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This document (Basic Testing Guide) is a practical guide describing the starter kit developed in thecontext of the 5G PPP Test, Measurement and KPI Validation work group. The guide enables the interested developer to understand how this can be applied to measure and verify basic 5G KPIs. The document starts from describing the idea intention to measure up to the actual realization of the test. To enable the test, a description of the environment, how to install it, the test tools and the methodology is provided. It goes from idea to run the actual test, step by step. The proposed framework with the support of the described android agents can in principle support the validation of application level KPIs running at the android UEs, while for other application-specific KPIs running at other systems, the development of specialized plugins is necessary.

The facilities developed in the three ICT-17 projects and further enhanced with on-site deployments and additional equipment in the ICT-19 projects provide all the required means to the experimenters to validate their applications in a fully operational 5G environment. In addition, they provide the opportunity to the verticals originated from several sectors to trial and validate their services in a real 5G deployment. In the aforementioned facilities a large number of 5G performance results are collected (mainly in the three ICT-17 projects), while other trials are ongoing and initial results are going to become available soon (in the ICT-19 projects). The first questions that emerge from the experts and non-experts (verticals) and tried to be answered using the outcome are the following: a) are the results close to the 5G theoretical values and the KPI targets promised by the 5G domain? b) can we identify some factors that practically affects the results, while others not? c) does the results fulfill the application requirements or better does the results satisfy the expectations of the verticals? In this whitepaper, we tried to give answers to the first and second questions, while the third question can be answered when the results from the ICT-19 projects will become available (as a next version of the current document and in cooperation with the vertical KPI Task Force). Therefore, in the current white paper the effort is focused on trying to clarify the details behind the performance numbers and provide a series of interpretation guidelines that could help the reader better understanding the 5G domain. In addition, based on the analysis of performance results, the main impact factors that affect the results are identified, while a high-level explanation is provided that is clearly understandable by non-experts. The motivation is to create a first bridge between the telecommunications and verticals domains and reach a common understanding in explaining what they can really expect from 5G. The plan is this whitepaper to be updated regularly as new projects are onboarding and new results are collected.

This white paper analysesvertical use cases of various domains for their performance KPIs and their mapping to 5G network KPIs. The scope is to identify (based on architectural elements analysis, information flow, etc.) the potential impact on the service performance and user perceived quality. The challenge is to understand the relative influence of 5G network performance indicators to the vertical services. The KPIs mapping methodology includes three steps: - Research on definitions and information derived from the respective 5G-PPP projects, standardisation bodies and respective alliances e.g. ITU, NGMNetc., as well as definition of use cases from 5G-PPP projects'respective. - Identification of relevant key service KPIs and their definitions that are of importance to the respective industry. - Mapping of selected services KPIs on the respective network KPIs that impact the operation of the architectural elements that participate in the service provision process.

This Deliverable contains the progresses related to the development of innovative testing methodologies and 5G Test Cases, and the development of the tools and components that will be part of the test orchestration framework. This document is structured as a report on the different activities of the Tasks T4.1 and T4.2 carried out during the second year of the 5G-VINNI project. It builds upon the use cases and KPIs defined in D4.1 [1]. D4.2 shares the same Annex structure as D4.1, where the main deliverable presents a detailed status of the work summarized in the annexes. These Annexes will be finalized at the end of the project to form the deliverable: “D4.4: Final Test Specification for the 5G-VINNI project”, containing the final collection of 5G-VINNI Test Cases and Testing Methodologies suggested to the community for the deployment of 5G infrastructures and slices., Suggested readers: Verticals projects of the 5G PPP, industry verticals seeking to conduct Testing on 5G systems

The four main 5G sites of 5G-VINNI in UK, Norway, Spain and Greece are now operational. As stated in the project proposal, the target of these 5G sites was to demonstrate 1). that these sites can be accessed and used by vertical industries to set up research trials of innovative use cases and 2). that the key 5G PPP network KPIs can be met. This whitepaper sheds light on these two targets by providing 1). an in-depth tutorial on how to onboard vertical applications on 5G-VINNI facility and 2). by listing the initial KPI results from 5G-VINNI facility. 5G-VINNI adopts Network Slice as a Service (NSaaS) delivery model to offer customized service experience to verticals. The architecture which allows this model is based on guidelines from telecom industry organizations and the normative specifications from standards bodies to ensure interoperability and reproducibility. To this end, TM forum OpenAPIs are exposed towards the verticals from 5G-VINNI service portal and the service catalogue. The APIs allow the verticals to directly trigger necessary operations for service ordering from a 5G-VINNI service catalogue. Upon receiving the order, the customer is offered with a service instance which in case of 5G-VINNI is related to the 5G-VINNI Service Blueprint (SB). The 5G-VINNI-SB is a template capturing the complete description of a given service. This template is used as a reference to conduct service management procedures both at instantiation and at run-time. To cover the necessities of any vertical with the use of a single service platform, 5G-VINNI has defined four (4) different exposure levels in order to provide customized access and insight into the slice instance. As a general principle, a higher exposure level offers more advanced capability to the vertical albeit requiring much more customization. Onboarding a vertical on a 5G test platform is challenging as it involves various iterative and parallel steps. The problem is compounded by the introduction of experimentation aspects as it involves monitoring and testing of KPIs when the network slice is in operation. It is therefore of utmost importance that the different stakeholders of 5G system co-design and co-develop different parts of the onboarding process for a successful service operation and KPI testing. This white paper presents in detail the 5G-VINNI vertical onboarding process which can be summarized as consisting of co-design period to understand vertical needs and how to enable them, the co-development period which involves the vertical customer and the 5G facility provider to jointly develop the final service including testing-as-a-service and monitoring-as-a-service and, the operational and KPI testing period which allows the vertical customer to make repeatable and scheduled service orders of the developed service blueprint and perform KPI testing, monitoring and assessment. The whitepaper concludes with initial KPI results from several categories of tests conducted on the 5G-VINNI facility. These tests, executed using state-of-the-art open source and commercial testing tools, have measured the current capabilities of the 5G-VINNI infrastructure that can be used by verticals as of today.

A hot-carrier solar cell (HCSC) is a high-efficiency photovoltaic concept where electrons and holes are at a higher temperature than the lattice, allowing an additional thermoelectric energy conversion. There are two requirements for a HCSC: establishing a hot-carrier population and converting the temperature into extra voltage through energy-selective contacts. We focus on the generation of hot carriers, and the design of absorbers that can make this generation easier. Fundamentally, this requires to increase the power density absorbed per volume unit, so the photocarriers cannot fully thermalize (phonon bottleneck). Beyond simply increasing the light intensity, the main control knobs to favor hot carriers include reducing the thickness of the absorber, increasing its absorptivity, and reducing its bandgap. In this proceeding, we report the fabrication of structures that aim at measuring the influence of these different parameters. We justify our choices for sample structure and fabrication method from the need for high thermal conductivity, in order to prevent lattice heating. We characterize our structures in order to determine precisely the final thickness of all layers, and the absorptivity of the absorber layer. These samples are to be used for an analysis of the temperature with many variable parameters, in order to better understand the thermalization mechanisms and design better absorbers. Ultimately, our objective is to implement all solutions together in order to evidence a hot carrier population under concentrated sunlight illumination.

Supplemental Material; Doping is a fundamental property of semiconductors and constitutes the basis of modern microelectronic and optoelectronic devices. Their miniaturization requires contactless characterization of doping with nanometer scale resolution. Here, we use low- and room-temperature cathodoluminescence (CL) measurements to analyze p-type and n-type GaAs thin films over a wide range of carrier densities ($2\times 10^{17}$ to $1\times 10^{19}$ cm$^{-3}$). The spectral shift and broadening of CL spectra induced by shallow dopant states and band filling are the signature doping. We fit the whole spectral lineshapes with the generalized Planck's law and refined absorption models to extract the bandgap narrowing (BGN) and the band tail for both doping types, and the electron Fermi level for n doping. This work provides a rigorous method for the quantitative assessment of p-type and n-type carrier density using CL. Taking advantage of the high spatial resolution of CL, it can be used to map the doping in GaAs nanostructures, and it could be extended to other semiconductor materials.

WP4 is focused on ensuring that the 5G-VINNI facility delivered by the project is verified with a uniform testing procedure, allowing the Mobile Network Operators that are part of the consortium to have confidence in the system. The focus of WP4 is on testing methodology, test execution and E2E network validation to verify that KPIs across different verticals are met. The WP is intended to provide all the needed testing and validation tools and support across the project, as well as providing the support needed by vertical projects hosted by the 5G-VINNI facility. This document is structured as a report on the different activities of the Tasks T4.1 and T4.2 carried out during the first Period, while the Annexes represent the initial structure of a live document that will become, at the end of the project, with D4.4 the official Test Specification handbook of the 5G-VINNI project.

5G-VINNI aims at providing a realistic 5G end-to-end test and experimentation facility that can be used by industry verticals to set up trials of innovative use cases, assessing their readiness and validating their KPIs under different load conditions. To allow different verticals to deploy their own use cases and execute test scenarios with isolation guarantees, 5G-VINNI provides them with isolated, tailored environments (network slices) as a service. This document specifies the network slice services offered per facility site, including information on their exposed capabilities and the APIs made available for vertical’s consumption. To enable desired reusability and reproducibility of network slice services across facility sites in the upcoming project releases, model-based service templates are proposed for the specification of these service offerings. Lessons learned during the implementation phase and feedback from ICT-19 verticals will be considered for the further refinements of these templates.

The involvement of vertical customers in the ongoing deployment of 5G networks increases the need for performing tests and measurements, considering the stringent requirements of the vertical applications and the introduction of new business models. The exploitation of network and computing resource virtualization and sharing, such as Network Functions Virtualization (NFV) and Software Defined Networking (SDN) and the different technology domains employed at the infrastructure substrate (i.e. radio, cloud, transport) are making the 5G network increasingly complex to manage, monitor and test. In case a vertical customer determines a Service Level Agreement (SLA) breach, the process of troubleshooting and conflict resolution includes cross-layer coordination of testing and monitoring. These are the main causes for a very broad and heterogeneous scenario that includes: -- Roles and expectation of the vertical customers -- Definition of testing and monitoring approaches and testing levels (from access network to service) -- The need for, and role of Test as a Service (TaaS) within the Zero-touch philosophy -- The need of clearly defined Key Performance Indicators (KPIs) to support the validation of the 5G technology -- The need of a clearly defined KPI Testing and Validation methodology, including KPI monitoring, analysis, verification, and performance diagnosis. -- The need for a common formalization process for standardizing tests representing different levels of the 5G network. This White Paper tries to be a first step into providing a more clear and homogeneous view over these topics, that will be briefly introduced and clarified. The idea is to establish a unified vision on the Test and Measurement topics for 5G, allowing for common procedures and terminology on how to solve some of these challenging problems. This is considered beneficial not only the 5G PPP infrastructure owners, but the entire 5G ecosystem. The technical direction is mainly the most predominant one, providing best practices, methodologies and applied solutions, focusing primarily on the actual testing and evaluation of 5G technologies. Nevertheless, the vision is providing substantiated answers to more high-level relevant questions such as “does slicing help fulfilling vertical requirements?”.

A focus area of phase 3 of 5G PPP is the design and deployment of a 5G end-to-end facility that can demonstrate that the key 5G network KPIs can be met, and which can be accessed and used by vertical industries. This poster paper presents key guidelines to implement such a 5G end-to-end facility.

International audience; Since LaPierre's first theorization of a nanowires (NWs)-based tandem solar cell (TSC) on Si substrate, 1 other theoretical studies have been carried out to investigate the high potentialities of such devices, 2 which can virtually reach an efficiency around 34 %. In spite of these very promising results, the research in this field has not yet developed that much on a practical level: to the best of our knowledge only one prototype of TSC has been realized so far by Yao et al, 3 and although not completely optimized, it reached the high conversion efficiency value of 11.4 %. Based on these considerations, we aimed to develop a fully optimized TSC capable to achieve higher efficiencies. 4 This consists in a top cell made of an ordered array of GaAs/AlGaAs core/shell NWs, with a radial p-in junction in the AlGaAs shell, directly grown on a bottom cell of Si(111), as shown in Figure 1(a). The optimization work has been carried out in different steps, i.e. theoretical simulations to identify the best set up for the array, optimization of the NW structure, composition and morphology, investigation for the most suitable passivation shell and growth on patterned substrates. The last point has notably lead to significant results, since we develop a protocol to obtain very high vertical yields (from 80 % to 90 %) of GaAs/AlGaAs core/shell NWs on large patterned areas (0.9 cm x 0.9 cm), as shown in Figure 1(b). Following these promising results, we are currently committed to using our ordered arrays of NWs for the fabrication of a TSC, now focusing our work on encapsulating and contacting the nanostructures: despite the complexity of the system, EBIC results in this respect (cf. V. Piazza's abstract) are encouraging and suggest that the realization of the TSC is at our fingertips. 5 Figure 1. (a) Scheme of the ultimate structure of the TSC. (b) Ordered array of p-GaAs core / p-in AlGaAs shell NWs on Si(111) with a high vertical yield (80-90 %); white scale bar corresponding to 2 µm.

The present invention pertains to the field of nanoimprint lithography (NIL) processes and more specifically to a soft NIL process used for providing a sol-gel patterned layer on a substrate. Specifically, this process comprises a step of adjusting the solvent uptake of the sol- gel film to 10 to 50% vol., preferably between 15 and 40% vol., by varying the relative pressure of the solvent while a soft mould is applied onto the substrate coated with the sol-gel film.

International audience

International audience; This book, written by leading experts from academia and industry, offers a condensed overview on hot topics among the Cognitive Radios and Networks scientific and industrial communities (including those considered within the framework of the European COST Action IC0902) and presents exciting visions for the future. Examples of the subjects considered include the design of new filter bank-based air interfaces for spectrum sharing, medium access control design protocols, the design of cloud-based radio access networks, an evolutionary vision for the development and deployment of cognitive TCP/IP, and regulations relevant to the development of a spectrum sharing market. The concluding chapter comprises a practical, hands-on tutorial for those interested in developing their own research test beds. By focusing on the most recent advances and future avenues, this book will assist researchers in understanding the current issues and solutions in Cognitive Radios and Networks designs.

The problem of spectrum scarcity in uncoordinated and/or heterogeneous wireless networks is the key aspect driving the research in the field of flexible management of frequency resources. In particular, distributed dynamic spectrum access (DSA) algorithms enable an efficient sharing of the available spectrum by nodes in a network, without centralized coordination. While proof-of-concept and statistical validation of such algorithms is typically achieved by using system level simulations, experimental activities are valuable contributions for the investigation of particular aspects such as a dynamic propagation environment, human presence impact and terminals mobility. This chapter focuses on the practical aspects related to the real world-experimentation with distributed DSA network algorithms over a testbed network. Challenges and solutions are extensively discussed, from the testbed design to the setup of experiments. A practical example of experimentation process with a DSA algorithm is also provided.

However, Cross Layer also carries a risk due to possibly unexpected and undesired effects. In this chapter, the authors provide architecture designers with a set of guidelines synthesized from an analysis of the state of the art, but enriched with the perspective of the development of future generations of communication systems such as Cognitive Radio. Wireless communications are a fast grown part of the telecommunication market. While new types of traffic and challenges related to the wireless medium are appearing, the methodologies for designing system architectures are substantially remaining the same. Under the increasing pressure of market, users, and physical medium issues, designers are in the need for new approaches.Cross Layer becomes than a handy solution for coping with such problems. In fact, it allows both tighter optimizations of the existing functionalities, and the introduction of new ones, that do not fit within the traditional protocol stack design methodology. However, Cross Layer also carries a risk due to possibly unexpected and undesired effects. In this chapter we want to provide architecture designers with a set of tools and recommendations synthesized from an analysis of the state of art, but enriched with the perspective of the development of future generations of communication systems such as Cognitive Radio.

Multi-user MIMO and Spectrum Aggregation (also referred to Carrier Aggregation) are two key enablers of next generation wireless systems. Although those techniques were already quite well investigated at theoretical level, their practical implementation is not immediate and raises numerous challenges. The SAMURAI project aims at investigating such challenges as well as at providing realistic performance results. This paper presents first outcomes of the project, with a specific focus of Carrier Aggregation (CA). Two aspects are discussed: CA at PHY/RF level with implementation challenges. Then, the system aspect of CA, providing new flexibility in terms of radio resource management is investigated. System simulations show capacity improvement when CA is enabled. SAMURAI outcomes in the MU-MIMO aspects are reported in a companion paper.

Femtocells are expected to take a major role on increasing the data rates on cellular network access over the next years. However, femtocells pose significant challenges, especially in terms of interference management and mitigation. In femtocell scenario, the costs for tradional network planning, management and optimization can be prohibitive. Instead, self-optimization of an uncoordinated deployment should be considered. Cognitive Radio enabled femtocells are considered to be a promising solution to enable self-optimizing femtocells to effectively manage the inter-cell interference, especially in densely deployed femto scenarios. In this paper, two key elements of cognitive femtocells are combined: a power control algorithm and a fully distributed dynamic spectrum allocation method. The resulting solution was evaluated through system-level simulations and compared to the separate algorithms and fixed frequency reuses. The outage throughput performance of the combined algorithm exceeds all other options, proving the efficiency of the method in reducing inter-cell interference.

The surface electronic and magnetic properties of epitaxial La2/3Sr1/3MnO3/SrTiO3(001) films with extended bulk metallicity above the Curie temperature have been investigated. By angle-resolved photoemission we show that the surface electronic structure presents the e(g) dispersing band, responsible for the half-metallicity, crossing the Fermi level and leading to a sharp Fermi edge. Quasiparticle excitations, reflecting the coherent polaronic ferromagnetic and metallic ground state, are clearly visible at the Fermi level and 16 K, while they disappear at room temperature, where a Fermi edge is still clearly visible. X-ray magnetic circular dichroism shows a robust subsurface magnetization up to T-C, while spin-polarization Mott spectroscopy indicates a rapid suppression of the surface magnetization which disappears around room temperature. These results clearly demonstrate that a robust surface metallic electronic structure does not necessarily ensure the concomitant stabilization of long-range magnetic order.

Projecte final de carrera fet en col.laboració amb Aalborg University i Nokia Siemens Networks English: The impact that WiFi networks have on today's society has been growing significantly during recent years. As a consequence, the number of devices and systems that give support to this technology nowadays is increasing exponentially. Only a limited number of investigations have been carried out on pushing forward the limits of WiFi. Nevertheless, mobile operators have started envisioning WiFi as a system which may give support to the mobile cellular networks as an offloading solution for part of the traffic they have to deal with. This work focuses on evaluating WiFi performance and behavior in medium and large scale deployments. Furthermore, we propose an algorithm for dynamic channel selection that can improve WiFi performance in congested areas. Results show an improvement in networks where dynamic channel selection is used. Castellano: El impacto que las redes WiFi tienen en la sociedad actual ha crecido significante durante los últimos años. Como consecuencia, el numero de dispositivos y sistemas que dan soporte a esta tecnología hoy en día esta creciendo exponencialmente. Solo un número limitado de investigaciones se han llevado a cabo en el impulso de los limites de WiFi. Sin embargo, los operadores móviles, han comenzado a pensar en como WiFi puede dar soporte como solución de descarga a las redes móviles celulares. El enfoque de este proyecto es en evaluar el rendimiento y comportamiento de WiFi en implementaciones de mediana y larga escala. Además, se propone un algoritmo para selección dinámica de canal que puede mejorar el rendimiento de WiFi en áreas congestionadas. Los resultados obtenidos muestran una mejora en el rendimiento de las redes cuando el mecanismo de selección dinámica de canal es utilizado. Català: L'impacte que les xarxes WiFi tenen en la societat actual ha crescut significant durant els últims anys. Com a conseqüència, el nombre de dispositius i sistemes que donen suport a aquesta tecnologia avui en dia està creixent exponencialment. Només un nombre limitat d'investigacions s'han dut a terme en l'impuls dels límits de WiFi. No obstant això, els operadors mòbils, han començat a pensar en com WiFi pot donar suport com a solució de descàrrega a les xarxes mòbils cel lulars. L'enfocament d'aquest projecte és en avaluar el rendiment i comportament de WiFi en implementacions de mitjana i llarga escala. A més, es proposa un algorisme per selecció dinàmica de canal que pot millorar el rendiment de WiFi en àrees congestionades. Els resultats obtinguts mostren una millora en el rendiment de les xarxes quan el mecanisme de selecció dinàmica de canal és utilitzat.

Research on intelligent and reconfigurable wireless systems is in continuous evolution. Nevertheless, in order to fix some keystones, more and more researchers are entering the idea of research-oriented test beds. Unfortunately, it is very difficult for a wide number of research groups to start with their own set up, since the potential costs and efforts could not pay back in term of expected research results. Software Defined Radio solutions offer an easy way to communication researchers for the development of customized research test beds. While several hardware products are commercially available, the software is most of the times open source and ready to use for third party users. Even though the software solution developers claim complete easiness in the development of custom applications, in reality there are a number of practical hardware and software issues that research groups need to face, before they are up and running in generating results. With this chapter we would like to provide a tutorial guide, based on direct experience, on how to enter in the world of test bed-based research, providing both insight on the issues encountered in every day development, and practical solutions. Finally, an overview on common research-oriented software products for SDR development, namely GNU Radio, Iris, and ASGARD, will be provided, including how to practically start the software development of simple applications. Finally, best practices and examples of all the software platforms will be provided, giving inspiration to researchers on how to possibly build their own customized systems.

Projecte realitzat en el marc d’un programa de mobilitat amb Nokia Siemens Networks (NSN) i Aalborg Universitet (AAU) Títol alternatiu emprat a la intranet docent de l'ETSETB: "Analysis of WiFi deployments applying Interference Rejection" [ANGLÈS] WiFi networks play an integral and essential role in the wireless communications of today's interconnected world. Originally introduced in 1997, the IEEE 802.11 standard has come a long way since its original specifications. Introducing a wide array of improvements and innovative features with each revision, WiFi has stayed the de facto Wireless Local Area Network technology for more than 15 years since its introduction. Unfortunately, with the spectrum being a limited resource, and the Industrial, Scientific and Medical (ISM) radio bands in which WiFi works being already congested, the prevalence and ubiquity of WiFi has lead to a situation of overcrowding. As the adoption and number of users of WiFi technologies keep increasing, this problem of medium efficiency will become more and more problematic. Introduced in this thesis is the Interference Aware Medium Access Control (IAMAC), an improvement over the current medium access specified in the standard. The proposed mechanism makes use of interference rejection and coordination between the nodes in the system to drastically increase the medium efficiency of WiFi networks in dense deployments. With results showing and increase of up to 210% in the achieved goodput and a reduction of up to a 90% of a node's deferring time, our system shows promise for dealing with the problem of medium efficiency in dense deployments of WiFi systems. [CASTELLÀ] Las redes WiFi desempeñan un papel integral y esencial en las comunicaciones inalámbricas del interconectado mundo de hoy en día. Introducido originalmente en 1997, el estándar IEEE 802.11 ha recorrido un largo camino desde sus especificaciones originales. A través de la introducción de una amplia gama de mejoras y características innovadoras con cada revisión, WiFi se ha mantenido como la tecnología de red de área local inalámbrica de facto por los hace más de 15 años desde su introducción. Desafortunadamente, siendo el espectro un recurso limitado, y la banda Industrial, Científica y Médica (ISM) en la que trabaja WiFi estando ya severamente utilizada, la prevalencia de WiFi ha dado lugar a una situación de congestión. Así como la adopción y el número de usuarios de las tecnologías WiFi siguen aumentando, este problema de eficiencia del medio será cada vez más problemático. Introducido en este tesis es el Interference Aware Medium Access Control (IAMAC), una mejora respecto al actual mecanismo de acceso al medio especificado en el estándar. El mecanismo propuesto hace uso de rechazo de interferencia y coordinación entre los nodos del sistema para incrementar drásticamente la eficiencia del medio de las redes WiFi en despliegues densos. Con resultados mostrando un incremento de hasta el 210% en el goodput logrado y una reducción de hasta el 90% del tiempo el el que un nodo se encuentra difiriendo, nuestro sistema se muestra prometedor para tratar el problema de la eficiencia del medio en despliegues densos de sistemas WiFi. [CATALÀ] Les xarxes WiFi tenen un paper integral i essencial en les comunicacions sense fils del interconnectat món d'avui en dia. Introduït originalment en 1997, l'estàndard IEEE 802.11 ha recorregut un llarg camí des de les seves especificacions originals. A través de la introducció d'una àmplia gamma de millores i característiques innovadores amb cada revisió, WiFi s'ha mantingut com la tecnologia de xarxa d'àrea local sense fils de facto per els més de 15 anys des de la seva introducció. Desafortunadament, essent l'espectre un recurs limitat, i la banda Industrial, Científica i Mèdica (ISM) en la que treballa WiFi essent ja severament utilitzada, la prevalença de WiFi ha donat lloc a una situació de congestió. Així com l'adopció i el nombre d'usuaris de les tecnologies WiFi segueixen augmentant, aquest problema d'eficiència del medi serà cada vegada més problemàtic. Introduït en aquesta tesis és el Interference Aware Medium Access Control (IAMAC), una millora respecte a l'actual mecanisme d'accés al medi especificat en l'estàndard. El mecanisme proposat fa ús de rebuig d'interferència i coordinació entre els nodes del sistema per incrementar dràsticament la eficiència del medi de les xarxes WiFi en desplegaments densos. Amb resultats mostrant un augment de fins al 210% en el goodput aconseguit i una reducció de fins al 90% del temps que un node es troba diferint, el nostre sistema se mostra prometedor per tractar el problema de la eficiència del medi en desplegaments densos de sistemes WiFi.

Projecte final de carrera fet en col.laboració amb Nokia Siemens Networks The requirements of the International Telecommunication Union (ITU) for the 4th generation of mobile devices raised up to 100 Mbps for high and 1Gbps for low mobility conditions. Reaching such challenging targets requires the deployment of picocells and femtocells. These techniques permit to achieve large cell capacity but also lead to di culties in terms of interference. The GRACE algorithm, based on Cognitive Radio and Game Theory, has shown a fair balance between cell capacity and outage as well as short convergence time, low complexity and easy scalability. The aim of this work is to find an e cient power control algorithm that fits GRACE these goals. Therefore, a study of Cognitive Radio, Game Theory and Power Control algorithms is developed and a new power control algorithm is proposed. The simulation results show that the Fractional Power Control can increase notably the outage performance and the energy saving to the mobile devices.

[ANGLÈS] When we refer to wireless communications, Wi-Fi quickly comes to our minds despite that the first Wi-Fi standard appeared over 15 years ago. In these 15 years, the standard has evolved a lot, bringing high throughput communications, QoS support, and many other features that granted Wi-Fi a wide footprint. Today, operators and network equipment vendors see Wi-Fi as part of a bigger picture, a powerful and robust Quality of Service (QoS) oriented network. Unfortunately, despite of the QoS benefits introduced in Wi-Fi by the 802.11e amendment, these improvements are not enough when combined with the aggregation mechanisms brought by the 802.11n High Throughput amendment. This lack of performance is where our thesis' study is focused and so we try to improve the throughput and delay presented by Wi-Fi QoS-enabled networks by introducing a Smart Aggregation mechanism. As described in this thesis, our Smart Aggregation mechanism serves not only as an improvement to the Wi-Fi MAC layer but also works as an adaptive mechanism for a set of aggregation features. In our implementation, it is proven that the proposed Smart Aggregation solution improves the MAC layer performance under certain conditions, while it does not degrade the performance of Wi-Fi 802.11e stations in the rest of the situations. In other words, we have demonstrated that in a large deployment of Wi-Fi networks we may actually improve the Best Effort goodput almost a 250% while barely affecting the goodput for the other access categories when compared to the 802.11e standard compliant stations. [CASTELLÀ] Cuando nos referimos a las comunicaciones inalámbricas, Wi-Fi llega rápidamente a nuestras mentes, a pesar de que el primer estándar Wi-Fi apareció hace 15 años. En estos 15 años, el estándar ha evolucionado mucho, dando soporte a comunicaciones de alto rendimiento, soporte QoS, y muchas otras características que han hecho que el sistema Wi-Fi deje huella. Hoy en día, los operadores y proveedores de equipos de red Wi-Fi ven el sistema como una potente y robusta red orientada a dar calidad de servicio (QoS). Desafortunadamente, a pesar de los beneficios introducidos por la QoS en Wi-Fi gracias a la corrección 802.11e, estas mejoras no son suficientes cuando se combina con el mecanismo de agregación presentado por la corrección 802.11n. Esta falta de rendimiento es donde centramos el estudio de nuestra tesis, para intentar mejorar el rendimiento y la demora presentada por Wi-Fi cuando la QoS está presente, y lo hacemos mediante la introducción de un mecanismo de agregación inteligente. Como se ha descrito en esta tesis, nuestro mecanismo de agregación inteligente no sólo es una mejora de la capa MAC de Wi-Fi, sino que también funciona como un mecanismo adaptativo para un conjunto de características de agregación. En nuestra implementación, se demuestra que nuestro mecanismo mejora el rendimiento de la capa MAC en determinadas condiciones, mientras que no degrada el rendimiento de estaciones 802.11e en el resto de situaciones. En otras palabras, hemos demostrado que en un gran despliegue de redes Wi-Fi, mejoramos el rendimiento del tráfico de tipo Best Effort casi un 250% sin afectar a penas el resto de categorías, en comparación con las estaciones estándar. [CATALÀ] Quan ens referim a les comunicacions inalàmbriques, Wi-Fi arriba ràpidament a les nostres ments, tot i que el primer estàndard Wi-Fi va aparèixer fa 15 anys. En aquests 15 anys, l'estàndard ha evolucionat molt, donant suport a comunicacions d'alt rendiment, suport QoS, i moltes altres característiques que han fet que el sistema Wi-Fi deixi empremta. Avui dia els operadors i proveïdors d'equips de xarxa Wi-Fi veuen el sistema com una potent i robusta xarxa orientada a donar qualitat de servei (QoS). Desafortunadament, tot i els beneficis introduïts per la QoS en Wi-Fi gràcies a la correcció 802.11e, aquestes millores no són suficients quan es combina amb el mecanisme d'agregació presentat per la correcció 802.11n. Aquesta falta de rendiment és on centrem l'estudi de la nostra tesi, per intentar millorar el rendiment i la demora presentada per Wi-Fi quan la QoS és present, i ho fem mitjançant la introducció d'un mecanisme d'agregació intel·ligent. Com s'ha descrit en aquesta tesi, el nostre mecanisme d'agregació intel·ligent no només és una millora de la capa MAC de Wi-Fi, sinó que també funciona com un mecanisme adaptatiu per a un conjunt de característiques d'agregació. En la nostra implementació, es demostra que el nostre mecanisme millora el rendiment de la capa MAC en determinades condicions, mentre que no degrada el rendiment d'estacions 802.11e en la resta de situacions. En altres paraules, hem demostrat que en un gran desplegament de xarxes Wi-Fi, millorem el rendiment del trànsit de tipus Best Effort gairebé un 250% sense afectar a penes la resta de categories, en comparació amb les estacions estàndard.

Projecte realitzat en el marc d’un programa de mobilitat amb Nokia Siemens Networks (NSN) i Aalborg Universitet (AAU) Títol alternatiu emprat a la intranet docent de l'ETSETB: "Analysis of WiFi deployments applying Interference Rejection" [ANGLÈS] WiFi networks play an integral and essential role in the wireless communications of today's interconnected world. Originally introduced in 1997, the IEEE 802.11 standard has come a long way since its original specifications. Introducing a wide array of improvements and innovative features with each revision, WiFi has stayed the de facto Wireless Local Area Network technology for more than 15 years since its introduction. Unfortunately, with the spectrum being a limited resource, and the Industrial, Scientific and Medical (ISM) radio bands in which WiFi works being already congested, the prevalence and ubiquity of WiFi has lead to a situation of overcrowding. As the adoption and number of users of WiFi technologies keep increasing, this problem of medium efficiency will become more and more problematic. Introduced in this thesis is the Interference Aware Medium Access Control (IAMAC), an improvement over the current medium access specified in the standard. The proposed mechanism makes use of interference rejection and coordination between the nodes in the system to drastically increase the medium efficiency of WiFi networks in dense deployments. With results showing and increase of up to 210% in the achieved goodput and a reduction of up to a 90% of a node's deferring time, our system shows promise for dealing with the problem of medium efficiency in dense deployments of WiFi systems. [CASTELLÀ] Las redes WiFi desempeñan un papel integral y esencial en las comunicaciones inalámbricas del interconectado mundo de hoy en día. Introducido originalmente en 1997, el estándar IEEE 802.11 ha recorrido un largo camino desde sus especificaciones originales. A través de la introducción de una amplia gama de mejoras y características innovadoras con cada revisión, WiFi se ha mantenido como la tecnología de red de área local inalámbrica de facto por los hace más de 15 años desde su introducción. Desafortunadamente, siendo el espectro un recurso limitado, y la banda Industrial, Científica y Médica (ISM) en la que trabaja WiFi estando ya severamente utilizada, la prevalencia de WiFi ha dado lugar a una situación de congestión. Así como la adopción y el número de usuarios de las tecnologías WiFi siguen aumentando, este problema de eficiencia del medio será cada vez más problemático. Introducido en este tesis es el Interference Aware Medium Access Control (IAMAC), una mejora respecto al actual mecanismo de acceso al medio especificado en el estándar. El mecanismo propuesto hace uso de rechazo de interferencia y coordinación entre los nodos del sistema para incrementar drásticamente la eficiencia del medio de las redes WiFi en despliegues densos. Con resultados mostrando un incremento de hasta el 210% en el goodput logrado y una reducción de hasta el 90% del tiempo el el que un nodo se encuentra difiriendo, nuestro sistema se muestra prometedor para tratar el problema de la eficiencia del medio en despliegues densos de sistemas WiFi. [CATALÀ] Les xarxes WiFi tenen un paper integral i essencial en les comunicacions sense fils del interconnectat món d'avui en dia. Introduït originalment en 1997, l'estàndard IEEE 802.11 ha recorregut un llarg camí des de les seves especificacions originals. A través de la introducció d'una àmplia gamma de millores i característiques innovadores amb cada revisió, WiFi s'ha mantingut com la tecnologia de xarxa d'àrea local sense fils de facto per els més de 15 anys des de la seva introducció. Desafortunadament, essent l'espectre un recurs limitat, i la banda Industrial, Científica i Mèdica (ISM) en la que treballa WiFi essent ja severament utilitzada, la prevalença de WiFi ha donat lloc a una situació de congestió. Així com l'adopció i el nombre d'usuaris de les tecnologies WiFi segueixen augmentant, aquest problema d'eficiència del medi serà cada vegada més problemàtic. Introduït en aquesta tesis és el Interference Aware Medium Access Control (IAMAC), una millora respecte a l'actual mecanisme d'accés al medi especificat en l'estàndard. El mecanisme proposat fa ús de rebuig d'interferència i coordinació entre els nodes del sistema per incrementar dràsticament la eficiència del medi de les xarxes WiFi en desplegaments densos. Amb resultats mostrant un augment de fins al 210% en el goodput aconseguit i una reducció de fins al 90% del temps que un node es troba diferint, el nostre sistema se mostra prometedor per tractar el problema de la eficiència del medi en desplegaments densos de sistemes WiFi.