22 research outputs found

    Silent alarm: Link lifetime prediction for reliable routing in VANET

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    Transmission of silent alarm messages from a target stolen vehicle node to its final destination node, such as a Police Station, is an attempt to deter problems related to vehicle theft by exploiting the VANET technology.This paper proposed a forwarding scheme for sending silent alarm messages between any two vehicle nodes in a VANET topology based on prediction of link reliability between them.Based on this single hop link prediction, the transmission of silent alarm messages through a complete route can be expected to be efficient and safe using the platform of vehicle to-vehicle communication and vehicle-to-roadside infrastructure on a highway. Two communication scenarios are considered: when the two vehicles are moving in the same direction and when they are moving in the opposite direction to each others.The strategy for computing a reliable link is based on lifetime prediction technique.The performance of this technique for link reliability will be evaluated using MATLAB simulation

    Performance Evaluation of AODV Routing Protocol in VANET with NS2

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    In intelligent transportation systems, the collaboration between vehicles and the road side units is essential to bring these systems to realization. The emerging Vehicular Ad Hoc Network (VANET) is becoming more and more important as it provides intelligent transportation application, comfort, safety, entertainment for people in vehicles. In order to provide stable routes and to get good performance in VANET, there is a need of proper routing protocols must be designed. In this paper, we are working with the very well-known ad-hoc on-demand distance vector (AODV) routing protocol. The existing Routing protocol AODV-L which is based on the Link expiration time is extended to propose a more reliable AODV-AD which is based on multichannel MAC protocol. For the performance evaluation of routing protocols, a simulation tool ‘NS2’ has been used. Simulation results show that the proposed AODV-AD protocol can achieves better performances in forms of high Route stability, Packet Delivery ratio and packet loss rate than traditional AODV-L and traditional AODV

    An Overview of QoS Enhancements for Wireless Vehicular Networks

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    Vehicular ad hoc networks (VANETs) allow vehicles to form a self-organized network without the need for permanent infrastructure. Even though VANETs are mobile ad hoc networks (MANETs), because of the intrinsic characteristics of VANETs, several protocols designed for MANETs cannot be directly applied for VANETs. With high number of nodes and mobility, ensuring the Quality of Service (QoS) in VANET is a challenging task. QoS is essential to improve the communication efficiency in vehicular networks. Thus a study of QoS in VANET is useful as a fundamental for constructing an effective vehicular network. In this paper, we present a timeline of the development of the existing protocols for VANETs that try to support QoS. Moreover, we classify and characterize the existing QoS protocols for VANETs in a layered perspective. The review helps in understanding the strengths and weaknesses of the existing QoS protocols and also throws light on open issues that remain to be addressed. Keywords: QoS, VANET, Inter-Vehicle Communications, MAC, Routin

    A Driving Path Based Opportunistic Routing in Vehicular Ad Hoc Network

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    Vehicular Ad Hoc Networks is a promising technologythat can widely apply to monitor the physical world in urban areas.Efficient data delivery is important in these networks and optimalroute selection is vital to improve this factor. Vehicular mobility isa reflection of human social activity and human trajectories show ahigh degree of temporal and spatial regularity. Therefore, vehiculardriving paths are predictable in a large extent. A new opportunisticrouting protocol (DPOR) is proposed in this study that uses drivingpath predictability and vehicular distribution in its route selectionprocedure. This protocol is composed of two phases: intersectionand next hop selection phases. A utility function is calculated toselect the next intersection and a new mechanism is also proposedfor the next hop selection phase. Simulation results show thatDPOR achieves high delivery ratio and low end-to-end delay in thenetwork

    Protocole de routage basé sur des passerelles mobiles pour un accÚs Internet dans les réseaux véhiculaires

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    La rapide progression des technologies sans fil au cours de ces derniĂšres annĂ©es a vu naĂźtre de nouveaux systĂšmes de communication dont les rĂ©seaux vĂ©hiculaires. Ces rĂ©seaux visent Ă  intĂ©grer les nouvelles technologies de l’information et de la communication dans le domaine automobile en vue d’amĂ©liorer la sĂ©curitĂ© et le confort sur le rĂ©seau routier. Offrir un accĂšs Internet aux vĂ©hicules et Ă  leurs occupants peut sans doute aider Ă  anticiper certains dangers sur la route tout en rendant plus agrĂ©ables les dĂ©placements Ă  bord des vĂ©hicules. Le dĂ©ploiement de ce service nĂ©cessite que des messages soient Ă©changĂ©s entre les vĂ©hicules. Le routage constitue un Ă©lĂ©ment crucial dans un rĂ©seau, car dĂ©finissant la façon dont les diffĂ©rentes entitĂ©s Ă©changent des messages. Le routage dans les VANETS constitue un grand dĂ©fi car ces derniers sont caractĂ©risĂ©s par une forte mobilitĂ© entraĂźnant une topologie trĂšs dynamique. Des protocoles ont Ă©tĂ© proposĂ©s pour Ă©tendre Internet aux rĂ©seaux vĂ©hiculaires. Toutefois, la plupart d’entre eux nĂ©cessitent un coĂ»t Ă©levĂ© de messages de contrĂŽle pour l’établissement et le maintien des communications. Ceci a pour consĂ©quence la saturation de la bande passante entrainant ainsi une baisse de performance du rĂ©seau. Nous proposons dans ce mĂ©moire, un protocole de routage qui s’appuie sur des passerelles mobiles pour Ă©tendre Internet aux rĂ©seaux vĂ©hiculaires. Le protocole prend en compte la mobilitĂ© des vĂ©hicules et la charge du rĂ©seau pour l’établissement et le maintien des routes.The fast progression of wireless technologies has motivated the emergence of new communications system called VANETS (Vehicular Adhoc Networks). VANETS enable vehicles on the roadway to communicate with each other and with road infrastructure using wireless capabilities. The applications of VANETS include improving safety and comfort on the road. For example, by providing Internet to vehicles, traveling can be safer and more comfortable. To provide Internet connectivity, messages need to be exchanged between the vehicles. However, it is hard to design an efficient routing protocol for connecting vehicles to Internet with a reasonable cost due to high mobility in VANETS. Although, several existing routing protocols have been proposed in the open literature to extend Internet to VANETS, they generate considerable overhead. This leads to unfairly consumption of bandwidth decreasing network performance. We design a routing protocol to connect vehicles to Internet through mobile gateways with the objective to make efficient use of the network bandwidth. Indeed, the protocol significantly reduces the communication overhead required to establish and maintain the routes relying on the mobility of the gateways and the network’s load

    Vehicular ad hoc networking based on the incorporation of geographical information in the IPv6 header

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    Several approaches can be identified in the domain of vehicular ad hoc networks (VANET). Internet Protocol version 6 (IPv6) networking and non-IP geographical networking can each fulfill a subset of the application requirements. In general, a combination of both techniques is proposed to meet all of the application requirements. In this case, packets of one VANET routing protocol are encapsulated inside packets of another. This tunneling, together with the position service required for non-IP geographical unicasting, makes such a combined solution rather complex, and hence more challenging to implement, debug, and maintain. In this article, a new VANET approach is presented that relies on the key assumptions that geo-anycast functionality is not required by the applications, and that geographic unicasting is not needed when IP-based unicasting is provided. This enables the adoption of an IPv6-only VANET solution, removing the need for tunneling and position services. New techniques are required to support IPv6-based geo-broadcasting. In this article, it is described how addresses should be assigned, how geographical data can be incorporated in the IPv6 address, how the other IPv6 header fields can be used to contain additional VANET information, and how routing should be handled to guarantee that no modifications are required to the application units. The implementation of the proposed techniques is described, and the correct functionality of the solutions is experimentally demonstrated. Finally, to prove the added value compared to current state-of-the-art propositions, the presented solution is stacked up against the recently released ETSI standards TS 102 636-4-1 (geographical addressing and forwarding) and TS 102 636-6-1 (transmission of IPv6 packets over GeoNetworking protocols)

    Vehicular ad hoc routing protocol with link expiration time (VARP-LET) information

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    This thesis presents a vehicular ad hoc routing protocol that uses link expiration time (LET) information in selection of routes. The proposed protocol is named as VARP-LET, which uses LET information to increase reliability and stability of the routes. LET information is used selectively in the route discovery mechanism to reduce the routing control overhead. In addition to LET a Route Break Indicator (RBI) message is introduced. RBI is generated when a link breakage is about to occur. A source node on receiving the RBI signal preemptively stops sending data packets through a route before it breaks. This provision decreases the packet loss. The effectiveness of LET and RBI is tested via network simulations with NS-2. These simulations show that VARP-LET protocol increases packet delivery ratio by 20.7% in street section mobility model and by 30% in highway mobility scenario compared to regular AODV protocol. It is also shown that the protocol significantly reduces frequent route failure and routing overhead

    Road-based routing in vehicular ad hoc networks

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    Vehicular ad hoc networks (VANETs) can provide scalable and cost-effective solutions for applications such as traffic safety, dynamic route planning, and context-aware advertisement using short-range wireless communication. To function properly, these applications require efficient routing protocols. However, existing mobile ad hoc network routing and forwarding approaches have limited performance in VANETs. This dissertation shows that routing protocols which account for VANET-specific characteristics in their designs, such as high density and constrained mobility, can provide good performance for a large spectrum of applications. This work proposes a novel class of routing protocols as well as three forwarding optimizations for VANETs. The Road-Based using Vehicular Traffic (RBVT) routing is a novel class of routing protocols for VANETs. RBVT protocols leverage real-time vehicular traffic information to create stable road-based paths consisting of successions of road intersections that have, with high probability, network connectivity among them. Evaluations of RBVT protocols working in conjunction with geographical forwarding show delivery rate increases as much as 40% and delay decreases as much as 85% when compared with existing protocols. Three optimizations are proposed to increase forwarding performance. First, one- hop geographical forwarding is improved using a distributed receiver-based election of next hops, which leads to as much as 3 times higher delivery rates in highly congested networks. Second, theoretical analysis and simulation results demonstrate that the delay in highly congested networks can be reduced by half by switching from traditional FIFO with Taildrop queuing to LIFO with Frontdrop queuing. Third, nodes can determine suitable times to transmit data across RBVT paths or proactively replace routes before they break using analytical models that accurately predict the expected road-based path durations in VANETs
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