Wireless sensor node mobility and its effect on transmission reliability

Abstract: Deploying a Wireless Sensor Network (WSN) poses certain challenges such as data reliability due to Electromagnetic Interference (EMI), multipath fading as well as faster energy depletion of nodes located near the base station creating communication holes in the network. Several energy efficient algorithms have been developed to improve the energy consumption of static nodes however the issue of battery depletion of nodes near the base station remains present. In this paper we attempt to model the relationship between the node mobility and the reliability of data transmission. Mobile nodes could move near static nodes experiencing high traffic in order to reduce the number of packets sent through the saturated nodes. This paper will investigate, using a real environment, the effect of speed and packet size on the reliability of the wireless link. This is a required prerequisite, prior to a detailed design of a Mobile relay node

Integrated Topology Control and Routing Problem in Cluster-Based Wireless Sensor Networks

ABSTRACT: Data-gathering wireless sensor networks (WSNs) are operated unattended over long time horizons to collect data in several applications. Typically, sensors have limited energy (e.g., an on-board battery) and are subject to the elements in the terrain. In-network operations, which largely involve periodically changing network flow decisions to prolong the network lifetime, are managed remotely, and the collected data are retrieved by a user via internet. An integrated topology control and routing problem in cluster-based WSNs are analyzed to improve the network lifetime. To prolong network lifetime via efficient use of the limited energy at the sensors , a hierarchical network structure with multiple sinks at which the data collected by the sensors are gathered through the cluster heads are adopted . A Mixed Integer Linear Programming (MILP) model to optimally determine the sink and CH locations as well as the data flow in the network is considered. This model effectively utilizes both the position and the energy-level aspects of the sensors while selecting the CHs and avoids the highest-energy sensors. For the solution of the MILP model, an effective Benders Decomposition (BD) approach that incorporates an upper bound heuristic algorithm is used

Energy Efficient Multi-Flow Routing in Mobile Sensor Networks.

International audienceControlled mobility is one of the most complex challenges in Wireless Sensor Networks (WSN). Only a few routing protocols consider controlled mobility in order to extend the network lifetime. They are all designed to optimize the physical route topology from a source to a destination. However, there is often more than one sensor which reports an event to the sink in WSN. In existing solutions, this leads to oscillation of nodes which belong to different routes and their premature death. Experiments show that the need of a routing path merge solution is high. As a response we propose the first routing protocol which locates and uses paths crossing to adapt the topology to the network traffic in a fully localized way while still optimizing energy efficiency. Furthermore the protocol makes the intersection to move away from the destination, getting closer to the sources, allowing higher data aggregation and energy saving. Our approach outperforms existing solutions and extends network lifetime up to 37%

Beacon-less mobility assisted energy efficient georouting in energy harvesting actuator and sensor networks

International audienceIn the next years, wireless sensor networks are expected to be more and more widely deployed. In order to increase their performance without increasing nodes' density, a solution is to add some actuators that have the ability to move. However, even actuators rely on batter- ies that are not expected to be replaced. In this paper, we introduce MEGAN (Mobility assisted Energy e cient Georouting in energy har- vesting Actuator and sensor Networks), a beacon-less protocol that uses controlled mobility, and takes account of the energy consumption and the energy harvesting to select next hop. MEGAN aims at prolonging the overall network lifetime rather than reducing the energy consump- tion over a single path. When node s needs to send a message to the sink d, it rst computes the \ideal" position of the forwarder node based on available and needed energy, and then broadcasts this data. Every node within the transmission range of s in the forward direction toward d will start a backo timer. The backo time is based on its available energy and on its distance from the ideal position. The rst node whose backo timer goes o is the forwarder node. This node informs its neighbor- hood and then moves toward the ideal position. If, on its route, it nds a good spot for energy harvesting, it will actually stop its movement and forward the original message by using MEGAN, which will run on all the intermediate nodes until the destination is reached. Simulations show that MEGAN reduces energy consumption up to 50% compared to algorithms where mobility and harvesting capabilities are not exploited

Energy Efficient Mobile Routing in Actuator and Sensor Networks with Connectivity Preservation

International audienceIn mobile wireless sensor networks, flows sent from data col- lecting sensors to a sink could traverse inefficient resource expensive paths. Such paths may have several negative effects such as devices bat- tery depletion that may cause the network to be disconnected and packets to experience arbitrary delays. This is particularly problematic in event- based sensor networks (deployed in disaster recovery missions) where flows are of great importance. In this paper, we use node mobility to im- prove energy consumption of computed paths. Mobility is a two-sword edge, however. Moving a node may render the network disconnected and useless. We propose CoMNet (Connectivity preservation Mobile routing protocol for actuator and sensor NETworks), a localized mechanism that modifies the network topology to support resource efficient transmissions. To the best of our knowledge, CoMNet is the first georouting algorithm which considers controlled mobility to improve routing energy consump- tion while ensuring network connectivity. CoMNet is based on (i) a cost to progress metric which optimizes both sending and moving costs, (ii) the use of a connected dominating set to maintain network connectivity. CoMNet is general enough to be applied to various networks (actuator, sensor). Our simulations show that CoMNet guarantees network connec- tivity and is effective in achieving high delivery rates and substantial energy savings compared to traditional approaches

GADMS: Gathering Aggregated Data using Mobile Sink in Wireless Sensor Networks

WSNs consist of resource constrained sensor nodes that monitor the physical environment and transmit their data to the Sink through multi-hop communication. Mobile sinks are used to reduce the number of hops the data travels and thereby reducing the overall energy consumption. In this paper we propose Gathering Aggregated Data using Mobile Sink in Wireless Sensor Networks (GADMS) protocol that allows the mobile sink to collect data from WSNs where path of the mobile sink is not predetermined. The mobile sink halts at a point in the network and broadcasts an aggregate query. The average path length of a data packet is a constant and hence it can withstand node failures. The performance analysis shows that GADMS incurs less energy consumption and improved packet delivery ratio in comparison to SinkTrail.

Optimal Location through Distributed Algorithm to Avoid Energy Hole in Mobile Sink WSNs

In multihop data collection sensor network, nodes near the sink need to relay on remote data and, thus, have much faster energy dissipation rate and suffer from premature death. This phenomenon causes energy hole near the sink, seriously damaging the network performance. In this paper, we first compute energy consumption of each node when sink is set at any point in the network through theoretical analysis; then we propose an online distributed algorithm, which can adjust sink position based on the actual energy consumption of each node adaptively to get the actual maximum lifetime. Theoretical analysis and experimental results show that the proposed algorithms significantly improve the lifetime of wireless sensor network. It lowers the network residual energy by more than 30% when it is dead. Moreover, the cost for moving the sink is relatively smaller

Multi-mode relaying for energy consumption reduction

Today mobile terminals offer today the possibility of switching between different physical layers of radio protocols. With a generalization of Software Defined Radio, this multi-mode property improves the connectivity but has an important cost in terms of energy consumption. In this paper, we study the possibility of reducing energy consumption by using a relay on possibly different communication modes. We show that a multi-mode relay, compared to simple (mono-mode) relay, has an impact on energy consumption. We propose an analytical study of energy consumption in multi-mode terminals. Then, we will compare the network energy consumption following two scenarios: in the first one, a mobile terminal relays other users, in the second one terminals connect directly to an Access Point. We evaluate the consumption of the terminals in an 802.11g-to-UMTS and an 802.15.4-to-802.11g relay scheme. We isolate rules to minimize the network global energy consumption through multi-mode relaying. We show that the most intuitive solution is not always the best one and that a very precise simulation is necessary to make good choices at run time.Aujourd'hui, les terminaux mobiles permettent de choisir parmi différentes couches physiques de protocoles radios. Avec la généralisation de la Radio Logicielle, cette propriété multi-mode améliore la connectivité, mais rajoute un important surcoût à la consommation d'énergie. Dans ce papier, nous étudions la possibilité de réduire la consommation d'énergie en proposant un relais peut communiquer sur ces différents modes. Nous montrons qu'un relais multi-mode a un impact sur la consommation d'énergie, en comparaison à un simple relais mono-mode. Nous proposons une étude analytique de la consommation d'énergie pour les terminaux multi-modes. Puis, nous comparons la comsommation d'énergie du réseau suivant deux scénarios: dans le premier, un terminal mobile joue le rôle de relais pour d'autres utilisateurs ; dans le second, tous les terminaux se connectent directement au point d'accès. Nous évaluons la consommation des terminaux dans des scénarios de relais 802.11g-vers-UMTS et 802.15.4-vers-802.11g. Nous isolons des règles qui permettent de minimiser la consommation global du réseau au travers des relais multi-modes. Nous montrons que la solution la plus intuitive n'est pas toujours la meilleure, et qu'une évaluation précise au travers de simulations est nécessaire afin de procéder à un bon choix de paramètres