527 research outputs found

    Reliable Message Dissemination in Mobile Vehicular Networks

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    Les rĂ©seaux vĂ©hiculaires accueillent une multitude d’applications d’info-divertissement et de sĂ©curitĂ©. Les applications de sĂ©curitĂ© visent Ă  amĂ©liorer la sĂ©curitĂ© sur les routes (Ă©viter les accidents), tandis que les applications d’info-divertissement visent Ă  amĂ©liorer l'expĂ©rience des passagers. Les applications de sĂ©curitĂ© ont des exigences rigides en termes de dĂ©lais et de fiabilitĂ© ; en effet, la diffusion des messages d’urgence (envoyĂ©s par un vĂ©hicule/Ă©metteur) devrait ĂȘtre fiable et rapide. Notons que, pour diffuser des informations sur une zone de taille plus grande que celle couverte par la portĂ©e de transmission d’un Ă©metteur, il est nĂ©cessaire d’utiliser un mĂ©canisme de transmission multi-sauts. De nombreuses approches ont Ă©tĂ© proposĂ©es pour assurer la fiabilitĂ© et le dĂ©lai des dites applications. Toutefois, ces mĂ©thodes prĂ©sentent plusieurs lacunes. Cette thĂšse, nous proposons trois contributions. La premiĂšre contribution aborde la question de la diffusion fiable des messages d’urgence. A cet Ă©gard, un nouveau schĂ©ma, appelĂ© REMD, a Ă©tĂ© proposĂ©. Ce schĂ©ma utilise la rĂ©pĂ©tition de message pour offrir une fiabilitĂ© garantie, Ă  chaque saut, tout en assurant un court dĂ©lai. REMD calcule un nombre optimal de rĂ©pĂ©titions en se basant sur l’estimation de la qualitĂ© de rĂ©ception de lien dans plusieurs locations (appelĂ©es cellules) Ă  l’intĂ©rieur de la zone couverte par la portĂ©e de transmission de l’émetteur. REMD suppose que les qualitĂ©s de rĂ©ception de lien des cellules adjacentes sont indĂ©pendantes. Il sĂ©lectionne, Ă©galement, un nombre de vĂ©hicules, appelĂ©s relais, qui coopĂšrent dans le contexte de la rĂ©pĂ©tition du message d’urgence pour assurer la fiabilitĂ© en multi-sauts. La deuxiĂšme contribution, appelĂ©e BCRB, vise Ă  amĂ©liorer REMD ; elle suppose que les qualitĂ©s de rĂ©ception de lien des cellules adjacentes sont dĂ©pendantes ce qui est, gĂ©nĂ©ralement, plus rĂ©aliste. BCRB utilise les rĂ©seaux BayĂ©siens pour modĂ©liser les dĂ©pendances en vue d’estimer la qualitĂ© du lien de rĂ©ception avec une meilleure prĂ©cision. La troisiĂšme contribution, appelĂ©e RICS, offre un accĂšs fiable Ă  Internet. RICS propose un modĂšle d’optimisation, avec une rĂ©solution exacte optimale Ă  l'aide d’une technique de rĂ©duction de la dimension spatiale, pour le dĂ©ploiement des passerelles. Chaque passerelle utilise BCRB pour Ă©tablir une communication fiable avec les vĂ©hicules.Vehicular networks aim to enable a plethora of safety and infotainment applications. Safety applications aim to preserve people's lives (e.g., by helping in avoiding crashes) while infotainment applications focus on enhancing the passengers’ experience. These applications, especially safety applications, have stringent requirements in terms of reliability and delay; indeed, dissemination of an emergency message (e.g., by a vehicle/sender involved in a crash) should be reliable while satisfying short delay requirements. Note, that multi-hop dissemination is needed to reach all vehicles, in the target area, that may be outside the transmission range of the sender. Several schemes have been proposed to provide reliability and short delay for vehicular applications. However, these schemes have several limitations. Thus, the design of new solutions, to meet the requirement of vehicular applications in terms of reliability while keeping low end-to-end delay, is required. In this thesis, we propose three schemes. The first scheme is a multi-hop reliable emergency message dissemination scheme, called REMD, which guarantees a predefined reliability , using message repetitions/retransmissions, while satisfying short delay requirements. It computes an optimal number of repetitions based on the estimation of link reception quality at different locations (called cells) in the transmission range of the sender; REMD assumes that link reception qualities of adjacent cells are independent. It also adequately selects a number of vehicles, called forwarders, that cooperate in repeating the emergency message with the objective to satisfy multi-hop reliability requirements. The second scheme, called BCRB, overcomes the shortcoming of REMD by assuming that link reception qualities of adjacent cells are dependent which is more realistic in real-life scenarios. BCRB makes use of Bayesian networks to model these dependencies; this allows for more accurate estimation of link reception qualities leading to better performance of BCRB. The third scheme, called RICS, provides internet access to vehicles by establishing multi-hop reliable paths to gateways. In RICS, the gateway placement is modeled as a k-center optimisation problem. A space dimension reduction technique is used to solve the problem in exact time. Each gateway makes use of BCRB to establish reliable communication paths to vehicles

    Mobile Ad Hoc Networks

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    Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms

    Cloud Computing in VANETs: Architecture, Taxonomy, and Challenges

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    Cloud Computing in VANETs (CC-V) has been investigated into two major themes of research including Vehicular Cloud Computing (VCC) and Vehicle using Cloud (VuC). VCC is the realization of autonomous cloud among vehicles to share their abundant resources. VuC is the efficient usage of conventional cloud by on-road vehicles via a reliable Internet connection. Recently, number of advancements have been made to address the issues and challenges in VCC and VuC. This paper qualitatively reviews CC-V with the emphasis on layered architecture, network component, taxonomy, and future challenges. Specifically, a four-layered architecture for CC-V is proposed including perception, co-ordination, artificial intelligence and smart application layers. Three network component of CC-V namely, vehicle, connection and computation are explored with their cooperative roles. A taxonomy for CC-V is presented considering major themes of research in the area including design of architecture, data dissemination, security, and applications. Related literature on each theme are critically investigated with comparative assessment of recent advances. Finally, some open research challenges are identified as future issues. The challenges are the outcome of the critical and qualitative assessment of literature on CC-V

    Mobile Ad Hoc Networks

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    Guiding readers through the basics of these rapidly emerging networks to more advanced concepts and future expectations, Mobile Ad hoc Networks: Current Status and Future Trends identifies and examines the most pressing research issues in Mobile Ad hoc Networks (MANETs). Containing the contributions of leading researchers, industry professionals, and academics, this forward-looking reference provides an authoritative perspective of the state of the art in MANETs. The book includes surveys of recent publications that investigate key areas of interest such as limited resources and the mobility of mobile nodes. It considers routing, multicast, energy, security, channel assignment, and ensuring quality of service. Also suitable as a text for graduate students, the book is organized into three sections: Fundamentals of MANET Modeling and Simulation—Describes how MANETs operate and perform through simulations and models Communication Protocols of MANETs—Presents cutting-edge research on key issues, including MAC layer issues and routing in high mobility Future Networks Inspired By MANETs—Tackles open research issues and emerging trends Illustrating the role MANETs are likely to play in future networks, this book supplies the foundation and insight you will need to make your own contributions to the field. It includes coverage of routing protocols, modeling and simulations tools, intelligent optimization techniques to multicriteria routing, security issues in FHAMIPv6, connecting moving smart objects to the Internet, underwater sensor networks, wireless mesh network architecture and protocols, adaptive routing provision using Bayesian inference, and adaptive flow control in transport layer using genetic algorithms

    Rohc-Mpls Tunnel Architecture For Wireless Mesh

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    Natural or human-made disasters are sudden events that can cause significant damage, especially to the network communication infrastructure. In these events, a rapid deployment of network communication systems is required in order to relay or receive the communication among the people in the disaster areas to conduct relief and rescue efforts. Wireless mesh networks have emerged and has been recognised for its potential for rapid deployment and last mile coverage of network infrastructure, which is highly suitable for emergency response management. While wireless mesh networks have beneficial attributes, it also introduces some crucial problems. During data transmission, the path recovery time is significantly higher resulting in the loss of data if node and link failures occur

    Routing protocol for V2X communications for Urban VANETs

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    Intelligent Transportation Systems (ITSs) have been attracting tremendous attention in both academia and industry due to emerging applications that pave the way towards safer enjoyable journeys and inclusive digital partnerships. Undoubtedly, these ITS applications will demand robust routing protocols that not only focus on Inter-Vehicle Communications but also on providing fast, reliable, and secure access to the infrastructure. This thesis aims mainly to introduce the challenges of data packets routing through urban environment using the help of infrastructure. Broadcasting transmission is an essential operational technique that serves a broad range of applications which demand different restrictive QoS provisioning levels. Although broadcast communication has been investigated widely in highway vehicular networks, it is undoubtedly still a challenge in the urban environment due to the obstacles, such as high buildings. In this thesis, the Road-Topology based Broadcast Protocol (RTBP) is proposed, a distance and contention-based forwarding scheme suitable for both urban and highway vehicular environments. RTBP aims at assigning the highest forwarding priority to a vehicle, called a mobile repeater, having the greatest capability to send the packet in multiple directions. In this way, RTBP effectively reduces the number of competing vehicles and minimises the number of hops required to retransmit the broadcast packets around the intersections to cover the targeted area. By investigating the RTBP under realistic urban scenarios against well-known broadcast protocols, eMDR and TAF, that are dedicated to retransmitting the packets around intersections, the results showed the superiority of the RTBP in delivering the most critical warning information for 90% of vehicles with significantly lower delay of 58% and 70% compared to eMDR and TAF. The validation of this performance was clear when the increase in the number of vehicles. Secondly, a Fast and Reliable Hybrid routing (FRHR) protocol is introduced for efficient infrastructure access which is capable of handling efficient vehicle to vehicle communications. Interface to infrastructure is provided by carefully placed RoadSide Units (RSUs) which broadcast beacons in a multi-hop fashion in constrained areas. This enables vehicles proactively to maintain fresh minimum-delay routes to other RSUs while reactively discovering routes to nearby vehicles. The proposed protocol utilizes RSUs connected to the wired backbone network to relay packets toward remote vehicles. A vehicle selects an RSU to register with according to the expected mean delay instead of the device’s remoteness. The FRHR performance is evaluated against established infrastructure routing protocols, Trafroute, IGSR and RBVT-R that are dedicated to for urban environment, the results showed an improvement of 20% to 33% in terms of packet delivery ratio and lower latency particularly in sparse networks due to its rapid response to changes in network connectivity. Thirdly, focusing on increasing FRHR’s capability to provide more stable and durable routes to support the QoS requirements of expected wide-range ITS applications on the urban environment, a new route selection mechanism is introduced, aiming at selecting highly connected crossroads. The new protocol is called, Stable Infrastructure Routing Protocol (SIRP). Intensive simulation results showed that SIRP offers low end-to-end delay and high delivery ratio with varying traffic density, while resolving the problem of frequent link failures

    Routing and interworking protocols for next generation wireless networks

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