Towards a Realistic Energy Model for Wireless Sensor Networks

Energy consumption is one of the most critical protocol properties in a wireless sensor network. Therefore, a precise energy model is required for the evaluation of protocols. In addition to evaluation, an energy model can also be used for on-line energy accounting. After processing user queries, nodes aware of the energy model can send an energy bill towards the network\u27s sink. This allows the user to adjust future queries to be more energy efficient. The contribution of this paper is twofold: First, a theoretical energy model based on simple finite automata is presented. This model can be used for on-line accounting, simulation and generation of a-priori knowledge. Second, the proposed theoretical model is backed up by practical measurements using a new measurement device called SNMD that also offers management functions for sensor-net testbeds. Therewith, output of the theoretical model can be compared to and justified by real-world measurements

Flexi-WVSNP-DASH: A Wireless Video Sensor Network Platform for the Internet of Things

abstract: Video capture, storage, and distribution in wireless video sensor networks (WVSNs) critically depends on the resources of the nodes forming the sensor networks. In the era of big data, Internet of Things (IoT), and distributed demand and solutions, there is a need for multi-dimensional data to be part of the Sensor Network data that is easily accessible and consumable by humanity as well as machinery. Images and video are expected to become as ubiquitous as is the scalar data in traditional sensor networks. The inception of video-streaming over the Internet, heralded a relentless research for effective ways of distributing video in a scalable and cost effective way. There has been novel implementation attempts across several network layers. Due to the inherent complications of backward compatibility and need for standardization across network layers, there has been a refocused attention to address most of the video distribution over the application layer. As a result, a few video streaming solutions over the Hypertext Transfer Protocol (HTTP) have been proposed. Most notable are Apple’s HTTP Live Streaming (HLS) and the Motion Picture Experts Groups Dynamic Adaptive Streaming over HTTP (MPEG-DASH). These frameworks, do not address the typical and future WVSN use cases. A highly flexible Wireless Video Sensor Network Platform and compatible DASH (WVSNP-DASH) are introduced. The platform's goal is to usher video as a data element that can be integrated into traditional and non-Internet networks. A low cost, scalable node is built from the ground up to be fully compatible with the Internet of Things Machine to Machine (M2M) concept, as well as the ability to be easily re-targeted to new applications in a short time. Flexi-WVSNP design includes a multi-radio node, a middle-ware for sensor operation and communication, a cross platform client facing data retriever/player framework, scalable security as well as a cohesive but decoupled hardware and software design.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

Evaluierung der Energie-Effizienz von Sicherheitsmechanismen in drahtlosen Sensornetzen

Im Rahmen dieser Arbeit wurde der Einfluss verschiedener Faktoren auf den Energiebedarf von Sicherheitsmechanismen in drahtlosen Sensornetzen evaluiert. Im Mittelpunkt der Untersuchungen stand insbesondere der Einfluss des Medienzugriffsverfahrens auf den Energiebedarf von (hardwarebasierten) Sicherheitsmechanismen. Als Evaluierungswerkzeuge kam dabei neben dem Testbed SANDBed auch der Simulator AVRORA+ zum Einsatz, dessen Energiemodell im Rahmen dieser Dissertation entstand

Codificação de rede na retransmissão oportunista de mensagens em redes de sensores sem fio IEEE 802.15.4

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia de Automação e Sistemas, Florianópolis, 2014As Redes de Sensores sem Fio (RSSF) vêm apresentando uma penetração cada vez maior nas mais distintas áreas, dados a sua versatilidade e o seu baixo custo. Mais recentemente foi proposto seu emprego no chão de fábrica, com o surgimento de diversos padrões específicos, com especial destaque ao padrão IEEE 802.15.4. O ambiente industrial possui duas características que o diferenciam dos demais ambientes de aplicação das RSSF: requisitos de tempo real na troca de mensagens e alto índice de ruído eletromagnético que provocam altas taxas de perdas de mensagens. Sendo assim, é determinante para a aplicação das RSSF no ambiente industrial que se maximize a confiabilidade na troca de mensagens com garantias temporais. Neste sentido, esta tese propõe um novo algoritmo de codificação de rede para retransmissão oportunista de mensagens, aplicado a redes de sensores sem fio no padrão IEEE 802.15.4. Essa proposta emprega técnicas de codificação de rede, cooperação e diversidade temporal objetivando aumentar a confiabilidade na troca de mensagens. A codificação de rede é utilizada em nodos retransmissores para, sempre que necessário, agrupar um conjunto de mensagens e retransmiti-las. O coordenador da rede, ao receber o conjunto de mensagens originais e mensagens codificadas, consegue aumentar significativamente a taxa de sucesso das mensagens recebidas e, consequentemente, minimizar o consumo energético e do uso do meio na rede. Para comprovar a eficácia dessa proposta foi realizado um conjunto de ensaios experimentais com várias plataformas de nodos, principalmente o MicaZ, e simulações no OMNeT++, em variadas topologias de rede. Com o comparativo da nova técnica com técnicas tradicionais de retransmissão de mensagens se comprovou o melhor desempenho da nova proposta. Também foram realizados ensaios experimentais que comprovaram a factibilidade da codificação de rede em nodos das RSSF.Abstract: Wireless Sensor Networks (WSN) based applications have been increased in different applications areas, due to their versatility and low cost. Recently, its adoption has been proposed on factory floor, with the emergence of several specific standards, with special emphasis on the IEEE 802.15.4 standard. The industrial environment has two particular features that differs from traditional WSN application environments:(i) real-time constraints in messaging streams and (ii) high level of electromagnetic noise, which causes high rates of loss messages.Therefore, it is mandatory for industrial WSN application to maximize the reliability in messages exchanging with temporal guarantees. In this sense, this thesis proposes a new network coding algorithm for opportunistic relaying messages, applied to IEEE 802.15.4 WSN. This proposal employs network coding techniques, time diversity and cooperation in order to increase the message reliability. Network coding is adopted at relays nodes to group a set of messages and retransmit them. The network coordinator, upon receiving the set of original messages and coded messages can signicantly increase the success rate of incoming messages and, consequently, minimize the energy consumption through the network. To assess the effectiveness of this proposal several studies have been conducred in diferent sensor nodes platforms, especially the MicaZ and simulations in OMNeT++ considering various network topologies. Simulation results show that the proposed approach outperforms traditional ralaying techniques. Experimental assessment indicates the feasibility of network coding in the WSN nodes

Verfahren und Protokolle für energiebewusste, gemeinsame Ressourcenverwendung mit mobilen Geräten

Voraussetzung für die gemeinsame Nutzung von Betriebsmitteln mobiler Geräte sind Verfahren, die es erlauben, den Energiebedarf für die Bereitstellung von Ressourcen abzuschätzen, unter mehreren Ressourcenanbietern einen geeigneten auszuwählen und diesen für den erbrachten Energieaufwand zu entschädigen. Diese Arbeit stellt hierfür entwickelte Verfahren vor, die insbesondere das geringe Energiebudget mobiler Geräte berücksichtigen