratio, data message size and frequency of the broadcast messages. Optimal parameters are determined and the protocol is then formulated to become adaptive to node density by keeping the field size constant and increasing the number of nodes. Adding message priority levels to propagate safety messages faster and farther than non-safety related messages is the next context we add to our adaptive protocol. We dynamically set the broadcast region to use multi-hop which has lower latency to propagate safety-related messages. Extensive simulation results have been obtained using realistic vehicular network scenarios. Results show that Context-Aware Hybrid Data Dissemination Protocol benefits from the low latency characteristics of multi-hop broadcast and low bandwidth consumption of store-and-forward. The protocol is adaptive to both urban and highway mobility models. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite. In the wired network, TCP performs remarkably well due to its scalability and distributed end-to-end congestion control algorithms. However, many studies have shown that the unmodified standard TCP performs poorly in networks with large bandwidth-delay products and/or lossy wireless links. In this thesis, we analyze the problems TCP exhibits in the wireless communication and develop TCP congestion control algorithm for mobile applications. We show that the optimal TCP congestion control and link scheduling scheme amounts to window-control oriented implicit primaldual solvers for underlying network utility maximization. Based on this idea, we used a scalable congestion control algorithm called QUeueIng-Control (QUIC) TCP where it utilizes queueing-delay based MaxWeight-type scheduler for wireless links developed in [34]. Simulation and test results are provided to evaluate the proposed schemes in practical networks. / by Gee Won Han. / Thesis (M.S.C.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite, which is used by major Internet applications such as World Wide Web, email, remote administration and file transfer. TCP implements scalable and distributed end-to-end congestion control algorithms to share network resources among competing users. TCP was originally designed primarily for wired networks, and it has performed remarkably well as the Internet scaled up by six orders of magnitude in the past decade. However, many studies have shown that the unmodified standard TCP performs poorly in networks with large bandwidth-delay products and/or lossy wireless links. In this thesis, we analyze the problems TCP exhibits in the wireless communication environment, and develop joint TCP congestion control and wireless-link scheduling schemes for mobile applications. ... Different from the existing solutions, the proposed schemes can be asynchronously implemented without message passing among network nodes; thus they are readily deployable with current infrastructure. Moreover, global convergence/stability of the proposed schemes to optimal equilibrium is established using the Lyapunov method in the network fluid model. Simulation results are provided to evaluate the proposed schemes in practical networks. / by Zhaoquan Li. / Thesis (Ph.D.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

We present an implementation of the IEEE WAVE (Wireless Access in Vehicular Environments) 1609.4 standard, Multichannel Operation. This implementation provides concurrent access to a control channel and one or more service channels, enabling vehicles to communicate among each other on multiple service channels while still being able to receive urgent and control information on the control channel. Also included is functionality that provides over-the-air timing synchronization, allowing participation in alternating channel access in the absence of a reliable time source. Our implementation runs on embedded Linux and is built on top of IEEE 802.11p, as well as a customized device driver. This implementation will serve as a key compo- nent in our IEEE 1609-compliant Vehicular Multi-technology Communication Device (VMCD) that is being developed for a VANET testbed under the Smart Drive initiative, supported by the National Science Foundation. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Ad hoc mobile wireless networks are self-configuring infrastructureless networks of mobile devices connected via wireless links. Each device can send and receive data, but it should also forward traffic unrelated to its own use. All need to maintain their autonomy, and effectively preserve their resources (e.g. battery power). Moreover, they can leave the network at any time. Their intrinsic dynamicity and fault tolerance makes them suitable for applications, such as emergency response and disaster relief, when infrastructure is nonexistent or damaged due to natural disasters, such as earthquakes and flooding, as well as more mundane, day-to-day, uses where their flexibility would be advantageous. Routing is the fundamental research issue for such networks and refers to finding and maintaining routes between nodes. Moreover, it involves selecting the best route where many may be available. However, due to the freedom of movement of nodes, new routes need to be constantly recalculated. Most routing protocols use pure broadcasting to discover new routes, which takes up a substantial amount of bandwidth. Intelligent rebroadcasting reduces these overheads by calculating the usefulness of a rebroadcast, and the likelihood of message collisions. Unfortunately, this introduces latency and parts of the network may become unreachable. This dissertation presents a routing protocol that uses a new parallel and distributed guided broadcasting technique to reduce redundant broadcasting and to accelerate the path discovery process, while maintaining a high reachability ratio as well as keeping node energy consumption low. This broadcasting scheme is implemented in a Mobile Ad Hoc Network (MANET) and a Wireless Mesh Network (WMN). To reduce overheads further, a Zone based Routing with Parallel Collision Guided Broadcasting Protocol (ZCG) in MANET is introduced. This uses a one hop clustering algorithm that splits the network into zones led by reliable leaders that are mostly static and have plentiful battery resources. For WMN, a Social-aware Routing Protocol (SCG) is designed that draws upon social network theory to associate longstanding social ties between nodes, using their communication patterns to divide the network into conceptual social groups, which allows cluster members to protect each other from redundant broadcasts by using intelligent rebroadcasting. The performance characteristics of the new protocols are established through simulations that measure their behaviour and by comparing them to other well-known routing protocols, namely the: AODV, DSR, TORA and the OLSR, as appropriate, it emerges that two new protocols, the ZCG and SCG, perform better in certain conditions, with the latter doing consistently well under most circumstances.

La mobilité est une composante importante de la liberté des personnes. L’évolution des moyens technologiques y contribue au premier chef. Outre la question du transport, celle du maintien du lien entre les individus est en ce sens particulièrement prégnante. Elle a mis à rude épreuve la notion de réseaux de télécommunications puisqu’il s’agit de répondre, pour des individus éparpillés ou concentrés, mais mobiles, au besoin de rester reliés. De l’ère des réseaux analogiques à celle des réseaux numériques, de l’ère des réseaux filaires à celle des réseaux sans fil et mobiles, la technologie n’a cessé d’évoluer. Ces dernières décennies ont vu apparaître des réseaux numériques sans fil, où non seulement il y a mobilité des utilisateurs mais aussi mobilité de l’infrastructure du réseau à laquelle ils contribuent. Ces réseaux se constituent de façon spontanée. Ils se maintiennent de manière autonome. On les désigne par le terme réseaux ad hoc mobiles (en anglais Mobile Ad hoc Networks ou MANET) qui s’oppose naturellement à celui de réseaux à infrastructure. La sécurité est une préoccupation générale des êtres humains. Ils en ressentent aussi le besoin en matière de réseaux. Ce besoin est particulièrement criant lorsque sont échangées des données critiques, financières ou stratégiques. La confidentialité des échanges, l’authentification des sources, l’assurance d’intégrité, la prévention de la récusation sont autant d’objectifs qu’il faut alors atteindre. Diverses solutions de sécurité ont été conçues dans cette optique pour les réseaux filaires puis ont ensuite été adaptées aux réseaux sans-fil et mobiles. Les architectures AAA (Authentication, Authorization, Accounting) en font partie. Elles sont en général utilisées dans un contexte commercial. Tant par leur facilité de déploiement que par la baisse des coûts de mise en œuvre qu’ils engendrent, les réseaux ad hoc mobiles, après avoir bien servi dans le domaine militaire, semblent avoir un avenir dans les applications commerciales. C’est pourquoi, nous nous proposons dans cette thèse de concevoir une architecture AAA adaptée aux spécificités de ces réseaux. Nous étudions d’abord les réseaux ad hoc mobiles et leurs caractéristiques. Ensuite, nous présentons les solutions de sécurité qui existent dans les réseaux à infrastructure. Nous examinons, en particulier, les solutions qui permettent le contrôle d’accès et dont sont engendrées les architectures AAA. Les solutions AAA proposées pour les MANETs sont par la suite analysées et classifiées afin de déterminer les manques et les vulnérabilités. Cette étude approfondie nous amène à proposer une architecture AAA répondant aux attentes identifiées. C’est une architecture distribuée qui répond, en particulier, au besoin d’autonomie des opérations dans les MANETs et où les protocoles exécutés peuvent impliquer simultanément plus de deux parties. Un ensemble de protocoles et de mécanismes d’authentification et d’autorisation s’intégrant avec la suite des protocoles IPv6 a été proposé. Leur sécurité a été discutée. Celle, en particulier du protocole d’authentification a fait l’objet de validation formelle. Contrairement aux protocoles utilisés dans la phase d’autorisation des services AAA proposés, le mode de communication multi-parties et multi-sauts du protocole d’authentification nous a poussé à mener une analyse approfondie de ses performances. Pour cela, nous avons eu recours, dans un premier temps, à la modélisation au moyen de calculs mathématiques explicites ensuite à la simulation. Les résultats obtenus montrent que ce protocole passe à l’échelle d’un MANET comprenant au moins cent nœuds. Dans certaines conditions d’implémentation que nous avons définies, ses performances, tant celle liée à sa probabilité de terminaison avec une issue favorable que celle portant sur son temps d’exécution, atteignent des valeurs optimales. / Mobility is an important component of people’s liberty. The evolution of technological means contributes to its enhancement. In addition to the transport issue, the question of keeping people connected is, in that context, particularly significant. Technological change strained the notion of telecommunications networks in the sense that scattered or clustered but mobile individuals had to remain in touch with others electronically. From the age of analogue networks to the digital networks era, from wired networks to wireless and mobile networks, technology has never stopped evolving. The last decades have witnessed the emergence of digital and wireless networks where not only the users, but also the network infrastructure to which they contribute, are mobile. These networks are spontaneously formed and autonomously maintained. They are termed Mobile Ad hoc Networks (MANETs), in contradistinction to infrastructure networks. Security is a general concern of human beings. They feel the need for it when using a network, too. This need is particularly glaring when it comes to exchanging critical, financial or strategic data. Confidentiality of communications, source authentication, integrity assurance, prevention of repudiation, are all objectives to be achieved. Various security solutions have been devised in this context as wired networks were then adapted to wireless and mobile networks. AAA (Authentication, Authorization and Accounting) frameworks are among these solutions. They are generally used for commercial purposes, which raises financial issues — and we all know how much important they are. Due to their ease of deployment and inexpensive implementation, MANETs, first used in the military field, seem to have a future in commercial applications. That is why the present thesis proposes to design an AAA service that is adapted to the characteristics of such networks. In this perspective, the thesis examines, to begin with, mobile ad hoc networks in order to understand their characteristics and potentials. It then probes the security solutions that exist in infrastructure networks, with special emphasis on those dealing with access control and AAA services. The AAA solutions for MANETs proposed up to now are subsequently analyzed and classified in order to determine their strengths and weaknesses. This in-depth study led to the design, in the second part of the thesis, of an AAA service that meets the expectations identified. It is a distributed service intended to answer the needs of autonomous operations in MANETs when a nearby operator is absent. It features several detailed authentication and authorization mechanisms and protocols with an authentication protocol simultaneously involving one or more parties. These protocols are designed such that they can be easily integrated to the IPv6 protocols suite. Moreover, their security is discussed — in particular, that of the authentication protocol thanks to a formal validation tool. Unlike the communication mode of the authorization protocols, that of the authentication protocol is one-to-many, which led us to study more deeply its performances thanks to modeling using explicit mathematical computations and to simulations techniques. The obtained results showed that the protocol scales for a MANET including a hundred nodes. Under certain conditions that we explained, its performances, in terms of the probability of authentication success and the length of the executing time, reach optimal values.

A incorporação das tecnologias de computação e de comunicação nos veículos modernos está viabilizando uma nova geração de automóveis conectados. Com a capacidade de se organizarem em rede, nas chamadas redes veiculares ad hoc (VANETs), eles poderão, num futuro próximo, (i) tornar o trânsito mais seguro para os motoristas, passageiros e pedestres e/ou (ii) promover uma experiência de transporte mais agradável, com maior conforto. É neste contexto que se destaca o Sensoriamento Veicular Colaborativo (VCS), um paradigma emergente e promissor que explora as tecnologias já embarcados nos próprios veículos para a obtenção de dados in loco. O VCS tem demonstrado ser um modelo auspicioso para o desenvolvimento e implantação dos Sistemas Inteligentes de Transporte (ITSs). Ocorre, todavia, que, em grandes centros urbanos, dependendo do fenômeno a ser monitorado, as aplicações de VCS podem gerar um tráfego de dados colossal entre os veículos e o centro de monitoramento. Considerando que as informações dos automóveis são geralmente enviadas para um servidor remoto usando as infraestruturas das redes móveis, o número massivo de transmissões geradas durante as atividades de sensoriamento pode sobrecarregá-las e degradar consideravelmente a Qualidade de Serviço (QoS) que elas oferecem. Este documento de tese descreve e analisa uma abordagem de clusterização geográfica que se apoia no uso de comunicações Veículo-para-Veículo (V2V) para promover o descarregamento de dados do VCS em redes celulares, de forma a minimizar os impactos supracitados. Os resultados experimentais obtidos mostraram que o uso das comunicações V2V como método complementar de aquisição de dados in loco foi capaz de diminuir consideravelmente a quantidade transmissões realizadas sobre as redes móveis, sem a necessidade de implantação de novas infraestruturas de comunicação no ambiente, e com um reduzido atraso médio adicional fim a fim na obtenção das informações. A abordagem desenvolvida também se apresenta como uma plataforma de software flexível sobre a qual podem ser incorporadas técnicas de agregação de dados, o que possibilitaria aumentar ainda mais a preservação dos recursos de uplink das redes celulares. Considerando que a era da Internet das Coisas (IoT) e das cidades inteligentes está apenas começando, soluções para o descarregamento de dados, tal como a tratada nesta pesquisa, são consideradas imprescindíveis para continuar mantendo a rede móvel de acesso à Internet operacional e capaz de suportar uma demanda de comunicação cada vez maior por parte das aplicações. / The incorporation of computing and communication technologies into modern vehicles is enabling a new generation of connected cars. With the ability to get into a network formation, in the so-called ad hoc networks (VANETs), these vehicles might, in the near future, (i) make the traffic safer for drivers, passengers and pedestrians and/or (ii) promote a more pleasant transportation experience, with greater comfort. It is in this context that emerges the Vehicle CrowdSensing (VCS), a novel and promising paradigm for performing in loco data collection from the vehicles embedded technologies. VCS has proved to be an auspicious scheme for the development and deployment of the Intelligent Transport Systems (ITSs). However, in large urban areas, depending on the phenomenon to be monitored, the VCS applications can generate a colossal data traffic between vehicles and the monitoring center. Considering that all the vehicles information is generally sent to the remote server by using mobile network infrastructures, this massive amount of transmissions generated during the sensing activities can overload them and degrade the Quality of Service (QoS) they offer. This thesis document describes and analyzes a geographic clustering approach that relies on the use of Vehicle-to- Vehicle (V2V) communications to promote the VCS data offloading in cellular networks, in order to minimize the above impacts. The experimental results obtained showed that the use of V2V communications as a complementary data acquisition method was able to considerably reduce the number of transmissions carried out on mobile networks, without the need for deploying new communication infrastructures in the environment, and with a reduced additional delay. The created approach also stands itself as a flexible software platform on which data aggregation techniques can be incorporated, in order to maximize the network resources preservation already provided by the proposal. Considering that we are just entering in the Internet of Things (IoT) and smart cities era, creating data offloading solutions, such as that treated in this research, is considered an essential task to keep the Internet access network operational and able to support the growing demand for mobile communications.

La coloration de graphes est un problème central de l’optimisation combinatoire. C’est un domaine très attractif par ses nombreuses applications. Différentes variantes et généralisations du problème de la coloration de graphes ont été proposées et étudiées. La coloration d’arêtes d’un graphe consiste à attribuer une couleur à chaque arête du graphe de sorte que deux arêtes ayant un sommet commun n’ont jamais la même couleur, le tout en utilisant le moins de couleurs possibles. Dans la première partie de cette thèse, nous étudions le problème de la coloration d’arêtes ℓ-distance, qui est une généralisation de la coloration d’arêtes classique. Nous menons une étude combinatoire et algorithmique du paramètre. L’étude porte sur les classes de graphes suivantes : les chaines, les grilles, les hypercubes, les arbres et des graphes puissances. Le paramètre de la coloration d’arêtes ℓ-distance permet de modéliser des problèmes dans des réseaux assez grands. Cependant, avec la multiplication du nombre de nœuds, les réseaux sont de plus en plus vulnérables aux défaillances (ou pannes). Dans la deuxième partie, nous nous intéressons aux algorithmes tolérants aux pannes et en particulier les algorithmes auto-stabilisants. Nous proposons un algorithme auto-stabilisant pour la coloration propre d’arêtes. Notre solution se base sur le résultat de vizing pour utiliser un minimum de couleurs possibles. Par la suite, nous proposons un algorithme auto-stabilisant de clustering destine a des applications dans le domaine de la sécurité dans les réseaux mobiles Ad hoc. La solution que nous proposons est un partitionnement en clusters base sur les relations de confiance qui existent entre nœuds. Nous proposons aussi un algorithme de gestion de clés de groupe dans les réseaux mobiles ad hoc qui s’appuie sur la topologie de clusters préalablement construite. La sécurité de notre protocole est renforcée par son critère de clustering qui surveille en permanence les relations de confiance et expulse les nœuds malveillants de la session de diffusion. / Graph coloring is a famous combinatorial optimization problem and is very attractive for its numerous applications. Many variants and generalizations of the graph-coloring problem have been introduced and studied. An edge-coloring assigns a color to each edge so that no two adjacent edges share the same color. In the first part of this thesis, we study the problem of the ℓ-distance-edge-coloring, which is a generalization of the classical edge-coloring. The study focuses on the following classes of graphs : paths, grids, hypercubes, trees and some power graphs. We are conducting a combinatorial and algorithmic study of the parameter. We give a sequential coloring algorithm for each class of graph. The ℓ-distance-edge-coloring is especially considered in large-scale networks. However, with the increasing number of nodes, networks are increasingly vulnerable to faults. In the second part, we focus on fault-tolerant algorithms and in particular self-stabilizing algorithms. We propose a self-stabilizing algorithm for proper edge-coloring. Our solution is based on Vizing’s result to minimize number of colors. Subsequently, we propose a selfstabilizing clustering algorithm for applications in the field of security in mobile ad hoc networks. Our solution is a partitioning into clusters based on trust relationships between nodes. We also propose a group key-management algorithm in mobile ad hoc networks based on the topology of clusters previously built. The security of our protocol is strengthened by its clustering criterion which constantly monitors trust relationships and expels malicious nodes out of the multicast session.

<p>With the constant development of wireless technologies, the usageof wireless devices tends to increase even more in the future.Wireless multi-hop networks (WMNs) have emerged as a keytechnology to numerous potential scenarios, ranging from disasterrecovery to wireless broadband internet access. The distributedarchitecture of WMNs enables nodes to cooperatively relay othernode's packets. Because of their advantages over other wirelessnetworks, WMNs are undergoing rapid progress and inspiringnumerous applications. However, many technical issues still existin this field. In this thesis we investigate how Voice over IP(VoIP) and peer-to-peer (P2P) application are influenced bywireless multi-hop network characteristics and how to optimizethem in order to provide scalable communication.We first consider the deployment of VoIP service in wirelessmulti-hop networks, by using the Session Initiation Protocol (SIP)architecture. Our investigation shows that the centralized SIParchitecture imposes several challenges when deployed in thedecentralized wireless multi-hop environment. We find that VoIPquality metrics are severely degraded as the traffic and number ofmultiple hops to the gateway increase. In the context ofscalability, we further propose four alternative approaches whichavoid current limitations.In the second part of this thesis we tackle the network capacityproblem while providing scalable VoIP service over wirelessmulti-hop networks. The performance evaluation shows the influenceof intra and inter-flow interference in channel utilization, whichdirect impacts the VoIP capacity. In order to avoid the small VoIPpacket overhead, we propose a new adaptive hop-by-hop packetaggregation scheme based on wireless link characteristics. Ourperformance evaluation shows that the proposed scheme can increasethe VoIP capacity by a two-fold gain.The study of peer-to-peer applicability over wireless multi-hopnetworks is another important contribution. A resource lookupapplication is realized through structured P2P overlay. We showthat due to several reasons, such as characteristics of wirelesslinks, multi-hop forwarding operation, and structured P2Pmanagement traffic aggressiveness the performance of traditionalP2P applications is rather low in wireless multi-hop environments.Therefore, we suggested that a trade-off between the P2P lookupefficiency and the P2P management traffic overhead can be achievedwhile maintaining the overlay network consistency in wirelessmulti-hop networks.</p>

Internet and mobile communications have had a profound effect on today's society. New services are constantly being deployed, in which personal data are being processed in return for personally tailored services. While mobile networks lay the groundwork for new innovative services, at the same time they pose numerous privacy challenges. There is the risk that honest citizens participating in mobile communications will have their privacy invaded for "the greater good". We argue that it is highly important that individuals are empowered to retain control over their personal spheres. Thus, the goal of this thesis is to design and evaluate anonymous overlay networks} adapted for mobile networks that allow users to control which information leaves their personal spheres in a mobile communication. Technically, by using an anonymous overlay network, users can communicate with their communication partners without disclosing their network identities. In this thesis, we propose three different anonymous overlay networks tailored for mobile networks. First, two approaches are proposed for anonymous browsing on the mobile Internet, namely mCrowds and a Tor-based approach. By applying theoretical analysis and\,/\,or practical experiments, we show that these approaches offer an appropriate trade-off between the offered degree of anonymity and performance loss. Second, an anonymous overlay network for use in mobile ad hoc networks - Chameleon - is suggested. Besides the actual design of these anonymous overlay networks, this thesis provides novel contributions in other essential areas of privacy protection and anonymous communication. First, also non-technical aspects of privacy protection are thoroughly discussed, including legal, social, and user interface aspects. Second, we survey existing metrics for quantifying anonymity and also propose new ideas regarding anonymity metrics. Third, we review and classify existing mechanisms for anonymous communication in mobile ad hoc networks. Lastly, we also propose a cryptographic technique for building up the user base of an anonymous overlay network in a secure and privacy-friendly manner.