111 research outputs found

    Routing for Wireless Sensor Networks: From Collection to Event-Triggered Applications

    Get PDF
    Wireless Sensor Networks (WSNs) are collections of sensing devices using wireless communication to exchange data. In the past decades, steep advancements in the areas of microelectronics and communication systems have driven an explosive growth in the deployment of WSNs. Novel WSN applications have penetrated multiple areas, from monitoring the structural stability of historic buildings, to tracking animals in order to understand their behavior, or monitoring humans' health. The need to convey data from increasingly complex applications in a reliable and cost-effective manner translates into stringent performance requirements for the underlying WSNs. In the frame of this thesis, we have focused on developing routing protocols for multi-hop WSNs, that significantly improve their reliability, energy consumption and latency. Acknowledging the need for application-specific trade-offs, we have split our contribution into two parts. Part 1 focuses on collection protocols, catering to applications with high reliability and energy efficiency constraints, while the protocols developed in part 2 are subject to an additional bounded latency constraint. The two mechanisms introduced in the first part, WiseNE and Rep, enable the use of composite metrics, and thus significantly improve the link estimation accuracy and transmission reliability, at an energy expense far lower than the one achieved in previous proposals. The novel beaconing scheme WiseNE enables the energy-efficient addition of the RSSI (Received Signal Strength Indication) and LQI (Link Quality Indication) metrics to the link quality estimate by decoupling the sampling and exploration periods of each mote. This decoupling allows the use of the Trickle Algorithm, a key driver of protocols' energy efficiency, in conjunction with composite metrics. WiseNE has been applied to the Triangle Metric and validated in an online deployment. The section continues by introducing Rep, a novel sampling mechanism that leverages the packet repetitions already present in low-power preamble-sampling MAC protocols in order to improve the WSN energy consumption by one order of magnitude. WiseNE, Rep and the novel PRSSI (Penalized RSSI, a combination of PRR and RSSI) composite metric have been validated in a real smart city deployment. Part 2 introduces two mechanisms that were developed in the frame of the WiseSkin project (an initiative aimed at designing highly sensitive artificial skin for human limb prostheses), and are generally applicable to the domain of cyber-physical systems. It starts with Glossy-W, a protocol that leverages the superior energy-latency trade-off of flooding schemes based on concurrent transmissions. Glossy-W ensures the stringent synchronization requirements necessary for robust flooding, irrespective of the number of motes simultaneously reporting an event. Part 2 also introduces SCS (Synchronized Channel Sampling), a novel mechanism capable of reducing the power required for periodic polling, while maintaining the event detection reliability, and enhancing the network coexistence. The testbed experiments performed show that SCS manages to reduce the energy consumption of the state-of-the-art protocol Back-to-Back Robust Flooding by over one third, while maintaining an equivalent reliability, and remaining compatible with simultaneous event detection. SCS' benefits can be extended to the entire family of state-of-the-art protocols relying on concurrent transmissions

    Building the Future Internet through FIRE

    Get PDF
    The Internet as we know it today is the result of a continuous activity for improving network communications, end user services, computational processes and also information technology infrastructures. The Internet has become a critical infrastructure for the human-being by offering complex networking services and end-user applications that all together have transformed all aspects, mainly economical, of our lives. Recently, with the advent of new paradigms and the progress in wireless technology, sensor networks and information systems and also the inexorable shift towards everything connected paradigm, first as known as the Internet of Things and lately envisioning into the Internet of Everything, a data-driven society has been created. In a data-driven society, productivity, knowledge, and experience are dependent on increasingly open, dynamic, interdependent and complex Internet services. The challenge for the Internet of the Future design is to build robust enabling technologies, implement and deploy adaptive systems, to create business opportunities considering increasing uncertainties and emergent systemic behaviors where humans and machines seamlessly cooperate

    Building the Future Internet through FIRE

    Get PDF
    The Internet as we know it today is the result of a continuous activity for improving network communications, end user services, computational processes and also information technology infrastructures. The Internet has become a critical infrastructure for the human-being by offering complex networking services and end-user applications that all together have transformed all aspects, mainly economical, of our lives. Recently, with the advent of new paradigms and the progress in wireless technology, sensor networks and information systems and also the inexorable shift towards everything connected paradigm, first as known as the Internet of Things and lately envisioning into the Internet of Everything, a data-driven society has been created. In a data-driven society, productivity, knowledge, and experience are dependent on increasingly open, dynamic, interdependent and complex Internet services. The challenge for the Internet of the Future design is to build robust enabling technologies, implement and deploy adaptive systems, to create business opportunities considering increasing uncertainties and emergent systemic behaviors where humans and machines seamlessly cooperate

    Software-hardware systems for the Internet-of-Things

    Get PDF
    Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.Cataloged from PDF version of thesis.Includes bibliographical references (pages [187]-201).Although interest in connected devices has surged in recent years, barriers still remain in realizing the dream of the Internet of Things (IoT). The main challenge in delivering IoT systems stems from a huge diversity in their demands and constraints. Some applications work with small sensors and operate using minimal energy and bandwidth. Others use high-data-rate multimedia and virtual reality systems, which require multiple-gigabits-per-second throughput and substantial computing power. While both extremes stress the computation, communications, and energy resources available to the underlying devices, each intrinsically requires different solutions to satisfy its needs. This thesis addresses both bandwidth and energy constraints by developing custom software-hardware systems. To tackle the bandwidth constraint, this thesis introduces three systems. First, it presents AirShare, a synchronized abstraction to the physical layer, which enables the direct implementation of diverse kinds of distributed protocols for loT sensors. This capability results in a much higher throughput in today's IoT networks. Then, it presents Agile-Link and MoVR, new millimeter wave devices and protocols which address two main problems that prevent the adoption of millimeter wave frequencies in today's networks: signal blockage and beam alignment. Lastly, this thesis shows how these systems enable new IoT applications, such as untethered high-quality virtual reality. To tackle the energy constraint, this thesis introduces a VLSI chip, which is capable of performing a million-point Fourier transform in real-time, while consuming 40 times less power than prior fast Fourier transforms. Then, it presents Caraoke, a small, low-cost and low-power sensor, which harvests its energy from solar and enables new smart city applications, such as traffic management and smart parking.by Omid Salehi-Abari.Ph. D

    Performance Assessment of Routing Protocols for IoT/6LoWPAN Networks

    Get PDF
    The Internet of Things (IoT) proposes a disruptive communication paradigm that allows smart objects to exchange data among themselves to reach a common goal. IoT application scenarios are multiple and can range from a simple smart home lighting system to fully controlled automated manufacturing chains. In the majority of IoT deployments, things are equipped with small devices that can suffer from severe hardware and energy restrictions that are responsible for performing data processing and wireless communication tasks. Thus, due to their features, communication networks that are used by these devices are generally categorized as Low Power and Lossy Networks (LLNs). The considerable variation in IoT applications represents a critical issue to LLN networks, which should offer support to different requirements as well as keeping reasonable quality-of-service (QoS) levels. Based on this challenge, routing protocols represent a key issue in IoT scenarios deployment. Routing protocols are responsible for creating paths among devices and their interactions. Hence, network performance and features are highly dependent on protocol behavior. Also, based on the adopted protocol, the support for some specific requirements of IoT applications may or may not be provided. Thus, a routing protocol should be projected to attend the needs of the applications considering the limitations of the device that will execute them. Looking to attend the demand of routing protocols for LLNs and, consequently, for IoT networks, the Internet Engineering Task Force (IETF) has designed and standardized the IPv6 Routing Protocol for Low Power and Lossy Networks (RPL). This protocol, although being robust and offering features to fulfill the need of several applications, still presents several faults and weaknesses (mainly related to its high complexity and memory requirement), which limits its adoption in IoT scenarios. An alternative to RPL, the Lightweight On-demand Ad Hoc Distancevector Routing Protocol – Next Generation (LOADng) has emerged as a less complicated routing solution for LLNs. However, the cost of its simplicity is paid for with the absence of adequate support for a critical set of features required for many IoT environments. Thus, based on the challenging open issues related to routing in IoT networks, this thesis aims to study and propose contributions to better attend the network requirements of IoT scenarios. A comprehensive survey, reviewing state-of-the-art routing protocols adopted for IoT, identified the strengths and weaknesses of current solutions available in the literature. Based on the identified limitations, a set of improvements is designed to overcome these issues and enhance IoT network performance. The novel solutions are proposed to include reliable and efficient support to attend the needs of IoT applications, such as mobility, heterogeneity, and different traffic patterns. Moreover, mechanisms to improve the network performance in IoT scenarios, which integrate devices with different communication technologies, are introduced. The studies conducted to assess the performance of the proposed solutions showed the high potential of the proposed solutions. When the approaches presented in this thesis were compared with others available in the literature, they presented very promising results considering the metrics related to the Quality of Service (QoS), network and energy efficiency, and memory usage as well as adding new features to the base protocols. Hence, it is believed that the proposed improvements contribute to the state-of-the-art of routing solutions for IoT networks, increasing the performance and adoption of enhanced protocols.A Internet das Coisas, do inglĂȘs Internet of Things (IoT), propĂ”e um paradigma de comunicação disruptivo para possibilitar que dispositivos, que podem ser dotados de comportamentos autĂłnomos ou inteligentes, troquem dados entre eles buscando alcançar um objetivo comum. Os cenĂĄrios de aplicação do IoT sĂŁo muito variados e podem abranger desde um simples sistema de iluminação para casa atĂ© o controle total de uma linha de produção industrial. Na maioria das instalaçÔes IoT, as “coisas” sĂŁo equipadas com um pequeno dispositivo, responsĂĄvel por realizar as tarefas de comunicação e processamento de dados, que pode sofrer com severas restriçÔes de hardware e energia. Assim, devido Ă s suas caracterĂ­sticas, a rede de comunicação criada por esses dispositivos Ă© geralmente categorizada como uma Low Power and Lossy Network (LLN). A grande variedade de cenĂĄrios IoT representam uma questĂŁo crucial para as LLNs, que devem oferecer suporte aos diferentes requisitos das aplicaçÔes, alĂ©m de manter nĂ­veis de qualidade de serviço, do inglĂȘs Quality of Service (QoS), adequados. Baseado neste desafio, os protocolos de encaminhamento constituem um aspecto chave na implementação de cenĂĄrios IoT. Os protocolos de encaminhamento sĂŁo responsĂĄveis por criar os caminhos entre os dispositivos e permitir suas interaçÔes. Assim, o desempenho e as caracterĂ­sticas da rede sĂŁo altamente dependentes do comportamento destes protocolos. Adicionalmente, com base no protocolo adotado, o suporte a alguns requisitos especĂ­ficos das aplicaçÔes de IoT podem ou nĂŁo ser fornecidos. Portanto, estes protocolos devem ser projetados para atender as necessidades das aplicaçÔes assim como considerando as limitaçÔes do hardware no qual serĂŁo executados. Procurando atender Ă s necessidades dos protocolos de encaminhamento em LLNs e, consequentemente, das redes IoT, a Internet Engineering Task Force (IETF) desenvolveu e padronizou o IPv6 Routing Protocol for Low Power and Lossy Networks (RPL). O protocolo, embora seja robusto e ofereça recursos para atender Ă s necessidades de diferentes aplicaçÔes, apresenta algumas falhas e fraquezas (principalmente relacionadas com a sua alta complexidade e necessidade de memĂłria) que limitam sua adoção em cenĂĄrios IoT. Em alternativa ao RPL, o Lightweight On-demand Ad hoc Distance-vector Routing Protocol – Next Generation (LOADng) emergiu como uma solução de encaminhamento menos complexa para as LLNs. Contudo, o preço da simplicidade Ă© pago com a falta de suporte adequado para um conjunto de recursos essenciais necessĂĄrios em muitos ambientes IoT. Assim, inspirado pelas desafiadoras questĂ”es ainda em aberto relacionadas com o encaminhamento em redes IoT, esta tese tem como objetivo estudar e propor contribuiçÔes para melhor atender os requisitos de rede em cenĂĄrios IoT. Uma profunda e abrangente revisĂŁo do estado da arte sobre os protocolos de encaminhamento adotados em IoT identificou os pontos fortes e limitaçÔes das soluçÔes atuais. Com base nas debilidades encontradas, um conjunto de soluçÔes de melhoria Ă© proposto para superar carĂȘncias existentes e melhorar o desempenho das redes IoT. As novas soluçÔes sĂŁo propostas para incluir um suporte confiĂĄvel e eficiente capaz atender Ă s necessidades das aplicaçÔes IoT relacionadas com suporte Ă  mobilidade, heterogeneidade dos dispositivos e diferentes padrĂ”es de trĂĄfego. AlĂ©m disso, sĂŁo introduzidos mecanismos para melhorar o desempenho da rede em cenĂĄrios IoT que integram dispositivos com diferentes tecnologias de comunicação. Os vĂĄrios estudos realizados para mensurar o desempenho das soluçÔes propostas mostraram o grande potencial do conjunto de melhorias introduzidas. Quando comparadas com outras abordagens existentes na literatura, as soluçÔes propostas nesta tese demonstraram um aumento do desempenho consistente para mĂ©tricas relacionadas a qualidade de serviço, uso de memĂłria, eficiĂȘncia energĂ©tica e de rede, alĂ©m de adicionar novas funcionalidades aos protocolos base. Portanto, acredita-se que as melhorias propostas contribuiem para o avanço do estado da arte em soluçÔes de encaminhamento para redes IoT e aumentar a adoção e utilização dos protocolos estudados

    Marshall Space Flight Center Research and Technology Report 2018

    Get PDF
    Many of NASAs missions would not be possible if it were not for the investments made in research advancements and technology development efforts. The technologies developed at Marshall Space Flight Center contribute to NASAs strategic array of missions through technology development and accomplishments. The scientists, researchers, and technologists of Marshall Space Flight Center who are working these enabling technology efforts are facilitating NASAs ability to fulfill the ambitious goals of innovation, exploration, and discovery

    Telecommunications Networks

    Get PDF
    This book guides readers through the basics of rapidly emerging networks to more advanced concepts and future expectations of Telecommunications Networks. It identifies and examines the most pressing research issues in Telecommunications and it contains chapters written by leading researchers, academics and industry professionals. Telecommunications Networks - Current Status and Future Trends covers surveys of recent publications that investigate key areas of interest such as: IMS, eTOM, 3G/4G, optimization problems, modeling, simulation, quality of service, etc. This book, that is suitable for both PhD and master students, is organized into six sections: New Generation Networks, Quality of Services, Sensor Networks, Telecommunications, Traffic Engineering and Routing
    • 

    corecore