Dissertations / Theses on the topic 'IoT and mobile networks'

The IoT refers to the idea of internetworking physical devices, vehicles, buildings, and any other item embedded with the appropriate electronics, software, sensors, actuators, and network connectivity to allows them to interchange data and to provide highly effective new services. In this thesis we focus on the communications issues of the IoT in relation to mobility and we provide different solutions to alleviate the impact of these potential problems and to guarantee the information delivery in mobile scenarios. Our reference context is a Smart City where various mobile devices collaboratively participate, periodically sending information from their sensors. We assume that these services are located in platforms based in cloud infrastructures where the information is protected through the use of virtualisation ensuring their security and privacy. This thesis is structured into seven chapters. We first detail our objectives and identify the current problems we intend to address. Next, we provide a thorough review of the state of the art of all the areas involved in our work, highlighting how we improved the existing solutions with our research. The overall approach of the solutions we propose in this thesis use prototypes that encompasses and integrates different technologies and standards in a small infrastructure, using real devices in real scenarios with two of the most commonly used networks around the world: WiFi and 802.15.4 to efficiently solve the problems we originally identified. We focussed on protocols based on a producer/consumer paradigm, namely AMQP and particularly MQTT. We observed the behaviour of these protocols using in lab experiments and in external environments, using a mesh wireless network as the backbone network. Various issues raised by mobility were taken into consideration, and thus, we repeated the tests with different messages sizes and different inter-message periodicity, in order to model different possible applications. We also present a model for dimensioning the number of sources for mobile nodes and calculating the number of buffers required in the mobile node as a function of the number of sources and the size of the messages. We included a mechanism for avoiding data loss based on intermediate buffering adapted to the MQTT protocol that, in conjunction with the use of an alternative to the Network Manager in certain contexts, improves the connection establishment for wireless mobile clients. We also performed a detailed study of the jitter behaviour of a mobile node when transmitting messages with this proposal while moving through a real outdoor scenario. To emulate simple IoT networks we used the Cooja simulator to study and determine the effects on the probability of delivering messages when both publishers and subscribers were added to different scenarios. Finally we present an approach that combines the MQTT protocol with DTN which we specifically designed for constrained environments and guarantees that important information will never be lost. The advantage of our proposed solutions is that they make an IoT system more resilient to changes in the point of attachment of the mobile devices in an IoT network without requiring IoT application & service developers to explicitly consider this issue. Moreover, our solutions do not require additional support from the network through protocols such as MobileIP or LISP. We close the thesis by providing some conclusions, and identifying future lines of work which we unable to address here.<br>Internet de las cosas (IoT) se refiere a la idea de interconectar sensores, actuadores, dispositivos físicos, vehículos, edificios y cualquier elemento dotado de la electrónica, así como del software y de la conectividad de red que los hace capaces de intercambiar datos para proporcionar servicios altamente efectivos. En esta tesis nos centramos en temas relacionados con la comunicación de sistemas IoT, específicamente en situaciones de movilidad y en los problemas que esto conlleva. Con este fin ofrecemos diferentes soluciones que alivian su impacto y garantizan la entrega de información en estas situaciones. El contexto de referencia es una ciudad inteligente donde varios dispositivos móviles participan de forma colaborativa enviando periódicamente información desde sus sensores hacia servicios ubicados en plataformas en la nube (cloud computing) donde mediante el uso de virtualización, la información está protegida garantizando su seguridad y privacidad. Las soluciones propuestas en esta tesis se enfocan en probar sobre una pequeña infraestructura un prototipo que abarca e integra diferentes tecnologías y estándares para resolver eficientemente los problemas previamente identificados. Hemos enfocado nuestro esfuerzo en el uso de dispositivos sobre escenarios reales con dos de las redes más extendidas en todo el mundo: WiFi y enlaces 802.15.4. Nos enfocamos en protocolos que ofrecen el paradigma productor/consumidor como el protocolo avanzado de colas de mensajes (AMQP) y particularmente el protocolo de transporte de mensajes telemétricos (MQTT), observamos su comportamiento a través de experimentos en laboratorio y en pruebas al aire libre, repitiendo las pruebas con diferentes tamaños de mensajes y diferente periodicidad entre mensajes. Para modelar las diferentes posibles aplicaciones de la propuesta, se tomaron en consideración varias cuestiones planteadas por la movilidad, resultando en un modelo para dimensionar eficientemente el número de fuentes para un nodo móvil y para calcular el tamaño requerido del buffer, en función del número de fuentes y del tamaño de los mensajes. Proponemos un mecanismo adaptado al protocolo MQTT que evita la pérdida de datos en clientes móviles, basado en un buffer intermedio entre la producción y publicación de mensajes que, en conjunto con el uso de una alternativa al gestor de conexiones inalámbricas "Network Manager", en ciertos contextos mejora el establecimiento de las conexiones. Para la evaluación de esta propuesta se presenta un estudio detallado de un nodo móvil que se mueve en un escenario real al aire libre, donde estudiamos el comportamiento del jitter y la transmisión de mensajes. Además, hemos utilizado emuladores de redes IoT para estudiar y determinar los efectos sobre la probabilidad de entrega de mensajes, cuando se agregan tanto publicadores como suscriptores a diferentes escenarios. Finalmente, se presenta una solución totalmente orientada a entornos con dispositivos de recursos limitados que combina los protocolos MQTT con redes tolerantes a retardos (DTN) para garantizar la entrega de información. La ventaja de las soluciones que proponemos reside en el hecho de que los sistemas IoT se vuelven resilientes a la movilidad y a los cambios de punto de acceso, permitiendo así que los desarrolladores creen fácilmente aplicaciones y servicios IoT evitando considerar estos problema. Otra ventaja de nuestras soluciones es que no necesitan soporte adicional de la red como sucede con protocolos como MobileIP o el protocolo que separa el identificador del localizador (LISP). Se destaca cómo hemos mejorado las soluciones existentes hasta el momento de la escritura de esta disertación, y se identifican futuras líneas de actuación que no han sido contempladas.<br>Internet de les coses (IoT) es refereix a la idea d'interconnectar sensors, actuadors, dispositius físics, vehicles, edificis i qualsevol element dotat de l'electrònica, així com del programari i de la connectivitat de xarxa que els fa capaces d'intercanviar dades per proporcionar serveis altament efectius. En aquesta tesi ens centrem en temes relacionats amb la comunicació de sistemes IoT, específicament en situacions de mobilitat i en els problemes que això comporta. A aquest efecte oferim diferents solucions que alleugeren el seu impacte i garanteixen el lliurament d'informació en aquestes situacions. El context de referència és una ciutat intel·ligent on diversos dispositius mòbils participen de forma col·laborativa enviant periòdicament informació des dels seus sensors cap a serveis situats en plataformes en el núvol (cloud computing) on mitjançant l'ús de virtualització, la informació està protegida garantint la seva seguretat i privadesa. Les solucions proposades en aquesta tesi s'enfoquen a provar sobre una xicoteta infraestructura un prototip que abasta i integra diferents tecnologies i estàndards per a resoldre eficientment els problemes prèviament identificats. Hem enfocat el nostre esforç en l'ús de dispositius sobre escenaris reals amb dos de les xarxes més esteses a tot el món: WiFi i enllaços 802.15.4. Ens enfoquem en protocols que ofereixen el paradigma productor/consumidor com el protocol avançat de cues de missatges (AMQP) i particularment el protocol de transport de missatges telemètrics (MQTT), observem el seu comportament a través d'experiments en laboratori i en proves a l'aire lliure, repetint les proves amb diferents grandàries de missatges i diferent periodicitat entre missatges. Per a modelar les diferents possibles aplicacions de la proposta, es van prendre en consideració diverses qüestions plantejades per la mobilitat, resultant en un model per a dimensionar eficientment el nombre de fonts per a un node mòbil i per a calcular la grandària requerida del buffer, en funció del nombre de fonts i de la grandària dels missatges. Proposem un mecanisme adaptat al protocol MQTT que evita la pèrdua de dades per a clients mòbils, basat en un buffer intermedi entre la producció i publicació de missatges que en conjunt amb l'ús d'una alternativa al gestor de connexions sense fils "Network Manager'', en certs contextos millora l'establiment de les connexions. Per a l'avaluació d'aquesta proposta es presenta un estudi detallat d'un node mòbil que es mou en un escenari real a l'aire lliure, on estudiem el comportament del jitter i la transmissió de missatges. A més, hem utilitzat emuladors de xarxes IoT per a estudiar i determinar els efectes sobre la probabilitat de lliurament de missatges, quan s'agreguen tant publicadors com subscriptors a diferents escenaris. Finalment, es presenta una solució totalment orientada a entorns amb dispositius de recursos limitats que combina els protocols MQTT amb xarxes tolerants a retards (DTN) per a garantir el lliurament d'informació. L'avantatge de les solucions que proposem resideix en el fet que els sistemes IoT es tornen resilients a la mobilitat i als canvis de punt d'accés, permetent així que els desenvolupadors creuen fàcilment aplicacions i serveis IoT evitant considerar aquests problema. Un altre avantatge de les nostres solucions és que no necessiten suport addicional de la xarxa com succeeix amb protocols com MobileIP o el protocol que separa l'identificador del localitzador (LISP). Es destaca com hem millorat les solucions existents fins al moment de l'escriptura d'aquesta dissertació, i s'identifican futures línies d'actuació que no han sigut contemplades.<br>Luzuriaga Quichimbo, JE. (2017). Managing Mobility for Distributed Smart Cities Services [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/84744<br>TESIS

Mobile devices connected to cloud based services are becoming a mainstream method of delivery up-to-date and context aware information to users. Connecting mobile applications to cloud service require significant developer effort. Yet this communication code usually follows certain patterns, varying accordingly to the specific type of data sent and received from the server. By analyzing the causes of theses variations, we can create a system that can automate the code creation for communication from a mobile device to a cloud server. To automate code creation, a general pattern must extracted. This general solution can then be applied to any database configuration. Automating this process frees up valuable development time, allowing developers to make other parts of the application and/or backend service a better experience for the end user.

Avec le développement des applications mobiles (téléphonie, IoT, domotique, …), les systèmes embarqués ont montré une croissance exponentielle ces dernières années. Or la principale caractéristique de ces nouveaux systèmes est la combinaison d’une puissance de calcul importante avec une grande autonomie de fonctionnement. Malheureusement, ces caractéristiques étant diamétralement opposées, les concepteurs de systèmes se heurtent à un dilemme leur imposant de limiter la puissance embarquée. Afin de pallier ce problème d'autonomie, de plus en plus d'architectures se tournent vers la mise en place d'étages de récupération d'énergie depuis une ou plusieurs sources. Dans le cadre d'une thèse CIFRE, l'étude a ainsi été portée sur la conception d'un module de récupération d'énergie optimisé s'interfaçant sur plusieurs sources. Deux directions ont ainsi été trouvées afin d'augmenter la quantité récupérée par un tel dispositif :- Le développement de l'approche multisources afin de proposer une architecture industrialisable.- L'optimisation des quantités d'énergie extraites de chaque source par l'intermédiaire d'algorithmes nouvelle génération permettant la recherche du point de fonctionnement maximum. Ces derniers sont ainsi optimisés grâce aux progrès réalisés récemment dans le domaine du Deep Learning et la commercialisation de microcontrôleurs à faible puissance de plus en plus performants. L’objectif final étant de déployer des réseaux de capteurs à grande échelle et faible coût, dont l’autonomie est améliorée voire infinie si le système parvient à produire plus d’énergie que ce qu’il consomme<br>With the development of mobile applications, such as telecoms, IoT and home automation, embedded systems have shown an exponential growth over the past years. The main characteristic of these newly build systems is to combine high processing capabilities and extended operational autonomy. Unfortunately, these parameters are fundamentally opposed and hardware designer facing this issue by limiting processing capability to ensure enough autonomy. To solve this autonomy problem, newly architectures choose to implement an energy harvesting stage with one or more sources. As part of this industrial thesis, the study has been carried out on the design of an optimized energy harvesting module using one or more sources. Two directions were found to increase the quantity of harvested energy: - Interfacing multiple harvester from complementary source in an industrialized architecture - Optimization of produced energy from each source by using next-generation algorithms of Maximum Power Point Tracking. These algorithms are optimized thanks to technical advances made in the field of Deep Learning and the availability of more efficient low power microcontroller. The final goal of this study is to deploy a low cost wide area network of sensors with enhanced or infinite autonomy

La quinta generación de redes móviles (5G) se encuentra a la vuelta de la esquina. Se espera provea de beneficios extraordinarios a la población y que resuelva la mayoría de los problemas de las redes 4G actuales. El éxito de 5G, cuya primera fase de estandarización ha sido completada, depende de tres pilares: comunicaciones tipo-máquina masivas, banda ancha móvil mejorada y comunicaciones ultra fiables y de baja latencia (mMTC, eMBB y URLLC, respectivamente). En esta tesis nos enfocamos en el primer pilar de 5G, mMTC, pero también proveemos una solución para lograr eMBB en escenarios de distribución masiva de contenidos. Específicamente, las principales contribuciones son en las áreas de: 1) soporte eficiente de mMTC en redes celulares; 2) acceso aleatorio para el reporte de eventos en redes inalámbricas de sensores (WSNs); y 3) cooperación para la distribución masiva de contenidos en redes celulares. En el apartado de mMTC en redes celulares, esta tesis provee un análisis profundo del desempeño del procedimiento de acceso aleatorio, que es la forma mediante la cual los dispositivos móviles acceden a la red. Estos análisis fueron inicialmente llevados a cabo por simulaciones y, posteriormente, por medio de un modelo analítico. Ambos modelos fueron desarrollados específicamente para este propósito e incluyen uno de los esquemas de control de acceso más prometedores: access class barring (ACB). Nuestro modelo es uno de los más precisos que se pueden encontrar en la literatura y el único que incorpora el esquema de ACB. Los resultados obtenidos por medio de este modelo y por simulación son claros: los accesos altamente sincronizados que ocurren en aplicaciones de mMTC pueden causar congestión severa en el canal de acceso. Por otro lado, también son claros en que esta congestión se puede prevenir con una adecuada configuración del ACB. Sin embargo, los parámetros de configuración del ACB deben ser continuamente adaptados a la intensidad de accesos para poder obtener un desempeño óptimo. En la tesis se propone una solución práctica a este problema en la forma de un esquema de configuración automática para el ACB; lo llamamos ACBC. Los resultados muestran que nuestro esquema puede lograr un desempeño muy cercano al óptimo sin importar la intensidad de los accesos. Asimismo, puede ser directamente implementado en redes celulares para soportar el tráfico mMTC, ya que ha sido diseñado teniendo en cuenta los estándares del 3GPP. Además de los análisis descritos anteriormente para redes celulares, se realiza un análisis general para aplicaciones de contadores inteligentes. Es decir, estudiamos un escenario de mMTC desde la perspectiva de las WSNs. Específicamente, desarrollamos un modelo híbrido para el análisis de desempeño y la optimización de protocolos de WSNs de acceso aleatorio y basados en cluster. Los resultados muestran la utilidad de escuchar el medio inalámbrico para minimizar el número de transmisiones y también de modificar las probabilidades de transmisión después de una colisión. En lo que respecta a eMBB, nos enfocamos en un escenario de distribución masiva de contenidos, en el que un mismo contenido es enviado de forma simultánea a un gran número de usuarios móviles. Este escenario es problemático, ya que las estaciones base de la red celular no cuentan con mecanismos eficientes de multicast o broadcast. Por lo tanto, la solución que se adopta comúnmente es la de replicar e contenido para cada uno de los usuarios que lo soliciten; está claro que esto es altamente ineficiente. Para resolver este problema, proponemos el uso de esquemas de network coding y de arquitecturas cooperativas llamadas nubes móviles. En concreto, desarrollamos un protocolo para la distribución masiva de contenidos, junto con un modelo analítico para su optimización. Los resultados demuestran que el modelo propuesto es simple y preciso, y que el protocolo puede reducir el con<br>La cinquena generació de xarxes mòbils (5G) es troba molt a la vora. S'espera que proveïsca de beneficis extraordinaris a la població i que resolga la majoria dels problemes de les xarxes 4G actuals. L'èxit de 5G, per a la qual ja ha sigut completada la primera fase del qual d'estandardització, depén de tres pilars: comunicacions tipus-màquina massives, banda ampla mòbil millorada, i comunicacions ultra fiables i de baixa latència (mMTC, eMBB i URLLC, respectivament, per les seues sigles en anglés). En aquesta tesi ens enfoquem en el primer pilar de 5G, mMTC, però també proveïm una solució per a aconseguir eMBB en escenaris de distribució massiva de continguts. Específicament, les principals contribucions són en les àrees de: 1) suport eficient de mMTC en xarxes cel·lulars; 2) accés aleatori per al report d'esdeveniments en xarxes sense fils de sensors (WSNs); i 3) cooperació per a la distribució massiva de continguts en xarxes cel·lulars. En l'apartat de mMTC en xarxes cel·lulars, aquesta tesi realitza una anàlisi profunda de l'acompliment del procediment d'accés aleatori, que és la forma mitjançant la qual els dispositius mòbils accedeixen a la xarxa. Aquestes anàlisis van ser inicialment dutes per mitjà de simulacions i, posteriorment, per mitjà d'un model analític. Els models van ser desenvolupats específicament per a aquest propòsit i inclouen un dels esquemes de control d'accés més prometedors: el access class barring (ACB). El nostre model és un dels més precisos que es poden trobar i l'únic que incorpora l'esquema d'ACB. Els resultats obtinguts per mitjà d'aquest model i per simulació són clars: els accessos altament sincronitzats que ocorren en aplicacions de mMTC poden causar congestió severa en el canal d'accés. D'altra banda, també són clars en què aquesta congestió es pot previndre amb una adequada configuració de l'ACB. No obstant això, els paràmetres de configuració de l'ACB han de ser contínuament adaptats a la intensitat d'accessos per a poder obtindre unes prestacions òptimes. En la tesi es proposa una solució pràctica a aquest problema en la forma d'un esquema de configuració automàtica per a l'ACB; l'anomenem ACBC. Els resultats mostren que el nostre esquema pot aconseguir un acompliment molt proper a l'òptim sense importar la intensitat dels accessos. Així mateix, pot ser directament implementat en xarxes cel·lulars per a suportar el trànsit mMTC, ja que ha sigut dissenyat tenint en compte els estàndards del 3GPP. A més de les anàlisis descrites anteriorment per a xarxes cel·lulars, es realitza una anàlisi general per a aplicacions de comptadors intel·ligents. És a dir, estudiem un escenari de mMTC des de la perspectiva de les WSNs. Específicament, desenvolupem un model híbrid per a l'anàlisi de prestacions i l'optimització de protocols de WSNs d'accés aleatori i basats en clúster. Els resultats mostren la utilitat d'escoltar el mitjà sense fil per a minimitzar el nombre de transmissions i també de modificar les probabilitats de transmissió després d'una col·lisió. Pel que fa a eMBB, ens enfoquem en un escenari de distribució massiva de continguts, en el qual un mateix contingut és enviat de forma simultània a un gran nombre d'usuaris mòbils. Aquest escenari és problemàtic, ja que les estacions base de la xarxa cel·lular no compten amb mecanismes eficients de multicast o broadcast. Per tant, la solució que s'adopta comunament és la de replicar el contingut per a cadascun dels usuaris que ho sol·liciten; és clar que això és altament ineficient. Per a resoldre aquest problema, proposem l'ús d'esquemes de network coding i d'arquitectures cooperatives anomenades núvols mòbils. En concret, desenvolupem un protocol per a realitzar la distribució massiva de continguts de forma eficient, juntament amb un model analític per a la seua optimització. Els resultats demostren que el model proposat és simple i precís<br>The 5th generation (5G) of mobile networks is just around the corner. It is expected to bring extraordinary benefits to the population and to solve the majority of the problems of current 4th generation (4G) systems. The success of 5G, whose first phase of standardization has concluded, relies in three pillars that correspond to its main use cases: massive machine-type communication (mMTC), enhanced mobile broadband (eMBB), and ultra-reliable low latency communication (URLLC). This thesis mainly focuses on the first pillar of 5G: mMTC, but also provides a solution for the eMBB in massive content delivery scenarios. Specifically, its main contributions are in the areas of: 1) efficient support of mMTC in cellular networks; 2) random access (RA) event-reporting in wireless sensor networks (WSNs); and 3) cooperative massive content delivery in cellular networks. Regarding mMTC in cellular networks, this thesis provides a thorough performance analysis of the RA procedure (RAP), used by the mobile devices to switch from idle to connected mode. These analyses were first conducted by simulation and then by an analytical model; both of these were developed with this specific purpose and include one of the most promising access control schemes: the access class barring (ACB). To the best of our knowledge, this is one of the most accurate analytical models reported in the literature and the only one that incorporates the ACB scheme. Our results clearly show that the highly-synchronized accesses that occur in mMTC applications can lead to severe congestion. On the other hand, it is also clear that congestion can be prevented with an adequate configuration of the ACB scheme. However, the configuration parameters of the ACB scheme must be continuously adapted to the intensity of access attempts if an optimal performance is to be obtained. We developed a practical solution to this problem in the form of a scheme to automatically configure the ACB; we call it access class barring configuration (ACBC) scheme. The results show that our ACBC scheme leads to a near-optimal performance regardless of the intensity of access attempts. Furthermore, it can be directly implemented in 3rd Generation Partnership Project (3GPP) cellular systems to efficiently handle mMTC because it has been designed to comply with the 3GPP standards. In addition to the analyses described above for cellular networks, a general analysis for smart metering applications is performed. That is, we study an mMTC scenario from the perspective of event detection and reporting WSNs. Specifically, we provide a hybrid model for the performance analysis and optimization of cluster-based RA WSN protocols. Results showcase the utility of overhearing to minimize the number of packet transmissions, but also of the adaptation of transmission parameters after a collision occurs. Building on this, we are able to provide some guidelines that can drastically increase the performance of a wide range of RA protocols and systems in event reporting applications. Regarding eMBB, we focus on a massive content delivery scenario in which the exact same content is transmitted to a large number of mobile users simultaneously. Such a scenario may arise, for example, with video streaming services that offer a particularly popular content. This is a problematic scenario because cellular base stations have no efficient multicast or broadcast mechanisms. Hence, the traditional solution is to replicate the content for each requesting user, which is highly inefficient. To solve this problem, we propose the use of network coding (NC) schemes in combination with cooperative architectures named mobile clouds (MCs). Specifically, we develop a protocol for efficient massive content delivery, along with the analytical model for its optimization. Results show the proposed model is simple and accurate, and the protocol can lead to energy savings of up to 37 percent when compared to the traditional approach.<br>Leyva Mayorga, I. (2018). On reliable and energy efficient massive wireless communications: the road to 5G [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/115484<br>TESIS

This work deals with user satisfaction with mobile data service. The main part is devoted to the development of a mobile application that provides testing network parameters to evaluate and use online databases shared with other users. Discussed the possibility of distributing applications among users over its testing and then to the App Store.

L'origine concernant l'idée d'ajouter de l'intelligence aux objets de base et de les faire communiquer n'est pas connue précisément. Mais ces derniers temps, l'émergence d'Internet en tant que réseau de communication global a aussi motivé l'utilisation de son architecture et de ses protocoles pour connecter des objets. C'est par exemple le cas célèbre du distributeur automatique de sodas connecté à l'ARPANET dans les années 1980. Au cours des deux dernières décennies, de nombreuses améliorations technologiques ont été développées pour rendre possible l'Internet des objets (IoT). Un scénario d'un réseau IoT typique consiste à connecter des dispositifs embarqués composés de capteurs environnementaux, de microcontrôleurs et de matériel de communication à un nœud de collecte central. L'ensemble des données recueillies par ces nœuds permettra d'analyser et de comprendre précisément les phénomènes et comportements se produisant dans cet environnement. Les applications des technologies IoT sont infinies, car elles sont adaptables à presque tous les systèmes, que l'on doit surveiller et contrôler à distance, pouvant fournir des informations sur son état, son fonctionnement et son environnement. Les villes intelligentes, les soins, l'automatisation industrielle et la technologie portable sont quelques-unes des applications de l'IoT qui promettent de rendre notre vie plus sûre et plus facile. Certains défis en matière de recherche et de technologie doivent être relevés pour la mise en œuvre et la large dissémination des applications de l'IoT comme le déploiement, la mise en réseau, la sécurité, la résilience et le contrôle de l'alimentation des équipements. Cette demande massive de connexion dans les réseaux IoT introduit de nouveaux défis en termes de connectivité, de fiabilité et de technologie. Au niveau de la radio, les réseaux IoT représentent un énorme afflux de divers appareils qui communiquent via le même support radio partagé. Cependant, bon nombre de ces appareils sont difficiles à sécuriser et à manipuler. L'un des principaux défis du déploiement des réseaux IoT est le manque de solutions efficaces qui permettent un nombre massif de connexions tout en répondant en même temps aux exigences de faible latence et de faible coût. De plus, il y a eu récemment une tendance vers des systèmes de communication à longue portée pour l'IoT et aussi pour les réseaux cellulaires. Pour de nombreux cas d'utilisation, tels que les communications massives de type machine (mMTC), les performances peuvent être améliorées en s'éloignant du modèle classique d'établissement de connexion et en adoptant des méthodes d'accès aléatoire sans attribution prédéterminée. Associé à des techniques de couche physique telles que l'annulation successive des interférences (SIC) ou l'accès multiple non orthogonal (NOMA), les performances de l'accès aléatoire peuvent être améliorées, donnant lieu à de nouvelles conceptions de protocoles d'accès aléatoire. Dans cette thèse, nous nous concentrons sur l'un des candidats modernes pour les protocoles d'accès aléatoire bien adaptés à l'IoT :ALOHA à répétition irrégulière (IRSA). Comme des solutions sont nécessaires pour surmonter les défis de l'IoT, nous étudions le schéma d'accès aléatoire IRSA sous de nouveaux points de vue et nous commençons par une analyse des performances des différentes variantes grâce à l'outil de l'évolution de la densité du débit. Précisément, nous commençons par revisiter le scénario du protocole IRSA avec la capacité de réception de paquets multiples (MPR) au niveau du récepteur. Ensuite, nous étudions IRSA dans différents scénarios où des hypothèses plus réalistes sont considérées comme : IRSA avec plusieurs puissances de transmission, avec effet de capture et avec des erreurs de décodage. Dans la deuxième partie de la thèse, nous nous concentrons sur l'apprentissage et l'ajustement dynamique des paramètres du protocole IRSA. Dans un premier temps, nous analysons les performances [...]<br>The origin of the idea of adding intelligence to basic objects and making them communicate has been lost to history. But in recent times, the emergence of the Internet as a global communication network has also motived the use of its architecture and protocols to connect objects (such as the soda vending machine famously connected to the ARPANET in the 1980s). In the past two decades, many technological enhancements have been developed to enable the ``Internet of Things'' (IoT). A scenario of a typical IoT network is to connect embedded devices composed of environmental sensors, microcontrollers, and communication hardware, to a central collection node. The set of data gathered by these nodes will increasingly help in analyzing and precisely understanding the phenomenons and behaviors occurring in this environment. The applications of IoT technologies are endless because they are adaptable to almost any system that can provide information about its status, operation, and the environment and that one needs to monitor and control at a distance. Smart cities, healthcare, industrial automation, and wearable technology are some IoT applications that promise to make our life safer and easier. Some research and technology challenges need to be addressed for the implementation and full popularization of IoT applications including deployment, networking, security, resilience, and power control. This massive demand for connection in IoT networks will introduce new challenges in terms of connectivity, reliability, and technology. At the radio network level, IoT networks represent a huge inflow of various devices that communicate through the same shared radio medium. However, many of these devices are difficult to secure and handle. One major challenge to deploying IoT networks is the lack of efficient solutions that allow for a massive number of connections while meeting the low-latency and low-cost demands at the same time. In addition, recently, there has been a trend towards long-range communications systems for the IoT, including cellular networks. For many use cases, such as massive machine-type communications (mMTC), performance can be gained by moving away from the classical model of connection establishment and adopting grant-free, random access methods. Associated with physical layer techniques such as Successive Interference Cancellation (SIC), or Non-Orthogonal Multiple Access (NOMA), the performance of random access can be dramatically improved, giving rise to novel random access protocol designs. In this thesis, we focus on one of the modern candidates for random access protocols ``well-fitted'' to the IoT: Irregular Repetition Slotted ALOHA (IRSA). As solutions are needed to overcome the challenges of IoT, we study the IRSA random access scheme from new points of view and we start with an analysis of the performance of different variations through the density evolution tool. Precisely, we start by revisiting the scenario of the IRSA protocol in the case of Multiple Packet Reception (MPR) capability at the receiver. Then, we study IRSA in different scenarios where more realistic assumptions are considered, such as IRSA with multiple transmissions powers, with capture effect, and with decoding errors. In the second part of the thesis, we concentrate on learning and dynamically adjusting IRSA protocol parameters. First, we analyze the protocol performance in a centralized approach through a variant of Reinforcement Learning and in a distributed approach through Game Theory. We also optimize short frame length IRSA through a Deep Reinforcement Learning approach. Finally, we introduce a sensing capability to IRSA, in line with carrier sense principles, and we tentatively explore how one can learn part of sensing protocols with the help of Deep Learning tools

En la actualidad, la Internet de las Cosas (Internet of Things, IoT) es una tecnología esencial para la próxima generación de sistemas inalámbricos. La conectividad es la base de IoT, y el tipo de acceso requerido dependerá de la naturaleza de la aplicación. Uno de los principales facilitadores del entorno IoT es la comunicación machine-to-machine (M2M) y, en particular, su enorme potencial para ofrecer conectividad ubicua entre dispositivos inteligentes. Las redes celulares son la elección natural para las aplicaciones emergentes de IoT y M2M. Un desafío importante en las redes celulares es conseguir que la red sea capaz de manejar escenarios de acceso masivo en los que numerosos dispositivos utilizan comunicaciones M2M. Por otro lado, los sistemas celulares han experimentado un tremendo desarrollo en las últimas décadas: incorporan tecnología sofisticada y nuevos algoritmos para ofrecer una amplia gama de servicios. El modelado y análisis del rendimiento de estas redes multiservicio es también una tarea desafiante que podría requerir un gran esfuerzo computacional. Para abordar los desafíos anteriores, nos centramos en primer lugar en el diseño y la evaluación de las prestaciones de nuevos mecanismos de control de acceso para hacer frente a las comunicaciones masivas M2M en redes celulares. Posteriormente nos ocupamos de la evaluación de prestaciones de redes multiservicio y proponemos una nueva técnica analítica que ofrece precisión y eficiencia computacional. Nuestro principal objetivo es proporcionar soluciones para aliviar la congestión en la red de acceso radio cuando un gran número de dispositivos M2M intentan conectarse a la red. Consideramos los siguientes tipos de escenarios: (i) los dispositivos M2M se conectan directamente a las estaciones base celulares, y (ii) forman grupos y los datos se envían a concentradores de tráfico (gateways) que les proporcionan acceso a la infraestructura. En el primer escenario, dado que el número de dispositivos añadidos a la red aumenta continuamente, esta debería ser capaz de manejar el considerable incremento en las solicitudes de acceso. El 3rd Generation Partnership Project (3GPP) ha propuesto el access class barring (ACB) como una solución práctica para el control de congestión en la red de acceso radio y la red troncal. El ajuste correcto de los parámetros de ACB de acuerdo con la intensidad del tráfico es crítico, pero cómo hacerlo de forma dinámica y autónoma es un problema complejo cuya solución no está recogida en las especificaciones del 3GPP. Esta tesis doctoral contribuye al análisis del rendimiento y al diseño de nuevos algoritmos que implementen efectivamente este mecanismo, y así superar los desafíos introducidos por las comunicaciones masivas M2M. En el segundo escenario, dado que la heterogeneidad de los dispositivos IoT y las arquitecturas celulares basadas en hardware imponen desafíos aún mayores para permitir una comunicación flexible y eficiente en los sistemas inalámbricos 5G, esta tesis doctoral también contribuye al diseño de software-defined gateways (SD-GWs) en una nueva arquitectura propuesta para redes inalámbricas definidas por software que se denomina SoftAir. Esto permite manejar tanto un gran número de dispositivos como el volumen de datos que estarán vertiendo en la red. Otra contribución de esta tesis doctoral es la propuesta de una técnica novedosa para el análisis de prestaciones de redes multiservicio de alta capacidad que se basa en un nuevo enfoque del modelizado analítico de sistemas que operan a diferentes escalas temporales. Este enfoque utiliza el análisis del transitorio de una serie de subcadenas absorbentes y lo denominamos absorbing Markov chain approximation (AMCA). Nuestros resultados muestran que para un coste computacional dado, AMCA calcula los parámetros de prestaciones habituales de un sistema con mayor precisión, en comparación con los resultados obtenidos por otr<br>Nowadays, Internet of Things (IoT) is an essential technology for the upcoming generation of wireless systems. Connectivity is the foundation for IoT, and the type of access required will depend on the nature of the application. One of the leading facilitators of the IoT environment is machine-to-machine (M2M) communication, and particularly, its tremendous potential to offer ubiquitous connectivity among intelligent devices. Cellular networks are the natural choice for emerging IoT and M2M applications. A major challenge in cellular networks is to make the network capable of handling massive access scenarios in which myriad devices deploy M2M communications. On the other hand, cellular systems have seen a tremendous development in recent decades; they incorporate sophisticated technology and algorithms to offer a broad range of services. The modeling and performance analysis of these large multi-service networks is also a challenging task that might require high computational effort. To address the above challenges, we first concentrate on the design and performance evaluation of novel access control schemes to deal with massive M2M communications. Then, we focus on the performance evaluation of large multi-service networks and propose a novel analytical technique that features accuracy and computational efficiency. Our main objective is to provide solutions to ease the congestion in the radio access or core network when massive M2M devices try to connect to the network. We consider the following two types of scenarios: (i) massive M2M devices connect directly to cellular base stations, and (ii) they form clusters and the data is forwarded to gateways that provide them with access to the infrastructure. In the first scenario, as the number of devices added to the network is constantly increasing, the network should handle the considerable increment in access requests. Access class barring (ACB) is proposed by the 3rd Generation Partnership Project (3GPP) as a practical congestion control solution in the radio access and core network. The proper tuning of the ACB parameters according to the traffic intensity is critical, but how to do so dynamically and autonomously is a challenging task that has not been specified. Thus, this dissertation contributes to the performance analysis and optimal design of novel algorithms to implement effectively this barring scheme and overcome the challenges introduced by massive M2M communications. In the second scenario, since the heterogeneity of IoT devices and the hardware-based cellular architectures impose even greater challenges to enable flexible and efficient communication in 5G wireless systems, this dissertation also contributes to the design of software-defined gateways (SD-GWs) in a new architecture proposed for wireless software-defined networks called SoftAir. The deployment of these SD-GWs represents an alternative solution aiming at handling both a vast number of devices and the volume of data they will be pouring into the network. Another contribution of this dissertation is to propose a novel technique for the performance analysis of large multi-service networks. The underlying complexity of the network, particularly concerning its size and the ample range of configuration options, makes the solution of the analytical models computationally costly. However, a typical characteristic of these networks is that they support multiple types of traffic flows operating at different time-scales. This time-scale separation can be exploited to reduce considerably the computational cost associated to determine the key performance indicators. Thus, we propose a novel analytical modeling approach based on the transient regime analysis, that we name absorbing Markov chain approximation (AMCA). For a given computational cost, AMCA finds common performance indicators with greater accuracy, when compared to the results obtained by other approximate methods proposed in the literature.<br>En l'actualitat, la Internet de les Coses (Internet of Things, IoT) és una tecnologia essencial per a la propera generació de sistemes sense fil. La connectivitat és la base d'IoT, i el tipus d'accés requerit dependrà de la naturalesa de l'aplicació. Un dels principals facilitadors de l'entorn IoT és la comunicació machine-to-machine (M2M) i, en particular, el seu enorme potencial per oferir connectivitat ubiqua entre dispositius intel · ligents. Les xarxes mòbils són l'elecció natural per a les aplicacions emergents de IoT i M2M. Un desafiament important en les xarxes mòbils que actualment está rebent molta atenció és aconseguir que la xarxa siga capaç de gestionar escenaris d'accés massiu en què una gran quantitat de dispositius utilitzen comunicacions M2M. D'altra banda, els sistemes mòbils han experimentat un gran desenvolupament en les últimes dècades: incorporen tecnologia sofisticada i nous algoritmes per oferir una àmplia gamma de serveis. El modelatge i análisi del rendiment d'aquestes xarxes multiservei és també un desafiament important que podria requerir un gran esforç computacional. Per abordar els desafiaments anteriors, en aquesta tesi doctoral ens centrem en primer lloc en el disseny i l'avaluació de les prestacions de nous mecanismes de control d'accés per fer front a les comunicacions massives M2M en xarxes cel · lulars. Posteriorment ens ocupem de l'avaluació de prestacions de xarxes multiservei i proposem una nova tècnica analítica que ofereix precisió i eficiència computacional. El nostre principal objectiu és proporcionar solucions per a alleujar la congestió a la xarxa d'accés ràdio quan un gran nombre de dispositius M2M intenten connectar-se a la xarxa. Considerem els dos tipus d'escenaris següents: (i) els dispositius M2M es connecten directament a les estacions base cel · lulars, i (ii) formen grups i les dades s'envien a concentradors de trànsit (gateways) que els proporcionen accés a la infraestructura. En el primer escenari, atès que el nombre de dispositius afegits a la xarxa augmenta contínuament, aquesta hauria de ser capaç de gestionar el considerable increment en les sol · licituds d'accés. El 3rd Generation Partnership Project (3GPP) ha proposat l'access class barring (ACB) com una solució pràctica per al control de congestió a la xarxa d'accès ràdio i la xarxa troncal. L'ajust correcte dels paràmetres d'ACB d'acord amb la intensitat del trànsit és crític, però com fer-ho de forma dinàmica i autònoma és un problema complex, la solució del qual no està recollida en les especificacions del 3GPP. Aquesta tesi doctoral contribueix a l'anàlisi del rendiment i al disseny de nous algoritmes que implementen efectivament aquest mecanisme, i així superar els desafiaments introduïts per les comunicacions massives M2M en les xarxes mòbils actuals i futures. En el segon escenari, atès que l'heterogeneïtat dels dispositius IoT i les arquitectures cel · lulars basades en hardware imposen desafiaments encara més grans per permetre una comunicació flexible i eficient en els sistemes sense fil 5G, aquesta tesi doctoral també contribueix al disseny de software-defined gateways (SD-GWS) en una nova arquitectura proposada per a xarxes sense fils definides per programari que s'anomena SoftAir. Això permet gestionar tant un gran nombre de dispositius com el volum de dades que estaran abocant a la xarxa. Una altra contribució d'aquesta tesi doctoral és la proposta d'una tècnica innovadora per a l'anàlisi de prestacions de xarxes multiservei d'alta capacitat que es basa en un nou enfocament del modelitzat analític de sistemes que operen a diferents escales temporals. Aquest enfocament utilitza l'anàlisi del transitori d'una sèrie de subcadenes absorbents i l'anomenem absorbing Markov chain Approximation (AMCA). Els nostres resultats mostren que per a un cost computacional donat, AMCA calcula els paràmetres de prestacions habituals d<br>Tello Oquendo, LP. (2018). Design and Performance Analysis of Access Control Mechanisms for Massive Machine-to-Machine Communications in Wireless Cellular Networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/107946<br>TESIS

Precision Agriculture (PA) is an emerging technology which enables efficient irrigation by employing the Internet of Things (IoT). We split the thesis in two parts. The first part is estimation of humidity level via experimentation. We focus on measuring Received Signal Strength Indicator (RSSI) to obtain humidity level of the field. Thus, we aim at eliminating the humidity sensors which are very expensive and estimate soil moisture through the variation of RSSI values measured by wireless devices buried underground. In the second part of the thesis, we aim at building an accurate and reliable irrigation system by the help of IoT technology via simulations. The advantage brought by our Wireless Sensor Network (WSN) is twofold: it minimizes the amount of wasted water during irrigation in farming, and it increases the yield with efficient irrigation. For these purposes, we tested the performance of LoRa protocol in different scenarios in both parts of the thesis.

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.<br>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.<br>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.<br>Arquitectura de computadors

Les réseaux « Internet des Objets » se composent de plusieurs millions d’objets qui possèdent une adresse IP et qui peuvent connecter sur Internet. En général, ces objets sont supposé d’être autonomes et peuvent résoudre des tâches; mesurer, traiter et fournir des informations pour les systèmes connectés et pour les utilisateurs. Aussi, ces réseaux sont vulnérables (c.-à-d. : les éléments peuvent être mobiles et la topologie du réseau peut changer dynamiquement), les changements peuvent influencer le (bon) fonctionnement du réseau. De plus, ils peuvent être alimentés par des batteries de durée de vie limitée, ce que nécessite la réduction de leur consommation.Ce travail de thèse aborde un sujet important dans le domaine de l’Internet des Objets, qui consiste à savoir comment assurer la robustesse et le fonctionnement tolérant aux pannes du réseau pour répondre aux exigences des missions critiques. Avec le large déploiement des services IdO, ce problème est deventé ou de détection de pannes et de sécurité industriel où l’état des objets communicants doit être constamment vérifié pour le rétablissement rapide en cas de problème particulièrement crucial pour les applications telles que le monitorage intelligent de sames de communication inattendus. On cherche alors de minimiser le coût du monitorage et l’utilisation de l’énergie, et aussi les charges additionnelles sur les réseaux.Nous avons proposé un algorithme qui vise à réaliser un placement distribué des moniteurs avec une complexité minimale pour le calcul. L’algorithme proposé fonctionne avec RPL. L’objectif principal est d’augmenter la robustesse dans les réseaux IdO ciblant les applications critiques en temps réel via le monitorage des liaisons dans les DODAGs construits par RPL. Dans notre première contribution, le problème est modélisé comme un problème de couverture minimale des sommets (VCP) sur le DODAG. Nous avons développé un algorithme à temps polynomial qui transforme le DODAG en une décomposition arborescente (Nice-Tree Decomposition) avec une largeur arborescente (treewidth) d’unité. Cette stratégie profite de la spécificité des DODAG et a abouti à une réduction significative de la complexité de la résolution du VCP sur les DODAG. Elle peut être résolue en temps polynomial.La deuxième proposition est un modèle approché pour l’optimisation de l’ordonnancement du rôle de monitorage des nœuds dans les réseaux IdO, afin de maximiser la durée de vie des dispositifs embarqués à ressources limitées, tout en minimisant le coût global du monitorage de réseau. Le monitorage de réseau est très coûteux, en particulier pour les réseaux à ressources limitées tels que l’IdO. Par conséquent, le monitorage doit être économe en énergie et avec des frais généraux minimaux sur la performance normale du réseau. Notre travail correspondant contient une proposition d’un modèle mathématique en trois phases pour assurer l’exigence d’une couverture des moniteurs tout en minimisant la consommation d’énergie de monitorage et les frais de communication.Notre modèle proposé décompose le problème abordé en trois problèmes d’optimisation bien connus, il s’agit du problème de couverture de sommets, problème d’affectation généralisé multi-objectives et problème de voyageur de commerce.Dans cette troisième partie, une approche exacte est proposée pour résoudre le problème décrit dans (Contribution 2). Comme nous avons vu, la décomposition en trois phases ne donne pas la solution exacte. Nous avons donc proposé une formulation exacte du problème qui consiste en un problème de l'affectation minimum des tâches de surveillance avec un fonctionnement de surveillance cyclique. Pour cela, nous avons formulé un programme en nombres entiers binaires. L'ordonnancement optimal garantit la couverture du graphe pour la surveillance avec une consommation d'énergie minimale<br>By connecting billions of things to the Internet, IoT created a plethora of applications that touch every aspect of human life. Time-sensitive, mission-critical services, require robust connectivity and strict reliability constraints. On the other hand, the IoT relies mainly on Low-power Lossy Networks, which are unreliable by nature due to their limited resources, hard duty cycles, dynamic topologies, and uncertain radio connectivity. Faults in LLNs are common rather than rare events, therefore, maintaining continuous availability of devices and reliability of communication, are critical factors to guarantee a constant, reliable flow of application data.After a comprehensive literature review, and up to our knowledge, it is clear that there is a call for a new approach to monitoring the unreliable nodes and links in an optimized, energy-efficient, proactive manner, and complete interoperability with IoT protocols. To target this research gap, our contributions address the correct assignment (placement) of the monitoring nodes. This problem is known as the minimum assignment problem, which is NP-hard. We target scalable monitoring by mapping the assignment problem into the well-studied MVC problem, also NP-hard. We proposed an algorithm to convert the DODAG into a nice-tree decomposition with its parameter (treewidth) restricted to the value one. As a result of these propositions, the monitor placement becomes only Fixed-Parameter Tractable, and can also be polynomial-time solvable.To prolong network longevity, the monitoring role should be distributed and balanced between the entire set of nodes. To that end, assuming periodical functioning, we propose in a second contribution to schedule between several subsets of nodes; each is covering the entire network. A three-phase centralized computation of the scheduling was proposed. The proposition decomposes the monitoring problem and maps it into three well-known sub-problems, for which approximation algorithms already exist in the literature. Thus, the computational complexity can be reduced.However, the one major limitation of the proposed three-phase decomposition is that it is not an exact solution. We provide the exact solution to the minimum monitor assignment problem with a duty-cycled monitoring approach, by formulating a Binary Integer Program (BIP). Experimentation is designed using network instances of different topologies and sizes. Results demonstrate the effectiveness of the proposed model in realizing full monitoring coverage with minimum energy consumption and communication overhead while balancing the monitoring role between nodes.The final contribution targeted the dynamic distributed monitoring placement and scheduling. The dynamic feature of the model ensures real-time adaptation of the monitoring schedule to the frequent instabilities of networks, and the distributed feature aims at reducing the communication overhead

Durant cette dernière décennie, plusieurs objets connectés tels que les ordinateurs, les capteurs et les montres intelligentes ont intégrés notre quotidien et forment aujourd’hui ce que l’on appelle l’Internet des Objets (IdO) ou Internet of Things (IoT) en anglais. L’IoT est un nouveau paradigme permettant une interaction entre les objets connectés afin d’améliorer notre qualité de vie, notre façon de produire des biens et notre façon d’interagir avec notre environnement. De nos jours, l’IoT se caractérise par la présence, de par le monde, de milliards d’objets connectés à faibles ressources (batterie, mémoire, CPU, bande passante disponible, etc) et hétérogènes, déployés pour permettre diverses applications couvrant de nombreux domaines de notre société tels que la santé, l’industrie, les transports, l’agriculture, etc. Cependant, en raison des contraintes lié aux ressources et de l’hétérogénéité des objets connectés, les réseaux IoT à faibles ressources présents font face à des problèmes de performance, notamment la dégradation de la qualité des liens radio, la défaillance (logicielle ou matérielle) de certains objets du réseau, la congestion du réseau, etc. Ainsi, il est donc important de gérer efficacement les réseaux IoT à faible ressources afin d’assurer leur bon fonctionnement. Pour ce faire, la solution de gestion du réseau doit être autonome (pour faire face à la nature dynamique des réseaux IoT), tenir compte de l’hétérogénéité des objets connectés et être moins consommatrice en énergie pour répondre aux défis de l’IoT. Dans cette thèse, nous nous sommes intéressés au problème de gestion des réseaux IoT à faibles ressources et avons proposés des solutions efficaces pour permettre une optimisation des performances de ces types de réseaux. Dans un premier temps nous avons procédé à une étude comparative des solutions de gestion des réseaux IoT à faibles ressources afin d’identifier les verrous techniques. Ensuite, nous avons proposé une solution intelligente qui se base sur un modèle de réseau de neurones profonds pour permettre une configuration de la portée radio dans les réseaux sans fil à faibles ressources de type RPL (IPv6 Routing Protocol for Low power and Lossy Networks). Une évaluation des performances de cette solution montre qu’elle est capable de déterminer la portée radio permettant une réduction de la consommation énergétique du réseau tout en garantissant une connectivité des objets connectés. Nous avons également proposé une solution efficace et adaptative pour configurer les paramètres de la couche MAC dans les réseaux dynamiques de type IEEE 802.15.4. Les résultats des simulations démontrent que notre solution améliore le délai de transmission bout en bout par rapport à l’utilisation des paramètres par défaut de la MAC IEEE 802.15.4. En outre, nous avons proposé une étude des solutions existante pour la gestion des problèmes de congestion des réseaux IoT à faibles ressources et par la suite nous avons proposé un procédé d’acheminement de l’information de congestion des objets connectés présents sur un chemin de routage donné dans des réseaux à ressources limitées. Cette méthode a pour but de permettre une réponse efficace aux problèmes de congestion<br>In these recent years, several connected objects such as computer, sensors and smart watches became part of modern living and form the Internet of Things (IoT). The basic idea of IoT is to enable interaction among connected objects in order to achieve a desirable goal. IoT paradigm spans across many areas of our daily life such as smart transportation, smart city, smart agriculture, smart factory and so forth. Nowadays, IoT networks are characterized by the presence of billions of heterogeneous embedded devices with limited resources (e.g. limited memory, battery, CPU and bandwidth) deployed to enable various IoT applications. However, due to both resource constraints and the heterogeneity of IoT devices, IoT networks are facing with various problems (e.g. link quality deterioration, node failure, network congestion, etc.). Considering that, it is therefore important to perform an efficient management of IoT low power networks in order to ensure good performance of those networks. To achieve this, the network management solution should be able to perform self-configuration of devices to cope with the complexity introduced by current IoT networks (due to the increasing number of IoT devices and the dynamic nature of IoT networks). Moreover, the network management should provide a mechanism to deal with the heterogeneity of the IoT ecosystem and it should also be energy efficient in order to prolong the operational time of IoT devices in case they are using batteries. Thereby, in this thesis we addressed the problem of configuration of IoT low power networks by proposing efficient solutions that help to optimize the performance of IoT networks. We started by providing a comparative analysis of existing solutions for the management of IoT low power networks. Then we propose an intelligent solution that uses a deep neural network model to determine the efficient transmission power of RPL networks. The performance evaluation shows that the proposed solution enables the configuration of the transmission range that allows a reduction of the network energy consumption while maintaining the network connectivity. Besides, we also propose an efficient and adaptative solution for configuring the IEEE 802.15.4 MAC parameters of devices in dynamic IoT low power networks. Simulation results show that our proposal improves the end-to-end delay compared to the usage of the standard IEEE 802.15.4 MAC. Additionally, we develop a study on solutions for congestion control in IoT low power networks and propose a novel scheme for collecting the congestion state of devices in a given routing path of an IoT network so as to enable an efficient mitigation of the congestion by the network manager (the device in charge of configuration of the IoT network)

Le nombre de dispositifs dans l’Internet des objets (IoT) communiquant sans fil est en rapide augmentation et devrait continuer à croître dans les années à venir. Pour soutenir cette connectivité massive, un certain nombre de nouvelles technologies, collectivement connu sous le nom de Low Power Wide Area Network (LPWAN), ont été développées. Le nombre de transmission des objets dans les LPWANs est limitée par les contraintes de duty cycle qui fixe la proportion de temps d’occupation d’une ressource radio. Pour des réseaux sans fil coexistant dans une même zone géographique et utilisant les mêmes ressources fréquentielles, le nombre croissant d’appareils entraîne la présence fréquente de signaux non désirés par le récepteur et connus sous le nom d’interférences. Dans cette thèse, nous caractérisons les statistiques d’interférence dans des LPWANs, avec un accent particulier mis sur le NB-IoT et les approches émergentes telles que le Sparse Code Multiple Access (SCMA). Une telle caractérisation est essentielle pour améliorer le traitement du signal au niveau du récepteur afin d’atténuer l’impact de l’interférence. Plusieurs facteurs influent sur les propriétés statistiques de l’interférence : l’emplacement des dispositifs, l’atténuation des signaux, les protocoles d’accès à la ressource radio. De nombreux travaux récents développent des modèles d’interférence mais beaucoup se limitent à la puissance ce qui n’est pas suffisant pour la conception des récepteurs. Nous proposons dans cette thèse un modèle de l’amplitude (complexe) de l’interférence en le liant aux principaux paramètres du réseau. La première contribution est de réexaminer l’interférence dans une seule dimension (par exemple une sous-porteuse), un cas largement rencontré dans les solutions actuelles de l’IoT. Dans ce scénario, l’hypothèse de départ est de distribuer les dispositifs interférents selon un processus de Poisson homogène. Il est connu depuis longtemps que l’interférence résultante est bien approximée par un modèle α-stable, plutôt qu’un modèle gaussien. Ce modèle est étendu au cas complexe (sous-Gaussien) et confronté à des hypothèses plus réalistes, notamment la présence de zones de garde, un réseau de rayon fini et des processus non homogènes régissant l’emplacement des appareils. La deuxième contribution est l’étude, pour la première fois, des statistiques sur les interférences dans les réseaux IoT multi-porteuses, par exemple le NB-IoT ou le SCMA. Motivé par les résultats obtenus dans le cas d’une seule sous-porteuse, un modèle multivarié basé sur des marginales α-stable et des relations de dépendance modélisées par des copules est proposé. Ce modèle est vérifié par simulation et justifié par un nouvel algorithme d’estimation des paramètres qui se révèle très proche de l’optimal mais avec une très faible complexité. Dans la troisième partie, les modèles d’interférence sont utilisées pour améliorer la conception des récepteurs. Les récepteurs non linéaires améliorent de manière significative les performances des systèmes. Si l’on se limite à des récepteurs linéaires, il est possible d’obtenir le système optimal et le taux d’erreurs binaires. Les résultats illustrent également comment la charge du réseau et la quantité moyenne d’information que chaque noeud essaie de transmettre affecte les performances du récepteur<br>The number of devices in wireless Internet of Things (IoT) networks is now rapidly increasing and is expected to continue growing in the coming years. To support this massive connectivity, a number of new technologies, collectively known as Low Power Wide Area Network (LPWAN), have been developed. Many devices in LPWANs limit their transmissions by duty cycle constraints; i.e., the proportion of time allocated for transmission. For nearby wireless networks using the same time-frequency resources, the increasing number of devices leads to a high level of unintended signals, known as interference. In this thesis, we characterize the statistics of interference arising from LPWANs, with a focus on protocols related to Narrowband IoT (NB-IoT) and emerging approaches such as Sparse Code Multiple Access (SCMA). Such a characterization is critical to improve signal processing at the receiver in order to mitigate the interference. We approach the characterization of the interference statistics by exploiting a mathematical model of device locations, signal attenuation, and the access protocols of individual interfering devices. While there has been recent work developing empirical models for the interference statistics, this has been limited to studies of the interference power, which has limited utility in receiver design. The approach adopted in this thesis has the dual benefits of providing a model for the amplitude and phase statistics and while also yielding insights into the impact of key network parameters. The first contribution in this work is to revisit interference in a single subcarrier system, which is widely used in current implementations of IoT networks. A basic model in this scenario distributes interfering devices according to a homogeneous Poisson point process. It has been long known that the resulting interference is well approximated via an α-stable model, rather than a Gaussian model. In this work, the α-stable model is shown via theoretical and simulation results to be valid in a wider range of models, including the presence of guard zones, finite network radii, and non-Poisson point processes governing device locations. The second contribution in this thesis is the study, for the first time, of interference statistics in multi-carrier IoT networks, including those that exploit NB-IoT and SCMA. Motivated by the results in the single subcarrier setting, a multivariate model based on α-stable marginals and copula theory is developed. This model is verified by extensive simulations and further justified via a new, near-optimal, parameter estimation algorithm, which has very low complexity.The third part of this thesis applies the characterizations of the interference statistics to receiver design. A new design for nonlinear receivers is proposed that can significantly outperform the state-of-the-art in multicarrier IoT systems. When receivers are restricted to be linear, the optimal structure is identified and the bit error rate characterized. Numerical results also illustrate how the average quantity of data interfering devices are required to transmit affects the receiver performance

Ubiquitous object networking has sparked the concept of the Internet of Things (IoT) which defines a new era in the world of networking. The IoT principle can be addressed as one of the important strategic technologies that will positively influence the humans’ life. All the gadgets, appliances and sensors around the world will be connected together to form a smart environment, where all the entities that connected to the Internet can seamlessly share data and resources. The IoT vision allows the embedded devices, e.g. sensor nodes, to be IP-enabled nodes and interconnect with the Internet. The demand for such technique is to make these embedded nodes act as IP-based devices that communicate directly with other IP networks without unnecessary overhead and to feasibly utilize the existing infrastructure built for the Internet. In addition, controlling and monitoring these nodes is maintainable through exploiting the existed tools that already have been developed for the Internet. Exchanging the sensory measurements through the Internet with several end points in the world facilitates achieving the concept of smart environment. Realization of IoT concept needs to be addressed by standardization efforts that will shape the infrastructure of the networks. This has been achieved through the IEEE 802.15.4, 6LoWPAN and IPv6 standards. The bright side of this new technology is faced by several implications since the IoT introduces a new class of security issues, such as each node within the network is considered as a point of vulnerability where an attacker can utilize to add malicious code via accessing the nodes through the Internet or by compromising a node. On the other hand, several IoT applications comprise mobile nodes that is in turn brings new challenges to the research community due to the effect of the node mobility on the network management and performance. Another defect that degrades the network performance is the initialization stage after the node deployment step by which the nodes will be organized into the network. The recent IEEE 802.15.4 has several structural drawbacks that need to be optimized in order to efficiently fulfil the requirements of low power mobile IoT devices. This thesis addresses the aforementioned three issues, network initialization, node mobility and security management. In addition, the related literature is examined to define the set of current issues and to define the set of objectives based upon this. The first contribution is defining a new strategy to initialize the nodes into the network based on the IEEE 802.15.4 standard. A novel mesh-under cluster-based approach is proposed and implemented that efficiently initializes the nodes into clusters and achieves three objectives: low initialization cost, shortest path to the sink node, low operational cost (data forwarding). The second contribution is investigating the mobility issue within the IoT media access control (MAC) infrastructure and determining the related problems and requirements. Based on this, a novel mobility scheme is presented that facilitates node movement inside the network under the IEEE 802.15.4e time slotted channel hopping (TSCH) mode. The proposed model mitigates the problem of frequency channel hopping and slotframe issue in the TSCH mode. The next contribution in this thesis is determining the mobility impact on low latency deterministic (LLDN) network. One of the significant issues of mobility is increasing the latency and degrading packet delivery ratio (PDR). Accordingly, a novel mobility protocol is presented to tackle the mobility issue in LLDN mode and to improve network performance and lessen impact of node movement. The final contribution in this thesis is devising a new key bootstrapping scheme that fits both IEEE 802.15.4 and 6LoWPAN neighbour discovery architectures. The proposed scheme permits a group of nodes to establish the required link keys without excessive communication/computational overhead. Additionally, the scheme supports the mobile node association process by ensuring secure access control to the network and validates mobile node authenticity in order to eliminate any malicious node association. The purposed key management scheme facilitates the replacement of outdated master network keys and release the required master key in a secure manner. Finally, a modified IEEE 802.15.4 link-layer security structure is presented. The modified architecture minimizes both energy consumption and latency incurred through providing authentication/confidentiality services via the IEEE 802.15.4.

This report is an exposition of the development of a measuring instrument whosetask is to map the physical coverage of the NB-IoT network. The measuringinstrument was developed on TietoEvry's initiative, as it was in their interest to obtaina measuring instrument that can be used to map the coverage in parts of VarmlandsNB-IoT network. Which in this way provides an assessment for any future projectsinvolving NB-IoT. The development of the measuring instruments you can carry withyou out into the field, uses a microcomputer for collecting measurement data savedin a log file using Python. The report also describes a complimentary program that inturn takes and visualizes the acquired data in the form of markers on a map, whichshows the signal strength of the NB-IoT network. The visualization program is writtenin Java and is based on the open source project: jxmapviewer2. However, themeasuring instrument as it is today needs further testing to ensure the accuracy ofthe measuring instrument. Something that can be looked over in the future.

UAV is widely used in civil applications such as environmental hazards monitoring, traffic management and pollution monitoring, all of those contribute to smart city development. Thanks to its high mobility and feasibility, UAVs can be employed as a base station, gathering data from IoT devices distribute in a certain area during its flight. In this case, an appropriate trajectory and suitable parameters set is necessary to achieve better performance. This thesis studies a scenario of NB-IoT machine-type communication network served by an unmanned aerial base station (UAB). In this scenario, the user devices are deployed with Tomas Cluster Process (TCP)[19]. Some of the nodes are named parent nodes and generated with Poisson Point Process (PPP). One single UAB is employed and its trajectory is predefined with a Travelling Salesman Problem model among the parent nodes. All the devices only generate one data packet for UL, whose activation time and expiration time is considered. Due to NB-IoT protocols, the number of resource units available on NPUSCH and the data rate for IoT devices is constrained. This study makes the network throughput and the number of users served as the main basis of performance evaluation, the variation of UAB speed, NPRACH periodicity, deployment variance, and size of the data packet as influencing factors. Finally, we present an analysis of how these parameters affect the overall performance and how the optimal configuration may be chosen according to arbitrary criteria.

Les réseaux dédiés pour l’Internet des Objets sont apparus avec la promesse de connecter des milliers de nœuds, voire plus, à une seule station de base dans une topologie en étoile. Cette nouvelle logique représente un changement fondamental dans la façon de penser les réseaux, après des décennies pendant lesquelles les travaux de recherche se sont focalisés sur les réseaux multi-sauts. Les réseaux pour l’Internet des Objets se caractérisent par la longue portée des transmissions, la vaste couverture géographique, une faible consommation d’énergie et un bas coût de mise en place. Cela a rendu nécessaire des adaptations à tous les niveaux protocolaires afin de satisfaire les besoins de ces réseaux. Plusieurs acteurs sont en concurrence sur le marché de l’Internet des Objets, essayant chacun d’établir la solution la plus efficiente. Ces acteurs se sont concentrés sur la modification de la couche physique, soit au niveau de la partie matérielle, soit par la proposition de nouvelles techniques de modulation. Toutefois, en ce qui concerne la solution de contrôle d’accès au canal (connue sous le nom de couche MAC), toutes les solutions proposées par ces acteurs se fondent sur des approches classiques, tel que Aloha et CSMA. L'objectif de cette thèse est de proposer une solution MAC dynamique pour les réseaux dédiés à l’Internet des Objets. La solution proposée a la capacité de s'adapter aux conditions du réseau. Cette solution est basée sur un algorithme d'apprentissage automatique, qui apprend de l'historique du réseau afin d'établir la relation entre les conditions du réseau, les paramètres de la couche MAC et les performances du réseau en termes de fiabilité et de consommation d'énergie. La solution possède également l'originalité de faire coexister des nœuds utilisant de différentes configurations MAC au sein du même réseau. Les résultats de simulations ont montré qu'une solution MAC basée sur l'apprentissage automatique pourrait tirer profit des avantages des différents protocoles MAC classiques. Les résultats montrent aussi qu'une solution MAC cognitive offre toujours le meilleur compromis entre fiabilité et consommation d'énergie, tout en prenant en compte l'équité entre les nœuds du réseau. La solution MAC cognitive testée pour des réseaux à haute densité a prouvé des bonnes propriétés de passage à l’échelle par rapport aux protocoles MACs classiques, ce qui constitue un autre atout important de notre solution<br>Dedicated networks for the Internet of Things appeared with the promise of connecting thousands of nodes, or even more, to a single base station in a star topology. This new logic represents a fundamental change in the way of thinking about networks, after decades during which research work mainly focused on multi-hop networks. Internet of Things networks are characterized by long transmission range, wide geographic coverage, low energy consumption and low set-up costs. This made it necessary to adapt the protocols at different architectural layers in order to meet the needs of these networks. Several players compete in the Internet of Things market, each trying to establish the most efficient solution. These players are mostly focused on modifying the physical layer, on the hardware part or through proposing new modulations. However, with regard to the channel access control solution (known as the MAC protocol), all the solutions proposed by these players are based on classic approaches such as Aloha and CSMA. The objective of this thesis is to propose a dynamic MAC solution for networks dedicated to the Internet of Things. The proposed solution has the ability to adapt to network conditions. This solution is based on a machine learning algorithm that learns from network history in order to establish the relationship between network conditions, MAC layer parameters and network performance in terms of reliability and energy consumption. The solution also has the originality of making possible the coexistence of nodes using different MAC configurations within the same network. The results of simulations have shown that a MAC solution based on machine learning could take advantage of the good properties of different conventional MAC protocols. The results also show that a cognitive MAC solution always offers the best compromise between reliability and energy consumption, while taking into account the fairness between the nodes of the network. The cognitive MAC solution tested for high density networks has proven better scalability compared to conventional MAC protocols, which is another important advantage of our solution

Fog computing was emerged as a treasured paradigm to improve the efficiency of the typical cloud of things (CoT) architecture of the Internet of Things (IoT) networks. Contrasting to the CoT in which the resource-rich high-performance data centers (DCs) are located far from the energy-constrained terminal nodes (TNs), fog nodes (FNs) in fog-enabled architecture provide computing resources in the proximity of the TNs. Therefore, the TNs consume less energy to offload their generated tasks to the FNs rather than the cloud DCs. Moreover, shortening the distance between the TNs and the FNs results in alleviating the transmission latency for the delay-sensitive tasks generated by the TNs. This is more significant for specific applications, such as smart healthcare, search and rescue, and disaster management, wherein making a prompt decision is vital to save lives. However, Fog-IoT networks still suffer from challenges regarding energy efficiency and provisioning quality of service (QoS) requirements, especially in terms of delay and throughput. The motivation behind this thesis is to tackle the corresponding challenges and improve the performance of the Fog-IoT networks. To this end, novel optimization problems, models, methods, and algorithms are proposed that mainly focus on the energy efficiency improvement and QoS provisioning in Fog-IoT networks. Moreover, due to the importance of the mobility of FNs, the contributions of the thesis encompass improving the performance of Fog-IoT networks with respect to both fixed and mobile FNs.

This project is based upon two previous projects handed to the author by the Norwegian University of Science and Technology in co-operation with Disruptive Technologies.   The report discusses sound sensing and Neural Networks, and their application in IoT. The goal was to determine what type of Neural Networks or classification methods was most suited for audio classification. This was done by applying various classification methods and Neural Networks on a data set consisting of 8732 sound samples. These methods where logistic regression, Feed-Forward Neural Network, Convolutional Neural Network, Gated Recurrent Unit, and Long Short-term Memory network. To compare the Neural Networks the accuracy of the training data set and the validation data set were evaluated. Out of these methods the feed-forward network yielded the highest validation accuracy and is the preferable classification method. However, with more work and refinement the Long Short-term memory may prove to be the better solution.   Future work with a Vesper V1010 piezoelectric microphone and IoT implementation is discussed, as well as the social and ethical difficulties proposed by what is essentially a data gathering system.

OMA’s Lightweight Machine to Machine (LwM2M) is an application protocol for device management in the Internet of Things (IoT) that has been recently published and widely adopted in a lot of projects. The protocol is designed to operate in sensor networks and machine-to-machine environments, where one of the main constraints is the energy consumption since the nodes are usually battery powered. Different strategies to achieve high energy efficiency in IoT networks have been developed, but there is no deep knowledge about the performance of LwM2M operating with them. Moreover, the specification of this protocol includes one strategy, called the Queue Mode, which could be more efficient than the usual ones because it has been specified for this particular protocol. This project aims to implement this Queue Mode at both sides of the communication, and then evaluate its performance by comparing it with TSCH, which is the standard MAC protocol used in IEEE 802.15.4 that defines a way of radio duty cycling. It has been proven to achieve a high energy efficiency, and that is the main reason why it is selected. The comparison is performed according to several metrics to have a comprehensive evaluation, and in different kind of scenarios, with different numbers of IoT devices and different parameters in the communication. The implementation was done inside the Contiki-NG OS for the client side, which is an operating systems designed for constrained devices. For the server side it has been carried out inside the Eclipse Leshan code, which is a LwM2M implementation in Java made by the Eclipse Foundation. As a result of the evaluation, it shown that both implementations operate correctly. This thesis contributes as a guideline for making decisions about which low power strategy is better to use depending on the IoT scenario and the type of application. It shows that for many use cases Queue Mode is a better option than TSCH because it achieves a higher energy efficiency and the rest of the metrics used in the evaluation have also improved values. TSCH has a better performance only in demanding scenarios or in cases where the communication is not produced at fixed time instants. The thesis was developed in cooperation with RISE SICS AB, Networked Embedded Systems Group.<br>OMA:s Lightweight Machine to Machine (LwM2M) är ett applikationsprotokoll för enhetshantering i Sakernas Internet (IoT) som nyligen har publicerats och börjat användas i många projekt. Protokollet är utformat för att fungera i sensornätverk och maskin-till-maskin miljöer, där en av de viktigaste begränsningarna är energiförbrukningen eftersom noderna vanligtvis är batteridrivna. Olika strategier för att uppnå hög energieffektivitet i sensornätverk har utvecklats, men det finns ingen djup kunskap om hur LwM2M fungerar med dem. Dessutom innehåller specifikationen av LwM2M en strategi kallad Queue Mode (köläge) som kan vara effektivare än de vanliga strategierna eftersom den har utvecklats direkt för det här protokollet.Detta examensarbete syftar till att implementera detta köläge på båda sidor av kommunikationen och sedan utvärdera prestandan genom att jämföra det med TSCH, vilket är ett MAC-protokoll specificerat i IEEE 802.15.4-standarden. Tidigare arbeten har visat att TSCH kan uppnå en låg energiförbrukning, vilket är den främsta anledningen till att detta protokoll väljs ut för att jämföra mot LwM2M:s köläge. Jämförelsen inkluderar flera olika typer av mätvärden och scenarier för att få en omfattande utvärdering, samt med flera olika antal sensor noder och parametrar.Implementationen gjordes för Contiki-NG OS på klientsidan, vilket är ett operativsystem för resursbegränsade IoT-enheter. På serversidan har implementationen gjorts för Eclipse Leshan, vilken är en LwM2M-implementation skriven i Java och publicerad av Eclipse Foundation. Som en följd av utvärderingen har det visat sig att båda implementationerna fungerar korrekt.Detta examensarbete bidrar med riktlinjer för att fatta beslut om vilken energibesparingsstrategi som är bättre att använda beroende på IoT-scenariot och typen av applikation. Utvärderingen visar hur Queue Mode i många användningsfall är ett bättre alternativ än TSCH eftersom det uppnår en högre energieffektivitet utan att de andra typerna av mätvärden påverkas av det. I vissa fall uppnås dessutom förbättrade resultat även i de andra typerna av mätvärden. TSCH har endast bättre prestanda i krävande scenarier eller i fall där kommunikationen inte genereras vid bestämda tillfällen.Examensarbetet har genomförts hos Networked Embedded Systems-gruppen på RISE SICS AB.

The Internet of Things promises to be a key-factor in the forthcoming industrial and social revolution. The Internet of Things concept rely on pervasive communications where ’things’ are ’always connected’. The focus of the thesis is on Heterogeneous Networks for Internet of Things and Machine Type Communications. Heterogeneous Networks are an enabling factor of paramount important in order to achieve the ’always connected’ paradigm. On the other hand, Machine Type Communications are deeply different from Human-to-Human communications both in terms of traffic patterns and requirements. This thesis investigate both concepts. In particular, here are studied short and long range solutions for Machine-to-machine applications. For this work a dual approach has been followed: for the short-range solutions analysis an experimental approach has been privileged; meanwhile for the long-range solutions analysis a theoretical and simulation approach has been preferred. In both case, a particular attention has been given to the feasibility of the solutions proposed, hence solutions based on products that already exist in the market have been privileged.

The Internet of Things promises to be a key-factor in the forthcoming industrial and social revolution. The Internet of Things concept rely on pervasive communications where ’things’ are ’always connected’. The focus of the thesis is on Heterogeneous Networks for Internet of Things and Machine Type Communications. Heterogeneous Networks are an enabling factor of paramount important in order to achieve the ’always connected’ paradigm. On the other hand, Machine Type Communications are deeply different from Human-to-Human communications both in terms of traffic patterns and requirements. This thesis investigate both concepts. In particular, here are studied short and long range solutions for Machine-to-machine applications. For this work a dual approach has been followed: for the short-range solutions analysis an experimental approach has been privileged; meanwhile for the long-range solutions analysis a theoretical and simulation approach has been preferred. In both case, a particular attention has been given to the feasibility of the solutions proposed, hence solutions based on products that already exist in the market have been privileged.

Telecommunication technologies and networks are constantly changing; with the introduction of the GSM system the shift from wired to wireless telephony experienced a unique boom. Since then, behaviour and communication needs of users (i.e. subscribers) have undergone rapid changes from initially the need for pure wireless voice transmission to now data and multimedia content traffic. Introduction of the 3rd Generation (UMTS/IMT 2000) promised the delivery of these services and the integration with the Internet. However, legacy technologies and networks are not likely to be replaced soon, the different wireless and wired communication and information infrastructures will co-exist and will have to work, seemingly seamless, together. The here documented research work delivers basic mechanisms supporting this integration, therefore a variety of technologies from different areas, ranging from Software Radio technology to Object-Oriented computing, have been brought together to introduce reconfigurability to mobile communication networks. Distributed object computing technologies are evaluated and their application as signalling and support platforms for reconfigureable systems is shown in different examples. Other novelties are the introduction of a protocol for download of reconfiguration software, from various software sources, these sources include Smart Cards, wired outlets and Over-The-Air. Furthermore, an object-oriented framework for flexible, 'on-the-fly' protocol exchange has been developed; the mechanisms and architecture of this framework are described within this thesis. Combining protocol reconfiguration, software download and distributed platforms and focusing on control and management of reconfiguration have led to the design and definition of a reconfiguration management architecture. Functionality and structure of this architecture are documented, and its single modules are described. Providing means and mechanisms enabling management and control of reconfiguration within reconfigureable mobile communication networks is the purpose of this thesis. KM, Guildford, July 2001 Key words: reconfiguration, reconfiguration management. Software Radio, object-orientation, middleware, CORBA, Universal Control CHannel.

Wireless sensor networks used in smart cities and elsewhere collect large amounts of sensor data that needs to be made available to respective audiences and have proper visualization. There is a lack of mobile applications capable of visualizing sensor data coming from multiple sources using different protocols and data formats in a clear way; an application that is easy for anyone to use. This paper will present the development and evaluation of Smart City IoT which is an Android application for visualization of IoT data collected from wireless sensor networks. The resulting application Smart City IoT is designed to be modular to the core to allow for easy extension with new sensor types, communication protocols and data formats. It demonstrates that an Android application can be developed to support multiple sources with different protocols and have a unified visualization without requiring extensive set up.<br>Trådlösa sensornät som används i smarta städer och på annat håll samlar in stora mängder data som behöver göras tillgängliga för respektive publik och använda sig av lämpliga visualiseringar. Det är brist på mobila applikationer som är kapabla att visualisera sensordata som kommer från flera källor med olika protokoll och data format på ett tydligt sätt; en applikation som är enkel att använda. Den här rapporten kommer att presentera utvecklingen och valideringen av Smart City IoT vilket är en applikation till Android för att visualisera IoTdata hämtat från trådlösa sensor-nätverk. Den resulterande applikationen Smart City IoT är designad för att vara modulär i sin kärna för att tillåta enkel utbyggnad av nya sensortyper, kommunikationsprotokoll och dataformat. Den demonstrerar att en applikation för Android kan utvecklas med stöd för flera källor, med olika protokoll och ha en gemensam visualisering utan att kräva en omfattande konfiguration.

Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (pages 111-112).<br>As the "Internet of Things" (IoT) grows and becomes more prevalent in society, it is important that everyone is able to understand and take advantage of IoT technology. I present the IoT Embedded Companion, a system integrated with MIT App Inventor that allows users to design and program IoT applications alongside a mobile app. This system uses the same block-based programming language as MIT App Inventor and includes live development features that allow users to see changes to their application in real-time while it runs on the mobile device and IoT device. The resulting projects consist of a mobile application and autonomous IoT program that together create the IoT application. Both the mobile app and the IoT program share global variables that either system can read and write, allowing the components to act together as a single application. In addition to writing the IoT Embedded Companion, I designed a curriculum for a workshop to teach and test the IoT Embedded Companion targeting middle-school aged students and held two iterations of the workshop. My findings indicate that students as young as middle school level are able to understand the concepts of IoT and that learning about it expands their knowledge of computing capabilities.<br>by Kathryn Elizabeth Hendrickson.<br>M. Eng.

A WIoT is a wireless network of low-power sensing nodes placed on the human body. While operating, these networks routinely collect physiological signals to send to offsite medical professionals for review. In this manner, these networks support a concept known as pervasive healthcare in which patients can be continuously monitored and treated remotely. Given that these networks are used to guide medical treatment and depend on transmitting sensitive data, it is important to ensure that the communication channel remains secure. Symmetric pairwise cryptography is a traditional scheme that can be used to provide such security. The scheme functions by sharing a cryptographic key between a pair of sensors. Once shared, the key can then be used by both parties to encrypt and decrypt all future messages. To configure a WIoT to support the use of symmetric pairwise cryptography a key distribution protocol is required. Schemes for pre-deployment are often used to perform this distribution. These schemes usually require inserting key information into WIoT devices before they can be used in the network. Unfortunately, this need to manually configure WIoT devices can decrease their usability. In this thesis we propose and evaluate an alternative approach to key distribution that uses physiological signals derived from accelerometer and gyroscope sensors. The evaluation of our approach indicates that more study is required to determine techniques that will enable ballistocardiography-derived physiological signals to provide secure key distribution.

Within the Internet of Things (IoT) a need for new IP-compatible communication technologies has grown stronger during the last few years as the need to connect these IoT networks to the Internet has become increasingly more important. In this report, we evaluate IPv6 over the TSCH mode of IEEE 802.15.4e (6TiSCH) with the purpose of observing how different values for the enhanced beacon (EB) period affect certain network metrics such as delay, energy consumption, join time, and throughput. The EB period is a periodic message used in the Time Slotted Channel hopping (TSCH) protocol used to advertise the network. Our goal is to evaluate the effect of different EB periods on the network and determine if there would be a benefit of integrating SDN to change the EB period dynamically. To fulfill our goal, we will evaluate the effect of the change in EB period on the network metrics. This would be an indication that the 6TiSCH network benefits from an integration with SDN. The reason that we would draw this conclusion is because SDN would be capable of predicting the state of the network and from that update the EB period for the 6TiSCH network. Our results indicate that a lower EB period has a positive effect on join times in the network while a longer EB period has a positive effect on the end-to-end delay. Our results display a promising future for future research on the integration of SDN and 6TiSCH.

Abstract. Wireless communication has grown rapidly in the last two decades. New applications and advancement in technology is boosting the demand. Internet of things (IoT) is nowadays topic of discussion for everyone related to the wireless communication industry. IoT is a system of interconnected devices which can be people, animals, things or machines each with a unique identifier and the ability to transfer data over a network without any interaction with humans or computers. The aim of this thesis is system design of RF transceiver for IoT devices operating in wide area networks. Several service providers are struggling to capture the IoT market. In this thesis detailed system design of third generation partnership project (3GPP) newly specified user equipment category M1 also known as long term evolution machine (LTE-M) is presented. LTE-M can operate in both full duplex and half duplex and it uses the same signal structure as the current operational standard long term evolution (LTE). The designed transceiver is able to operate in half duplex and meet the performance requirement (95 % throughput) specified by 3GPP. Radio frequency transceivers have various architectures and each architecture has its own pros and cons associated with it. This transceiver is designed to be integrated in a wearable device. Constraints like small size and low power restrictions led to the choice of direct conversion architecture for the design. Simulations were performed in ADS to verify the theoretical results.

Cette thèse étudie le problème de planification des ressources pour les réseaux IoT longues portées basés sur les technologies NB-IoT et LoRa. Dans les deux cas, on suppose que les capteurs et les collecteurs sont distribués suivant des processus de points de Poisson spatial indépendants marqués par le caractère aléatoire du canal. Pour le NB-IoT, nous élaborons un modèle de dimensionnement statistique qui estime le nombre de ressources radio nécessaires en fonction du délai d’accès toléré, de la densité des nœuds actifs, des collecteurs et de la configuration de l’antenne. Pour le réseau LoRa, nous proposons une technique d’allocation de plusieurs sous-bandes pour atténuer le niveau élevé d’interférence induit par les nœuds qui transmettent avec le même facteur d’étalement. Pour allouer dynamiquement le facteur d’étalement et la puissance, nous présentons une approche d’apprentissage automatique avec multi-agents qui permet d’améliorer l’efficacité énergétique<br>In this thesis, we focus on radio resource planning issues for low power wide area networks based on NB-IoT and LoRa technologies. In both cases, the average behavior of the network is considered by assuming the sensors and the collectors are distributed according to independent random Poisson Point Process marked by the channel randomness. For the NB-IoT, we elaborate a statistical dimensioning model that estimates the number of radio resources in the network depending on the tolerated delay access, the density of active nodes, the collectors, and the antenna configuration with single and multi-user transmission. For the LoRa network, we propose a multi-sub band allocation technique to mitigate the high level of interference induced by nodes that transmit with the same spreading factor. To dynamically allocate the spreading factor and the power, we present a Q-learning multi-agent approach to improve the energy efficiency

In the Internet of things (IoT), many applications will require low-power and low-cost to achieve long lifetime and scale (respectively). These types of applications are referred to as massive IoT, as opposed to critical IoT, which emphasizes ultra-high reliability and availability and low latency. One type of network catering to massive IoT applications are Low-Power Wide Area Networks (LPWANs), and presently, many LPWAN standards are trying to assert their role in the IoT ecosystem. This thesis explores LPWANs from both technical and non-technical perspectives to ascertain their use-case versatility and influence on the future telecommunications’ landscape. With respect to spectrum, the studied LPWANs may be categorized as unlicensed LPWAN or licensed LPWAN. The prior category typically refers to proprietary solutions and in this thesis are represented by SigFox and LoRaWAN. The latter group includes EC-GSM-IoT, eMTC, and NB-IoT and can be considered synonymous with cellular LPWAN because they are designed to be integrated into existing cellular infrastructures. The results indicate that all of the different types of explored LPWANs support applications without strict downlink, payload size, and latency requirements. For use cases without these specific demands (typically sensors, meters, tracking, etc.), it is not a question of whether or not a network fulfills the requirements, but rather how flexible the requirements are. As a result the choice of network will be determined by non-technical aspects and a cost versus functionality trade-off where unlicensed LPWAN is typically cheaper. Hence, both categories of LPWANs offer a unique value proposition; therefore, they can be considered complementary. This notion is reinforced when looking at non-technical aspects such as ecosystem, regulation, network ownership and control, and network coordination, which differ quite significantly. Furthermore, unlicensed LPWANs are likely to be the vanguard of a new type of competitor offering the core service of connectivity.<br>Inom Internet of Things (IoT) kommer många applikationer att kräva låg effekt och låg kostnad för att uppnå en lång livstid och skala. Dessa typer av applikationer refereras till som massiv IoT, vilket står i motsats till kritisk IoT som kräver ultrahög tillförlitlighet och tillgänglighet och låg fördröjning. En typ av nätverk som ämnar tillgodose kraven av massiv IoT är Low-Power Wide Area Networks (LPWANs), och idag försöker många av dessa hävda sig inom IoT ekosystemet. Detta examensarbete undersöker LPWANs from ett teknisk och icke-tekniskt perspektiv för att utröna deras mångsidighet och påverkan på det framtida telekomlandskapet. Med avseende på spektrum kan de i detta examensarbete undersökta nätverken kategoriseras som olicensierat LPWAN eller licensierat LPWAN. Den tidigare hänvisar typiskt till proprietära lösningar och representeras i detta arbete av SigFox och LoRaWAN. Den senare kategorin består av EC-GSM-IoT, eMTC, och NB-IoT och kan betraktas som synonymt med mobil LPWAN eftersom de designade för att bli integrerade i existerande mobila nätverk. Resultaten indikerar att alla nätverk stödjer applikationer utan strikta krav när det gäller nedlänkens funktionalitet, mängden data per meddelande, och fördröjning. För applikationer utan dessa specifika krav (typiskt sensorer, mätare, spårning, etc.) är det inte en fråga om huruvida ett nätverk uppfyller kraven eller ej, utan snarare hur flexibla kraven är. Därför kommer valet av nätverk att bestämmas av icke-tekniska aspekter och en avvägning mellan kostnad och funktionalitet vari olicensierat LPWAN är vanligtvis billigare. Därmed erbjuder båda kategorier av nätverk en unik värde proposition och kan därför betraktas som komplementerande. Denna föreställning är förstärkt av att nätverken skiljer sig signifikant när det gäller deras icke-tekniska aspekter såsom ekosystem, reglering, ägandeskap och kontroll, och nätverks koordinering. Dessutom är olicensierade LPWANs troligen är förtruppen av en ny typ av konkurrent som erbjuder den grundläggande servicen av konnektivitet.

This report presents a project carried out for the company Cybercom by eight students from Linköping University. The aim of the project has been to develop a real-time multiplayer game using an existing system for communication between different devices. The game has been developed as a web app that contains multiple game modes. The specific development methodology that has been used throughout the project is presented in this report. This methodology has been iterative, agile and followed a simplified version of the Scrum framework. The end result of the project is a well functioning product that directly creates value for the customer, but also allows for further development.<br>I denna rapport presenteras ett projekt för företaget Cybercom utfört av åtta studenter från Linköpings universitet. Projektet har gått ut på att utveckla ett realtidsspel som använder sig av ett existerande system för kommunikation mellan enheter. Spelet har utvecklats som en webbapplikation och innehåller flera olika spellägen. I det genomförda projektet har en modifierad, nedskalad variant av arbetsmetodiken Scrum följts och denna presenteras i rapporten. Utvecklingen har därmed varit iterativ och agil. Resultatet av projektet är en väl fungerande produkt som direkt skapar värde för kunden, men även tillåter smidig vidareutveckling.

This thesis project explores two well-known real-time web technologies: WebSocket and WebRTC. It explores the use of a mobile phone as a gateway to connect wireless devices with short range of radio links to the Internet in order to foster an Internet of Things (IoT). This thesis project aims to solve the problem of how to collect real-time data from an IoT device, using the Earl toolkit. With this thesis project an Earl device is able to send real-time data to Internet connected devices and to other Earl devices via a mobile phone acting as a gateway. This thesis project facilitates the use of Earl in design projects for IoT devices. IoT enables communication with many different kinds of “things” such as cars, fridges, refrigerators, light bulbs, etc. The benefits of IoT range from financial savings due to saving energy to monitoring the heart activity of a patient with heart problems. There are many approaches to connect devices in order to create an IoT. One of these approaches is to use a mobile phone as a gateway, i.e., to act as a router, between IoT and the Internet. The WebSocket protocol provides efficient communication sessions between web servers and clients by reducing communication overhead. The WebRTC project aims to provide standards for real-time communications technology. WebRTC is important because it is the first real-time communications standard which is being built into browsers. This thesis evaluates the benefits which these two protocols offer when using a mobile phone as a gateway between an IoT and Internet. This thesis project implemented several test beds, collected data concerning the scalability of the protocols and the latency of traffic passing through the gateway, and presents a numerical analysis of the measurement results. Moreover, an LED module was built as a peripheral for an Earl device. The conclusion of the thesis is that WebSocket and WebRTC can be utilized to connect IoT devices to Internet.<br>I detta examensarbete utforskas två välkända realtidsteknologier på internet: WebSocket och WebRTC. Det utforskar användandet av en mobiltelefon som gateway för att ansluta trådlösa enheter - med kort räckvidd - till Internet för att skapa ett Internet of Things (IoT). Det här examensarbetet försöker med hjälp av verktyget Earl lösa problemet med hur insamlandet av realtidsdata från en IoT-enhet skall genomföras. I det här examensprojektet kan en Earl-enhet skicka data i realtid till enheter med Internetanslutning, samt till andra Earl-enheter, med hjälp av en mobiltelefon som gateway. Detta projektarbete förenklar användandet av Earl i design-projekt ör IoT-enheter. IoT tillåter kommunikation mellan olika sorters enheter, så som bilar, kyl- och frysskåp, glödlampor etc. Fördelarna med IoT kan vara allt från ekonomiska - tack vare minskad energiförbrukning - till medicinska i form av övervakning av puls hos patienter med hjärtproblem. Det finns många olika tillvägagångssätt för att sammankoppla enheter till ett IoT. Ett av dessa är att använda en mobiltelefon som en gateway, dvs en router mellan IoT och internet. WebSocket-protokollet erbjuder effektiv kommunikation mellan web-servrar och klienter tack vare minskad överflödig dataöverföring. WebRTC-projektet vill erbjuda standarder för realtidskommunikation. WebRTC är viktigt då det är den första sådana standarden som inkluderas i webläsare. Det här examensarbetet utvärderar fördelarna dessa två protokoll erbjuder i det fallet då en mobiltelefon används som gateway mellan ett IoT och Internet. I det här examensprojektet implementerades ett flertal testmiljöer, protokollens skalbarhet och fördröjningen av trafiken genom mobiltelefonen (gateway) undersöktes. Detta presenteras i en numerisk analys av mätresultaten. Dessutom byggdes en LED-modul som tillbehör till en Earl-enhet. Slutsatsen av examensarbetet är att WebSocket och WebRTC kan användas till att ansluta IoT-enheter till Internet.

This thesis proposes some solutions to relieve, using Wi-Fi wireless networks, the data consumption of cellular networks using cooperation between nodes, studies how to make a good deployment of access points to optimize the dissemination of contents, analyzes some mechanisms to reduce the nodes' power consumption during data dissemination in opportunistic networks, as well as explores some of the risks that arise in these networks. Among the applications that are being discussed for data off-loading from cellular networks, we can find Information Dissemination in Mobile Networks. In particular, for this thesis, the Mobile Networks will consist of Vehicular Ad-hoc Networks and Pedestrian Ad-Hoc Networks. In both scenarios we will find applications with the purpose of vehicle-to-vehicle or pedestrian-to-pedestrian Information dissemination, as well as vehicle-to-infrastructure or pedestrian-to-infrastructure Information dissemination. We will see how both scenarios (vehicular and pedestrian) share many characteristics, while on the other hand some differences make them unique, and therefore requiring of specific solutions. For example, large car batteries relegate power saving techniques to a second place, while power-saving techniques and its effects to network performance is a really relevant issue in Pedestrian networks. While Cellular Networks offer geographically full-coverage, in opportunistic Wi-Fi wireless solutions the short-range non-fullcoverage paradigm as well as the high mobility of the nodes requires different network abstractions like opportunistic networking, Disruptive/Delay Tolerant Networks (DTN) and Network Coding to analyze them. And as a particular application of Dissemination in Mobile Networks, we will study the malware spread in Mobile Networks. Even though it relies on similar spreading mechanisms, we will see how it entails a different perspective on Dissemination.

In the last 20 years mobile devices gained an important role in daily life and became must have items for everyone. As mobile devices give us the much needed flexibility and mobility, they also represent one major concern; security. As the information is transmitted from node to node via radio frequencies, an imposter can gain access into a mobile network without the need to gain physical access to firewalls and gateways. Also, as they are light and small, mobile devices are easily lost and often used without any PIN or password protection enabled. Hence, it is not difficult for someone even without any technical knowledge to gain access to such devices if they have been left behind or stolen. As traditional intrusion detection systems are not very effective against this kind of attack, there is a need of a different approach that can assist in the identification of a potential imposter. This thesis begins by assessing the security needs of the mobile devices, and establishes the perceived inadequacy of existing safeguards in this respect. Therefore this research considers using Behaviour-Based Mobile Intrusion Detection System (BeMIDS) that aims to assist the identification of anomalous user activity. This in return presents the two main characteristics needed to classify a legitimate user inside a mobile network: first with whom, when and what type of connection is established and then at where the mobile device is left open. After this the research proposes a novel approach that investigates the application of three machine learning algorithms to profile user behaviour in mobile networks. In BeMIDS, historical user profiles are created and then compared with the real-time ones in order to detect unusual activity in mobile networks. If a user’s behaviour changes, this results in alerting the system as an anomalous activity. Specific examples of behaviours that BeMIDS appears to be particularly sensitive to include duration (of calls and of connection with cell towers), time of day (calls are made and cell towers are connected), and frequency of caller usage. In order to classify a legitimate user over a mobile network the thesis then validates this approach by implementing C4.5, RIPPER and SOM algorithms over MIT’s Reality Mining Dataset. The results support the proposed architecture and present accuracy rate as high as 96% for call logs and 94% for tower logs under training conditions.

This thesis explores the physical layer feasibility, performance and limitations of MANETs through simulation and evaluation of a novel application scenario. The results of the work are intended to help researchers understand how and where MANETs can be used in the future, as well as to better understand physical layer considerations and methods of improving the physical layer performance of large scale, highly mobile MANETs. The thesis also investigates the effect and feasibility of using fixed relay or dispatch points that act as intermediate relays or source/sinks for messages. The results show the relative benefits of using relays vs. dispatch points, as well as the differences owing to the position, configuration and number of fixed points. We are then able to deduce the optimum configuration and type of fixed nodes to use to achieve the best results under various circumstances. Given the limited unlicensed spectrum available and the potentially high number of nodes in a bounded area, it is likely that interference will become a significant limiting factor for performance. The thesis explores this and other related issues to discover the significance of their effects and the necessary bounds for reasonable performance. We also explore the use of various techniques to mitigate these effects. The thesis concludes by investigating the issue of cooperation incentives. Without sufficient nodes cooperating to provide relaying functions, a MANET cannot function properly. Consequently various proposals have been made which provide incentives for individual users of a MANET to cooperate with each other. We examine the drawbacks of currently proposed incentive systems and propose a new solution.

In the current mobile network architecture, network traffic between user equipment (UE) and services deployed on the public cloud is tromboned towards the anchor point which could lead to network congestion. Deploying services closer to the UE, for example near the eNodeB, is a potential solution. The services are deployed on small scale data centers connected to, or collocated with the eNodeB, called ’eNodeB-Cloud’ (eNBC). Mobility of UEs presents a challenge for deploying services in an eNBC. When the UE is handed over from one eNodeB to another, seamless migration of UE context between the service instances running in different eNBCs needs to be ensured. In this thesis, we propose a Platform as a Service framework to enable UE context migration between eNBCs. The architecture consists of handover signaling mechanism, network session migration technology, context transfer protocol and a set of APIs towards the service. The evaluation of the prototype implementation shows that virtualization causes some extra delays to the UE context migration time. Whereas when virtualization is omitted, the time taken to migrate a UE context between two eNBCs is in the order of 12 ms on average, which is within the limit of handover interruption time between two LTE-eNodeBs.

Given a set of positions for wireless nodes, the interference minimization problem is to assign a transmission radius (i.e., a power level) to each node such that the resulting communication graph is connected, while minimizing the maximum (respectively, average) interference. We consider the model introduced by von Rickenbach et al. (2005), in which each wireless node is represented by a point in Euclidean space on which is centered a transmis- sion range represented by a ball, and edges in the corresponding graph are symmetric. The problem is NP-complete in two or more dimensions (Buchin 2008) and no polynomial-time approximation algorithm is known. We show how to solve the problem efficiently in settings typical for wireless ad hoc networks. We show that if node positions are represented by a set P of n points selected uniformly and independently at random over a d-dimensional region, then the topology given by the closure of the Euclidean minimum spanning tree of P has O(log n) maximum interference, O(1) average inter- ference with high probability and O(1) expected average interference. This work is the first to examine average interference in random settings. We extend the first bound to a general class of communication graphs over a broad set of probability distributions. We present a local algorithm that constructs a graph from this class; this is the first local algorithm to provide an upper bound on expected maximum interference. To verify our results, we perform an empirical evaluation using synthetic as well as real world node placements.

<p> Wireless sensor networks has been growing rapidly over the past few decades. Due to their flexibility, wireless sensor networks have been in practice in many areas. Unlike other network architectures, Mobile Ad hoc networks (MANETs) have no central architecture; every node is free to work both as a transmitter and receiver and it depends on neighboring nodes to send relay messages. Due to their advantages, MANETs are used in many different applications like health care and military. However the wide distribution of MANETs makes it vulnerable to malicious attacks. Hence it is necessary to design a secure system for MANETs. In this report, we implement a secure system named Enhanced Adaptive Acknowledgement especially for MANETs. To ensure higher security and reduce the network overhead and delay, we use a different approach called hybrid cryptography in our proposed scheme. Enhanced Adaptive Acknowledgment detects higher malicious attackers without greatly disturbing the network performances. In the simulation we compare the differences within the Enhanced Adaptive Acknowledgment (EAACK) before and after introducing the Hybrid cryptography approach.</p>

Recent advances in processor speeds, mobile communications and battery life have enabled computers to evolve from completely wired to completely mobile. In the most extreme case, all nodes are mobile and communication takes place at available opportunities – using both traditional communication infrastructure as well as the mobility of intermediate nodes. These are mobile opportunistic networks. Data communication in such networks is a difficult problem, because of the dynamic underlying topology, the scarcity of network resources and the lack of global information. Establishing end-to-end routes in such networks is usually not feasible. Instead a store-and-carry forwarding paradigm is better suited for such networks. This dissertation describes and analyzes algorithms for forwarding of messages in such networks. In order to design effective forwarding algorithms for mobile opportunistic networks, we start by first building an understanding of the set of all paths between nodes, which represent the available opportunities for any forwarding algorithm. Relying on real measurements, we enumerate paths between nodes and uncover what we refer to as the path explosion effect. The term path explosion refers to the fact that the number of paths between a randomly selected pair of nodes increases exponentially with time. We draw from the theory of epidemics to model and explain the path explosion effect. This is the first contribution of the thesis, and is a key observation that underlies subsequent results. Our second contribution is the study of forwarding algorithms. For this, we rely on trace driven simulations of different algorithms that span a range of design dimensions. We compare the performance (success rate and average delay) of these algorithms. We make the surprising observation that most algorithms we consider have roughly similar performance. We explain this result in light of the path explosion phenomenon. While the performance of most algorithms we studied was roughly the same, these algorithms differed in terms of cost. This prompted us to focus on designing algorithms with the explicit intent of reducing costs. For this, we cast the problem of forwarding as an optimal stopping problem. Our third main contribution is the design of strategies based on optimal stopping principles which we refer to as Delegation schemes. Our analysis shows that using a delegation scheme reduces cost over naive forwarding by a factor of O(√N), where N is the number of nodes in the network. We further validate this result on real traces, where the cost reduction observed is even greater. Our results so far include a key assumption, which is unbounded buffers on nodes. Next, we relax this assumption, so that the problem shifts to one of prioritization of messages for transmission and dropping. Our fourth contribution is the study of message prioritization schemes, combined with forwarding. Our main result is that one achieves higher performance by assigning higher priorities to young messages in the network. We again interpret this result in light of the path explosion effect.<br>Thomson Research, Paris; National Science Foundation (CCR-0325701, ANI-0322990); HAGGLE FET Project; Erramilli family.

The Internet-of-Things (IoT) is envisioned as a promising paradigm for carrying the interconnections of massive devices through various communications protocols. With the rapid development of fifth-generation (5G), IoT has incentivized a large number of new computation-intensive applications and bridges diverse technologies to provide ubiquitous services with intelligence. However, with billions of devices anticipated to be connected in IoT systems in the coming years, IoT devices face a series of challenges from their inherent features. For instance, the IoT devices are usually densely deployed, and the vast data exchange among numerous devices will cause large overheads and communication/computing resource limitations. Integrated with mobile edge computing (MEC), which pushes the computation and storage resources to the edge of the network much closer to the local devices, IoT systems will benefit from a low propagation delay and privacy/security enhancement. Hence, merging MEC and IoT is a new promising paradigm for task offloading and resource allocation in future wireless communications in mobile networks. In this thesis, we introduce different task offloading and resource allocation strategies for IoT devices to efficiently utilize the limited resource, e.g., spectrum, computation, and budget. Bandit learning (BL), a typical online learning approach, offers a promising solution to deal with the communication/computing resource limitation. The inherent idea behind MEC is to design policies to make a better selection for devices or MEC servers. This coincides with the design purpose of BL. This match-in mechanism provides selection policies for better performance, such as lower latency, lower energy consumption, and higher task completion ratio.

Internet of Things(IoT) has in recent years become a topic of broad and current interest. The purpose of this thesis is to anticipate weather conditions by constructing a system for collecting information about atmospheric pressure. The development of the system will solve the following problem: it should be possible to implement a system that allows for the collection of information from sensors through a mobile phone. The problem was solved through an iOS application together with a Micro Controller Unit (MCU) and a sensor. To collect weather data, the BME280, with its atmospheric pressure, temperature and humidity sensor, was used. Bluetooth was chosen for the interaction between the Automat and the iOS application. This proved to be a possible solution to a problem in a growing area of application. An advantage to this hardware solution is the mobility and flexibility of the Automat, making it ideal for mobile IoT solutions. Arduino is, however, the better choice for developers, as it has a larger community and clear documentation.<br>Internet of Things (IoT) har på senare år blivit ett alltmer omtalat område. Syftet med tesen är att förutspå väderförhållanden genom att konstruera ett IoT system som samlar in information om lufttryck, detta för att besvara frågeställningen: Det bör gå att samla in sensordata med hjälp av mobiltelefon. För att besvara detta följdes Ekholms modell för teknisk forskning och arbetsmetoden Scrum. Frågestallningen löstes genom en iOS applikation med tillhörande Microcontroller Unit(MCU) och sensor. För att samla in väderdata användes sensorn BME280, som har lufttrycks-, temperaturoch luftfuktighetssensorer, tillsammans med MCU:n Automat. För interaktionen mellan Automat och iOS applikationen tillämpades bluetooth-kommunikation. Detta var en möjlig lösning på ett problem i ett växande tillämpningsområde. Fördelar med denna lösning av hårdvara är att den är välanpassad till mobila IoT lösningar tack vare Automats minimala storlek i förhållande till funktionalitet. I många fall är däremot Arduino ett bättre val för utvecklaren, då den har större samfund och tydligare dokumentation.

The increased globalisation of information and communication technologies has transformed the world into the internet of things (IoT), which is accomplished within the resources of wireless sensor networks (WSNs). Therefore, the future IoT networks will consist of high density of connected nodes that suffer from resource limitation, especially the energy one, and distribute randomly in a harsh and large-scale areas. Accordingly, the contributions in this thesis are focused on the development of energy efficient design protocols based on optimisation algorithms, with consideration of the resource limitations, adaptability, scalability, node density and random distribution of node density in the geographical area. One MAC protocol and two routing protocols, with both a static and mobile sink, are proposed. The first proposed protocol is an energy efficient hybrid MAC protocol with dynamic sleep/wake-up extension to the IEEE 802.15.4 MAC, namely, HSW-802.15.4. The model automates the network by enabling it to work exibly in low and high-density networks with a lower number of collisions. A frame structure that offers an enhanced exploitation for the TDMA time slots (TDMAslots) is provided. To implement these enhanced slots exploitation, this hybrid protocol rst schedules the TDMAsslots, and then allocates each slot to a group of devices. A three-dimensional Markov chain is developed to display the proposed model in a theoretical manner. Simulation results show an enhancement in the energy conservation by 40% - 60% in comparison to the IEEE 802.15.4 MAC protocol. Secondly, an efficient centralised clustering-based whale optimisation algorithm (CC- WOA) is suggested, which employs the concept of software de ned network (SDN) in its mechanism. The cluster formulation process in this algorithm considers the random di- versi cation of node density in the geographical area and involves both sensor resource restrictions and the node density in the tness function. The results offer an efficient con- servation of energy in comparison to other protocols. Another clustering algorithm, called centralised load balancing clustering algorithm (C-LBCA), is also developed that uses par- ticle swarm optimisation (PSO) and presents robust load-balancing for data gathering in IoT. However, in large scale networks, the nodes, especially the cluster heads (CHs), suffer from a higher energy exhaustion. Hence, in this thesis, a centralised load balanced and scheduling protocol is proposed utilising optimisation algorithms for large scale IoT net- works, named, optimised mobile sink based load balancing (OMS-LB). This model connects the impact of the Optimal Path for the MS (MSOpath) determination and the adjustable set of data aggregation points (SDG) with the cluster formulation process to de ne an op- timised routing protocol suitable for large scale networks. Simulation results display an improvement in the network lifespan of up to 54% over the other approaches.