Dissertations / Theses on the topic 'Long Range (LoRa) technology'

Les progrès des technologies de communication à faible consommation d’énergie et à faible cout ont révolutionne les applications de télédétection et de surveillance. L’Internet des objets (IoT) a promis la création d’un écosystème d’appareils connectes à travers un large éventail d’applications, telles que les villes intelligentes. A l’heure actuelle, de nombreuses normes et technologies concurrentes tentent de saisir l’IoT, en particulier dans le domaine des technologies de télédétection et de communication. LoRa (Long Range) est l’une de ces technologies qui gagne en popularité et en attraction dans les réseaux de capteurs sans fil (WSN). La possibilité d’établir des communications longue distance avec des nœuds relativement simples, une infrastructure minimale, des besoins en énergie réduits et l’utilisation de bandes ISM sans licence offre un avantage concurrentiel significatif. Bien que la portée de communication dans LoRa puisse dépasser 15 kilomètres en visibilité directe, le débit binaire maximal pouvant être atteint est limite à quelques kilobits par seconde. De plus, lorsqu’une collision se produit dans LoRa, le débit est encore réduit en raison de pertes de trames et de retransmissions. Les travaux de cette thèse traitent le problème des collisions dans LoRa qui peuvent survenir sous une charge importante et qui dégradent les performances du réseau.Premièrement, nous considérons le contexte des communications en liaison montante dans LoRaWAN. Nous étudions le contexte des signaux LoRa en collision synchronisée, ou chaque appareil terminal doit retransmettre toute sa trame en collision après qu’une collision se produit dans LoRa. Ce comportement diminue le débit global et augmente la consommation d’énergie des terminaux et le délai des trames. Pour cette raison, afin d’atténuer les effets néfastes des collisions, nous avons proposé un algorithme de décodage pour résoudre les signaux LoRa en collision synchronisée, dans un trafic réseau sature et confirme. Nous avons remplacé le modèle de retransmission conventionnel de LoRa en un modèle faisant en sorte que les dispositifs terminaux transmettent des bitmaps au lieu de retransmettre des trames entières pour déterminer les symboles corrects de chaque trame en collision. Notre algorithme a pu améliorer significativement le débit global de la couche LoRaWAN MAC à base de LoRa, et diminuer la consommation d’énergie des émetteurs et le délai des trames.Deuxièmement, nous considérons le contexte des communications en liaison descendante dans LoRaWAN. Nous avons remarqué que la liaison descendante dans LoRa est un goulot d’étranglements. Nous avons donc travaillé sur la sélection de la passerelle par le serveur de réseau et son impact sur le débit, la consommation d’énergie et le délai. Nous avons étudié trois types de déploiement de passerelle et nous avons montre que les performances du système dépendent de ce déploiement. Nous avons montré que l’équilibrage du nombre de terminaux par passerelle (également connu sous le nom de charge) améliore le débit par rapport au choix de la passerelle avec la meilleure qualité de signal. En outre, nous avons montré que la combinaison de la charge et de la qualité du signal n’améliore pas davantage le débit. De plus, nous avons montré que le choix de la passerelle avec la meilleure qualité de signal diminue le délai des trames et la consommation d’énergie des terminaux par rapport au choix de la passerelle avec la charge la plus faible<br>The progress in low-energy, low-cost communication technologies have revolutionized remote sensing and monitoring applications. Internet of Things (IoT) has promised an ecosystem of connected devices across a wide range of applications such as in smart cities.Currently, many competing standards and technologies are attempting to seize the IoT, particularly in the area of remote sensing and communication technologies. LoRa (Long Range) is one of those technologies that is gaining popularity and attraction in the Wireless Sensor Networks (WSN) applications. The ability to make long-distance communications with relatively simple nodes, minimal infrastructure, reduced power requirements, and the use of unlicensed ISM bands provides a significant competitive advantage. Although the communication range in LoRa can exceed 15 kilometers in line of sight, the maximum bit rate that can be achieved is limited to few kilobits per second. Additionally, when a collision occurs in LoRa, the throughput is further reduced due to frame losses and retransmissions. The work of this thesis deals with the problem of collisions in LoRa that may occur under heavy load, and which degrade the performance of the network.First, we consider the context for LoRaWAN uplink communications. We study the context of fully synchronized colliding LoRa signals, where each end-device has to retransmit its entire colliding frame after a collision occurs in LoRa. This behavior decreases the overall throughput, and increases the energy consumption of the end-devices, and the delay of the frames. Therefore, in order to mitigate the damaging effects of collisions, we proposed a decoding algorithm to resolve synchronized colliding LoRa signals, in a saturated and confirmed network traffic. We substituted the conventional retransmission model of LoRa by having end-devices transmitting bitmaps instead of retransmitting whole frames to determine the correct symbols of each colliding frame. Our algorithm was able to significantly improve the overall throughput of the LoRaWAN MAC layer based on LoRa, and to decrease the energy consumption of the transmitters and the delay of the frames.Second, we consider the context for LoRaWAN downlink communications. We noticed that the downlink in LoRa is a bottleneck. Hence, we worked on the gateway selection by the network server and its impact on the throughput, the energy consumption and the delay. We studied three types of gateway deployment and we show that the system performance depends on this deployment. We showed that balancing the number of end-devices per gateway (also known as load) improves the throughput compared to choosing the gateway with the highest signal quality. Moreover, we showed that combining load and signal quality does not further improve the throughput. In addition, we showed that choosing the gateway with the highest signal quality decreases the delay and energy consumption compared to choosing the gateway with the lowest load

Greenhouse gas emissions in indoor or outdoor areas are dangerous and can have short- or long-term effects on people’s health. There are several methods to monitor the air quality in such environments. This thesis project attempts to design and evaluate a wireless sensor network with two main characteristics such as long range and low power consumption. The sensor network is built upon Long Range Wide Area Network (LoRaWAN) protocol and is composed of sensor nodes and gateways. The sensor nodes are built upon a Raspberry Pi model 3B, a LoRa SX1276 transceiver and gas sensors. The sensors are intended to measure CO2, CH4, temperature, pressure and relative humidity. The collected data is then logged and sent to The Things Network (TTN) via a backhaul connection.

The thesis is about the construction of a GPS-tracker that can read NFC (Near Field Communication)-tags and communicate with LoRa (Long Range) and BLE (Bluetooth low energy) and investigate which of the components in the GPS-tracker that consumes most power. The usage area for the GPS-tracker is to make the work on disaster affected sites more efficient and secure by having an operation leader that can organizing the operation with help of the information provided by the GPS-trackers that are placed on the injured people and recuing personnel. The GPS-tracker is built around the sensor development kit Thingy:52 from Nordic Semiconductor. The Firmware (FW) for the Thingy:52 is developed by modifying the provided factory FW by Nordic Semiconductor. The GPS-module and the NFC-reader showed to be the most power consuming parts of the GPS-tracker. An energy optimization proposal for these parts are given in the report. A proposal to a circuit diagram for the GPS-tracker is also given in the report, that can be used for future miniaturization of the GPS-tracker.<br>Projektet har innefattat att ta fram en GPS-spårsändare som kan läsa NFC (Near Field Communication)-taggar, kommunicera med LoRa (Long Range) och BLE (Bluetooth low energy) samt undersöka vilka av GPS-spårsändarens olika delar som konsumerar mest energi. Användningsområdet för GPS-spårsändaren är att effektivisera räddningsinsatser på skadeplatser där det finns skadade människor exempelvis efter en översvämning eller terroristattack. Effektiviseringen är tänkt ska ske genom att en operationsledare styr räddningsinsatsen med hjälp av informationen som skickas från GPS-spårsändarna som kommer att bäras av skadade personer och räddningspersonalen på skadeplatsen. GPS-spårsändaren är utvecklad kring sensorutvecklings kittet Thingy:52 från Nordic Semiconductor och dess mjukvara har utvecklats genom att modifiera den mjukvara som Nordic Semiconductor har utvecklat för Thingy:52. De delar av GPS-spårsändaren som visade sig konsumera mest energi var GPS-modulen och NFC-läsaren. I rapporten finns energioptimerings förslag för dessa delar. Rapporten innehåller även ett förslag till ett kretsschema för GPS-spårsändaren som kan användas vid framtida miniatyrisering av GPS-spårsändaren.

The main goal of this thesis is to highlight the various limitations that the LPWAN LoRa and by proxy other similar technologies currently suffers from to give further insight into how these limitations can affect implementations and products using such a network. The thesis will be supported by experiments that test how a LoRa network gets affected by different environmental attributes such as distance, height and surrounding area by measuring the signal strength, signal to noise ratio and any resulting packet loss. The experiments are conducted using a fully deployed LoRa network made up of a gateway and sensor available to the public. To successfully deploy a LoRa network one needs to have concrete information about how to set it up depending on different use cases as battery lifetime and a solid connection has to be kept in mind. We test the various performance aspects of a LoRa network including signal quality and packet loss at different communication ranges. In addition to that we also test different environments and investigate how these can impact the performance. The conclusions made in this thesis are that a LoRa network is limited in its use cases for smaller scale projects with low gateway elevation that still require a large distance. This is due to the obstruction of the signal quickly making it reach unusable levels at roughly 300m in a city and 600m in a forest. Making the line of sight free either by elevation of the hardware or by adapting to the terrain makes the network perform very well making the possibility for packet loss lower which in combination with the low duty cycle of the transmissions is needed as every packet lost is going to be very noticeable.

Mestrado em Engenharia Eletrónica e Telecomunicações<br>Low-Power Wide Area Networks (LPWANs) are one set of technologies that are growing in the eld of the Internet of Things (IoT). Due to the long range capabilities and low energy consumption, Low-Power Wide Area Networks (LPWANs) are the ideal technologies to send small data occasionally. With their unique characteristics, LPWANs can be used in many applications and in di erent environments such as urban, rural and even indoor. The work developed in this dissertation presents a study on the LPWAN LoRa technology, by testing and evaluate its range, signal quality properties and its performance in delivering data. For this, three distinct scenarios are proposed and tested. The inclusion of LoRa in a multi-technology data gathering platform is the key objective of this dissertation. For this it is proposed: (1) an organization based in clusters of sensor nodes; (2) a Media Access Control (MAC) protocol to provide e cient communications through the LoRa technology; and nally, (3) a Connection Manager that is capable of managing the di erent available technologies in the sensor nodes and that is able to adapt its actions according to the acquired data type is proposed. The performed tests aim to perceive which type of parameters can in uence the performance of the overall proposed solution, as well as the advantages of a multi-technology approach in a data gathering platform.<br>Low-Power Wide Area Networks (LPWANs) são um conjunto de tecnologias em crescimento na área da Internet of Things (IoT). Devido ás suas capacidades de comunicar a longo alcance e de baixo consumo energético, as LPWANs apresentam-se como a tecnologia ideal para o envio ocasional de pequenas porções de dados. Ao possuírem características únicas, as LPWANs podem ser usadas em diversas aplicações e em diferentes ambientes, sejam eles urbanos, rurais ou interiores. O trabalho desenvolvido nesta dissertação apresenta um estudo acerca da tecnologia Long Range (LoRa), uma LPWAN, testando e avaliando o seu alcance, a qualidade do sinal e o desempenho na entrega de dados. Para isso, três cenários distintos são propostos e testados. A inclusão de LoRa numa plataforma de aquisição de dados com múltiplas tecnologias e um dos objectivos chave desta dissertação. Para isso, são propostas: (1) uma organização baseada em clusters de sensores; (2) um protocolo de controlo de acesso ao meio (MAC) para permitir que as comunicações através de LoRa sejam eficientes; e finalmente, (3) um gestor de conectividade com capacidade de gerir as diferentes tecnologias disponíveis nos sensores e que seja capaz de agir consoante o tipo de dados adquiridos. Os testes efectuados tem como objectivo perceber que tipo de parâmetros podem influenciar o desempenho global da soluçao proposta, bem como as vantagens de usar uma abordagem baseada em múltiplas tecnologias numa plataforma de aquisição de dados.

Dagens smarta enheter bygger nuförtiden allt mer på att ständigt hålla sig uppkopplade till allt inom dess omgivning. Industrier och hem innehåller alltmer små batteridrivna sensorer samt enheter som kommunicerar med varandra, dock är detta en begränsning när det gäller räckvidden av en enhet. Målet med denna uppsatsen är att undersöka användarbarhet av nya funktioner inom Bluetooth, samt belysa fördelar och nackdelar vilket kan uppstå med respektive teknologi när det gäller förlängd räckvidd. Vidare utfördes en jämförelsestudie, med målet att framföra skillnader för hur Bluetooth Mesh skiljer sig gentemot de andra Mesh teknologierna.Resultatet av denna uppsatsen visar att Bluetooth Mesh och Long-range har diverse svagheter och styrkor när det gäller olika användningsområden. Överföring av data med en högre hastighet och ett måttligt avstånd skulle vara tillräckligt för Long-range, medan Bluetooth Mesh anpassar sig mer för en större täckning och lättare dataöverföringar.<br>The smart devices of today are more and more dependent on being constantly connected to everything in its surrounding. Industries and homes contain more and more small battery powered sensors and devices, communicating with each other. However, there is a limitation when it comes to the range coverage of a device. The purpose of this thesis is to investigate the usefulness of the new features mesh networking and extended range for Bluetooth, as well as highlight the pros and cons that may exist with respective extended range technologies. Furthermore, a theoretical comparative study was conducted, with the aim of presenting some of the differences between Bluetooth Mesh and other common Mesh technologies. The results show that both Bluetooth Mesh and Long-range have strengths and weaknesses when it comes to different use cases. Transferring data with a bit higher throughput and a moderate distance would be suitable for a Long-range purpose, while Bluetooth Mesh is more suitable for a larger coverage and lighter data transfer.

Thesis (M.S. in Modeling, Virtual Environments and Simulation (MOVES))--Naval Postgraduate School, September 2008.<br>Thesis Advisor(s): Brutzman, Don. "September 2008." Description based on title screen as viewed on November 10, 2008. Includes bibliographical references (p. 95-96). Also available in print.

Every year, certain animal and insect species flock together to make long-range migrations to reach their feeding or breeding grounds. A number of interesting observations can be made regarding this phenomenon. First, individuals tend to create large flocks, which can include millions of individuals in fishes, for these migrations. Second, migrations typically cover long distances. Third, despite all kinds of disturbances affecting the individuals during these migrations, the flocks can reach the very same breeding or feeding grounds with remarkable accuracy. Biological studies indicated that these animals mainly use the magnetic field of earth (among many other environmental cues) to determine the direction of their travel. It was also claimed that migrating in flocks has been the key factor behind the accuracy of reaching the same grounds at the end of the migration. In this thesis, we take a constructivist approach towards investigating the effects of flocking in long-range travels using a swarm of physical and simulated mobile robots. Specifically, we extend a self-organized flocking behavior that was developed by Turgut et al. (2008) that allows the long-range migration of a robotic swarm in space using the magnetic field of the earth. Using this behavior, we analyze how the accuracy of the robotic swarm reaching a particular &quot<br>breeding ground&quot<br>is affected by four factors<br>namely, (1) averaging through the heading alignment, (2) noise in sensing the homing direction, (3) differences in the characteristics of the individuals, and (4) disturbances caused by the proximal interactions of the robots during flocking. Through systematic experiments with physical and simulated robots, we analyze how these factors affect the accuracy along with the flock size and different sources of noise.

Att detektera ljudnivå ger mycket information i stadsområde såsom bullernivå, antal skottlossningar, antal kollisioner och detekterar plats på en ljudkälla. I detta projekt monteras en ljuddetektor som kommunicera via LoRa Long Range när ljudet överstiger ett tröskelvärde. Ljuddetektorn implementeras som en fristående modul bestående av tre befintliga moduler. Modulerna som används i projektet innefattar: Lopy4 med Expansionskort 3.1, GPS modul och Ljud sensor  Ljudnivån, batterinivå, koordinater, datum och tid överförs via LoRa-nät till en gateway och vidare till The Thing of Network, TTN websidan och samtidigt sparas data lokalt i ett SD minneskort när ljudet överstiger ett tröskelvärde. Tröskelvärdet kan modifieras efter användarens önskningar.<br>Detecting noise levels explains a lot in urban areas such as noise levels, number of shots, and number of collisions. In this project, a sound detector is installed that communicates via LoRa, Long Range when the sound exceeds a threshold value. The sound detector is implemented as a stand-alone module consisting of three existing modules. The modules used in the project include Lopy4 with Expansion Card 3.1, GPS module, and Sound sensor. The sound level, battery level, coordinates, date, and time are transferred via LoRa to a gateway and on to The Thing of Network, TTN website, and at the same time data is saved locally in an SD memory card when the sound exceeds a threshold. The threshold can be modified according to the user's wishes.

Cette thèse s'inscrit dans le contexte de l'Internet des Objets (Internet of Things, IoT), de l'identification et de la traçabilité d'objets dans des environnements dits complexes, réalisées au moyen de la technologie ULB (Ultra-Large Bande) dite de haute précision temporelle. L'ambition est de contribuer à l'évolution des systèmes ULB de localisation en temps réel par la conception et l'optimisation d'antennes ULB qui soient reconfigurables, multistandards et multifonctionnelles. Ainsi, tout système de localisation intégrant des antennes optimisées sera doté d'une qualité de localisation meilleure et de fonctions nouvelles.Les contributions principales développées dans cette thèse ont consisté en l'apport d'améliorations aux systèmes de localisation en temps réel (RTLS) basé sur la technologie ULB : conception et fabrication d'antennes ULB reconfigurables en fréquence ; conception et fabrication d'une carte électronique de localisation multistandards (ULB et Long Range - LoRa) ; étude expérimentale des systèmes RTLS intégrant les antennes conçues et validation de l'évolution de la localisation en termes de portées supérieures, de détectabilité d'objets sans connaissance préalable de leurs orientations, et en précision améliorée par l'atténuation de signaux multi-trajets<br>This thesis is part of the concept of the Internet of Things (IoT), object identification, and traceability in so-called complex environments through Ultra-Wide Band (UWB) technology known for its high temporal precision. The objective is to contribute to the advancement of real-time UWB-based localization systems through the design and optimization of UWB antennas that are reconfigurable, multi-standards, and multi-functions. Therefore, any localization system integrating the optimized antennas will have improved localization quality and new functionalities.The main contributions developed in this thesis involve enhancements to real-time localization systems (RTLS) based on UWB technology: design and fabrication of frequency reconfigurable UWB antennas; design and fabrication of a multi-standard localization electronic board (UWB and Long Range - LoRa); experimental study of RTLS systems incorporating the designed antennas and validation of the evolution of the localization in terms of extended reading ranges, detectability of objects without prior knowledge of their orientations, and improved location accuracy through the attenuation of multi-path signals

As applications like IPTV and VoD (Video on demand) are gaining popularity, it is becoming more important to study the behavior of video signals in the Internet access infrastructures such as ADSL and cable networks. Average delay, average jitter and packet loss in these networks affect the quality of service, hence transmission and access speeds need to be determined such that these parameters are minimized. In this study the behavior of the above mentioned IP networks under variable bit rate (VBR) video traffic is investigated. ns-2 simulator is used for this purpose and actual as well as artificially generated signals are applied to the networks under test. Variable bit rate (VBR) traffic is generated synthetically using ON/OFF sources with ON/OFF times taken from exponential or Pareto distributions. As VBR video shows long range dependence with a Hurst parameter between 0.5 and 1, this parameter was used as a metric to measure the accuracy of the synthetic sources. Two different topologies were simulated in this study: one similar to ADSL access networks and the other behaving like cable distribution network. The performance of the networks (delay, jitter and packet loss) under VBR video traffic and different access speeds were measured. According to the obtained results, minimum access speeds in order achieve acceptable quality video delivery to the customers were suggested.

La presente Tesi è focalizzata sulla valutazione e la modellazione delle Wireless Sensor Network a basso consumo. Il primo argomento ha riguardato la progettazione di un sistema di sensori indossabili, le scarpe intelligenti, connesse tramite Bluetooth Low Energy (BLE) ad uno smartphone in una classica rete a stella. Si è dimostrata l'appropriatezza del protocollo BLE per applicazioni come questa, in cui è richiesto basso throughput, ma affidabilità del dato. Il secondo lavoro ha riguardato lo studio della procedura di scansione, implementata dal BLE per la ricerca dei nodi nelle vicinanze o per la comunicazione dei dati senza connessione. Si è quindi sviluppato un modello deterministico del protocollo di scansione (Periodic-Random-Access-to-Link-Layer – PRALL), dimostratosi coerente con i dati del simulatore. E’ stata, inoltre, implementata una modifica al PRALL, che lo rende performante in termini di abbassamento dei massimi di latenza. Il terzo argomento ha inquadrato il BLE in uno scenario in cui dispositivi in connessione e senza connessione devono coesistere, comunicando con un nodo centrale condiviso. Si è, quindi, modellato l’accesso al mezzo del nodo centrale, ottenendo un valido strumento per la fase di progettazione delle reti miste BLE. Il quarto e ultimo argomento ha analizzato l'adozione del paradigma di comunicazione data-centrico del protocollo MQTT (Message Queue Telemetry Transport). In una prima applicazione per ambienti assistivi (Ambient Assisted Living - AAL) è stata valutata la sua integrazione a vari livelli dell'architettura, come gateway verso Internet o integrato nativamente sui sensori. Nella seconda applicazione per l’automazione degli edifici, la struttura dei dati del protocollo MQTT è stata integrata per la comunicazione su mezzo fisico LoRa. Le campagne di misura realizzate hanno dimostrato che LoRa è in grado di assicurare un'adeguata copertura di segnale negli scenari indoor, compresi i grandi edifici.<br>This Thesis is mainly focused on the low-power WSN communication modeling. The first goal has been to model and properly design the BLE in a scenario characterized by low throughput, but strict reliability requirement. The result of this activity has been the development of smart shoes connected via BLE to a smartphone, forming a classic star-topology. This study has shown that BLE fulfills the requirements, opening the way to further investigations on power management analysis. The second work has dealt with the neighbour discovery procedure, implemented by BLE, and has modeled the energy-efficiency of the Periodic-Random-Access-to-Link-Layer (PRALL) protocol, that is modeled through a deterministic approach. The comparison with the simulation results, has shown the developed model has the capability to evaluate the discovery-latency for the most of parameterizations. These considerations have led to the development of a modified version of PRALL that improves its performance. The third work has been aimed at the characterization of the medium access of the central node, which has to schedule both connection -less and oriented communication. The developed models are merged into a single tool, intended to properly design device parameters. In the fourth and last topic, the adoption of data-centric communication paradigm by the MQTT protocol, has been investigated, firstly, in an AAL scenario and, secondly, in a building automation context. In the first work the power consumption estimation for several designed configurations, has shown that MQTT may be effectively adopted for a quick and reliable distribution of notification messages among the different actors involved by the platform. In the second work, the MQTT data-structure has been adopted over LoRa physical communication link to support real-time building automation services. Extensive measurement campaigns have proved that LoRa is well suited to ensure adequate radio coverage even in big and bulky buildings.

I requisiti di molte applicazioni IoT necessitano di trasmettere dati su lunghe distanze, con basso data rate e con il minor impatto possibile sul consumo energetico. Le tecnologie LPWAN (Low Power Wide Area Network) sono state progettate per complementare ed in alcuni casi sostituire le soluzioni offerte dalla reti cellulari e dalle reti di sensori a corto/medio raggio. Nonostante la pletora di standards LPWAN disponibili sul mercato, la tecnologia LoRa/LoRaWAN sta riscuotendo notevole successo grazie alle performance che riesce a garantire. L’imponente mole di dati generata dalle applicazioni IoT richiede soluzioni in grado di poter archiviare e gestire in maniera efficiente il ciclo di vita delle informazioni. L’utilizzo di piattaforme di data analytics basate su sistemi NoSQL permettono una gestione più agile dei Big Data. In questa tesi è stata progettata ed implementata un’infrastruttura per il monitoraggio ambientale tramite LoRaWAN e la relativa piattaforma di data analytics adoperata per lo studio delle metriche relative alla trasmissione radio LoRa. I risultati ottenuti dalla sperimentazione possono essere usati per fare tuning delle configurazioni per il deploy in contesti reali.

Post-Cold War military conflicts have highlighted the need for a flexible, agile joint force responsive to emerging crises around the globe. The 2005 Joint Capabilities Integration and Development System (JCIDS) acquisition policy document mandates a shift away from stove-piped threat-based acquisition to a capability-based model focused on the multiple ways and means of achieving an effect. This shift requires a greater emphasis on scenarios, tactics, and operational concepts during the conceptual phase of design and structured processes for technology evaluation to support this transition are lacking. In this work, a methodology for quantitative technology evaluation for systems-of-systems is defined. Physics-based models of an aircraft system are exercised within a hierarchical, object-oriented constructive simulation to quantify technology potential in the context of a relevant scenario. A major technical challenge to this approach is the lack of resources to support real-time human-in-the-loop tactical decision making and technology analysis. An approach that uses intelligent agents to create a "Meta-General" capable of forecasting strategic and tactical decisions based on technology inputs is used. To demonstrate the synergy between new technologies and tactics, surrogate models are utilized to provide intelligence to individual agents within the framework and develop a set of tactics that appropriately exploit new technologies. To address the long run-times associated with constructive military simulations, neural network surrogate models are implemented around the forecasting environment to enable rapid trade studies. Probabilistic techniques are used to quantify uncertainty and richly populate the design space with technology-infused alternatives. Since a large amount of data is produced in the analysis of systems-of-systems, dynamic, interactive visualization techniques are used to enable "what-if" games on assumptions, systems, technologies, tactics, and evolving threats. The methodology developed in this dissertation is applied to a notional Long Range Strike air vehicle and system architecture in the context of quantitative technology evaluation for the United States Air Force.

碩士<br>國立中正大學<br>通訊工程研究所<br>106<br>Numerous types of IoT application emerge rapidly nowadays, such as indoor positioning, industrial equipment monitoring and human body movement monitoring. The requirements of these IoT sensors for different applications are diverse. For instance, an IoT system monitoring a large-scale area needs to emphasize the transmission range of the wireless sensors; battery-powered wireless sensors need to reduce the energy consumption; multiple sensors also may need to address accurate time synchronization. For the IoT which requiring low-power, long-distance and accurate time synchronization, no single existing wireless technology can meet all these requirements. By taking the advantage of low-power 2.4 GHz RF and long-distance LoRa technology, this study proposed a new design to achieve these goals without comprising the need of time synchronization. In this work, we develop a special router with dual RF interfaces, which can reduce the energy consumption of the wireless sensor nodes while also extend the communication range at the same time. The proposed design also enabling the wireless sensors can be time synchronized in the order of sub-microseconds, which resolve the issue of the conventional Bluetooth Low Energy (BLE) is difficult to perform very accurate time synchronization over multiple wireless sensors. The proposed design allowing the battery-powered wireless sensor extending its sleep duration to at-most four minutes for saving valuable energy. By comparing to BLE the proposed design the wireless sensors can reduce the radio receiving time for 86%. The field experiment was conducted in a real factory to monitoring machine tools with 30 wireless sensors. The performance of communication distance, power consumption and time synchronization accuracy was evaluated to demonstrate the correctness of this design.

Nowadays there is a profusion of effort to analyses and finding new solutions related to multiple sensor networks used for IoT applications. Using LoRa (long range) transceiver it is easy to communicate with hundreds of sensors in the long range that is 2km for NLOS and 21km for LOS. And we can control these sensors using IoT technology in the smart way. Modulation techniques used in LoRa transceiver are OOK, FSK, GFSK, MSK, GMSK. It entitles the long-range transfer of information with a low power consumption. This project presents a review of the challenges and the obstacles of IoT concept with emphasis on the long-range wireless communication technology. LoRa uses license free Gigahertz radio frequency bands like 433 MHz, 868 MHz and 915MHz. LoRa enables very long-range transmission in village areas with low power consumption. The technology is presented in two layers, which are physical layer (LoRa) and upper layer (LoRaWAN). A LoRa WAN network (Long Range Network Protocol) is of the Low Power Wide Area Network (LPWAN) type and a battery powered device that ensure bidirectional communication. Communication with the LoRa transceiver module is done via SPI protocol, serial peripheral interfaces used to send data between microcontrollers for connecting with one or more peripheral devices. Using SPI connection, we control the peripheral devices such as shift registers, sensors.

碩士<br>國立交通大學<br>環境工程系所<br>105<br>Water supply system in Nankan is a mix of purified water and desalinated water. The quality of tap water is affected by the mixing ratio of purified water and desalinated water. When the equipment of the desalination plant is improperly operated or failed, the conductivity of tap water often increases sharply. However, there is no real-time water quality monitoring system to alarm in water supply system. In addition, there have other problem is that the wireless communication system at water purification plant is General Packet Radio Service (GPRS), and National Communication Committee announced 2G spectrum to be withdrawn in June 30, 2017. They affect the operation of the monitoring system. This study aimed to use the Long-Range wireless communication system to establish a real-time water quality monitoring system in outlying islands. The real-time water quality monitoring system was divided into four parts, including sensor, uploader, wireless communication modules, and server. Because the signal generated by the conductivity probe could not be transmitted by Long-Range wireless communication module, the signal was converted by the evaluation board to the data format, which could be transmitted to uploader. The data that was integrated by the evaluation board and Long-Range wireless communication module was classified by program into data, time, and value. The server saved the data to the database and generated display interface. The real-time water quality monitoring system was set in water purification plant in Nangan Township, Lianjiang County, and the stability and feasibility of the system are tested and evaluated. In the indoor signal transmission stability testing, data transmission loss rate of Long-Range wireless communication module was less than 5%, and data transmission loss rate of the real-time water quality monitoring system was less than 5%. The result has shown that Long-Range wireless communication module is feasible to the real-time water quality monitoring practice, and available to combine other water quality sensor probe in the system.

LoRa technology has recently gained popularity, attesting itself as one of the most promising and widely adopted Low Power Wide Area Networks (LPWANs). Highly compatible with Internet of Things (IoT) applications and urban environments, this technology enables large range communications although with low data-rates and duty-cycle restrictions. The work developed in this dissertation targets the medium access in LoRa, focusing on its performance in delivering data, especially in large-scale networks. To do so, it is proposed: (1) a probabilistic packet collision model that estimates the success delivery of two or more LoRa concurrent transmissions, based on an exhaustive evaluation of the packet capture effect; (2) an adaptation of LoRa’s state of the art Medium Access Control (MAC) protocol, LoRaWAN, through the use of control packets; and lastly, (3) a new MAC protocol, denoted as LoRa Mode Adaptive Protocol (LoRa-MAP), that manages to maintain the best possible connection between end-nodes and the gateway by changing LoRa’s physical layer parameters. An analysis on different medium access schemes is conducted, aiming to perceive how different parameters and network layouts influence the information exchange process. The performed evaluations, that consider the results obtained from the real capture effect characterization, showed that the proposed MAC solution increases the LoRa network scalability, deeming it a great candidate for IoT environments.<br>A tecnologia Long Range (LoRa) tem vindo a ganhar bastante popularidade, tornando-se numa das tecnologias mais promissoras e frequentemente utilizadas entre as Low Power Wide Area Networks (LPWANs). Altamente compatível com aplicações da Internet of Things (IoT), LoRa permite comunicações de longo alcance, ainda que com baixas taxas de transmissão e restrições de duty-cycle. O trabalho desenvolvido ao longo desta dissertação tem como alvo o acesso ao meio em redes LoRa, focando-se especialmente no seu desempenho em termos de entrega de dados em redes de larga escala. Para isto, são propostos: (1) um modelo probabilístico de colisões que estima a probabilidade de sucesso de duas ou mais transmissões simultâneas, com base numa avaliação exaustiva do efeito de captura da tecnologia LoRa; (2) uma adaptação ao protocolo de acesso ao meio LoRaWAN, através da inclusão de pacotes de controlo; e por fim, (3) um novo protocolo de acesso ao meio, denominado LoRa Mode Adaptive Protocol (LoRa-MAP), que permite manter a melhor ligação possível entre os dispositivos e o ponto de acesso ao variar os parâmetros de camada física do LoRa. E realizada uma análise aos diferentes mecanismos de acesso ao meio, de ´ forma a compreender como diferentes parâmetros e disposições de rede influenciam o processo de troca de informação. A avaliação realizada, que considera os resultados obtidos com a caracterização do efeito de captura, mostra que a solução proposta contribui para aumentar a escalabilidade das redes LoRa, tornando-a numa excelente candidata para ambientes IoT.<br>Mestrado em Engenharia Eletrónica e Telecomunicações

During the past years, there has been an increasing interest in the exploration of underwater wireless communications. This interest has been related mainly to the need for establishing a reliable way of transferring large amounts of data gathered on remote locations in the ocean. This data comes from environmental exploration, oil and gas industries, or marine data from Autonomous Underwater Vehicles (AUVs). These activities require innovative solutions that can provide high bitrates at low costs. With this in mind, and given the current solutions - Optical, Acoustic, and Radio Frequency -, there is the need to create a solution that takes advantage of each technology and overcomes their limitations. In the case of optical communications, they can provide high bitrates, but requires line of sight, and depend significantly on water turbidity. Although acoustic solutions can provide a large range of operation, they have a low bandwidth due to the frequency of operation, and so they are not suitable for transferring high amounts of data. Finally, current radio frequency (RF) solutions allow high bit rates but are limited by the operation range due to the substantial attenuation of electromagnetic waves underwater. With this in mind, it is possible to say that currently, there is no solution for broadband long-range underwater communications. This dissertation aims to develop a solution that allows the increase of throughput and range of underwater wireless communications. To achieve this, a set of underwater data mules will be used. They will take advantage of the high bitrates of RF wireless communications and the long-range associated with acoustic solutions. With this dissertation, communication protocols designed for delay and disruption tolerant networks (DTNs) will be explored, and a protocol that will enable the scheduling of mules will be proposed and implemented, taking advantage of an out-of-band acoustic channel for controlling the mules, and the DTN for data transfer. The solution will be evaluated in a freshwater testbed.

During the past years, there has been an increasing interest in the exploration of underwater wireless communications. This interest has been related mainly to the need for establishing a reliable way of transferring large amounts of data gathered on remote locations in the ocean. This data comes from environmental exploration, oil and gas industries, or marine data from Autonomous Underwater Vehicles (AUVs). These activities require innovative solutions that can provide high bitrates at low costs. With this in mind, and given the current solutions - Optical, Acoustic, and Radio Frequency -, there is the need to create a solution that takes advantage of each technology and overcomes their limitations. In the case of optical communications, they can provide high bitrates, but requires line of sight, and depend significantly on water turbidity. Although acoustic solutions can provide a large range of operation, they have a low bandwidth due to the frequency of operation, and so they are not suitable for transferring high amounts of data. Finally, current radio frequency (RF) solutions allow high bit rates but are limited by the operation range due to the substantial attenuation of electromagnetic waves underwater. With this in mind, it is possible to say that currently, there is no solution for broadband long-range underwater communications. This dissertation aims to develop a solution that allows the increase of throughput and range of underwater wireless communications. To achieve this, a set of underwater data mules will be used. They will take advantage of the high bitrates of RF wireless communications and the long-range associated with acoustic solutions. With this dissertation, communication protocols designed for delay and disruption tolerant networks (DTNs) will be explored, and a protocol that will enable the scheduling of mules will be proposed and implemented, taking advantage of an out-of-band acoustic channel for controlling the mules, and the DTN for data transfer. The solution will be evaluated in a freshwater testbed.

Over the past three decades, agricultural machinery has made the transition from purely mechanical systems to hybrid machines, reliant on both mechanical and electronic systems. A this transformation continues, the most modern agricultural machinery uses networked systems that require a network connection to function to their full potential. In rural areas, providing this network connection has proven difficult. Obstacles, distance from access points, and incomplete coverage of cellular connection are all challenges to be overcome. “Off the shelf” commercial-grade Wi-Fi equipment, including many products from Ubiquiti like the Bullet M2 transceiver and the PowerBeam point-to-point linking system, as well as antennas by Terrawave, Crane, and Hawking, were installed in a purpose-built system which could be implemented on a production farm. This system consisted of a tower-mounted access point which used an antenna with a 65^o beamwidth, and the test included distances up to 1150 meters in an agricultural setting with corn and soybeans. Some sensors were stationary and the other platform was a tractor following a path around the farm with both 8dBi and 15dBi gain antennas. Through all tests, throughput never dropped below 5 Mb/s, and the latency of successful connections never exceeded 20ms. Packets were rarely dropped and never accounted for a significant portion of all packet transmission attempts. Environmental effects like immediate precipitation, crop heights, recent rainfall, and ambient temperature had little or no effect on wireless network characteristics. As a result, it was proven that as long as line-of-sight was maintained, reliable wireless connectivity could be achieved despite varying conditions using microwave radiation. Network throughput was marginally affected by the change in free space path loss due to increased distance between the access point and the client, as well as travel by the mobile client outside the beamwidth of the access point. By enabling this coverage, it is hoped that the implementation of new agricultural technology utilizing a live network connection will progress more rapidly.

The underwater communications are essential for the operation and collect large amounts of data (video and images) obtained by Autonomous Underwater Vehicles (AUVs) and remotely controlled underwater vehicles (ROVs) in inspection and monitoring missions at sea. Acoustic waves, despite the high range, allow only narrowband communications, which prevents quick and effective transfer of data. On the other hand, aquatic environment, in particular salt water, severely limits the scope of networks based on electromagnetic waves, having such a range of radius of a few meters. This thesis aims to study and evaluate the use of small vehicles (underwater drones - date mules) capable of transporting data across networks with tolerance to delay (Delay-Tolerant Networks - DTN) between a transmitter and an underwater receiver, taking advantage of high transfer rates at close range. The student must implement a file transfer application that can tolerate high delays in the delivery of information packages. The application will be tested in the underwater environment using the large tank available at INESC TEC and tight cylinder, and compared with simulation results for this scenario. 163/5000 This thesis also presupposes the elaboration of a scientific article for publication in a conference or magazine to disseminate the relevant results of the work.<br>As comunicações subaquáticas são essenciais para a operação e recolha de grandes quantidades de dados (vídeo e imagens) obtidas por Veículos Autónomos Subaquáticos (AUVs) e por veículos subaquáticos controlados remotamente (ROVs) em missões de inspeção e monitorização no mar. As ondas acústicas, apesar do elevado alcance, permitem apenas comunicações de banda estreita, o que inviabiliza a transferência desses dados de forma rápida e eficiente. Por outro lado, o meio aquático, em especial a água salgada, limita severamente o alcance das redes baseadas em ondas eletromagnéticas, tendo estas um raio de alcance de apenas alguns metros. Nesta tese pretende-se estudar e avaliar a utilização de pequenos veículos (drones subaquáticos - data mules) capazes de transportar dados através de redes tolerantes ao atraso (Delay-Tolerant Networks - DTN) entre um emissor e um recetor subaquático, tirando partido das elevadas taxas de transferência a curto alcance. O estudante deverá implementar uma aplicação de transferência de ficheiros capaz de tolerar elevados atrasos na entrega de pacotes de informação. A aplicação será testada em ambiente subaquático recorrendo ao tanque de grandes dimensões disponível no INESC TEC e a cilindros estanques, e comparada com resultados de simulação para esse cenário. Esta tese pressupõe também a elaboração de um artigo científico para publicação em conferência ou revista para disseminação dos resultados relevantes do trabalho.

The underwater communications are essential for the operation and collect large amounts of data (video and images) obtained by Autonomous Underwater Vehicles (AUVs) and remotely controlled underwater vehicles (ROVs) in inspection and monitoring missions at sea. Acoustic waves, despite the high range, allow only narrowband communications, which prevents quick and effective transfer of data. On the other hand, aquatic environment, in particular salt water, severely limits the scope of networks based on electromagnetic waves, having such a range of radius of a few meters. This thesis aims to study and evaluate the use of small vehicles (underwater drones - date mules) capable of transporting data across networks with tolerance to delay (Delay-Tolerant Networks - DTN) between a transmitter and an underwater receiver, taking advantage of high transfer rates at close range. The student must implement a file transfer application that can tolerate high delays in the delivery of information packages. The application will be tested in the underwater environment using the large tank available at INESC TEC and tight cylinder, and compared with simulation results for this scenario. 163/5000 This thesis also presupposes the elaboration of a scientific article for publication in a conference or magazine to disseminate the relevant results of the work.<br>As comunicações subaquáticas são essenciais para a operação e recolha de grandes quantidades de dados (vídeo e imagens) obtidas por Veículos Autónomos Subaquáticos (AUVs) e por veículos subaquáticos controlados remotamente (ROVs) em missões de inspeção e monitorização no mar. As ondas acústicas, apesar do elevado alcance, permitem apenas comunicações de banda estreita, o que inviabiliza a transferência desses dados de forma rápida e eficiente. Por outro lado, o meio aquático, em especial a água salgada, limita severamente o alcance das redes baseadas em ondas eletromagnéticas, tendo estas um raio de alcance de apenas alguns metros. Nesta tese pretende-se estudar e avaliar a utilização de pequenos veículos (drones subaquáticos - data mules) capazes de transportar dados através de redes tolerantes ao atraso (Delay-Tolerant Networks - DTN) entre um emissor e um recetor subaquático, tirando partido das elevadas taxas de transferência a curto alcance. O estudante deverá implementar uma aplicação de transferência de ficheiros capaz de tolerar elevados atrasos na entrega de pacotes de informação. A aplicação será testada em ambiente subaquático recorrendo ao tanque de grandes dimensões disponível no INESC TEC e a cilindros estanques, e comparada com resultados de simulação para esse cenário. Esta tese pressupõe também a elaboração de um artigo científico para publicação em conferência ou revista para disseminação dos resultados relevantes do trabalho.