Analyse bi-objectif pour la couverture de cibles par des drones

International audienceDans cet article, nous étudions le problème de couverture de cibles au sol par des drones. Le but est de minimiser le nombre de drones déployés et de maximiser la qualité des communications radio afin de collecter efficacement l'information des cibles au sol jusqu'à une station de base centrale. Nous modélisons ce problème à l'aide d'un programme linéaire multi-objectif dans lequel nous étudions le compromis entre le coût de déploiement et l'altitude des drones assurant une communication air-sol efficace. Nous proposons une solution équitable permettant de limiter l'ajout de drones nécessaires à l'optimisation des transmissions pour la collecte de données

CLUSTERING SOLUTION TO MAXIMIZE LIFETIME OF WIRELESS SENSOR NETWORK: A SURVEY

ABSTRACT Wireless sensor networks consist of small nodes with sensing, computation, and wireless communications capabilities. The purpose of the network is to sense the environment and report what happens in the area it is deployed in. The sensor networks can be used for various application areas (e.g., health, military, home) Moreover, most of the Wireless Sensor Network (WSN) applications render it impossible to charge or replace the battery of sensor nodes. Therefore, optimal use of node energy is a major challenge in wireless sensor networks to enhance the lifetime of whole network. Clustering of sensor nodes is an effective method to use the node energy optimally and prolong the lifetime of energy constrained wireless sensor network. .In the paper we give out the survey of clustering solution to lifetime maximization in wireless sensor network. In this paper we also points out the open research issues and intends to spark new interests and developments in this field

COVERAGE PROBLEM IN HETEROGENEOUS WIRELESS SENSOR NETWORKS

A heterogeneous wireless sensor network consists of different types of nodes in sequence. Some of these nodes have high process powers and significant energy, which are called the manager nodes or super-nodes. The second type nodes, which have normal process power, are only used as monitoring nodes or act as relay nodes in the path to the manager nodes are called the normal nodes. In this paper, an energy-aware algorithm is presented for the optimum selection of sensor and relay groups that are used for monitoring and sending messages from goals in point coverage, using the competition between the nodes. This algorithm is effective in decreasing the energy consumption of the network and increasing its life-time. Moreover, providing that no node saves the information about the routing table and relay nodes; therefore, it will have less complexity and overload

Efficient Deployment of Connected Unmanned Aerial Vehicles for Optimal Target Coverage

International audienceAnytime and anywhere network access can be provided by Unmanned Aerial Vehicles (UAV) with air-to-ground and air-to-air communications using directional antennas for targets located on the ground. Deploying these Unmanned Aerial Vehicles to cover targets is a complex problem since each target should be covered, while minimizing (i) the deployment cost and (ii) the UAV altitudes to ensure good communication quality. We also consider connectivity between the UAVs and a base station in order to collect and send information to the targets, which is not considered in many similar studies. In this paper, we provide an efficient optimal program to solve this problem and show the trade-off analysis due to conflicting objectives. We propose a fair trade-off optimal solution and also evaluate the cost of adding connectivity to the UAV deployment

Gathering with Minimum Delay in Sensor Networks

Data gathering is a fundamental operation in wireless sensor networks in which data packets generated at sensor nodes are to be collected at a base station. The network is a multi-hop wireless network and the time is slotted so that one--hop transmission of one data item consumes one time slot. In this paper we suppose that each sensor is equipped with an half--duplex interface; hence, a node cannot receive and transmit at the same time. Moreover, each node is equipped with omnidirectional antennas allowing the transmission over distance R. We model the network with a graph where the vertices represent the nodes and two nodes are connected if they are in the transmission/interference range of each other. Due to interferences a collision happens at a node if two or more of its neighbors try to transmit at the same time. Furthermore we suppose that an intermediate node should forward a message as soon as it receives it. We give an optimal collision free gathering schedule for tree networks

Integrated placement and routing of relay nodes for fault-tolerant hierarchical sensor networks

In two-tiered sensor networks, using higher-powered relay nodes as cluster heads has been shown to lead to further improvements in network performance. Placement of such relay nodes focuses on achieving specified coverage and connectivity requirements with as few relay nodes as possible. Existing placement strategies typically are unaware of energy dissipation due to routing and are not capable of optimizing the routing scheme and placement concurrently. We, in this thesis, propose an integrated integer linear program (ILP) formulation that determines the minimum number of relay nodes, along with their locations and a suitable communication strategy such that the network has a guaranteed lifetime as well as ensuring the pre-specified level of coverage (ks) and connectivity (kr). We also present an intersection based approach for creating the initial set of potential relay node positions, which are used by our ILP, and evaluate its performance under different conditions. Experimental results on networks with hundreds of sensor nodes show that our approach leads to significant improvement over existing energy-unaware placement schemes

An Adaptable Energy-Efficient Medium Access Control Protocol for Wireless Sensor Networks

Wireless networks have become ubiquitous recently and therefore their usefulness has also become more extensive. Wireless sensor networks (WSN) detect environmental information with sensors in remote settings. One problem facing WSNs is the inability to resupply power to these energy-constrained devices due to their remoteness. Therefore to extend a WSN\u27s effectiveness, the lifetime of the network must be increased by making them as energy efficient as possible. An energy efficient medium access control (MAC) can boost a WSN\u27s lifetime. This research creates a MAC protocol called Adaptive sensor Medium Access Control (AMAC) which is based on Sensor Medium Access Control (SMAC) which saves energy by periodically sleeping and not receiving. AMAC adapts to traffic conditions by incorporating multiple duty cycles. Under a high traffic load, AMAC has a short duty cycle and wakes up often. Under a low traffic load, AMAC has a longer duty cycle and wakes up infrequently. The AMAC protocol is simulated in OPNET Modeler using various topologies. AMAC uses 15% less power and 22% less energy per byte than SMAC but doubles the latency. AMAC is promising and further research can decrease its latency and increase its energy efficiency

Design of Three-Tiered Sensor Networks with a Mobile Data Collector under Energy and Buffer Constraints

A sensor network consists of a network with a large number of sensor nodes deployed around some phenomenon to gather information. Since the nature of sensor nodes is that their energy is limited, many techniques focus on addressing the problem of minimizing the energy consumption in order to extend the network lifetime. One approach is to deploy relay nodes. However, the requirement to transmit over large distances leads to a high rate of energy dissipation. Therefore, mobile data collectors are introduced to resolve this problem. In this thesis, we present an Integer Linear Programming formulation that takes different parameters into consideration to determine an optimal relay node placement scheme in networks with a mobile data collector, which ensures that there is no data loss and the energy dissipation does not exceed a specified level. The simulation results show that our formulation can significantly extend the network lifetime and provide Quality of Service