Understanding the limits of LoRaWAN

The quick proliferation of LPWAN networks, being LoRaWAN one of the most adopted, raised the interest of the industry, network operators and facilitated the development of novel services based on large scale and simple network structures. LoRaWAN brings the desired ubiquitous connectivity to enable most of the outdoor IoT applications and its growth and quick adoption are real proofs of that. Yet the technology has some limitations that need to be understood in order to avoid over-use of the technology. In this article we aim to provide an impartial overview of what are the limitations of such technology, and in a comprehensive manner bring use case examples to show where the limits are

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

Sub-GHz LPWAN network coexistence, management and virtualization : an overview and open research challenges

The IoT domain is characterized by many applications that require low-bandwidth communications over a long range, at a low cost and at low power. Low power wide area networks (LPWANs) fulfill these requirements by using sub-GHz radio frequencies (typically 433 or 868 MHz) with typical transmission ranges in the order of 1 up to 50 km. As a result, a single base station can cover large areas and can support high numbers of connected devices (> 1000 per base station). Notorious initiatives in this domain are LoRa, Sigfox and the upcoming IEEE 802.11ah (or "HaLow") standard. Although these new technologies have the potential to significantly impact many IoT deployments, the current market is very fragmented and many challenges exists related to deployment, scalability, management and coexistence aspects, making adoption of these technologies difficult for many companies. To remedy this, this paper proposes a conceptual framework to improve the performance of LPWAN networks through in-network optimization, cross-technology coexistence and cooperation and virtualization of management functions. In addition, the paper gives an overview of state of the art solutions and identifies open challenges for each of these aspects

A LoRaWAN testbed design for supporting critical situations: prototype and evaluation

The Internet of Things is one of the hottest topics in communications today, with current revenues of $151B, around 7 billion connected devices, and an unprecedented growth expected for next years. A massive number of sensors and actuators are expected to emerge, requiring new wireless technologies that can extend their battery life and can cover large areas. LoRaWAN is one of the most outstanding technologies which fulfill these demands, attracting the attention of both academia and industry. In this paper, the design of a LoRaWAN testbed to support critical situations, such as emergency scenarios or natural disasters, is proposed. This self-healing LoRaWAN network architecture will provide resilience when part of the equipment in the core network may become faulty. This resilience is achieved by virtualizing and properly orchestrating the different network entities. Different options have been designed and implemented as real prototypes. Based on our performance evaluation, we claim that the usage of microservice orchestration with several replicas of the LoRaWAN network entities and a load balancer produces an almost seamless recovery which makes it a proper solution to recover after a system crash caused by any catastrophic event.Postprint (published version

Hybrid LoRa-IEEE 802.11s Opportunistic Mesh Networking for Flexible UAV Swarming

Unmanned Aerial Vehicles (UAVs) and small drones are nowadays being widely used in heterogeneous use cases: aerial photography, precise agriculture, inspections, environmental data collection, search-and-rescue operations, surveillance applications, and more. When designing UAV swarm-based applications, a key "ingredient" to make them effective is the communication system (possible involving multiple protocols) shared by flying drones and terrestrial base stations. When compared to ground communication systems for swarms of terrestrial vehicles, one of the main advantages of UAV-based communications is the presence of direct Line-of-Sight (LOS) links between flying UAVs operating at an altitude of tens of meters, often ensuring direct visibility among themselves and even with some ground Base Transceiver Stations (BTSs). Therefore, the adoption of proper networking strategies for UAV swarms allows users to exchange data at distances (significantly) longer than in ground applications. In this paper, we propose a hybrid communication architecture for UAV swarms, leveraging heterogeneous radio mesh networking based on long-range communication protocols—such as LoRa and LoRaWAN—and IEEE 802.11s protocols. We then discuss its strengths, constraints, viable implementation, and relevant reference use cases

Towards Next Generation Teaching, Learning, and Context-Aware Applications for Higher Education: A Review on Blockchain, IoT, Fog and Edge Computing Enabled Smart Campuses and Universities

[Abstract] Smart campuses and smart universities make use of IT infrastructure that is similar to the one required by smart cities, which take advantage of Internet of Things (IoT) and cloud computing solutions to monitor and actuate on the multiple systems of a university. As a consequence, smart campuses and universities need to provide connectivity to IoT nodes and gateways, and deploy architectures that allow for offering not only a good communications range through the latest wireless and wired technologies, but also reduced energy consumption to maximize IoT node battery life. In addition, such architectures have to consider the use of technologies like blockchain, which are able to deliver accountability, transparency, cyber-security and redundancy to the processes and data managed by a university. This article reviews the state of the start on the application of the latest key technologies for the development of smart campuses and universities. After defining the essential characteristics of a smart campus/university, the latest communications architectures and technologies are detailed and the most relevant smart campus deployments are analyzed. Moreover, the use of blockchain in higher education applications is studied. Therefore, this article provides useful guidelines to the university planners, IoT vendors and developers that will be responsible for creating the next generation of smart campuses and universities.Xunta de Galicia; ED431C 2016-045Xunta de Galicia; ED431G/01Agencia Estatal de Investigación de España; TEC2016-75067-C4-1-

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