44 research outputs found

    HHLS: A Hybrid Routing Technique for VANETs

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    International audienceIn this paper, we propose a combination between a routing protocol Greedy Perimeter Stateless Routing (GPSR) and Hierarchical Location Service (HLS) that we denote Hybrid Hierarchical Location Service (HHLS). HLS and GPSR used to be combined in the original work with a direct method, i.e. GPRS takes care of routing packets and HLS is called to get the destination position when the target node position is not known or is not fresh enough. When a destination is quite far away from the sender, the exact position of the target is calculated, and an extra overhead is generated from sender to receiver. Our main purpose is to reduce this overhead in HHLS. We suggest to proceed as follows: when a packet has to be sent to the destination, it will be sent directly to the former position of the target instead of requesting for the exact position. When the packet is approaching the former position, the exact position request is then sent. We have proposed a patch over the NS-2 simulator for HHLS according to our proposal. We have conducted experimentations which show promising results in terms of latency, packet delivery rate and overhead

    Contribution to Intra-Vehicular and Inter-Vehicular Communications

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    Les véhicules modernes sont équipés de périphériques permettant d'automatiser des tâches (changement de vitesse de transmission, régulation de vitesse, etc.) ou de fournir des services à l'utilisateur (aide à la conduite, détection d'obstacles, etc.). Les communications entre les véhicules permettent d'élargir ces services grâce à la collaboration de plusieurs véhicules (prévention des accidents, gestion du trafic routier, etc.). La multiplication de ces périphériques, de leurs interfaces et protocoles rend l'échange de données plus complexe. Par ailleurs, la communication inter- véhicules est plus contraignante à cause de la haute mobilité des véhicules. Dans cette thèse, nous proposons la conception d'un canal de communication Connect to All (C2A) qui permet d'assurer l'interopérabilité entre les périphériques embarqués dans un véhicule. En effet, il détecte la connexion à chaud d'un équipement, le reconnaît et lui permet d'échanger des données avec les autres périphériques connectés. La conception du canal commence par la modélisation de ce canal en utilisant deux techniques différentes (l'outil de modélisation et de vérification UPPAAL et le Langage de Description et de Spécification (LDS)). La vérification des modèles proposés a pour but de valider le fonctionnement. Ensuite, nous détaillons une implémentation réelle du canal sur une carte embarquée qui vise à démontrer la faisabilité du concept d'interopérabilité de C2A.Nous avons aussi étudié les effets de la mobilité dans la communication inter-véhiculaires grâce à une approche hybride mixant le routage et un service de localisation. Cette approche offre un mécanisme qui permet de réduire les coûts de la localisation des véhicules tout en augmentant les performances de routage. En plus, nous comparons deux applications de cette approche : Hybrid Routing and Grid Location Service (HRGLS) et Hybrid Routing and Hierarchical Location Service (HRHLS) avec des approches originelles pour démontrer la valeur ajoutée. Cette approche est enrichie avec un algorithme de prédiction de mobilité. Ce dernier permet de mieux cerner le déplacement des véhicules en les estimant. De même, l'approche hybride avec prédiction de mobilité Predictive Hybrid Routing and Hierarchical Location Service (PHRHLS) est comparée à HRHLS et l'approche originelle afin de révéler les bénéfices de la prédiction de mobilité.Modern vehicles are equipped with various devices that aim to automate tasks (shift transmission, cruise control, etc.) or to provide services to the user (driver assistance, obstacle detection, etc.). Communications between vehicles help to expand these services through the collaboration of several vehicles (accident prevention, traffic management, etc.). The proliferation of these devices, their interfaces and protocols makes the data exchange more complex. In addition, inter-vehicle communication is more restrictive because of the vehicles' high mobility.In this work, we propose the design of a communication channel Connect to All (C2A) that ensures the interoperability between embedded devices in a vehicle. In fact, it detects the equipment connection, recognizes it and allows it to exchange data with other devices. The channel design starts by the modelling step using two different techniques (the model checker tool UPPAAL and the Specification and Description Language (SDL). Then, we validate the designed models. We also detail a concrete implementation of the channel on an embedded chip that aims to show the C2A interoperability concept feasibility.We also studied the mobility effects in the inter-vehicular communication through a hybrid approach mixing routing and location-based service. This approach provides a mechanism to reduce vehicle-tracking costs while increasing routing performances. Moreover, we compare two applications of this approach: Hybrid Routing and Grid Location Service (HRGLS) and Hybrid Routing and Hierarchical Location Service (HRHLS) with classical approaches to prove the added value. Then, this approach is improved with a mobility prediction algorithm. The latter allows a better understanding of the vehicle movements by estimating them. Similarly, the hybrid approach with mobility prediction Predictive Hybrid Routing and Hierarchical Location Service (PHRHLS) is compared with the basic approach and HRHLS in order to show the mobility prediction advantages

    A Novel Cloud Approach for Connected Vehicles

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    Cooperative intelligent transport systems (C-ITSs) are being deployed all around the world. Shortly, in addition to vehicles, bicycles, pedestrians, buses, and all moving equipment will be compatible with C-ITS. These systems are connected through wireless local area networks based on WIFI IEEE 802.11p. The large number of C-ITSs and services will lead to a glut in the bandwidth of wireless networks. To overcome this limitation, we propose in this paper a new approach using the information-centric networking (ICN) paradigm which allows vehicles to communicate with the cloud environment. This scheme is denoted by vehicular central data networking (GeoVCDN). Our approach aims to reduce bandwidth consumption and improve data freshness by taking benefit from the existing application beacons and the geographical routing used by C-ITS actors. We have compared the performances (in terms of the network overhead and data freshness) of our solution to two other well-known ICN-based solutions. Each of them represents one of ICN categories, in particular, rendez-vous network (RENE) and named data networking (NDN). To do so, we have proposed a probabilistic model that allows us to evaluate the freshness and the load of the network. Furthermore, we have implemented these methods in a simulator. Our proposal outperforms the other methods in terms of network overhead and data freshness

    Partial Paving Strategy: Application to optimize the Area Coverage Problem in Mobile Wireless Sensor Networks

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    International audienceFinding the minimum number of sensor nodes to ensure coverage of an area for a maximum of time duration is an NP-difficult problem, especially in large areas. The mathematical solutions proposed for this problem consist in answering to the question: "How to place the sensor nodes in n equal circular areas of a given radius to cover the area of interest as much as possible?" Discrete geometry models have been proposed in the literature to analyze and solve this mathematical problem, and we have seen that paving techniques are considered to be the most suitable methods for this kind of problems. Consequently, this paper provides a basic solution of discrete geometry, based on tiling a circle by a minimal number of circles to optimize the coverage problem in wireless sensor networks in this work entiteled: "Partial Paving of a Circle by Equal Circles strategy (PPoCEC)". We have proven mathematically the effectiveness of our solution. The simulation which consists of a statistical evaluation step: Asymptotic Confidence Interval (ACI) calculation and another step of comparison with clustering strategies showed that the proposed strategy achieves coverage at 100% for the first 10 nodes deployed in the area of interest compared to the other coverage strategies in sensor networks proposed in the literature

    How mobile RSUs can enhance communications in VANETs?

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    Semi-Deterministic Deployment based Area Coverage Optimization in Mobile WSN

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    Hybrid Model Approach for Wireless Sensor Networks Coverage Improvement

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    International audienceThe area coverage is a non-trivial problem in Wireless Sensors Network (WSN) due to the lack of knowledge in the minimum sensor nodes set that can cover an area of interest and limitation of energy reserve, monitoring and communication ranges. Coverage protocols address two fundamental questions: how can the coverage performance of deployed sensor nodes in a monitoring region be evaluated; and how can the coverage performance be improved when wireless sensor network cannot effectively satisfy quality of service requirements? Constructing sets of minimal nodes to optimize the coverage problem push researchers to use different techniques from different domains, such as VoronoĂŻ Diagram, Connected Dominating Set, Clustering, and others. Each technique deals with the problem by its own philosophy. Our approach aims to use a hybrid model combining Diagram of VoronoĂŻ, Clustering, and Connected Dominating Set in order to benefit from the advantages of these three models to optimize area coverage, keep connectivity, and minimize energy consumption. The simulation showed the ability of our approach to ensure optimal coverage with minimal power consumption for a longtime

    A Data Mining-based Intrusion Detection System for Cyber Physical Power Systems

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