Analysis of the impact of hello protocol parameters over a wireless network self-organization

International audienceThe neighborhood discovery and its maintenance are very important in wireless networks for any applications, especially for routing and every self-$*$ algorithm. Neighbor nodes are usually discovered thanks to the use of the HELLO protocol. This makes this HELLO protocol very important for wireless networks especially for self-organizing the network. Most of layer-$3$ protocols assume an ideal MAC layer. In such a case, HELLO protocol parameters have no impact over the self-organization. But this is not the case when considering realistic MAC and physical layers. In this paper, we investigate the impact of the parameters of such a protocol over a self-organization structure when considering realistic a MAC layer. We analyze theoretically and by simulations, the joint effect of the HELLO protocol parameters and of the MAC layer characteristics over several network self-organizations

MobileR : Multi-hop energy efficient localised mobile georouting in wireless sensor and actuator networks

International audienceThis paper addresses the usage of actuators (sensors with controlled mobility) for routing in wireless sensor and actuator networks. Different routing protocols have been proposed to improve routing in terms of energy efficiency through the use of controlled mobility enabled sensors . We introduce MobileR. Unlike literature proposals also using actuators, MobileR considers the cost of a full path toward one of its neighbours instead of the cost of the direct edge toward it. To do so, MobileR computes in advance the possible routing paths over the next hops relying on the one-hop neighbours and their possible relocations. Moreover MobileR is fully localised and stateless. We evaluate our solution in terms of cumulative energy consumption with regard to network density. Experiments show that, with sufficient node degree, energy used for routing is significantly reduced and so network lifetime is extended

Adapting dynamically neighbourhood table entry lifetime in wireless sensor networks

International audienceNeighbour discovery and maintenance of neighbourhood tables have importance in wireless sensor networks. Almost every upper layer application such as routing or self-organizing relies on neighbourhood tables. Imprecise tables may lead to failures that may be costly in terms of resources which are very limited in such networks. Neighbourhood tables are achieved thanks to the Hello protocol. Several studies propose smart schemes to dynamically adapt the frequency of Hello messages but none of them investigates the way the refreshment period of entries in table should be adapted. In this paper, we introduce the Neighbourhood Lifetime Algorithm (NLA), the very first algorithm that adapts dynamically the refreshment period of entries in neighbourhood tables, based on the speed of node and the frequency of the Hello message. Our simulation results show and demonstrate the efficiency of NLA and its high performance to keep neighbourhood tables consisten

From the Internet of things to the Internet of physical world

International audienceThis article describes the different kinds of RFID tags. It details passive and active RFID tags different functions and uses

Clustering pour l'optimisation de la durée de vie des réseaux de capteurs sans fil

International audienceLe clustering dans les réseaux de capteurs sans fil est un moyen efficace de structurer le réseau. Son but est d'identifier un sous-ensemble de nœuds dans le réseau et de lui attribuer un chef (un cluster-head). Celui-ci sera en charge de tâches spécifiques comme l'agrégation de données. L'exécution de ces tâches additionnelles entraîne une augmentation de la consommation énergétique et une diminution de la durée de vie du nœud. Dans ce papier, nous introduisons BLAC, une nouvelle famille d'algorithmes pour clustering. BLAC considère la combinaison du niveau d'énergie restante à d'autres métriques pour l'élection du cluster-head. Les résultats de simulations montrent que BLAC permet de multiplier par 7 la durée de vie du réseau sans nœud éteint sur le réseau considéré

On the Impact of Network Topology on Wireless Sensor Networks Performances - Illustration with Geographic Routing

Poster in the Tenth ACM International Symposium on Performance Evaluation of Wireless Ad Hoc, Sensor, and Ubiquitous Networks (PE-WASUN 2013)Wireless Sensor Networks (WSN) are composed of constrained devices and deployed in unattended and hostile environments. Most papers presenting solutions for WSN evaluate their work over random topologies to highlight some of their "good" performances. They rarely study these behaviors over more than one topology. Yet, the topology used can greatly impact the routing performances. This is what we demonstrate in this paper. We present a study of the impact of network topology on algorithms performance in Wireless Sensor Networks and illustrate it with geographic routing. Geographic routing is a family of routing algorithms using nodes coordinates to route data packet from source to destination. We measure the impact of different network topologies from realistic ones to regular and unrealistic ones through extensive simulations. Studied algorithms are common geographic greedy algorithms with different heuristics from the literature. We show that different topologies can lead to a difference of up to 25% on delivery ratio and average route length and more than 100% on overall cost of transmissions

Reliable Routing in Vehicular Ad hoc Networks.

International audienceOne of the notoriously difficult problems in vehicular ad-hoc networks (VANET) is to ensure that established routing paths do not break before the end of data transmission. This is a difficult problem because the network topology is constantly changing and the wireless communication links are inherently unstable, due to high node mobility. In this paper we classify existing VANET routing protocols into five categories: connectivity-based, mobility-based, infrastructure-based, geographic-location-based, and probability-model-based, according to their employed routing metrics. For each category, we present the general design ideas and state of the art. Our objective is to attract more attention to the VANET routing problem and encourage more research efforts on developing reliable solutions

Geographic Routing with Partial Position Information

International audienceGeographic routing protocols show good properties for Wireless Sensor Networks (WSN). They are stateless, local and scalable. However they require that each node of the network is aware of its own position. While it may be possible to equip each node with GPS receiver, even if it is costly, there are some issues and receiving a usable GPS signal may be difficult in some situations. For these reasons, we propose a geographic routing algorithm, called HGA, able to take advantages of position informations of nodes when available but also able to continue the routing in a more traditional way if position information is not available. We show with simulations that our algorithm offers an alternative solution to classical routing algorithm (non-geographic) and offers better performances for network with a density above 25 and more than 5% of nodes are aware of their position

Balancing energy consumption in clustered wireless sensor networks

International audienceClustering in wireless sensor networks is an efficient way to structure and organize the network. It aims at identifying a subset of nodes within the network and bind it to a leader (i.e. cluster-head). The leader becomes in charge of specific additional tasks like gathering data from all nodes in its cluster and sending them by using a longer range communication to a sink. As a consequence, a cluster-head exhausts its battery more quickly than regular nodes. In this paper, we present four variants of BLAC, a novel Battery-Level Aware Clustering family of schemes. BLAC considers the battery-level combined with another metric to elect the cluster-head . The cluster-head role is taken alternately by each node to balance energy consumption. Due to the local nature of the algorithms, keeping the network stable is easier. BLAC aims at maximizing the time with all nodes alive to satisfy application requirements. Simulation results show that BLAC improves the full network lifetime three times more than traditional clustering schemes by balancing energy consumption over nodes and still delivering high data ratio.Le clustering dans les réseaux de capteurs sans-fil est un moyen efficace de structurer et d'organiser le réseau. Il vise à identifier un sous-ensemble de nœuds dans le réseau et à lui attribuer un leader (i.e. un cluster-head). Le leader est alors chargé de tâches supplémentaires spécifiques comme collecter les données des autres nœuds du cluster et les envoyer à un puits via des communications longue distance. En conséquence, le cluster-head épuise sa batterie plus rapidement que les nœuds ordinaires. Dans cet article, nous présentons quatre variantes de BLAC, une nouvelle famille d'algorithmes de clustering sensible au niveau de batterie. BLAC considère le niveau de batterie combiné à une autre métrique pour élire les cluster-heads. Le rôle de cluster-head est assumé alternativement par différent nœuds pour équilibrer la consommation énergétique. Grâce à la nature locale des algorithmes, le réseau reste stable. BLAC maximise la durée de vie du réseau avec tous les nœuds en vie pour remplir les besoins des applications. Les résultats de simulation montrent que BLAC améliore le durée de vie du réseau jusqu'à trois fois plus que les algorithmes de clustering traditionnels en équilibrant la consommation énergétique sur les différents nœuds tout en conservant un bon taux de livraison

Energy-based Clustering for Wireless Sensor Network Lifetime Optimization

International audienceClustering in wireless sensor networks is an efficient way to structure and organize the network. It aims to identify a subset of nodes within the network and bind it a leader (i.e. cluster-head). This latter becomes in charge of specific additional tasks like gathering data from all nodes in its cluster and sending them by using a longer range communication to a sink. As a consequence, a cluster-head exhausts its battery more quickly than regular nodes. In this paper, we present BLAC, a novel Battery-Level Aware Clustering family of schemes. BLAC considers the battery-level combined with another metric to elect the cluster-head. It comes in four variants. The cluster-head role is taken alternately by each node to balance energy consumption. Due to the local nature of the algorithms, keeping the network stable is easier. BLAC aims to maximize the time with all nodes alive to satisfy application requirements. Simulation results show that BLAC improves the full network lifetime 3-time more than traditional clustering schemes by balancing energy consumption over nodes and still delivering high data percentage