GNSS-free outdoor localization techniques for resource-constrained IoT architectures : a literature review

Large-scale deployments of the Internet of Things (IoT) are adopted for performance improvement and cost reduction in several application domains. The four main IoT application domains covered throughout this article are smart cities, smart transportation, smart healthcare, and smart manufacturing. To increase IoT applicability, data generated by the IoT devices need to be time-stamped and spatially contextualized. LPWANs have become an attractive solution for outdoor localization and received significant attention from the research community due to low-power, low-cost, and long-range communication. In addition, its signals can be used for communication and localization simultaneously. There are different proposed localization methods to obtain the IoT relative location. Each category of these proposed methods has pros and cons that make them useful for specific IoT systems. Nevertheless, there are some limitations in proposed localization methods that need to be eliminated to meet the IoT ecosystem needs completely. This has motivated this work and provided the following contributions: (1) definition of the main requirements and limitations of outdoor localization techniques for the IoT ecosystem, (2) description of the most relevant GNSS-free outdoor localization methods with a focus on LPWAN technologies, (3) survey the most relevant methods used within the IoT ecosystem for improving GNSS-free localization accuracy, and (4) discussion covering the open challenges and future directions within the field. Some of the important open issues that have different requirements in different IoT systems include energy consumption, security and privacy, accuracy, and scalability. This paper provides an overview of research works that have been published between 2018 to July 2021 and made available through the Google Scholar database.5311-8814-F0ED | Sara Maria da Cruz Maia de Oliveira PaivaN/

A Survey on Long-Range Wide-Area Network Technology Optimizations

Long-Range Wide-Area Network (LoRaWAN) enables flexible long-range service communications with low power consumption which is suitable for many IoT applications. The densification of LoRaWAN, which is needed to meet a wide range of IoT networking requirements, poses further challenges. For instance, the deployment of gateways and IoT devices are widely deployed in urban areas, which leads to interference caused by concurrent transmissions on the same channel. In this context, it is crucial to understand aspects such as the coexistence of IoT devices and applications, resource allocation, Media Access Control (MAC) layer, network planning, and mobility support, that directly affect LoRaWAN’s performance.We present a systematic review of state-of-the-art works for LoRaWAN optimization solutions for IoT networking operations. We focus on five aspects that directly affect the performance of LoRaWAN. These specific aspects are directly associated with the challenges of densification of LoRaWAN. Based on the literature analysis, we present a taxonomy covering five aspects related to LoRaWAN optimizations for efficient IoT networks. Finally, we identify key research challenges and open issues in LoRaWAN optimizations for IoT networking operations that must be further studied in the future

Towards LoRa mesh networks for the IoT

There are several LPWAN radio technologies providing wireless communication to the billions of connected devices that form the so-called IoT. Among them, LoRa has emerged in recent years as a popular solution for low power embedded devices to transmit data at long distances on a reduced energy budget. Most often, LoRa is used as the physical layer of LoRaWAN, an open standard that defines a MAC layer and specifies the star-of-stars topology, operation, roles and mechanisms for an integrated, full-stack IoT architecture. Nowadays, millions of devices use LoRaWAN networks in all sorts of agriculture, smart cities and buildings, industry, logistics and utilities scenarios. Despite its success in all sorts of IoT domains and environments, there are still use cases that would benefit from more flexible network topologies than LoRaWAN's star-of-stars. For instance, in scenarios where the deployment and operation of the backbone network infrastructure is technically or economically challenging, a more flexible model may improve certain performance metrics. As a first major contribution, this thesis investigates the effects of adding multi-hop capability to LoRaWAN, by means of the realistic use case of a communication system based on this architecture that provides a coordinated response in the aftermath of natural disasters like an earthquake. The capacity of end nodes to forward packets and perform multi-hop transmissions is explored, as a strategy to overcome gateway infrastructure failures, and analyzed for challenges, benefits and drawbacks in a massive system with thousands of devices. LoRa is also used as a stand-alone radio technology, independently from the LoRaWAN architecture. Its CSS modulation offers many advantages in LPWANs for IoT deployments. In particular, its different SFs available determine a trade-off between transmission time (i.e., data rate) and sensitivity (i.e., distance reach), and also generate quasi-orthogonal signals that can be demodulated concurrently by different receivers. The second major contribution of this thesis is the design of a minimalistic distance-vector routing protocol for embedded IoT devices featuring a LoRa transceiver, and the proposal of a path cost calculation metric that takes advantage of the multi-SF capability to reduce end-to-end transmission time. The protocol is evaluated through simulation and compared with other well-known routing strategies, analyzing and discussing its suitability for heterogeneous IoT LoRa mesh networks.Hi ha diverses tecnologies de ràdio LPWAN que proporcionen comunicació sense fils als milers de milions de dispositius connectats que conformen l'anomenada IoT. D'entre elles, LoRa ha emergit en els darrers anys com una solució popular per a què dispositius encastats amb pocs recursos transmetin dades a llargues distàncies amb un cost energètic reduït. Tot sovint, LoRa s'empra com la capa física de LoRaWAN, un estàndard obert que defineix una capa MAC i que especifica la topologia en estrella d'estrelles, l'operació, els rols i els mecanismes per implementar una arquitectura de la IoT integrada. A dia d'avui, milions de dispositius fan servir xarxes LoRaWAN en escenaris d'agricultura, edificis i ciutats intel·ligents, indústria, logística i subministraments. Malgrat el seu èxit en tot tipus d'entorns i àmbits de la IoT, encara romanen casos d'ús que es beneficiarien de topologies de xarxa més flexibles que l'estrella d'estrelles de LoRaWAN. Per exemple, en escenaris on el desplegament i l'operació de la infraestructura troncal de xarxa és tècnicament o econòmica inviable, una topologia més flexible podria millorar certs aspectes del rendiment. Com a primera contribució principal, en aquesta tesi s'investiguen els efectes d'afegir capacitat de transmissió multi-salt a LoRaWAN, mitjançant el cas d'ús realista d'un sistema de comunicació, basat en aquesta arquitectura, per proporcionar una resposta coordinada en els moments posteriors a desastres naturals, tals com un terratrèmol. En concret, s'explora l'estratègia d'afegir la capacitat de reenviar paquets als nodes finals per tal d'eludir les fallades en la infraestructura, i se n'analitzen els reptes, beneficis i inconvenients per a un sistema massiu amb milers de dispositius LoRa s'empra també com a tecnologia de ràdio de forma autònoma, independentment de l'arquitectura LoRaWAN. La seva modulació CSS li confereix molts avantatges en xarxes LPWAN per a desplegaments de la IoT. En particular, els diferents SFs disponibles hi determinen un compromís entre la durada de les transmissions (i.e., la taxa de dades) i la sensibilitat en la recepció (i.e., l'abast en distància), alhora que generen senyals quasi-ortogonals que poden ser desmodulades de forma concurrent per receptors diferents. La segona contribució principal d'aquesta tesi és el disseny d'un protocol d'encaminament dinàmic vector-distància per a dispositius de la IoT encastats amb un transceptor LoRa, i la proposta d'una mètrica per calcular el cost d'un camí que aprofita la capacitat multi-SF per minimitzar el temps de transmissió d'extrem a extrem. El protocol és avaluat mitjançant simulacions i comparat amb altres estratègies d'encaminament conegudes, analitzant la seva conveniència per a xarxes LoRa mallades per a la IoT.Existen varias tecnologías de radio LPWAN que proporcionan comunicación inalámbrica a los miles de millones de dispositivos conectados que forman el llamado IoT. De entre ellas, LoRa ha emergido en los últimos años como una solución popular para que dispositivos embebidos con pocos recursos transmitan datos a largas distancias con un coste energético reducido. Habitualmente, LoRa se usa como la capa física de LoRaWAN, un estándar abierto que define una capa MAC y que especi_ca la topología en estrella de estrellas, la operación, los roles y los mecanismos para implantar una arquitectura del IoT integrada. A día de hoy, millones de dispositivos utilizan redes LoRaWAN en escenarios de agricultura, edificios y ciudades inteligentes, industria, logística y suministros. A pesar de su éxito en todo tipo de entornos y ámbitos del IoT, existen casos de uso que se beneficiaran de topologías de red más flexibles que la estrella de estrellas de LoRaWAN. Por ejemplo, en escenarios en los que el despliegue y la operación de la infraestructura troncal de red es técnica o económicamente inviable, una topología más flexible podrá mejorar ciertos aspectos del rendimiento. Como primera contribución principal, en esta tesis se investigan los efectos de añadir capacidad de transmisión multi-salto a LoRaWAN, mediante el caso de uso realista de un sistema de comunicación basado en dicha arquitectura, para proporcionar una respuesta coordinada en los momentos posteriores a desastres naturales, tales como un terremoto. En concreto, se explora la estrategia de añadir la capacidad de reenviar paquetes a los nodos finales para sortear las fallas en la infraestructura, y se analizan los retos, beneficios e inconvenientes para un sistema masivo con miles de dispositivos. LoRa se usa también como tecnología de radio de forma autónoma, independientemente de la arquitectura LoRaWAN. Su modulación CSS le confiere muchas ventajas en redes LPWAN para despliegues de IoT. En particular, los distintos SFs disponibles determinan un compromiso entre la duración de las transmisiones (i.e., la tasa de datos) y la sensibilidad en la recepción (i.e., el alcance en distancia), a la vez que generan señales cuasi-ortogonales que pueden ser desmoduladas de forma concurrente por receptores distintos. En segundo lugar, esta tesis contiene el diseño de un protocolo de enrutamiento dinámico vector-distancia para dispositivos Internet of Things (IoT) embebidos con un transceptor LoRa, y propone una métrica para calcular el coste de un camino que aprovecha la capacidad multi-SF para minimizar el tiempo de transmisión de extremo a extremo. El protocolo es evaluado y comparado con otras estrategias de enrutamiento conocidas, analizando su conveniencia para redes LoRa malladas para el IoT.Postprint (published version

Application of ultrafiltration for drinking water production in decentralised systems: 20 years of the AQUAPOT project

[EN] Access to drinking water is a basic human right which has become an international goal. However, despite the efforts made in the framework of the Millennium Development Goals of the United Nations, about 700 million people are still without access to an adequate source of drinking water in rural areas of developing countries, especially in Africa Sub-Saharan. The AQUAPOT project, developed by the "Instituto Universitario de Seguridad, Radiofisica y Medioambiental (ISIRYM)" of the "Universitat Politecnica de Valencia (UPV)", both in Spain, has been focused research on the design, development and installation of decentralised drinking water systems as an alternative to existing water management systems in developing areas. AQUAPOT systems are based on ultrafiltration technology and have been successfully applied in different localities in Ecuador and Mozambique to produce safe drinking water for human consumption. The present paper describes the main actions carried out within the project AQUAPOT over the last 20 years. It describes the main features of the installed plants and the protocol to choose the best location; it also shows the main results achieved within the project, and discusses the lessons learned throughout the years in relation to the operation of the plants as well as the quality of the treated water.Arnal Arnal, JM.; García-Fayos, B.; Sancho, M. (2018). Application of ultrafiltration for drinking water production in decentralised systems: 20 years of the AQUAPOT project. Desalination and Water Treatment. 103:296-306. https://doi.org/10.5004/dwt.2018.21989S29630610

Low Cost LoRa based Network for Forest Fire Detection

[EN] Forest fires are one of the main environmental problems in the entire Mediterranean basin. In a context where low power and long-range networks (LPWAN) are increasingly common to the rise of Internet of Things (IoT) architecture, the interest in providing solutions to monitor scenarios and fire prevention based on these technologies is huge. This paper presents a low cost Long Range (LoRa) based network able to evaluate level of fire risk and the presence of a forest fire. The system is composed by a LoRa node and a set of sensors to measure the temperature, relative humidity, wind speed and CO2. The evaluation algorithm is based on the 30- 30-30 rule. Through website the users can see the parameters measured by nodes in real time. The system has been tested in a real environment and the results show that it is possible to cover a circular area of 1.1km or radius.This work has been partially supported by the Ministerio de Ciencia, Innovación y Universidades through the Ayudas para la adquisición de equipamiento científicotécnico, Subprograma estatal de infraestructuras de investigación y equipamiento científico-técnico (plan Estatal I+D+i 2017-2020) (project EQC2018-004988-P) and through the Research Contracts of Youth Employment of the University of Granada, through its operative program of Youth Guarantee of the Regional Government of Andalusia and the European Social Fund.Vega-Rodríguez, R.; Sendra, S.; Lloret, J.; Romero-Díaz, P.; García-Navas, JL. (2019). Low Cost LoRa based Network for Forest Fire Detection. IEEE. 177-184. https://doi.org/10.1109/IOTSMS48152.2019.8939193S17718

A Wearable Fall Detection System based on LoRa LPWAN Technology

Several technological solutions now available in the market offer the possibility of increasing the independent life of people who by age or pathologies otherwise need assistance. In particular, internet-connected wearable solutions are of considerable interest, as they allow continuous monitoring of the user. However, their use poses different challenges, from the real usability of a device that must still be worn to the performance achievable in terms of radio connectivity and battery life. The acceptability of a technology solution, by a user who would still benefit from its use, is in fact often conditioned by practical problems that impact the person’s normal lifestyle. The technological choices adopted in fact strongly determine the success of the proposed solution, as they may imply limitations both to the person who uses it and to the achievable performance. In this document, targeting the case of a fall detection sensor based on a pair of sensorized shoes, the effectiveness of a real implementation of an Internet of Things technology is examined. It is shown how alarming events, generated in a metropolitan context, are effectively sent to a supervision system through Low Power Wide Area Network technology without the need for a portable gateway. The experimental results demonstrate the effectiveness of the chosen technology, which allows the user to take advantage of the support of a wearable sensor without being forced to substantially change his lifestyle

Road Traffic Management using Vehicle-to- Everything (V2X) Communication

Traffic congestion is the primary concern in dense cities; while the increased number of automobiles is becoming uncontrollable in some cities, it is more challenging to manage or change how people use cars. To contribute to solving traffic congestion in cities, this project examines the study of transferring vehicles to be competent in a way that can help the government entities analyze the received vehicles’ data and for better decisions on reducing traffic congestion as well as the real-time monitoring of traffic wherever it is located using the Vehicle-to-Everything (V2X) communication methodology. This study proposes a hardware “system” that can be attached to any vehicle to collect real-time data from vehicles and communicate with the Road and Transportation Authority. The hardware system, however, is connected to the cars through a wireless On-Board Diagnostics (OBD) connection in favor of collecting all the necessary information from the vehicle, such as the car speed and Revolutions Per Minute (RPM) data. On the other hand, a GPS sensor is used to inquire about the vehicle’s location, a GSM module to make sure the device is always connected to the internet for data transmission, a LiDAR sensor for distance and safety measurement, and a camera module accessed only by the driver for object detection such as cars, pedestrians, traffic signs, damaged roads, and road hazards. Moreover, system updates and maintenance can be done remotely to reduce the number of visits to the traffic department since all devices are to be connected to a single platform. As a result, it was possible to create a prototype for a single vehicle, including the sensors mentioned above, returning valuable data that include vehicle speed and exact location, which will help future researchers develop an application platform to monitor and track traffic congestion in real time