Rozprawy doktorskie na temat „NB-IoT NETWORKS”

Low Power Wide Area Networks (LPWAN) are able to combine long range communication with a low energy consumption sacrificing performance in terms of bit rate and message frequency. This thesis presents a general evaluation of the LPWAN characteristics and a description of the LPWAN protocols LoRaWAN, SigFox and NB-IoT. It also covers a method to evaluate if a LPWAN technology would be a suitable choice of communication technology for a certain use case. Lastly, it covers the implementation of LoRaWAN on a connected electromechanical lock and investigates in the real life performance of the lock by using eight nodes in two case studies involving four locations each. The lock was evaluated from how often it was able to send a heartbeat (a status message), how reliable the communication was, what latency a user could expect and how much energy a data transmission required. Two of the eight nodes were placed in a deep indoor environment. One of them, located 0.794 km from a gateway was able transmit every 150th second. The other one located 1.85 km from a gateway was not able to successfully deliver any packets at all. Five nodes were able to transmit most heartbeats within 10 seconds. The Packet Delivery Ratio (PDR) was below 90% for all locations except for one. In this location, the node was placed close to a large window and managed to communicate with a gateway 3.22 km away with a PDR of 97% and almost exclusively with less than 10 seconds between transmission. The results in this thesis show the potential in LoRaWAN but highlights how dependent the performance will be of the placement of the lock.
Genom att kombinera låg dataöverföringshastighet och låg meddelandefrekvens kan LPWAN uppnå en kommunikation med lång räckvidd och låg energiförbrukning. Denna uppsats går igenom vad som karaktäriserar LPWAN i stort samt presenterar LPWAN-protokollen LoRaWAN, SigFox och NB-IoT. Den visar även en metod vilken kan användas för att utvärdera hur väl ett use case lämpar sig för LPWAN-tekniken. Slutligen görs en implementering av LoRaWAN i ett uppkopplat lås från ASSA ABLOY för att undersöka vilken prestanda som är möjlig att uppnå för åtta olika noder i två olika fallstudier. Låset utvärderades utfirån hur ofta det kunde skicka statusmeddelanden, hur tillförlitlig kommunikationen var samt hur mycket energi som förbrukades. Två av åtta noder placera-des långt in i sina respektive byggnader, den ena kunde endast skicka statusuppdateringar i intervaller om 150 sekunder och den andra lyckades inte leverera några datapaket alls. Fem noder lyckades skicka de flesta statusuppdateringerna i intervall under tio sekunder. Resultatet visade på en packet delivery ratio under 90% i samtliga fall förutom ett. Där placerades noden nära ett stort fönster och lyckades kommunicera med en gateway 3.22 km bort med en PDR på 97% och mindre än 10 sekunder mellan sändningarna. Detta resultat visar potentialen för LoRaWAN men belyser även hur beroende prestandan kommer att vara av hur låset placeras.

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.

The United States Federal Communications Commission (FCC) in its recent report and order has prescribed the creation of Citizens Broadband Radio Service (CRBS) in the 3.5 GHz band to enable sharing between wireless broadband devices and incumbent radar systems. This sharing will be enabled by use of geolocation database with supporting infrastructure termed as Spectrum Access System (SAS). Although using SAS for spectrum sharing has many pragmatic advantages, it also raises potentially serious operational security (OPSEC) issues. In this thesis, we explore OPSEC, location privacy in particular, of incumbent radars in the 3.5 GHz band. First, we show that adversarial secondary users can easily infer the locations of incumbent radars by making seemingly innocuous queries to the database. Then, we propose several obfuscation techniques that can be implemented by the SAS for countering such inference attacks. We also investigate obfuscation techniques' efficacy in minimizing spectral efficiency loss while preserving incumbent privacy. Recently, the 3GPP Rel.13 has specified a new standard to provide wide-area connectivity for IoT, termed as Narrowband IoT (NB-IoT). NB-IoT achieves excellent coexistence with legacy mobile standards, and can be deployed in any of the 2G/3G/4G spectrum (450 MHz to 3.5 GHz). Recent industry efforts show deployment of IoT networks in unlicensed spectrum, including shared bands (e.g., 3.5 GHz band). However, operating NB-IoT systems in the 3.5 GHz band can result in significant BLER and coverage loss. In this thesis, we analyse results from extensive experimental studies on the coexistence of NB-IoT and radar systems, and demonstrate the coverage loss of NB-IoT in shared spectrum.
Master of Science

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.
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.

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
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

The Internet of Things (IoT) is a fundamental pillar in the digital transformation since it enables the interaction with the physical world by means of sensing and actuation. 3GPP recognized the importance of IoT by introducing new features aimed at supporting this technology. In details, in Rel.13, the 3GPP has launched the NB-IoT to provide support for LPWAN. Since these devices will be distributed also in such area where the terrestrial networks are not feasible or commercially viable, satellite networks will have a complementary role thanks to their capability to provide worldwide connectivity through their large footprint size and short service deployment time. In this context, the aim of this thesis is to analyze the feasibility of integration of the NB-IoT technology with satellite communication systems focusing on the Random-Access Procedure. Indeed, the RA is the most critical procedure since it allows the UE to achieve uplink synchronization, obtain the permanent ID, and get the resources for the uplink transmission. The objective of the thesis is the assessment of the preamble detection in the SatCom environment. The elaborate is divided in four chapters: the first one highlights the main characteristics of the NBIoT technology. In the second chapter, a detail description of the synchronization and RA procedures is presented with a review of the Stat of Art of the detection of the preamble; in the third chapter the main features of SatCom systems are shown, with particular emphasis on the impairments which could hamper the RA procedure. In the fourth chapter, a thorough analysis on the detection process and the implementation of the transmission and reception chain, obtained by the means of simulator built in MATLAB, are provided, with the results. Finally, chapter five concludes this work.

L'Internet des objets (IoT, pour Internet of Things, en anglais) ouvre la porte vers la réalisation de nouvelles applications, telles que les compteurs intelligents et le suivi environnemental, destinées à adresser nos défis sociétaux et écologiques actuels et futurs. Les objets, possiblement mobiles ou distants, nécessitent une connectivité sans fil pour la centralisation des données et le contrôle à distance. Les réseaux longue portée et basse consommation (LPWA, pour Low Power Wide Area, en anglais) offrent des transmissions radio bande étroite avec une couverture à l’échelle typique d’une ville, tout en respectant les contraintes de consommation énergétique bas coût des objets. Intégrer la possibilité de localiser ces objets ajouterait de la valeur à leurs données et permettrait leur suivi géographique. Voilà pourquoi c'est un domaine de recherche très actif actuellement. L'utilisation du temps de propagation des signaux radio de communication, sans intégration supplémentaire de modules matériels dédiés à la localisation, est une approche très intéressante pour la complexité, la consommation et le coût des objets. Néanmoins la radio localisation dans les réseaux LPWA pose des défis liés d'une part aux transmissions à bande étroite qui n'offrent pas une résolution temporelle suffisante et d'autre part aux canaux de propagation qui peuvent introduire des biais sur les estimées de position. Cette thèse adresse ces défis en étudiant un système de mesure multicanaux de distance pour les réseaux LPWA. La combinaison cohérente des signaux bande étroite transmis séquentiellement sur des canaux différents améliore la précision d’estimation des temps de propagation et permet de résoudre en partie les multi-trajets pour une meilleure précision de localisation. Cette technique basée sur les signaux à bande instantanée étroite conserve la capacité longue portée des transmissions et reste compatible avec les réseaux LPWA. Un modèle détaillé prenant en compte les imperfections matérielles ainsi que les besoins protocolaires pour la synchronisation en temps, fréquence et phase est développé. Basé sur ce modèle, les variantes des architectures des émetteurs-récepteurs radios et leurs impacts sur la cohérence de phase pour l’estimation multicanaux de distance sont discutés. Les limites théoriques de précision sont dérivées pour la propagation en espace libre et dans des canaux de propagation multi-trajets, illustrant l’amélioration de précision possible entre l'approche multicanaux et l'approche monocanal pour l'estimation de distance. Des estimateurs de distance sont développés et appliqués aux signaux radio simulés afin de montrer que leurs performances atteignent les limites théoriques. Ces résultats de simulation sont validés avec des expérimentations menées avec un démonstrateur implémenté avec une radio logicielle (SDR, pour Software Defined Radio, en anglais). Les tests terrains réalisés en environnement urbain permettent de confirmer l'apport d'un système d'estimation multicanaux de distance, en combinaison avec du traitement de signal avancé, pour fournir une fonctionnalité de localisation intrinsèque et précise pour les réseaux LPWA
The Internet of Things (IoT) is an enabler to new applications, such as smart metering and environmental monitoring, intended to address current and future societal and ecological challenges. Things, possibly mobile or in distant locations, require wireless connectivity for data collection and remote control. Low Power Wide Area (LPWA) networks provide city-scale long-range, narrowband radio transmissions respecting the energy constraints of battery-powered low-cost objects. Being capable to localize these objects will add value to their data, enables tracking applications and is therefore a demanded and recent research topic. Precise and accurate radio signal delay based positioning without integrating additional hardware but taking advantage of intrinsic wireless communication signals is appealing in terms of device complexity, cost and energy consumption. However, radio localization within LPWA networks is challenging due to narrowband transmissions, resulting in a lack of delay precision as well as due to radio propagation channels, which degrade the accuracy of location estimates. This work addresses both challenges by investigating a multi-channel ranging system for LPWA networks. Coherently combining multiple sequentially transmitted narrowband signals on different radio channels improves delay estimation precision and allows resolving multipath channels for refined positioning accuracy. This scheme, based on instantaneous narrowband signals, conserves the LPWA long-range feature and is hence compatible with LPWA networks. A detailed signal model considering hardware imperfections as well as the required protocol exchanges for time, frequency and phase synchronization is developed. Based on this model, the requirements on radio transceiver architectures regarding the necessary phase coherence for multi-channel ranging are discussed. Lower bounds on the ranging precision are derived for both, free-space and multipath propagation channels, illustrating the improved precision compared to narrowband single channel ranging. Numerical simulations of radio signals for the two-way multi-channel ranging protocol illustrate that the performance of developed range estimators attains the theoretical precision bound and pave the way towards implementation. A flexible Software Defined Radio (SDR) based demonstrator is implemented to validate simulation results. Field trials in real urban outdoor environments are in accordance with simulation results and prove how scalable multi-channel ranging, in combination with advanced signal processing methods, will be an enabler towards precise and accurate localization in LPWA networks

Nowadays it is more clear that the Internet of things (IoT) is not a transient trend but a completely new industry. The internet of things has the capability to enhance current industries (Industry 4.0), as well as to help protecting the environment and people. The latter is the case with the system developed and described in this thesis. The possibilities that IoT brings are due to the interconnection of heterogeneous embedded devices to the internet. This thesis focus on LPWANs (Low Power Wide Area Networks), which is a new set of technologies specifically design for the needs of IoT devices.Due to the recent deploy of NB-IoT (Narrow Band IoT) networks it has become more difficult to know what LPWAN is best for a certain application. Thus, the first half of this thesis involves the comparative study of NB-IoT and LoRaWAN LPWANs. This comparison required an in depth study of each technology, specially on the physical and datalink layers. The comparison briefly displays the main characteristics of each technology and explain the main conclusions in a concise manner. The second part of the thesis describes the development of a GNSS tracker. This tracker will be used on train wagons carrying goods that are dangerous for people and the environment. This thesis report describes the different steps taken, from the requirement specification to the partial development of the software.

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
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
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.
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
TESIS

Diploma thesis deals with the implementation of LTE Cat-M1 technology in simulator NS--3 (Network Simulator 3). The theoretical part of the thesis summarizes key terms concerning IoT (Internet of Things), M2M (Machine-to-Machine) communication, LTE (Long Term Evolution) and LPWA (Low-Power Wide Area) networks. The practical part summarizes the possibilities of currently available modules for cellular technologies for NS-3, ie. the LENA module and the subsequent extension of LENA+ and ELENA. Simulation scenarios offer a comparison of LTE/LTE-A and LTE Cat-M1 (also known as eMTC - enhanced Machine Type Communication) technologies for M2M communication. The results of the simulations are well-arranged in the form of graphs and discussed at the end of the thesis.

Technology Narrowband IoT is a representative LPWA (Low Power Wide Area) tech-nology that due to its promising features aims for demands of the Internet of Thingsapplications for autonomous data sending from sensors in areas of poor mobile coverage.For such applications, it is beneficial to firstly map properties of communication technol-ogy in areas of intended use and evaluate whether or not is this technology applicable.This Master thesis deals with the design of the hand-held measuring device for evaluationof Narrowband IoT properties. The output of this thesis is firstly comparison of LPWAtechnologies secondly, design of the mentioned device and verification of its functional-ity. And in last part description of measurement of transmission delay for delay-tolerantapplications. Transmission delay is a critical parameter for delay-tolerant applications.Such an application can be, for example, smart electrometers for which there is definedmaximal allowed transmission delay of 10 seconds and therefore it is desirable to evalu-ate whether or not is the deployment of the communication technology Narrowband IoTsuitable in the intended area for delay-tolerant or even for delay-intolerant applications.

1.1 Introduction Cellular technologies are evolving to help connect people and with the ever-increasing demand for and provision of Internet access. During this development cycle, there has been an increase in data speed, a decrease in latency and an improvement in the overall quality of communication that is carried out using the wireless medium. However, mobile networks are not only developing in this direction. There is an increase in aspects of the Internet of Things and machine-to-machine communication. This aspect is not new as such, but is gaining more and more popularity for various existing and new use cases that would enable a better connected world where technology enables such connectivity to improve the overall quality of life, safety and efficiency of various tasks. The concept is popularly known as the Internet of Things (IoT) and covers machine-to-machine (M2M) and machine-to-machine (MTC) communications with device use cases ranging from video surveillance requiring higher data rates to meter monitoring requiring very small, intermittent data capabilities . . The networks used to connect these IoT devices are usually referred to as Low Power Wide Area Networks (LPWAN) due to the nature of the devices that connect to such networks. The Narrowband IoT (a.k.a. NB-IoT) industry is on the rise. The most unique characteristic of NB-IoT is that it can be deployed over the operators existing network on the existing spectrum bands. One important feature of NB-IoT includes effective and efficient indoor coverage which cannot be matched by any other technology in this industry. It supports connections with massive low-throughput and low-cost devices. Low power consumption and optimized network architecture are some of the additional advantages worth mentioning. It is expected that NB-IoT will soon evolve into a large-scale deployment across various industries and across the world. The LPWAN market has existed for a decade now. The existing solutions in the market are fragmented and not standardized, hence leading to shortcomings like poor reliability, poor security, high operational and maintenance costs. Furthermore, the new overlay network deployment is not simple and involves lot of complexities. [22] NB-IoT overcomes the above issues by providing ubiquitous coverage, faster network upgrade, low power consumption, very long battery life, low cost terminal devices, high reliability and high carrier-class network security. The initial investment in the network implementation can be quite substantial and the superimposed costs are very little. In such a scenario, NB-IoT proves to be an ideal solution to the LPWA requirements. Moreover, it enables the communication service providers (CSPs) to enter into this new field. Traditional applications like smart tracking, smart metering, smart agriculture, smart parking, etc. can be provided by NB-IoT at and ultra-low cost ($5) per module and a extremely high connectivity (100K/cell) and opens up more industry opportunities like smart city, smart health and other low data rate applications yet to be uncovered. [22] NB-IoT is a new mobile radio access technology specified by the 3GPP in version 13 to address the rapidly expanding market for low power broadband connectivity. To ensure broad coverage and widespread adoption of NB-IoT services, MNOs (Mobile Network Operators) must ensure that devices and end-to-end services from different operators must connect to the NB-IoT systems that have been deployed. Data transfer options and connection modes must be well understood. [23] Various guidelines are available for the design and deployment of NB-IoT networks. This is done to ensure interoperability and smooth roaming. The GSMA guide contains the functions standardized in 3GPP Release 10-13, regarding the key functions that will be deployed in the coming time. The GSMA provided recommendations based on entry and implementation plans shared by members of the NB-IoT Operator Forum, which plan to roll out NB-IoT networks in more than 40 countries in Europe, the Middle East and Africa, South America and APAC, including Japan, China and South Korea.. Machine type correspondence (MTC) has a trademark which is expansive range of capacities. For instance, CCTV observation cameras need to convey immense measure of uplink (UL) information while being practically fixed. Then again, gadgets for armada following, pet following, and so on have a limited quantity of information while playing out a great deal of handovers. One more class of gadgets has neither of these abilities. Models for these incorporate gadgets for metering including power, gas or water utilization. These are many times standard and needn't bother with a streamlined handover. Non-defer delicate data is typically moved in little Delhi Technological University Study of Cellular-IoT and Development of a Business Case for Smart Campus Page 7 sums as it were. Nonetheless, the quantity of developing MTC gadgets might turn out to be very enormous, even up to a few significant degrees contrasted with the conventional gadgets. In any event, utilizing the current fast organizations would prompt an organization clog, in light of the fact that notwithstanding of their modest quantity of client information, how much flagging is about something very similar. The principal detail of NB-IoT focusses on this class of gadgets. These gadgets are frequently introduced at places without power supply. Subsequently, they run totally on battery and it could be extravagant to change the battery, since they may just be gotten to via prepared staff. Consequently, the battery lifetime now and again could decide the lifetime of the entire gadget. An enhanced power utilization is in this way fundamental for a legitimate activity. Moreover, the inclusion at these spots is in many cases very terrible. Subsequently, the indoor inclusion must be fundamentally improved, up to 23 dB are viewed as required. In this research, I have attempted to addresses the specialized potential outcomes of the equipment and programming engineering for terminals in view of LTE Feline M. I have attempted to give examinations that feature the contrasts between LTE Feline M and different classifications. Likewise, I have depicted the potential distinctions in structures among classes and how I can profit from the proposed changes in LTE Feline M. I have moreover tended to the LTE-NB (LTE Restricted Band) proposition that exist in 3GPP and contrasted them and existing advancements. Other contending advancements will likewise be contrasted with the LTE classifications and proposed classifications, featuring upsides and downsides. 1.2 Objective We at Delhi Technological University (DTU) are trying to develop a theoretical business pilot of a smart campus keeping the DTU Campus as a reference for the research. The main aim of this research is to improve the systems which exist and may also call for a full replacement of the existing system in case of implementing this pilot project. Under this project I plan to cover various domain including – smart classrooms, smart attendance, smart infrastructure including water and electricity management, smart parking, smart monitoring, pet tracking, implementation of AR/VR to improve the classroom experience, flipped classrooms, etc. With the advancements in technology, there has always been a change in the way the existing system operates. Technological advancements help in better capturing the requirements and data and also helps in taking preventive and corrective actions. The low power wide area (LPWA) technologies have always existed since a decade. However, large scale and wide geographical implementation of these technologies has pushed 3GPP to enable the mobile network operators (MNOs) to enter into the IoT space. With the standardization and wide implementation of cellular-IoT (CIoT) various new business cases can be implemented. Using the C-IoT technologies which include the underlying network of NB-IoT or LTE-Cat-M, I will try to present a theoretical business pilot. In this research I plan to include the details of the technologies including NB-IoT, LTE-Cat-M and justification why that particular technology should be implemented for the respective business case. 1.3 Conclusion Using the power of technology and with the growing IoT market in cellular domain, various business challenges can be solved and various new business cases can be implemented. Thus, the intention of implementing this pilot project is expected to lead to betterment in management of the resources, lower the wastage, enhance the learning experience, improve tracking and attendance systems. The underlying technology though explained may not be the soul solution to the project and the respective business case could be implemented using an alternative technology in the same domain. For example, implementation of a smart dustbin and waste management could be carried out using a NB-IoT network as well as LTE-Cat-M network. However, the case demands for the low data rate, stationary or low mobility solution which would call for implementing the NB-IoT network.

碩士
國立臺灣大學
電信工程學研究所
107
For monitoring on water distribution networks, the sensor network lifetime is important to be as long as possible due to the high cost to replace dead nodes underground. Narrow Band Internet of Things (NB-IoT) is a novel radio technology that well suits the features of public civil resource monitoring systems, such as massive amount of devices, low transmission data rates, and the needs of low energy consumption and good penetration to indoor or underground. Using NB-IoT as the wireless communication intermediary in our monitoring system, an operational strategy is proposed to prolong the sensor network lifetime. Our strategy can be divided into two phases. First, a k-extended-cover algorithm is designed to adjust the data resolution and prioritize the reporting of the data according to the distance between the sensor nodes. Second, an eDRX assignment policy is presented to balance power consumption and wake-up latency tradeoff, by using the result of the k-extended-cover algorithm. Next, a semi-Markov process is modeled to numerically analyze the system performance and to obtain the power saving factor and wake-up latency. Finally, the system performance is discussed with the simulation results.

碩士
國立交通大學
網路工程研究所
106
For 5G wireless communications, the 3GPP Narrowband Internet of Thing (NB-IoT) is one of the most promising technologies, which provides multiple types of Resource Unit (RU) with a special repetition mechanism to improve scheduling flexibility, coverage, and transmission reliability. Besides, NB-IoT supports different operation modes to reuse the spectrum of LTE and GSM, making bandwidth use more efficiently. As IoT devices usually need to operate for very long time, their energy consumption becomes a critical issue. NB-IoT provides discontinuous reception operation to save devices' energy. However, how to reduce transmission energy while ensuring required reliability under these operations is still an open issue. In this paper, we study how to guarantee reliable communication and satisfy devices' quality of service (QoS) while minimizing energy consumption for IoT devices. We first model the optimization problem and prove it to be NP-complete. Then, we propose an energy-efficient, ultra-reliable, and low-complexity scheme, which consists of two phases. The first phase tries to optimize the default transmit configurations of devices which incur the lowest energy consumption and satisfy devices' QoS requirements. The second phase leverages a weighting strategy to balance the urgency and slot availability and ensure delay constraint while maintaining energy efficiency. Extensive simulation results show that our scheme can serve more devices with guaranteed QoS while saving their energy effectively.

碩士
國立臺北大學
資訊工程學系
107
Using a general licensed band like 4G positioning and unlicensed band like Lora have made many results, this thesis uses narrowband internet of things (NB-IoT) to achieve the target of reduce equipment costs and iterated through and build multiple kernel spaces to change the traditional training signal method. First performs outdoor location cluster classification, and then proposes a method of kernel-gradient learning, the kernel learning maps the input labeled, unlabeled and cross-domain data to the three- dimensional plane space, then uses the gradient learning method to fine-tune the parameters during the mapping process. In our approach, we propose a cluster classification scheme that combines unlabeled and cross-domain data based on finding the relationship of existing labeled data from the source domain. Using the new labeled data of unlabeled and cross-domain data, we repeatedly iterative fine-tune our target model by adding some new unlabeled samples, improved the output after several iteration. Basically, the more labeled data are used and added to the fine-tuning process, the higher the positioning accuracy, in our actual implementation, the standardization process handles a number of different signal characteristics, such as RSSI, SNR and localization to increase the prediction accuracy of positional accuracy. Finally, the experimental results show that the proposed scheme effectively improves the location average accuracy up about 87% and reduces the localization average error about 4 m, compared with another existing localization results.

碩士
國立交通大學
網路工程研究所
105
IoT (Internet of Things) is an emerging network paradigm connecting a huge number of things. For energy saving, small things (sensors) usually stay in the idle mode and only wake up when they have traffic demands. In traditional LTE, the MME invokes UEs by notifying them via a paging message including a list of their IDs. However, such one-by-one notification will incur an unacceptable signaling overhead in an IoT network when the ID list is long. To address this issue, this work presents “page by hint” (p-Hint), an ID-free paging mechanism that allows the MME to page a large number of UEs using only a fixed-length hint. The key idea of p-Hint is to leverage hashing to encode and decode the hint message. In this thesis, we design two schemes for different scenario. Two schemes are based on simple hashing processes with one or multiple bit-vectors as filter. One is single-filter scheme while the other is dual-filter scheme. Through these filters, each UE checks whether its information is contained in the hint message via same hashing processes, and determines whether it should get up to do random access. To improve spectrum efficiency, we further mathematically derive the optimal length of the hint so as to maximize the expected number of UEs that can be successfully paged per unit of overhead. The simulation results show that p-Hint can page much more UEs simultaneously in a single paging procedure. As compared to legacy LTE-A, single-filter scheme reduces the overhead of successfully paging one UE, on average, by 85.7%, while dual-filter scheme reduces the overhead, on average, by 90.1%. We also observe that the average overhead required for successfully paging one UE in no more than 25 bits for single-filter scheme, and no more than 11 bits for dual-filter scheme, which both are much smaller than the size of UE ID (40-bit S-TMSI).

碩士
國立中央大學
通訊工程學系
106
The 5G is coming soon after the 4G, the 5G will bring a great impact on the Internet of Things.It will be able to support the connection of wireless devices and support huge data traffic. It will provide IoT services at lower cost than today. Before the 5G is opened officially,The LPWAN (Low Power Wide Area Network,LPWAN) provides the power which the industry goes forward continually. It is worth noting that the use of licensed band NB-IoT (NarrowBand-IoT). Recently, the NB-IoT (FDD) application possibly can be affected by the LTE (TDD) construction. When the NB-IoT small base station uses the LTE frequency band for the uplink transmission.It can be interference by downlink power to leak from nearby the LTE eNB (Marco cell). For this reason, this paper proposed the NB-IoT (FDD) how to effectively and accurately allocate the power under the LTE (TDD) environment. Finally,it simulates the result indication the KM-Q algorithm which this paper proposed in any leakage environment all to be able to show the better power parameter, and establishes the leakage regression model achievement to prevent leakage the interference for the ultimate goal.

Il 5G sta compiendo una trasformazione significativa del panorama delle reti mobili, introducendo capacità flessibili ed eterogenee che coordinano armoniosamente numerose componenti tecniche dal momento che sono attualmente in fase di sviluppo una grande varietà di servizi avanzati, ognuno dei quali caratterizzato da requisiti diversi. Di conseguenza, appare naturale come il 5G non abbia un'unica interfaccia radio, bensì una famiglia di interfacce radio, tutte opportunamente inserite in un unico framework comune, al fine di rispondere adeguatamente ai diversi casi d'uso. Tuttavia, la gestione efficace di una così ampia diversità è un obiettivo estremamente ambizioso da raggiungere. A tal scopo, questo lavoro si pone l'obiettivo di studiare, analizzare e presentare modelli di simulazione, nonché procedure di gestione all’avanguardia delle reti di accesso 5G & Beyond. In particolare, in questa tesi si propone un simulatore system-level ed open source per modellare gli elementi chiave della rete di accesso 5G e supportare quindi l'analisi delle prestazioni di diversi scenari di riferimento. Inoltre, si disamina la NarrowBand IoT, considerata una tecnologia di accesso radio particolarmente promettente per soddisfare i requisiti dello sviluppo 5G & Beyond in ambito Internet of Things (IoT). Infine, si pone un accento sul problema del RAN Slicing sfruttando l'Edge Computing e l'Intelligenza Artificiale, che promettono di trasformare le future reti mobili in infrastrutture che tengano in considerazione i servizi e il canale radio.
5th Generation (5G) is providing a significant transformation in the mobile network landscape. It introduces flexible and heterogeneous capabilities to harmoniously blend numerous technical components since a variety of advanced services are being developed, each one entailing different requirements. For this reason, 5G does not have a single air interface, but rather a family of air interfaces to adequately address specific use cases, all plugged into a common framework. Nonetheless, the effective management of such a broad diversity is an extremely ambitious goal to accomplish. To this end, this work pursues the goal of investigating several cutting-edge management techniques and simulation models for 5G & Beyond Radio Access Networks (RANs). Specifically, this thesis presents an open-source system-level tool to model the key elements of the 5G RAN and support the performance analysis of reference scenarios. Moreover, it examines NarrowBand IoT (NB-IoT), which is usually regarded as a promising radio access technology to meet the requirements of the 5G & Beyond development for the Internet of Things (IoT). Finally, it addresses the RAN Slicing problem leveraging Edge Computing and Artificial Intelligence (AI), which promise to turn future mobile networks into service- and radio-aware infrastructures.

碩士
國立臺灣大學
資訊工程學研究所
106
The well development of Mobile Communications Networks (MCNs) causes the dramatically increasing of the smart devices. The smart devices such as wearable devices have limited battery lifetime so that it has the better choice to use the NB-IoT protocol to transmit the small data for the purpose of power saving. The wearable devices are also able to make the voice call through the VoLTE. Therefore, the interworking of the NB-IoT and LTE networks is necessary in the future. The power saving issue is generated if both NB-IoT and LTE interface of the UE attach to the networks. We propose the Protocol to Protocol Switching Mechanism (P2PSM) to enable the dual-mode UE to be supported in the NB-IoT and LTE interworking network and reduce the power consumption. The analytical models and simulation experiments are conducted to investigate the performance of the P2PSM mechanism. Our study shows that the proposed P2PSM mechanism can efficiently reduce the power consumption of the UE.

碩士
國立中央大學
通訊工程學系
106
3rd Generation Partnership Project (3GPP) proposed NB-IoT for IoT application in Release 13. It improves the scheduling for uplink from original LTE which determines the length of NPUSCH (Narrowband Physical Uplink Shared Channel) by the number of subcarriers and slots in NB-IoT. This design supports the IoT scenario which have the feature of massive devices and short data transmission. In Release 14, 3GPP also proposes that random access procedures can be supported in non-anchor carriers which can ease the congestion if all the UE used random access resource by anchor carrier. However, if eNB schedules NPRACH (Narrowband Physical Random Access Channel) in non-anchor carrier then it also compresses the resource that NPUSCH can use. So how to use non-anchor carrier resource efficiently would be an important issue. In this paper, we propose an algorithm which dynamic allocates non-anchor carrier resource adaptive according to the collision report send by UE. Finally, we try to strike a balance between keeping the random access successful rate and saving non-anchor carrier resource as far as possible.

碩士
國立中央大學
通訊工程學系
106
With the massive deployment of Internet of Things (IoT) devices, low-power wide area IoT connectivity has been introduced for LTE. In LTE Rel-13, two new features supporting narrowband machine type communications (MTC) are being introduced. The features are called eMTC (enhanced MTC) and Narrowband IoT (NB-IoT). Since NB-IoT design is based on existing LTE functionalities, it is possible to reuse the same hardware and also to share spectrum without coexistence issues. However, older equipment may not be able to support both LTE and NB-IoT simultaneously and a hardware upgrade may be required. In this case, NB-IoT deployment can be phased in where existing cell sites are incrementally upgraded to NB-IoT. So we investigate some of the problems arising from partial deployment of NB-IoT and potential solutions to resolve them. They include power boosting, coverage extension using repetition, and interference mitigation techniques such as resource blanking, LBT. In this paper we present the Adaptive interference and power allocation method to lower the collision and the energy consumption. The goal is to optimize the energy efficiency and resource allocation of the UE.