Contributions to IEEE 802.11-based long range communications

The most essential part of the Internet of Things (IoT) infrastructure is the wireless communication system that acts as a bridge for the delivery of data and control messages between the connected things and the Internet. Since the conception of the IoT, a large number of promising applications and technologies have been developed, which will change different aspects in our daily life. However, the existing wireless technologies lack the ability to support a huge amount of data exchange from many battery-driven devices, spread over a wide area. In order to support the IoT paradigm, IEEE 802.11ah is an Internet of Things enabling technology, where the efficient management of thousands of devices is a key function. This is one of the most promising and appealing standards, which aims to bridge the gap between traditional mobile networks and the demands of the IoT. To this aim, IEEE 802.11ah provides the Restricted Access Window (RAW) mechanism, which reduces contention by enabling transmissions for small groups of stations. Optimal grouping of RAW stations requires an evaluation of many possible configurations. In this thesis, we first discuss the main PHY and MAC layer amendments proposed for IEEE 802.11ah. Furthermore, we investigate the operability of IEEE 802.11ah as a backhaul link to connect devices over possibly long distances. Additionally, we compare the aforementioned standard with previous notable IEEE 802.11 amendments (i.e. IEEE 802.11n and IEEE 802.11ac) in terms of throughput (with and without frame aggregation) by utilizing the most robust modulation schemes. The results show an improved performance of IEEE 802.11ah (in terms of power received at long range while experiencing different packet error rates) as compared to previous IEEE 802.11 standards. Additionally, we expose the capabilities of future IEEE 802.11ah in supporting different IoT applications. In addition, we provide a brief overview of the technology contenders that are competing to cover the IoT communications framework. Numerical results are presented showing how the future IEEE 802.11ah specification offers the features required by IoT communications, thus putting forward IEEE 802.11ah as a technology to cater the needs of the Internet of Things paradigm. Finally, we propose an analytical model (named e-model) that provides an evaluation of the RAW onfiguration performance, allowing a fast adaptation of RAW grouping policies, in accordance to varying channel conditions. We base the e-model in known saturation models, which we adapted to include the IEEE 802.11ah’s PHY and MAC layer modifications and to support different bit rate and packet sizes. As a proof of concept, we use the proposed model to compare the performance of different grouping strategies,showing that the e-model is a useful analysis tool in RAW-enabled scenarios. We validate the model with existing IEEE 802.11ah implementation for ns-3.La clave del concepto Internet de las cosas (IoT) es que utiliza un sistema de comunicación inalámbrica, el cual actúa como puente para la entrega de datos y mensajes de control entre las "cosas" conectadas y el Internet. Desde la concepción del IoT, se han desarrollado gran cantidad de aplicaciones y tecnologías prometedoras que cambiarán distintos aspectos de nuestra vida diaria.Sin embargo, las tecnologías de redes computacionales inalámbricas existentes carecen de la capacidad de soportar las características del IoT, como las grandes cantidades de envío y recepción de datos desde múltiples dispositivos distribuidos en un área amplia, donde los dispositivos IoT funcionan con baterías. Para respaldar el paradigma del IoT, IEEE 802.11ah, la cual es una tecnología habilitadora del Internet de las cosas, para el cual la gestión eficiente de miles de dispositivos es una función clave. IEEE 802.11ah es uno de los estándares más prometedores y atractivos, desde su concepción orientada para IoT, su objetivo principal es cerrar la brecha entre las redes móviles tradicionales y la demandada por el IoT. Con este objetivo en mente, IEEE 802.11ah incluye entre sus características especificas el mecanismo de ventana de acceso restringido (RAW, por sus siglas en ingles), el cual define un nuevo período de acceso al canal libre de contención, reduciendo la misma al permitir transmisiones para pequeños grupos de estaciones. Nótese que para obtener una agrupación óptima de estaciones RAW, se requiere una evaluación de las distintas configuraciones posibles. En esta tesis, primero discutimos las principales mejoras de las capas PHY y MAC propuestas para IEEE 802.11ah. Además, investigamos la operatividad de IEEE 802.11ah como enlace de backhaul para conectar dispositivos a distancias largas. También, comparamos el estándar antes mencionado con las notables especificaciones IEEE 802.11 anteriores (es decir, IEEE 802.11n y IEEE 802.11ac), en términos de rendimiento (incluyendo y excluyendo la agregación de tramas de datos) y utilizando los esquemas de modulación más robustos. Los resultados muestran mejores resultados en cuanto al rendimiento de IEEE 802.11ah (en términos de potencia recibida a largo alcance, mientras se experimentan diferentes tasas de error de paquetes de datos) en comparación con los estándares IEEE 802.11 anteriores.Además, exponemos las capacidades de IEEE 802.11ah para admitir diferentes aplicaciones de IoT. A su vez, proporcionamos una descripción general de los competidores tecnológicos, los cuales contienden para cubrir el marco de comunicaciones IoT. También se presentan resultados numéricos que muestran cómo la especificación IEEE 802.11ah ofrece las características requeridas por las comunicaciones IoT, presentando así a IEEE 802.11ah como una tecnología que puede satisfacer las necesidades del paradigma de Internet de las cosas.Finalmente, proponemos un modelo analítico (denominado e-model) que proporciona una evaluación del rendimiento utilizando la característica RAW con múltiples configuraciones, el cual permite una rápida adaptación de las políticas de agrupación RAW, de acuerdo con las diferentes condiciones del canal de comunicación. Basamos el e-model en modelos de saturación conocidos, que adaptamos para incluir las modificaciones de la capa MAC y PHY de IEEE 802.11ah y para poder admitir diferentes velocidades de transmisión de datos y tamaños de paquetes. Como prueba de concepto, utilizamos el modelo propuesto para comparar el desempeño de diferentes estrategias de agrupación, mostrando que el e-model es una herramienta de análisis útil en escenarios habilitados para RAW. Cabe mencionar que también validamos el modelo con la implementación IEEE 802.11ah existente para ns-3

Low-Power Wireless for the Internet of Things: Standards and Applications: Internet of Things, IEEE 802.15.4, Bluetooth, Physical layer, Medium Access Control,coexistence, mesh networking, cyber-physical systems, WSN, M2M

International audienceThe proliferation of embedded systems, wireless technologies, and Internet protocols have enabled the Internet of Things (IoT) to bridge the gap between the virtual and physical world through enabling the monitoring and actuation of the physical world controlled by data processing systems. Wireless technologies, despite their offered convenience, flexibility, low cost, and mobility pose unique challenges such as fading, interference, energy, and security, which must be carefully addressed when using resource-constrained IoT devices. To this end, the efforts of the research community have led to the standardization of several wireless technologies for various types of application domains depending on factors such as reliability, latency, scalability, and energy efficiency. In this paper, we first overview these standard wireless technologies, and we specifically study the MAC and physical layer technologies proposed to address the requirements and challenges of wireless communications. Furthermore, we explain the use of these standards in various application domains, such as smart homes, smart healthcare, industrial automation, and smart cities, and discuss their suitability in satisfying the requirements of these applications. In addition to proposing guidelines to weigh the pros and cons of each standard for an application at hand, we also examine what new strategies can be exploited to overcome existing challenges and support emerging IoT applications

Wireless communication technologies for the Internet of Things

Internet of Things (IoT) is the inter-networking paradigm based on many processes such as identifying, sensing, networking and computation. An IoT technology stack provides seamless connectivity between various physical and virtual objects. The increasing number of IoT applications leads to the issue of transmitting, storing, and processing a large amount of data. Therefore, it is necessary to enable a system capable to handle the growing traffic requirements with the required level of QoS (Quality of Service). IoT devices become more complex due to the various components such as sensors and network interfaces. The IoT environment is often demanding for mobile power source, QoS, mobility, reliability, security, and other requirements. Therefore, new IoT technologies are required to overcome some of these issues. In recent years new wireless communication technologies are being developed to support the development of new IoT applications. This paper provides an overview of some of the most widely used wireless communication technologies used for IoT applications

Design and analysis of LTE and wi-fi schemes for communications of massive machine devices

Existing communication technologies are designed with speciÿc use cases in mind, however, ex-tending these use cases usually throw up interesting challenges. For example, extending the use of existing cellular networks to emerging applications such as Internet of Things (IoT) devices throws up the challenge of handling massive number of devices. In this thesis, we are motivated to investigate existing schemes used in LTE and Wi-Fi for supporting massive machine devices and improve on observed performance gaps by designing new ones that outperform the former. This thesis investigates the existing random access protocol in LTE and proposes three schemes to combat massive device access challenge. The ÿrst is a root index reuse and allocation scheme which uses link budget calculations in extracting a safe distance for preamble reuse under vari-able cell size and also proposes an index allocation algorithm. Secondly, a dynamic subframe optimization scheme that combats the challenge from an optimisation solution perspective. Thirdly, the use of small cells for random access. Simulation and numerical analysis shows performance improvements against existing schemes in terms of throughput, access delay and probability of collision. In some cases, over 20% increase in performance was observed. The proposed schemes provide quicker and more guaranteed opportunities for machine devices to communicate. Also, in Wi-Fi networks, adaptation of the transmission rates to the dynamic channel condi-tions is a major challenge. Two algorithms were proposed to combat this. The ÿrst makes use of contextual information to determine the network state and respond appropriately whilst the second samples candidate transmission modes and uses the e˛ective throughput to make a deci-sion. The proposed algorithms were compared to several existing rate adaptation algorithms by simulations and under various system and channel conÿgurations. They show signiÿcant per-formance improvements, in terms of throughput, thus, conÿrming their suitability for dynamic channel conditions

5G and beyond networks

This chapter investigates the Network Layer aspects that will characterize the merger of the cellular paradigm and the IoT architectures, in the context of the evolution towards 5G-and-beyond, including some promising emerging services as Unmanned Aerial Vehicles or Base Stations, and V2X communications

Heterogeneous Wireless Networks QoE Framework

With the appearance of small cells and the move of mobile networks towards an all-IP 4G network, the convergence of these with Wi-Fi becomes a possibility which at the same time opens the path to achieve what will become 5G connectivity. This thesis describes the evolution of the different mainstream wireless technologies deployed around the world and how they can interact, and provides tools to use this convergence to achieve the foreseen requirements expected in a 5G environment and the ideal user experience. Several topics were identified as needing attention: handover between heterogeneous networks, security of large numbers of small cells connected via a variety of backhaul technologies to the core networks, edge content distribution to improve latency, improvement of the service provided in challenging radio environments and interference between licensed and unlicensed spectrum. Within these topics a contribution was made to improve the current status by analysing the unaddressed issues and coming up with potential improvements that were tested in trials or lab environment. The main contributions from the study have been: 1. A patent in the wireless security domain that reuses the fact that overlapping coverage is and will be available and protects against man in the middle attacks (Section 5.3). 2. A patent in the content distribution domain that manages to reduce the cost to deliver content within a mobile network by looking for the shortest path to the requested content (Section 6.3). 3. Improvements and interoperability test of 802.21 standard which improves the seamlessness of handovers (Section 4.2). 4. 2 infill trials which focus on how to improve the user experience in those challenging conditions (Sections 7.2 and 7.3). 5. An interference study with Wi-Fi 2.4GHz for the newly allocated spectrum for 4G (Section 8.2). This thesis demonstrates some of the improvements required in current wireless networks to evolve towards 5G and achieve the coverage, service, user experience, latency and security requirements expected from the next generation mobile technology

Pyöräilyn ympäristötekijöiden mittaaminen esineiden internetin sovelluksia varten

Increasing population in cities creates increasing amount of traffic, which leads to emissions and traffic congestion. Smart Cities set out to solve the challenges urban cities face due to the increased population, using Internet of Things as means to monitor the assets as it allows non-traditional devices to connect as a part of global information network. At the same time, cycling has increased its popularity as an environmentally friendly as well as healthy transportation method. To further its usage, infrastructure in cities must support cycling as a serious transportation method. For this purpose, it is important to include bicycles to Smart City with measurements of cycling and its environment. This thesis studies if it is possible to measure factors affecting cycling environment and assess route quality without using sensors built in bicycle frame. Decision to avoid sensors embedded in frame stemmed from incentive to have easily available and inexpensive measuring device, which does not bind the cyclists to use bicycles from specific brand or require them to purchase new bike if they are interested in participating in measuring. For evaluating the feasibility of cycling environment measuring, prototype called BikeBox was built and used during test drives. In addition, an online survey was held, which received answers from 97 cyclists. The survey queried about their cycling habits and preferences to better understand what kind of data they would be interested in. The prototype included accelerometer for measuring road quality, photoresistor to identify poorly lit areas and GPS module for location and timestamps, which are needed for other measurements as well as finding possible stopping points and slow areas on the route. Based on the test drives it is possible to identify quality changes on road surface as well as changes in lighting. Inaccurate GPS positioning does pose a challenge for pinpointing exact locations, though. Using location and timestamps it is possible to calculate the speed along different parts of the route, including areas which cause interruptions for the cyclists. This thesis presents results from 7 different example drives, though during testing phase more test driving was done. To get comprehensive coverage, crowdsourcing should be considered as the data gathering method. Based on the survey fastness and length of the route, amount of stops and interruptions and road condition are one of the most important factors for the cyclists. When queried what kind of information cyclists would like to receive, the road condition related factors were most commonly mentioned.Kaupungistumisen seurauksena väkimäärät kaupungeissa kasvavat, mikä tuo mukanaan kasvavat liikennemäärät, ruuhkat ja liikennepäästöt. Älykkäät kaupungit ovat reaktio kaupungistumisesta seuraaviin haasteisiin. Älykkäät kaupungit pyrkivät seuraamaan ja kontrolloimaan kaupungin infrastruktuuria, apunaan esineiden internet. Esineiden internet mahdollistaa epäperinteisten laitteiden yhdistämisen maailmanlaajuiseen tietoverkkoon. Samaan aikaan pyöräilyn suosio on kasvanut ympäristöystävällisenä ja terveellisenä liikennemuotona. Jos pyöräilyn määrää halutaan jatkossakin kasvattaa, kaupungin infrastruktuurin täytyy tukea pyöräilyä vakavasti otettavana liikennemuotona. Jotta tämä voidaan saavuttaa, on pyöräilijöiden pyöräily-ympäristön ja pyöräilytapojen ymmärtäminen tärkeää. Tässä työssä tutkitaan, onko pyöräily-ympäristöön vaikuttavia tekijöitä mahdollista mitata sensoreilla, joita ei ole istutettu polkupyörän runkoon. Runkoon upotettuja sensoreita haluttiin välttää, jotta mittauslaitteet voisivat olla mahdollisimman suuren joukon saatavilla, eikä pyöräilijä olisi sidottu käyttämään tietyn valmistajan polkupyörää. Lisäksi pyritään selvittämään, minkälaisesta pyöräily-ympäristöön liittyvästä datasta pyöräilijät olisivat kiinnostuneita. Tähän tarkoitukseen rakennettiin prototyyppi PyöräPurkista (BikeBox). Lisäksi toteutettiin internet-kysely, johon vastasi 97 polkupyöräilijää. Kyselyllä selvitettiin pyöräilijöiden pyöräilytapoja ja -mieltymyksiä ja sitä, millainen pyöräily-ympäristöstä kertova data kiinnostaisi heitä. Prototyyppiin sisällytettiin kiihtyvyysanturi tien pinnan laadun mittaamiseen, valoanturi heikosti valaistujen alueiden tunnistamiseen ja GPS-moduuli, jolla saadaan sijantitieto ja kellonaika muita mittauksia varten. Lisäksi sijaintitiedosta ja kellonajasta voidaan laskea ajonopeus ja paikat, missä pyöräilijä on joutunut keskeyttämään ajonsa. Testiajojen perusteella on mahdollista havaita tien pinnanlaadun muutos sekä muutos valaistusolosuhteissa. Epätarkkuudet GPS-paikannuksessa vaikeuttavat kuitenkin ongelmakohtien tarkkaa paikallistamista. Tämä työ käsittelee aiheita 7 erillisen testiajon kautta, vaikka testausvaiheessa ajettiinkin useampia testiajoja. Kattavien mittausten saamiseksi joukkoistamista kannattaisi harkita datankeräysmetodina. Tehdyn kyselyn perusteella reitin nopeus, pituus, reitillä olevien keskeytysten määrä ja tien kunto ovat tärkeimpiä reitin laatuun vaikuttavia tekijöitä. Erilaiset pyöräilyreitin kuntoon liittyvät asiat kiinnostivat eniten kun kysyttiin, minkälaista dataa pyöräilijät haluaisivat saada

Journal of Telecommunications and Information Technology, 2014, nr 3

kwartalni

Security issues in Internet of Things

The main idea behind the concept of the Internet of Things (IoT) is to connect all kinds of everyday objects, thus enabling them to communicate to each other and enabling people to communicate to them. IoT is an extensive concept that encompasses a wide range of technologies and applications. This document gives an introduction to what the IoT is, its fundamental characteristics and the enabling technologies that are currently being used. However, the technologies for the IoT are still evolving and maturing, leading to major challenges that need to be solved for a successful deployment of the IoT. Security is one of the most significant ones. Security issues may represent the greatest obstacle to general acceptance of the IoT. This document presents an assessment of the IoT security goals, its threats and the security requirements to achieve the goals. A survey on a representative set of already deployed IoT technologies is done to assess the current state of the art with regards to security. For each solution, a description of its functionality, its security options and the issues found in the literature is given. Finally, the common issues are identified and a set of future solutions are given.La idea principal detrás del concepto de Internet de las cosas (IoT) es conectar todo tipo de objetos cotidianos, para permitir comunicarse entre sí y que personas se comuniquen con ellos. IoT es un amplio concepto que abarca una extensa gama de tecnologías y aplicaciones. Este documento da una introducción a lo que es el IoT, sus características fundamentales y las tecnologías que se están utilizando actualmente. Sin embargo, las tecnologías usadas en el IoT todavía están en evolución y madurando, dando lugar a grandes desafíos que deben resolverse para un despliegue exitoso del IoT. La seguridad es uno de las más significativos. Los problemas de seguridad pueden representar el mayor obstáculo para la aceptación general del IoT. Este documento presenta una evaluación de los objetivos de seguridad en el IoT, sus amenazas y los requisitos necesarios para alcanzar dichos objetivos. Se realiza un estudio sobre un conjunto representativo de tecnologías IoT en uso para evaluar su estado actual respecto a la seguridad. Para cada solución, se da una descripción de su funcionalidad, sus protecciones y los problemas encontrados. Finalmente, se identifican los problemas comunes y se dan un conjunto de soluciones futuras.La idea principal darrera del concepte d'Internet de les coses (IoT) és connectar tot tipus d'objectes quotidians, per permetre comunicar-se entre sí i que les persones es comuniquin amb ells. IoT és un ampli concepte que engloba una extensa gamma de tecnologies i aplicacions. Aquest document dona una introducció al que és el IoT, les seves característiques fonamentals i les tecnologies que s'estan utilitzant actualment. No obstant, les tecnologies utilitzades en el IoT encara estan evolucionant i madurant, donant lloc a grans reptes que s'han de resoldre per a un desplegament exitós del IoT. La seguretat és un dels reptes més significatius. Els problemes de seguretat poden representar el major obstacle per l'acceptació general de l'IoT. Aquest document presenta una avaluació dels objectius de seguretat en el Iot, les seves amenaces i els requisits necessaris per assolir aquests objectius. Es realitza un estudi sobre un conjunt representatiu de tecnologies IoT en ús per avaluar el seu estat actual respecte a la seguretat. Per cada solució, es dona una descripció de la seva funcionalitat, les seves proteccions i els problemes trobats. Finalment, s'identifiquen els problemes comuns i es donen un conjunt de solucions futures

Recent Advances in Wireless Communications and Networks

This book focuses on the current hottest issues from the lowest layers to the upper layers of wireless communication networks and provides "real-time" research progress on these issues. The authors have made every effort to systematically organize the information on these topics to make it easily accessible to readers of any level. This book also maintains the balance between current research results and their theoretical support. In this book, a variety of novel techniques in wireless communications and networks are investigated. The authors attempt to present these topics in detail. Insightful and reader-friendly descriptions are presented to nourish readers of any level, from practicing and knowledgeable communication engineers to beginning or professional researchers. All interested readers can easily find noteworthy materials in much greater detail than in previous publications and in the references cited in these chapters