Analysis of LoRaWAN Uplink with Multiple Demodulating Paths and Capture Effect

Low power wide area networks (LPWANs), such as the ones based on the LoRaWAN protocol, are seen as enablers of large number of IoT applications and services. In this work, we assess the scalability of LoRaWAN by analyzing the frame success probability (FSP) of a LoRa frame while taking into account the capture effect and the number of parallel demodulation paths of the receiving gateway. We have based our model on the commonly used {SX1301 gateway chipset}, which is capable of demodulating {up to} eight frames simultaneously; however, the results of the model can be generalized to architectures with arbitrary number of demodulation paths. We have also introduced and investigated {three} policies for Spreading Factor (SF) allocation. Each policy is evaluated in terms of coverage {probability}, {FSP}, and {throughput}. The overall conclusion is that the presence of multiple demodulation paths introduces a significant change in the analysis and performance of the LoRa random access schemes

A survey on the viability of confirmed traffic in a LoRaWAN

Internet of Things (IoT) deployments are on the rise globally with Low Power Wide Area Networks (LPWAN) providing the wireless networks needed for this expansion. One of these technologies namely Long Range Wide Area Network (LoRaWAN) has proven to be a very popular choice. The LoRaWAN protocol allows for confirmed traffic from the end device to the gateway (uplink) and the reverse (downlink), increasing the number of IoT use cases that it can support. However, this comes at a cost as downlink traffic severely impacts scalability due to in part a gateway's duty cycle restrictions. This paper highlights some of the use cases that require confirmed traffic, examines the recent works focused on LoRaWAN confirmed traffic and discusses the mechanism with which is implemented. It was found that confirmed traffic is viable in small networks, especially when data transfer is infrequent. Additionally, the following aspects negatively impact the viability of confirmed traffic in large networks: the duty cycle restrictions placed on gateways, the use of spreading factor 12 for receive window 2 transmissions, a high maximum number of transmissions (NbTrans) and the ACK_TIMEOUT transmission backoff interval. The paper also raises and suggests solutions to open research challenges that must be overcome to increase the viability of confirmed traffic.The Council for Scientific and Industrial Research of South Africa and Telkom.http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=6287639am2020Electrical, Electronic and Computer Engineerin

Performance of a live multi-gateway LoRaWAN and interference measurement across indoor and outdoor localities

Little work has been reported on the magnitude and impact of interference with the performance of Internet of Things (IoT) applications operated by Long-Range Wide-Area Network (LoRaWAN) in the unlicensed 868 MHz Industrial, Scientific, and Medical (ISM) band. The propagation performance and signal activity measurement of such technologies can give many insights to effectively build long-range wireless communications in a Non-Line of Sight (NLOS) environment. In this paper, the performance of a live multi-gateway in indoor office site in Glasgow city was analysed in 26 days of traffic measurement. The indoor network performances were compared to similar performance measurements from outdoor LoRaWAN test traffic generated across Glasgow Central Business District (CBD) and elsewhere on the same LoRaWAN. The results revealed 99.95% packet transfer success on the first attempt in the indoor site compared to 95.7% at the external site. The analysis shows that interference is attributed to nearly 50 X greater LoRaWAN outdoor packet loss than indoor. The interference measurement results showed a 13.2–97.3% and 4.8–54% probability of interfering signals, respectively, in the mandatory Long-Range (LoRa) uplink and downlink channels, capable of limiting LoRa coverage in some areas

LoRaWAN simulation and analysis for performance enhancement of realistic networks

The Internet of Things (IoT) is becoming an ubiquitous technology, with new devices, solutions and applications being developed at an ever-increasing rate. Fundamental to the IoT revolution is the adoption of wireless protocols purposely designed to enable low-cost, long-range communication for numerous connected devices. Low Power Wide Area Networks (LPWANs) are wide area wireless telecommunication networks designed specifically for IoT applications. They allow for long-range communication at a low bit-rate among connected items, such as battery-powered sensors. However, with these benefits come also a number of drawbacks, including the limited data rate available and the reliance on low power channel access methods which can negatively impact performance in a highly dense network. The purpose of the research contained in this work is to measure the performance in terms of Quality-of-Service (QoS), Packet Delivery Ratio (PDR) and scalability of one LPWAN in particular, Long Range Wide Area Network (LoRaWAN), as well as providing possible improvements that current and future network owners can put into practice. LoRaWAN simple channel access protocol, based on pure Additive Links On-line Hawaii Area (ALOHA) is intended to reduce cost, complexity, and energy consumption while increasing transmission range. However, it also severely limits the scalability of the technology, making it more prone to packet collision, despite LoRaWAN being particularly resilient to self-interference, thanks to the underlining, proprietary Long Range (LoRa) modulation. In this thesis, LoRaWAN technology is evaluated through both software simulation and experimental deployments, with the goal of gaining a deeper understanding of the technology to then create better models and better performing deployments. The innovations and novel results presented throughout will accelerate the pervasiveness of LPWAN networks such as LoRaWAN, and ultimately their effectivness. Despite being developed in 2015, LoRa and LoRaWAN have both not been fully characterised, particularly in regard to large-scale behaviour. This is partly due to the low feasibility of deploying vast networks. To address this, the first recorded instance of anurban digital twin of 20 devices LoRaWAN network was deployed and analysed. The available simulation models, despite being successfully used in various research studies, are also not fully complete, and a deeper understanding of the technology is required to fix some remaining open issues. To give additional insight into their operation as well as practical improvements that can be carried out to maximise performance, both from a consumer and an industrial standpoint, existing LoRa and LoRaWAN modules for the network simulator NS-3 are enhanced and used throughout the work presented. Scalability and Quality-of-Service improvements are also presented, based on the knowledge gaps found in current LoRaWAN research and the results of the simulations performed. In particular, improvements on PDR up to 10% are reported using novel techniques of downlink independent optimisation, and new insight on the positioning of gateways to achieve maximum scalability in a two-gateways network are also highlighted

Coded LoRa Frame Error Rate Analysis

In this work, we study the coded frame error rate (FER) of LoRa under additive white Gaussian noise (AWGN) and under carrier frequency offset (CFO). To this end, we use existing approximations for the bit error rate (BER) of the LoRa modulation under AWGN and we present a FER analysis that includes the channel coding, interleaving, and Gray mapping of the LoRa physical layer. We also derive the LoRa BER under carrier frequency offset and we present a corresponding FER analysis. We compare the derived frame error rate expressions to Monte Carlo simulations to verify their accuracy

IoT network : design and implementation

Dissertação para obtenção do grau de mestre em Engenharia Eletrónica e de TelecomunicaçõesIn recent years a new concept known in the anglo-saxonic language as IoT (Internet of Things) has gained prominence in the world of technology. IoT's main objective is to allow various types of physical objects, such as cars, houses and cities to transmit the information they obtain autonomously through sensors, to platforms that receive and use them intelligently, forming a network of interconnected objects, without any kind of human intervention. To understand this concept, a study was made of the networks that underlie this concept, LPWA (Low Power Wide Area Networks), and in more detail to LoRa technology. In order to estimate the coverage of this technology, a theoretical planning was performed using the OH model (Okumura-Hata), and based on the results obtained, an electromagnetic simulator (CloudRF), was used, which allowed to estimate in more detail the coverage in the area of study. In order to validate the results obtained theoretically and by simulation, a set of meas-urements was made in the field in some points of the city of Aveiro. From the global analysis of the obtained results, it was concluded that LoRa technology is in fact quite feasible to be used in an implementation of an IoT network in an urban environ-ment. The OH model when adapted with the appropriate coverage margins for the type of study environment allows a good approximation in terms of outdoor coverage. Despite being very sensitive to movements, it was possible to obtain distances up to 2 km in a mostly urban prop-agation environment, and more than 5 km in a more open area with a greater line of sight.Nos últimos anos um novo conceito conhecido na linguagem anglo-saxónica como IoT (In-ternet of Things) ganhou destaque no mundo da tecnologia. A IoT tem como principal objetivo permitir que diversos tipos de objetos físicos, como por exemplo carros, casas e cidades consi-gam transmitir a informação que obtêm de forma autónoma através de sensores, para platafor-mas que as recebem e as utilizam de forma inteligente, moldando assim uma rede de objetos interligados, sem existir qualquer tipo de intervenção humana. Para se perceber este conceito, foi efetuado um estudo às redes que servem de base a este conceito, as redes LPWA (Low Power Wide Area), e em mais detalhe à tecnologia LoRa. De forma a estimar a cobertura desta tecnologia, foi efetuado um planeamento teórico utilizando o modelo de OH (Okumura-Hata), e com base nos resultados obtidos, recorreu-se a um simulador electromagnético, o CloudRF, que permitiu estimar mais em detalhe a cobertura para a zona de Aveiro. De forma a validar os resultados obtidos teoricamente e por simulação, foi efetuado um conjunto de medidas em campo em alguns pontos da cidade de Aveiro. Da análise global de resultados obtidos, concluiu-se que a tecnologia LoRa é de facto bas-tante viável para ser utilizada numa implementação de uma rede IoT num ambiente urbano. O modelo de OH quando adaptado com as margens de cobertura adequadas para o tipo de ambi-ente em estudo permite obter uma boa aproximação em termos de cobertura outdoor. Apesar de ser bastante sensível a movimentações, a tecnologia LoRa através das medidas realizadas permitiu obter coberturas até 2 km num ambiente de propagação maioritariamente urbano, e superiores a 5 km numa área mais aberta e com uma maior linha de vista.N/

Performances et Gestion de l'itinérance dans les réseaux LoRaWAN

LoRaWAN est l’un des principaux protocoles de communication sans fil déployés pour répondre aux exigences des applications IoT (Internet of Things) nécessitant une communication à longue portée avec une faible consommation d’énergie. On compte actuellement plus d’un milliard de dispositifs IoT utilisés dans le monde et LoRaWAN apparaît comme l’une des solutions les plus prometteuses pour de nombreuses applications. Bien que l’étude de ces réseaux, des mécanismes associés et de leurs performances soit un sujet particulièrement brûlant, certains aspects restent peu explorés, notamment la gestion de la mobilité et de l’itinérance (roaming). De même, de nombreux travaux reposent exclusivement sur des approches de simulation pour leur validation ou manquent d’outils et de bancs de test pour conduire des expérimentations réelles. Dans cette thèse, nous proposons d’apporter des solutions `a des problèmes bien connus au sein de la communauté LoRaWAN, notamment l’allocation des paramètres de transmission pour augmenter les performances du réseau. Nous proposons alors L3SFA et L3SFA-TPC pour améliorer le taux de délivrance, la capacité du réseau et la consommation énergétique des terminaux. Par la suite, nous nous sommes concentrés sur des sujets moins explorés. Nous proposons LoRaRoam, le premier système prenant en charge l’itinérance active ou itinérance Handover dans les réseaux LoRaWAN. Face au manque ou `a l’absence d’outils de référence, nous nous sommes attachés au développement de solutions et au déploiement de bancs de test pour la validation des solutions proposées et pour l’analyse de leurs performances à large échelle. Nous avons conçu LoRa Roaming Emulator (LDE), le premier émulateur d’itinérance dédié à l’évaluation des réseaux LoRaWAN itinérant. De plus, nous avons proposé LoRaDL, un framework pour prendre en charge les communications sur la liaison descendante (commandes MAC, trames de données) facilitant ainsi la mise en oeuvre des solutions centrées sur les passerelles (gateway-centric) et l’évaluation des performances de la liaison descendante