Ultra Wideband-based wireless synchronization of IEEE 1588 clocks

Time-Sensitive Networking (TSN) requires clock synchronization superior to the well-known Network Time Protocol (NTP). The IEEE 802.1AS-2020 used for synchronization in TSN networks is based on the IEEE 1588-2019 standard (also known as Precision Time Protocol, PTP) defines methods and tools to perform sub-microsecond time synchronization over vari- ous communication channels. However, the IEEE 1588 implementation is commonly used with wired communication protocols, although there are use cases that could gain an advantage from a wireless solution. This paper investigates the possibility of PTP clock synchronization through wireless Ultra Wideband (UWB) communication. UWB excels where other wireless technologies are lacking: it provides high accuracy timestamping even if multipath propagation is present. The method is evaluated using commercial, well-accessible cheap hardware, resulting in the order of 10-nanosecond accuracy. The paper also highlights the main error components and requirements for improving wireless PTP synchronization

Distributed synchronization algorithms for wireless sensor networks

The ability to distribute time and frequency among a large population of interacting agents is of interest for diverse disciplines, inasmuch as it enables to carry out complex cooperative tasks. In a wireless sensor network (WSN), time/frequency synchronization allows the implementation of distributed signal processing and coding techniques, and the realization of coordinated access to the shared wireless medium. Large multi-hop WSN\u27s constitute a new regime for network synchronization, as they call for the development of scalable, fully distributed synchronization algorithms. While most of previous research focused on synchronization at the application layer, this thesis considers synchronization at the lowest layers of the communication protocol stack of a WSN, namely the physical and the medium access control (MAC) layer. At the physical layer, the focus is on the compensation of carrier frequency offsets (CFO), while time synchronization is studied for application at the MAC layer. In both cases, the problem of realizing network-wide synchronization is approached by employing distributed clock control algorithms based on the classical concept of coupled phase and frequency locked loops (PLL and FLL). The analysis takes into account communication, signaling and energy consumption constraints arising in the novel context of multi-hop WSN\u27s. In particular, the robustness of the algorithms is checked against packet collision events, infrequent sync updates, and errors introduced by different noise sources, such as transmission delays and clock frequency instabilities. By observing that WSN\u27s allow for greater flexibility in the design of the synchronization network architecture, this work examines also the relative merits of both peer-to-peer (mutually coupled - MC) and hierarchical (master-slave - MS) architectures. With both MC and MS architectures, synchronization accuracy degrades smoothly with the network size, provided that loop parameters are conveniently chosen. In particular, MS topologies guarantee faster synchronization, but they are hindered by higher noise accumulation, while MC topologies allow for an almost uniform error distribution at the price of much slower convergence. For all the considered cases, synchronization algorithms based on adaptive PLL and FLL designs are shown to provide robust and scalable network-wide time and frequency distribution in a WSN

Selected Papers from the 5th International Electronic Conference on Sensors and Applications

This Special Issue comprises selected papers from the proceedings of the 5th International Electronic Conference on Sensors and Applications, held on 15–30 November 2018, on sciforum.net, an online platform for hosting scholarly e-conferences and discussion groups. In this 5th edition of the electronic conference, contributors were invited to provide papers and presentations from the field of sensors and applications at large, resulting in a wide variety of excellent submissions and topic areas. Papers which attracted the most interest on the web or that provided a particularly innovative contribution were selected for publication in this collection. These peer-reviewed papers are published with the aim of rapid and wide dissemination of research results, developments, and applications. We hope this conference series will grow rapidly in the future and become recognized as a new way and venue by which to (electronically) present new developments related to the field of sensors and their applications

JTIT

kwartalni

Soluciones TIC para envejecimiento activo y saludable en el hogar, en el puesto de trabajo y en la sociedad

[SPA] Esta tesis doctoral se presenta bajo la modalidad de compendio de publicaciones.La presente tesis doctoral compendia las publicaciones resultado de varios años de trabajo en el marco de tres líneas de investigación relacionadas con envejecimiento activo y soluciones e-health y Ambient Assisted Living para la población de edad más avanzada: Mobiliario inteligente y espacios inteligentes, envejecimiento activo y saludable, y soluciones de las Tecnologías de la Información y las Comunicaciones (TIC) enfocadas al cuidado de la salud en general y a las personas mayores en particular. Dichos trabajos muestran los resultados de un análisis del estado del arte, patentes y otros, para poder establecer una definición precisa del concepto de Mobiliario Inteligente con el objetivo de destacar sus propiedades en cuanto a funcionalidad y al elemento digital activo y conectado. Además, es necesario destacar que el mobiliario inteligente debe ser considerado como un ente integrado en el concepto de ciudades inteligentes o calidad de vida. Por ello la investigación del estado del arte se centra en envejecimiento de la población activa, tendencias recientes, direcciones futuras y envejecimiento en el trabajo. El objetivo es poder extraer conclusiones en cuanto a los principales problemas de motivación y proponer respuestas eficaces que apoyen el envejecimiento en el trabajo y soluciones e-health que permita a la población senior vivir de manera independiente durante más tiempo a través, tanto de una arquitectura IoT de bajo rango para ayudar a abordar los retos de despliegue de servicios e-health en áreas rurales, como de un sistema de teleasistencia basado en el cuidado proactivo, el envejecimiento activo, la prevención y las necesidades de los usuarios y sus entornos. [ENG] This doctoral dissertation has been presented in the form of thesis by publication. The present doctoral thesis summarises a set of publications resulting from several years of work within the framework of three research lines on active ageing and e-health solutions and Ambient Assisted Living for the ageing population: Smart furniture and Smart habitats, active and healthy ageing and Information and Communication Technology solutions focused on health care in general and on the adult population in particular. Such works show the results of an analysis of the state of the art, patents, and others, to establish a precise definition of the concept of Smart Furniture to highlight its properties in terms of functionality and the active and connected digital element, and to underline that smart furniture must be considered as an integrated entity in the concept of Smart Cities or Quality of Life. For this reason, the state-of-the- art research focuses on the aging workforce, recent trends, future directions, and aging at work. The aim is to draw conclusions on the main motivational issues and to propose effective responses that support the concept of aging at work, as well as e-health solutions for the senior population to live independently for longer through both, a low-range IoT architecture to help address the challenges of deploying a e-health system in rural areas, and a tele-assistance system based on proactivity, prevention, and users’ needs and their environments.Esta tesis doctoral se presenta bajo la modalidad de compendio de publicaciones. Está formada por un total de cuatro artículos. Artículo 1.-: Krejcar, O., Maresova, P., Selamat, A., Melero, F. J., Barakovic, S., Husic, J. B., Herrera-Viedma, E., Frischer, R., & Kuca, K., 2019. Smart furniture as a component of a smart city—definition based on key technologies specification. IEEE Access, volumen 7. https://doi.org/10.1109/ACCESS.2019.2927778. Artículo 2.-: Barakovic Husic, J., Melero, F. J., Barakovic, S., Lameski, P., Zdravevski, E., Maresova, P., Krejcar, O., Chorveb, I., Garcia, N.M, & Trajkovik, V., 2020. Aging at Work: A Review of Recent Trends and Future Directions. International journal of environmental research and public health, volumen 17 https://doi.org/10.3390/ijerph17207659. Artículo 3.-: Dimitrievski, A., Filiposka, S., Melero, F. J., Zdravevski, E., Lameski, P., Pires, I. M., Garcia N.M., Lousado, J.P. & Trajkovik, V., 2021. Rural Healthcare IoT Architecture Based on Low-Energy LoRa. International Journal of Environmental Research and Public health, volumen 18. https://doi.org/10.3390/ijerph18147660 Artículo 4.-: Melero, F. J., Bueno, M.V., Martínez, R., Maestre, R., Beteta, M.A., Puebla, T., Bleda, A.L., Sánchez, G., Pérez, R. & Álvarez, M., 2022. Design and Development of a Heterogeneous Active Assisted Living Solution for Monitoring and Following-up with Chronic Heart Failure Patients in Spain. Sensors, Volumen 22, https://doi.org/10.3390/s22228961Escuela Internacional de Doctorado de la Universidad Politécnica de CartagenaUniversidad Politécnica de CartagenaPrograma de Doctorado en Tecnologías de la Información y las Comunicacione