Dynamic Reconfiguration for Software and Hardware Heterogeneous Real-time WSN

International audienceWireless Sensor Network (WSN) technology has imposed itself in civilian and industrial applications as a promising technology for wireless monitoring due to its wireless connectivity, removing many hardware constraints. Initially used in low frequency sampling applications, the increasing performances of electronic circuits has driven WSNs to integrate more powerful computation units, paving the way for a new generation of applications based on distributed computation. These new applications (process control, active control, visual surveillance, multimedia streaming) involving medium to heavy computation present real-time requirements at node level where reactivity becomes a primary concern as well as at the network level where latency must be bounded. In this paper, we present the implementation of a high-level language MinTax coupled with an in-situ compilation solution for real time Operating Systems enabling energy-aware dynamic reconfiguration while supporting hardware heterogeneity in Wireless Sensor Networks

Heterogeneous Wireless Sensor Network Simulation

International audienceBased on our previous work on the development of a Wireless Sensor Network (WSN) simulation platform, we present here its ability to run simulations on heterogeneous nodes. This platform allows system-level simulations with low level accurate models, with graphical inputs and outputs to easily simulate such distributed systems. In the testbed we consider, the well known IEEE 802.15.4 standard is used, and different microcontrollers units (MCU) and radiofrequency transceivers compose the heterogeneous nodes. It is also possible to simulate complex networks or interacting networks; that is a more realistic case, as more and more hardware devices exist and standards permit their interoperability. This simulation platform can be used to explore design space in order to find the hardware devices and IEEE 802.15.4 algorithm that best fit a given application. Packet Delivery Rate (PDR) and packet latency can be evaluated, as other network simulators do. Energy consumption of sensor nodes is detailed with a very fine granularity: partitioning over and into hardware devices that compose the node is studied

Reconfiguration dynamique et simulation fine modélisée au niveau de transaction dans les réseaux de capteurs sans fil hétérogènes matériellement-logiciellement

Cette thèse porte premièrement sur la reconfiguration dynamique et la simulation hétérogène dans les Réseaux des Capteurs sans Fil. Ces réseaux sont constitués d une multitude de systèmes électroniques communicants par radio-fréquence, très contraints en énergie. La partie de communication radio entre ces nœuds est la plus consommatrice. C est pourquoi la minimisation du temps effectif est désirée. On a implémenté une solution qui consiste à envoyer au nœud un fichier de reconfiguration codé utilisant un langage de programmation haut niveau (MinTax). Le nœud sera capable de compiler ce fichier et générer le code object associé à son architecture, in-situ. Grâce au caractère abstrait du MinTax, plusieurs architectures matérielles et systèmes d exploitation sont visés. Dans un deuxième temps, ce travail de thèse est lié au simulateur de réseaux de capteurs IDEA1TLM.IDEA1TLM permet de prédire quels circuits et configurations sont les plus adéquats à une application sans fil donnée. Ce simulateur a été amélioré pour permettre la simulation rapide des systèmes électroniques matériellement différents dans le même réseau ainsi que le logiciel présent sur les noeuds. Mots clés : Reconfiguration dynamique, Compilation in-situ, MinTax, Hétérogénéité, IDEA1TLM.This PhD thesis concerns the dynamic reconfiguration and simulation of heterogeneous Wireless Sensor Networks. These networks consist of a multitude of electronic units called ?nodes ?, which communicate through a radio interface. The radio interface is the most power-consuming on the node. This is why the minimisation of the radio-time would lead to improved energy efficiency. We have implemented a software solution which consists in sending an update to a node which is coded in a high-level language (MinTax). This file is compiled by the node and machine code is generated for the target hardware architecture. Owing to the abstract nature of MinTax, multiple hardware architectures. as well as operating systems are supported. As a second part of this PhD, work has been focused on a network simulator called IDEATLM.IDEA1TLM allows us to predict which circuits and configurations are the most appropriate for a given task. This solution has been improved to allow a faster simulation of electronic systems which are different from a hardware standpoint, yet part of the same network, as well as to model the actual software running on them.LYON-Ecole Centrale (690812301) / SudocSudocFranceF

Design Framework for Heterogeneous Hardware and Software in Wireless Sensor Networks

International audienceWireless Sensor Networks are composed of many autonomous resource-constrained sensor nodes. Constrains are low energy, memory and processing speed. Nowadays, several limitations exist for heterogeneous Wireless Sensor Networks: various hardware and software are hardly supported at design and simulation levels. Meanwhile, to optimize a self-organized network, it is essential to be able to update it with new nodes, to ensure interoperability, and to be able to exchange not only data but functionalities between nodes. Moreover, it is difficult to make design space exploration, as accurate hardware-level models and network-level simulations have very different (opposite) levels. We propose a simulator-based on SystemC language-that allows such design space explorations. It is composed of a library of hardware and software blocks. More and more sophisticated software support is implemented in our simulator. As trend is to deploy heterogeneous nodes, various software levels have to be considered. Our simulator is also thought to support many levels: from machine code to high level languages

Fablab et DIY : de nouvelles voies pour l’enseignement de l’électronique ?

L’enseignement de l’électronique est devenu aujourd’hui, en université, un enseignement de spécialité et d’experts. Pourtant, avec l’avènement de l’ère de l’Internet des Objets, jamais l’électronique n’a été aussi pervasive et imbriqué dans la vie quotidienne de l’homme. En parallèle à cette tendance, de nouveaux mouvements tels que celui des makers et en particulier des fablabs rendent la technologie accessible à tout un chacun. Ce papier va présenter comment, inspire de cette approche des makers, l’enseignement d’électronique peut être prodigué et rendre en peu de temps les étudiants autonomes et désireux d’aller plus loin dans le domaine

A Distributed Computing Solution Based on Distributed Kalman Filter for Leak Detection in WSN-Based Water Pipeline Monitoring

Wireless Sensor Network (WSN) applications that favor more local computations and less communication can contribute to solving the problem of high power consumption and performance issues plaguing most centralized WSN applications. In this study, we present a fully distributed solution, where leaks are detected in a water distribution network via only local collaborations between a sensor node and its close neighbors, without the need for long-distance transmissions via several hops to a centralized fusion center. A complete approach that includes the design, simulation, and physical measurements, showing how distributed computing implemented via a distributed Kalman filter improves the accuracy of leak detection and the power consumption is presented. The results from the physical implementation show that distributed data fusion increases the accuracy of leak detection while preserving WSN lifetime

Modélisation de liaisons optiques inter- et intra-puces à haut débit

Les taux de transfert globaux des systèmes intégrés actuels vont atteindre le Térabit par seconde. A contrario, les interconnexions inter- et intra-puces s'approchent de leurs limites physiques et représentent actuellement un goulot d'étranglement majeur des perforrnances des systèmes. Parmi toutes les solutions étudiées, les interconnexions optiques permettraient de résoudre la majeure partie des problèmes liés aux interconnexions tels que la diaphonie, la distorsion des signaux, la limitation de la bande passante, ...Les développements industriels intègrent des réseaux de VCSELs (Vertical-Cavity Surface-Emitting Laser) associés à des photodétecteurs, la communication étant assurée en espace libre ou guidé. En effet, les VCSELs sont une génération prometteuse d'émetteurs optiques présentant également des perspectives intéressantes pour la photodétection. Le développement de ces solutions alternatives ne peut se faire sans l'utilisation d'outils de CAO (Conception Assistée par Ordinateur) efficients. De manière générale, la construction de bibliothèques de modèles hiérarchiques, offrant aux concepteurs différentes valeurs du compromis temps de simulation/précision des résultats, est une étape incontournable dans la réalisation de tels outils. Dans le cas de systèmes multidomaines, il est nécessaire de disposer de simulateurs permettant de prendre en cornpte les différentes natures des composants et leurs interactions. VHDL-AMS est un langage à priori capable de répondre à ces besoins. Cette thèse a été réalisée dans le cadre d'un contrat avec le LETI/CEA de Grenoble. L'objectif est de modéliser un lien optoélectronique opérant à 2.5Gb/s avec un taux d'erreur par bit de 10 puiss.-18 afin d'en évaluer les performances et de l'optimiser.LYON-Ecole Centrale (690812301) / SudocSudocFranceF

Evaluation of the Leak Detection Performance of Distributed Kalman Filter Algorithms in WSN-Based Water Pipeline Monitoring of Plastic Pipes

Water is a basic necessity and one of the most valuable resources for human living. Sadly, large quantities of treated water get lost daily worldwide, especially in developing countries, through leaks in the water distribution network. Wireless sensor network-based water pipeline monitoring (WWPM) systems using low-cost micro-electro-mechanical systems (MEMS) accelerometers have become popular for real-time leak detection due to their low-cost and low power consumption, but they are plagued with high false alarm rates. Recently, the distributed Kalman filter (DKF) has been shown to improve the leak detection reliability of WWPM systems using low-cost MEMS accelerometers. However, the question of which DKF is optimal in terms of leak detection reliability and energy consumption is still unanswered. This study evaluates and compares the leak detection reliability of three DKF algorithms, selected from distributed data fusion strategies based on diffusion, gossip and consensus. In this study, we used a combined approach involving simulations and laboratory experiments. The performance metrics used for the comparison include sensitivity, specificity and accuracy. The laboratory results revealed that the event-triggered diffusion-based DKF is optimal, having a sensitivity value of 61%, a specificity value of 93%, and an accuracy of 90%. It also has a lower communication burden and is less affected by packet loss, making it more responsive to real-time leak detection