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The concept of Digital Twin (DT) has been broadly adopted in the Industry 4.0, in the healthcare and in the Smart Cities. It represents a digital model of the reality where it is possible to test and evaluate different actions before implementing them into the real world. In the context of Smart City, the digital copy of the city includes the representation of the road infrastructure, vehicles, pedestrians, .... Its main objectives are to ease the road maintenance, to provide the means for mobility simulations, and to create traffic information management systems. This pr Nowadays, Vehicular-to-Everything (V2X) communications are becoming an essential element to improve safe driving conditions and autonomous driving. This thesis presents a comparison of two V2X communication technologies: IEEE 802.11p, and Cellular-V2X. The objective of this study is to evaluate the performance of both technologies in terms of the Medium Acces Control (MAC) layer, especially in a congested environment. Therefore, we analyze the different schemes used on these technologies to access shared channel resources and avoid interferences. The study is conducted using several simulation tools: SUMO which allows us to create personalized scenarios, and OMNeT++ used to simulate the network and transmit all the V2X messages between the vehicles. With SUMO we created a highway scenario that can support a high density of vehicles. And OMNeT++ is used to change the main simulation parameters, and obtain results such as all the packets received and sent through the network. Finally, we defined some performance metrics to analyze the results and observe how the technologies react over a congested scenario, with high densities of vehicles.

This project presents an analysis of the state of the art of mobile communications. A brief introduction to the history of mobile telephony and the predecessor generations is shown. The spectrum available in Europe for the emerging 5G technology is shown, where the auction of the 700 MHz and 3.5 GHz band is promoted. We show the active demand for data during the last years and an estimation for the next ones. We also show the services where this amount of data is consumed the most. To finish this analysis, an estimation of 5G subscriptions is presented in context with predecessor technologies. In Europe, the 26 GHz millimeter band is also promoted, which is indicated as a viable option for the development of 5G. Techniques such as Massive MIMO or beamforming can help encourage the use of mmWave. We present a set of simulations to provide indoor coverage with DAS for different frequency bands and technologies (LTE and 5G). This study is carried out in real work offices of Cellnex, the company with which the project is carried out. Finally, we show some conclusions of signal quality and quantity with estimated costs for each solution presented. Este proyecto presenta un análisis del estado del arte de las comunicaciones móviles. Se muestra una breve introducción de la historia de la telefonía móvil y las generaciones predecesoras. Se muestra el espectro disponible en Europa para la tecnología emergente 5G, donde se promueve la subasta de la banda de 700 MHz y 3.5 GHz. Mostramos la demanda activa de datos durante los últimos años y una estimación de los próximos. También dejamos ver los servicios donde más se consume esta cantidad de datos. Para terminar este análisis, se presenta una estimación de suscripciones a 5G en contexto con las tecnologías predecesoras. En Europa también se promueve la banda milimétrica 26 GHz, que se indica como una opción viable para el desarrollo del 5G. Se muestran técnicas como el Massive MIMO o beamforming que pueden ayudar a incentivar el uso de mmWave. Presentamos un conjunto de simulaciones para dar cobertura interior con DAS para distintas bandas de frecuencia y tecnologías (LTE y 5G). Este estudio se realiza en unas oficinas de trabajo reales de Cellnex, empresa con la que se realiza el proyecto. Finalmente, mostramos unas conclusiones de calidad y cantidad de señal con unos costes estimados para cada solución presentada. Aquest projecte presenta un anàlisi de l?estat de l?art de les comunicacions mòbils. Es mostra una breu introducció de la història de la telefonia mòbil i les generacions predecessores. Es mostra l'espectre disponible a Europa per a la tecnologia emergent 5G, on es promou la subhasta de la banda de 700 MHz i 3.5 GHz. Mostrem la demanda activa de dades durant els darrers anys i una estimació dels propers. També deixem veure els serveis on més es consumeix aquesta quantitat de dades. Per acabar aquest anàlisi, es presenta una estimació de subscripcions a 5G en context amb les tecnologies predecessores. A Europa també es promou la banda mil·limètrica 26 GHz, que s'indica com una opció viable per al desenvolupament del 5G. Es mostren tècniques com el Massive MIMO o beamforming que poden ajudar a incentivar l?ús de mmWave. Presentem un conjunt de simulacions per donar cobertura interior amb DAS per a diferents bandes de freqüència i tecnologies (LTE i 5G). Aquest estudi es realitza a unes oficines de treball reals de Cellnex, empresa amb què es realitza el projecte. Finalment, mostrem unes conclusions de qualitat i quantitat de senyal amb uns costos estimats per a cada solució presentada.

The demand for mobile data traffic is increasing at a rapid pace. Specifically, at highly dense areas where the population is high, it is really hard for carriers to provide uninterrupted service. The carriers are installing more base stations in small area order to keep a smooth flow of traffic. These base stations instead of satisfying the high demand creates interference with each other and causes loss of energy and increase in cost. They work at maximum capability even at non-peak hours causing wastage of power. The traditional Radio Access Network (RAN) has become more expensive in terms of cost as well as in terms of energy consumption. (As cited in abstract.) *Publication date not found.

Future wireless networks are expected to be ultra-dense and heterogeneous not just in terms of the number and type of base stations but also in terms of the number of users and the application types they access. Such a network architecture will require mobility management mechanisms that adapt rapidly to these highly dynamic network characteristics. In particular, the optimality of the handover signaling within these future network architectures will be extremely critical given their density and heterogeneity. In this paper, the optimality is relevant for both the total amount of signaling created and the total delay per handover process. In this paper, we first present a novel and optimized message mapping and signaling mechanism for the handover preparation and failure phases. We also develop a novel handover failure aware preparation signaling methodology, which accounts for the possibility of a handover failure and grants additional enhancements to the handover preparation and failure signaling phases. Through the analytical framework provided in this paper, we conduct studies to quantify the performance gains promised by the proposed mechanisms. These studies cover myriad handover scenarios as identified by 3GPP and use the statistics from cellular network operators and vendors. We then develop the idea and analytical framework for network wide analysis, in which the network wide processing cost and network occupation time for various handover failure rates are computed. Finally, we propose an evolutionary network architecture that facilitates the proposed signaling mechanism as well as assists operators in maintaining a manageable capital expenditure. It combines the current day and 3GPP proposed 5G network architecture with the software-defined networking approach. As a result, we argue that the proposed mechanisms are viable and outperform the legacy handover signaling mechanisms in terms of latency incurred, total network occupation time, number of messages generated, and total bytes transferred.

En aquest treball es realitza un prototip de xarxa LTE (Long Term Evolution o Evolució a Llarg Termini) amb l'objectiu de monitorar-la i segmentar els seus recursos en diferents slices (o segments). Per tal de dur-ho a terme es segueixen els estàndards oficials que presenta el 3GPP (Third Generation Partnership Project o Projecte d'Associació de Tercera Generació). El prototip de xarxa empra el programari de software de lliure accés a través de la plataforma de codi obert OAI (Open-Air-Interface) i Mosaic5G. La configuració dels principals elements de la xarxa es realitza sobre una mateixa estació de treball i l'UE (User Equipment o Equip de l'Usuari) és un dongle que té inserida una targeta SIM (Subscriber Identity Module o Mòdul d'Identificació del Subscriptor). Aquest dongle fa de hotspot (o punt calent) a una Raspberry que és l'element que s'usa al prototip per a dur a terme la verificació del projecte. En este trabajo se realiza un prototipo de red LTE (Long Term Evolution o Evolución a largo plazo) con el objetivo de monitorizarla y segmentar sus recursos en diferentes slices (o segmentos). Para llevarlo a cabo se siguen los estándares oficiales que presenta el 3GPP (Third Generation Partenariado Project o Proyecto de Asociación de Tercera Generación). El prototipo de red emplea el software de libre acceso a través de la plataforma de código abierto OAI (Open-Air-Interface) y Mosaic5G. La configuración de los principales elementos de la red se realiza sobre una misma estación de trabajo y el UE (User Equipment o Equipo del Usuario) es un dongle que tiene insertada una tarjeta SIM (Subscriber Identity Modulo o Módulo de Identificación del Subscriptor). Este dongle hace de hotspot (o punto caliente) a una Raspberry que es el elemento que se usa al prototipo para llevar a cabo la verificación del proyecto. In this project a LTE (Long Term Evolution) network has been developed in order to monitor it and its consequent segmentation. Thereinafter, the official standards established by the 3GPP (Third Generation Partnership Project) are taken into consideration. The network's prototype is based on the software proportioned by open-code platforms named OAI (Open-Air-Interface) and Mosaic5G, and its main constituents configuration are developed under the same working machine. What is more, the UE (User Equipment) is a dongle which has a SIM (Subscriber Identity Module), and acts as a hotspot to a Raspberry, the element used in the prototype to verify the project.

Natural disasters and terrorist attacks cause a large number of deaths and damage each year. One of the main problems in an emergency scenario is the network outage, either physical or due to over-traffic. In order to avoid this, the state of the art communication technologies include Device- to-Device (D2D) communication with Sidelink (SL) technique based on the LTE network and the support of Unmmanned Aerial Vehicles (UAV). This technique allows the creation of SyncRef UEs, which are network synchro- nised UEs that can act as signal repeaters for out of coverage UEs. In this thesis, the synchronisation process has been studied, because it is a key player in the creation of the SyncRefs. The UL interference in the creation of these devices also is really important. Therefore, it is shown that the UL interference has a lognormal probability density function and, as a conse- quence, also the SINR follows this type of distribution. Moreover, a Matlab simulator of LTE Sidelink, has been created in order to analyse these type of networks. The optimal thresholds of the system have been investigated, as well as other important parameters. It is verified that it can be reached the 80% of connected devices in urban areas, w.r.t. an original system with an initial 33% of coverage. Moreover, it is shown that the system increases till to 100% of devices connected to the network by adding a UAV. Finally, it is analysed the network with an UAV considering different parameters and proposing an adaptive system for the LTE Sidelink thresholds according to the position of the drone. Els desastres naturals i els atacs terroristes causen un gran nombre de morts i danys cada any. Un dels principals problemes en un escenari d'emergència és la interrupció de la xarxa, ja sigui física o per excés de trànsit. Per evitar- ho, les tecnologies de comunicació més avancades inclouen la comunicació de Dispositiu A Dispositiu (D2D) amb la tècnica Sidelink (SL) basada en la xarxa LTE i el suport de Vehicles Aèris No Tripulats (UAV).Aquesta tècnica permet crear SyncRef UE, que són UE sincronitzats a la xarxa que poden actuar com a repetidors de senyal per als UE fora de cobertura. En aquesta tesi s'ha estudiat el procès de sincronització perquè és un factor clau en la creació dels SyncRefs. La interferència UL en la creació d'aquests dispositius també és realment important. Per tant, s'ha demostrat que la interferència UL té una funció de densitat de probabilitat lognormal i, com a conseqüencia, tambè el SINR ho segueix. A més, s'ha creat un simulador amb Matlab de LTE Sidelink per analitzar aquest tipus de xarxes. S'ha investigat els llindars òptims del sistema, així com altres paràmetres importants. S'ha comprovat que es pot assolir el 80% dels dispositius connectats a les zones urbanes amb una cobertura inicial de 33%. A més, s'ha demostrat que el sistema augmenta fins al 100% dels dispositius connectats a la xarxa afegint un UAV. Finalment, s'ha analitzat la xarxa amb un UAV considerant diferents paràmetres i proposant un sistema adaptatiu per els llindars LTE Sidelink segons la posició del dron. Los desastres naturales y los ataques terroristas causan un gran número de muertes y daños cada año. Uno de los principales problemas en un escenario de emergencia es la interrupción de la red, ya sea física o por exceso de tráfico. Para evitar esto, las tecnologías de comunicación m ás avanzadas incluyen la comunicación Dispositivo a Dispositivo (D2D) con la técnica Sidelink (SL) basada en la red LTE y el soporte de Vehículos Aéreos No Tripulados (UAV). Esta técnica permite la creación de UE SyncRef, que son UE sincronizados en red que pueden actuar como repetidores de señal para los UE fuera de cobertura. En esta tesis se ha estudiado el proceso de sincronización, porque es una pieza clave en la creación de SyncRefs. La interferencia de UL en la creación de estos dispositivos también es realmente importante. Por tanto, se ha demostrado que la interferencia UL tiene una función de densidad de probabilidad lognormal y, como consecuencia, también la SINR sigue esta distribución. Además, se ha creado un simulador con Matlab de LTE Sidelink, para analizar este tipo de redes. Se han investigado los umbrales óptimos del sistema, así como otros parámetros importantes. Se ha verificado que se pueden alcanzar el 80% de dispositivos conectados en áreas urbanas, con una cobertura inicial del 33%. Además, se ha demostrado que el sistema aumenta hasta el 100% de dispositivos conectados a la red al añadir un UAV. Finalmente, se ha analizado la red con un UAV considerando diferentes parámetros y se ha propuesto un sistema adaptativo para los umbrales LTE Sidelink según la posición del dron.

With the advent of bandwidth-intensive applications and powerful wireless devices, service providers face a challenge to satisfy the needs of customers in a cost effective manner. Legacy wireless backhaul networks are limited in their flexibility to scale well with rapidly increasing backhaul bandwidth requirement. Service providers are beginning to deploy 4G LTE technology and are planning for widespread coverage in the near future. (As cited in introduction.) *Publication date not found.

©2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Macrocells are expected to be densely overlaid by small cells (SCs) to meet increasing capacity demands. Due to their dense deployment, some SCs will not be connected directly to the core network, and thus, they may forward their traffic to the neighboring SCs until they reach it, thereby forming a multihop backhaul (BH) network. This is a promising solution, since the expected short length of BH links enables the use of millimeter-wave (mmWave) frequencies to provide high-capacity BH. In this context, user association becomes challenging due to the multihop BH architecture, and therefore, new optimal solutions should be developed. Thus, in this paper, we study the user association problem aiming at the joint maximization of network energy efficiency (EE) and spectrum efficiency (SE), without compromising the user quality of service (QoS). The problem is formulated as an e-constraint problem, which considers the transmit energy consumption both in the access network, i.e., the links between the users and their serving cells, and the BH links. The optimal Pareto-front solutions of the problem are analytically derived for different BH technologies, and insights are gained into the EE and SE tradeoff. The proposed optimal solutions, despite their high complexity, can be used as a benchmark for the performance evaluation of user association algorithms. We also propose a heuristic algorithm, which is compared with reference solutions under different traffic scenarios and BH technologies. Our results motivate the use of mmWave BH, whereas the proposed algorithm achieves near-optimal performance.

The project consists on a Matlab-based 5G link level cellular communications simulator. The main objective of this thesis is to study the channel estimation subject in LTE ( Long Term Evolution). LTE uses coherent detection and, with the purpose of obtaining information about the channel, pilot signals are used. The main axis of this study is how the reference signals according to the 3GPP standard (3th generation partnership project) are generated. In this project it is expected to understand the differences between different channel estimators using a 5G simulator developed at the Technische Universität Wien . The advantages of some pilot sequences and allocation in the signal will be studied. It is also an objective of the thesis to study the advantages from the estimator point of view in using more than one antenna in each base station with their corresponding reference signals. 1 En este proyecto se pretende estudiar el problema de la estimación de canal en LTE ( Long Term Evolution). LTE utiliza detección coherente y con el objetivo de conocer el canal se proporcionan secuencias de referencia. El estudio se realiza en cómo se generan estas señales piloto a partir del 3GPP standard (3th generation partnership project). Este proyecto tiene como principal objetivo entender las diferencias entre diferentes estimadores a partir del uso de un simulador de 5G desarrollado en la Technische Universität Wien . Se comparan qué ventajas tiene usar determinadas secuencias piloto y su posición. También se pretende estudiar qué ventajas tiene utilizar más de una antena por estación base con sus respectivas señales de referencia a nivel del estimador de canal. En aquest projecte s'estudia el problema de l'estimació de canal en LTE ( Long Term Evolution). LTE fa servir detecció coherent i per tal de conèixer el canal es proporcionen seqüències de referència. L'estudi es realitzarà sobre com es construeixen aquestes senyals pilot a partir del 3GPP standard (3th generation partnership project). Aquest projecte té com a principal objectiu estudiar les diferències entre diferents estimadors de canal a partir de l'ús d'un simulador de 5G desenvolupat a la Technische Universität Wien. Es comparan quins avantatges té fer servir diferents seqüències pilot i la seva posició. També es pretén estudiar els avantatges d'utilitzar més d'una antena per estació base amb les seves respectives senyals pilot a nivell del estimador de canal.

The great demand for mobile data traffic has led to the development of new technologies. The last of these is known as LTE-Advanced. This incorporates great improvements that have revolutionized the mobile technology market. The project focuses on the study and comparison of LTE-Advanced with its predecessor, LTE. To carry out the project, a virtual network of the town of Cerdanyola del Vallés has been implemented. In order to perform this simulation, according to the greatest possible likelihood, the current data of a real deployment have been obtained. The results obtained show that a LTE-Advanced network, if applied correctly, can achieve a great improvement both in coverage and in the throughput. On the other hand, a bad deployment would adversely affect and we would get worse results than in previous standards. La gran demanda de tráfico de datos móviles ha propiciado el desarrollo de nuevas tecnologías. La última de estas se conoce con el nombre de LTE-Advanced. Esta incorpora grandes mejoras que han revolucionado el mercado de la tecnología móvil. El proyecto se centra en el estudio y la comparación de LTE-Advanced con su predecesora, LTE. Para realizar el proyecto se ha implementado una red virtual del municipio de Cerdanyola del Vallés. Para realizar esta simulación, acuerdo a la máxima verosimilitud posible, se han obtenido los datos actuales de un despliegue real. Los resultados obtenidos muestran que una red LTE-Advanced, si se aplica correctamente, puede obtener una gran mejora tanto en la cobertura como en el throughput. Por otro lado, un mal despliegues afectaría negativamente, llegando a empeorar incluso estándares anteriores. La gran demanda de tràfic de dades mòbils ha propiciat el desenvolupament de noves tecnologies. L’última d’aquestes es coneix amb el nom de LTE-Advanced. Aquesta incorpora grans millores que han revolucionat el mercat de la tecnologia mòbil. El projecte es centra en l’estudi i la comparació de LTE-Advanced amb la seva predecessora, LTE. Per realitzar el projecte s’ha implementat una xarxa virtual del municipi de Cerdanyola del Vallés. Per tal de realitzar aquesta simulació, acord a la màxima versemblança possible, s’han obtingut les dades actuals d’un desplegament real. Els resultats obtinguts mostren que una xarxa LTE-Advanced, si s’aplica correctament, pot obtenir una gran millora tant en la cobertura com en el throughput. Per altra banda, un dolent desplegament afectaria negativament, arribant a empitjorar fins i tot estàndards anteriors.

Best Paper Award, 9th. International Conference on Wireless and Mobile Communications, ICWMC 2013 Intercell Interference Coordination (ICIC) encompasses techniques aiming at reducing the intercell interference at cell edges, an issue affecting not only data but also control channels in Long Term Evolution (LTE) and LTE-Advanced (LTE-A). This paper presents several ICIC-based optimization schemes to improve the performance of the control channels: the Physical Downlink Control Channel (PDCCH) in LTE and the enhanced PDCCH (ePDCCH) in LTE-A. The study is focused on realistic deployments, where the amount of intercell interference received at different cells varies considerably, making very difficult the task of homogenizing the performance of the ePDCCH in the coverage area. The PDCCH is time-multiplexed, and hence, traditional ICIC schemes such as Soft Frequency Reuse cannot be applied. As an answer to this, LTE-A introduces the ePDCCH. This new structure increases the signaling capacity and allows frequency domain ICIC. However, the optimization of the ePDCCH poses a new problem. The resources devoted to the ePDCCH need to be borrowed from the data channels. In order to address these problems, several multiobjective optimization schemes based on evolutionary algorithms are proposed to adjusts the configuration of the control channels, and consequently, to reduce the consumption of control resources. The results show that significant capacity gains, up to 30%, are obtained in severely interfered cells with notorious savings in terms of transmitted power. Peer Reviewed Award-winning

The range and number of new applications and services are growing at an unprecedented rate. Computer networks need to be able to provide connectivity for these services and meet their constantly changing demands. This requires not only support of new network protocols and security requirements, but often architectural redesigns for long-term improvements to efficiency, speed, throughput, cost, and security. Networks are now facing a drastic increase in size and are required to carry a constantly growing amount of heterogeneous traffic. Unfortunately such dynamism greatly complicates security of not only the end nodes in the network, but also of the nodes of the network itself. To make matters worse, just as applications are being developed at faster and faster rates, attacks are becoming more pervasive and complex. Networks need to be able to understand the impact of these attacks and protect against them. Network control devices, such as routers, firewalls, censorship devices, and base stations, are elements of the network that make decisions on how traffic is handled. Although network control devices are expected to act according to specifications, there can be various reasons why they do not in practice. Protocols could be flawed, ambiguous or incomplete, developers could introduce unintended bugs, or attackers may find vulnerabilities in the devices and exploit them. Malfunction could intentionally or unintentionally threaten the confidentiality, integrity, and availability of end nodes and the data that passes through the network. It can also impact the availability and performance of the control devices themselves and the security policies of the network. The fast-paced evolution and scalability of current and future networks create a dynamic environment for which it is difficult to develop automated tools for testing new protocols and components. At the same time, they make the function of such tools vital for discovering implementation flaws and protocol vulnerabilities as networks become larger and more complex, and as new and potentially unrefined architectures become adopted. This thesis will present the design, implementation, and evaluation of a set of tools designed for understanding implementation of network control nodes and how they react to changes in traffic characteristics as networks evolve. We will first introduce Firecycle, a test bed for analyzing the impact of large-scale attacks and Machine-to-Machine (M2M) traffic on the Long Term Evolution (LTE) network. We will then discuss Autosonda, a tool for automatically discovering rule implementation and finding triggering traffic features in censorship devices. This thesis provides the following contributions: 1. The design, implementation, and evaluation of two tools to discover models of network control nodes in two scenarios of evolving networks, mobile network and censored internet 2. First existing test bed for analysis of large-scale attacks and impact of traffic scalability on LTE mobile networks 3. First existing test bed for LTE networks that can be scaled to arbitrary size and that deploys traffic models based on real traffic traces taken from a tier-1 operator 4. An analysis of traffic models of various categories of Internet of Things (IoT) devices 5. First study demonstrating the impact of M2M scalability and signaling overload on the packet core of LTE mobile networks 6. A specification for modeling of censorship device decision models 7. A means for automating the discovery of features utilized in censorship device decision models, comparison of these models, and their rule discovery

University of Technology Sydney. Faculty of Engineering and Information Technology. There has been a huge increase in demand towards improving the Quality of Service (QoS) of wireless services. Long Term Evolution (LTE) is a development of the Third-Generation Partnership Project (3GPP) with the aim to meet the needs of International Telecommunication Union (ITU). Some of its aspects are highlighted as follows: increase in data rate, scalable bandwidth, reduced latency and increase in coverage and capacity that result in better quality of service in communication. LTE employs Orthogonal Frequency Division Multiple Access (OFDMA) to simultaneously deliver multimedia services at a high speed rate. Packet switching is used by LTE to support different media services. To meet the QoS requirements for LTE networks, packet scheduling has been employed. Packet scheduling decides when and how different packets are delivered to the receiver. It is responsible for smart user packet selection to allocate radio resources appropriately. Therefore, packet scheduling should be cleverly designed to achieve QoS that is similar to fixed line services. eNodeB is a node in LTE network which is responsible for radio resource management that involves packet scheduling. There are two main categories of application in multimedia services: RT (Real Time) and NRT (None Real Time) services. RT services are either delay sensitive (e.g. voice over IP), loss sensitive (e.g. Buffered Video) or both (delay &loss sensitive) for example video conferencing. Best effort users are an example of NRT services that do not have exact requisites and have been allocated to spare resources. Reaching higher throughput has sometimes resulted in unfair allocation to users who are located far from the base station or users who suffer from bad channel conditions. Therefore, a sufficient trade-off between throughput and fairness is essential. The scarce bandwidth, fading radio channels and the QoS requirement of the users, makes resource allocation a demanding issue. Different scheduling approaches have been suggested for different service demands described briefly throughout the thesis. Initially, a comprehensive literature review of existing work on the packet scheduling topic has been accomplished in this thesis to realize the characteristics of packet scheduling and the resource allocation for the wireless network. Many packet scheduling algorithms developed to provide satisfactory QoS for multimedia services in downlink LTE systems. Several algorithms considered in this thesis include time and frequency domain algorithms and their way of approach has been investigated. The next objective of this thesis is to improve the performance of packet scheduling in LTE downlink systems. A new packet scheduling algorithm has been introduced in this thesis. A study on VoLTE (Voice over LTE), video streaming and best effort traffic under three different scheduling algorithms has been conducted. Heterogeneous traffic based on precise modelling of packets has been used in the simulation. The main resource allocation and assignment technique used in this work namely Dynamic Subcarrier Allocation scheme is shown to provide a solution to solve the cross layer optimisation problem. It depends on Channel Quality Information (CQI) and has been broadly investigated for single carrier and multicarrier wireless networks. The problem is based on the maximisation of average utility functions. Different scheduling algorithms in this method consider to be utility functions. The throughput, fairness and Packet Loss Ratio have been considered as the requirements for examining the performance of algorithms. Simulation results show that the proposed algorithm significantly increases the performance of streaming and best effort users in terms of PLR and throughput. Fairness has also been improved with less computational complexity compared to previous algorithms that have been introduced in this thesis.

The 3GPP has raised the need to revisit the design of next generations of cellular networks in order to make them capable and efficient to provide M2M services. One of the key challenges that has been identified is the need to enhance the operation of the random access channel of LTE and LTE-A. The current mechanism to request access to the system is known to suffer from congestion and overloading in the presence of a huge number of devices. For this reason, different research groups around the globe are working towards the design of more efficient ways of managing the access to these networks in such circumstances. This paper aims to provide a survey of the alternatives that have been proposed over the last years to improve the operation of the random access channel of LTE and LTE-A. A comprehensive discussion of the different alternatives is provided, identifying strengths and weaknesses of each one of them, while drawing future trends to steer the efforts over the same shooting line. In addition, while existing literature has been focused on the performance in terms of delay, the energy efficiency of the access mechanism of LTE will play a key role in the deployment of M2M networks. For this reason, a comprehensive performance evaluation of the energy efficiency of the random access mechanism of LTE is provided in this paper. The aim of this computer-based simulation study is to set a baseline performance upon which new and more energy-efficient mechanisms can be designed in the near future.

High consumption data that currently exists worldwide requires that access networks meet the expectations of user providing a fast download of data and a good network quality. The pre-4G technology is the so-called LTE (Long Term Evolution) is currently one of the most used technologies around the world and achieves high throughputs compared with previous technologies. In the environment of mobile or cellular communications the territory is divided into cells that serve, and these cells are reusing the radio spectrum. In order to mitigate interference between cells advanced techniques of wireless communications are required. One of these techniques is the Inter-Cell Interference Coordination (ICIC). The aim of this project is to study the effect of the ICIC strategy in its different types and in various scenarios in order to make a qualitative comparison of the results obtained in each of the scenarios. The first phase is a theoretical research on LTE technology, ICIC strategies, the radio planning tool used and the studied areas. The next phase is based in all necessary studies for a further analysis and comparison, so that conclusions can be drawn from the effect of the ICIC strategy and its effectiveness in each environment. El consumo masivo de datos que existe actualmente en todo el mundo requiere que las redes de acceso cumplan con las expectativas de los usuarios, proporcionando una rápida descarga de los datos y una buena calidad de la red. La tecnología previa al denominado 4G es LTE (Long Term Evolution), actualmente es una de las tecnologías más utilizadas en gran parte del mundo y logra altas velocidades de descarga comparándola con tecnologías anteriores. En el entorno de las comunicaciones móviles o celulares, el territorio se divide en celdas o células a las que dar servicio, que reutilizan el espectro radioeléctrico. Con el objetivo de mitigar la interferencia entre estas celdas, se requieren técnicas avanzadas de comunicaciones inalámbricas. Una de estas técnicas es la Coordinación de Interferencias entre Celdas (ICIC, Inter-Cell Interference Coordination). En este proyecto se pretende estudiar el efecto de la estrategia ICIC en sus diferentes tipos y en diversos escenarios con el objetivo de hacer una comparación cualitativa de los resultados obtenidos en cada uno de los escenarios. Para ello se parte de una primera fase de investigación teórica sobre la tecnología LTE, las estrategias ICIC, la herramienta de planificación radio utilizada y las zonas de estudio. En la siguiente fase se realizan todos los estudios necesarios para su posterior análisis y comparación, de manera que se puedan sacar conclusiones del efecto de la estrategia ICIC y su eficacia en cada entorno. El consum massiu de dades que existeix actualment arreu de tot el món requereix que les xarxes d’accés compleixin amb les expectatives dels usuaris, proporcionant una ràpida descàrrega de les dades i una bona qualitat de la xarxa. La tecnologia prèvia al denominat 4G és LTE (Long Term Evolution), actualment és una de les tecnologies més utilitzades en gran part del món i aconsegueix altes velocitats de descàrrega comparantla amb tecnologies anteriors. A l’entorn de les comunicacions mòbils o cel·lulars, el territori es divideix en cel·les o cèl·lules a les quals donar servei, que reutilitzen l’espectre radioelèctric. Amb l’objectiu de mitigar la interferència entre aquestes cel·les, es requereixen tècniques avançades de comunicacions sense fils. Una d’aquestes tècniques és la Coordinació d’Interferències entre Cel·les (ICIC, Inter-Cell Interference Coordination). En aquest projecte es pretén estudiar l’efecte de l’estratègia ICIC amb els seus diferents tipus i en diversos escenaris amb l’objectiu de fer una comparació qualitativa dels resultats obtinguts en cadascun dels escenaris. Per això es parteix d’una primera fase de recerca teòrica sobre la tecnologia LTE, les estratègies ICIC, l’eina de planificació radio utilitzada i les zones d’estudi. En la següent fase es realitzen tots els estudis necessaris pel posterior anàlisis i comparació, de manera que es puguin extreure conclusions de l’efecte de la estratègia ICIC i la seva eficàcia a cada entorn.

Elements and parameters of the LTE networks are configured manually on a large scale. The complication or problem with manual configuring LTE networks is that it demands great expertise and effort at the operator's end. The deployment of new base stations, configurations, making neighbor relations, healing of networks and managing the operational network are the main areas where huge manual effort and expertise is required. Human interaction with the network architecture and functions are prone to errors and cost-intensive too. With the increase in data traffic, manual configurations are getting more complicated and therefore there was a sheer need of a system that can redefine operations carried out by the network in order to achieve optimal performance. Self-Organizing Networks (SON) were therefore introduced by 3GPP which ensures operational efficiency and automate the mobile wireless networks. For my project, I will be discussing all the Functions of SON and its Architecture in Long Term Evolution with accordance to the 3GPP standards through analysis and research.

Developed by 3GPP, LTE (Long Term Evolution) is a technology used in mobile communications that provides higher data rates than older technologies. However, because of the higher usage of smartphones during the last years, the data traffic that a base station must be able to manage has increased drastically and it is expected that current networks will be unable to manage all traffic in a near future. Some solutions have been proposed to solve this problem. Ultrasectorization and hyperdensification are two strategies designed to densify existing networks and so solve capacity problems. The first one proposes to maintain existing sites but increasing the number of sectors available in a base station. The other one proposes to create a layer of low-power stations near the user to reduce the distance between base stations and end users. In this project both strategies are analysed by using a simulation-tool designed with Matlab, which allows users to simulate different coverage maps and analyse their results with various statistical tools. Simulations are done in different scenarios and conditions. One is built on non-real conditions, which just gives a theoretical approximation meanwhile the other one is built on real conditions using some cartographic maps of Vienna. Finally, the main objective is to conclude of which strategy gives better results in terms of capacity and throughput in order to analyse the effect of implementing one strategy or other upon a typical trisectorized cellular network.

High consumption data that currently exists worldwide requires that access networks meet the expectations of user providing a fast download of data and a good network quality. The pre-4G technology is the so-called LTE (Long Term Evolution) is currently one of the most used technologies around the world and achieves high throughputs compared with previous technologies. In the environment of mobile or cellular communications the territory is divided into cells that serve, and these cells are reusing the radio spectrum. In order to mitigate interference between cells advanced techniques of wireless communications are required. One of these techniques is the Inter-Cell Interference Coordination (ICIC). The aim of this project is to study the effect of the ICIC strategy in its different types and in various scenarios in order to make a qualitative comparison of the results obtained in each of the scenarios. The first phase is a theoretical research on LTE technology, ICIC strategies, the radio planning tool used and the studied areas. The next phase is based in all necessary studies for a further analysis and comparison, so that conclusions can be drawn from the effect of the ICIC strategy and its effectiveness in each environment. El consumo masivo de datos que existe actualmente en todo el mundo requiere que las redes de acceso cumplan con las expectativas de los usuarios, proporcionando una rápida descarga de los datos y una buena calidad de la red. La tecnología previa al denominado 4G es LTE (Long Term Evolution), actualmente es una de las tecnologías más utilizadas en gran parte del mundo y logra altas velocidades de descarga comparándola con tecnologías anteriores. En el entorno de las comunicaciones móviles o celulares, el territorio se divide en celdas o células a las que dar servicio, que reutilizan el espectro radioeléctrico. Con el objetivo de mitigar la interferencia entre estas celdas, se requieren técnicas avanzadas de comunicaciones inalámbricas. Una de estas técnicas es la Coordinación de Interferencias entre Celdas (ICIC, Inter-Cell Interference Coordination). En este proyecto se pretende estudiar el efecto de la estrategia ICIC en sus diferentes tipos y en diversos escenarios con el objetivo de hacer una comparación cualitativa de los resultados obtenidos en cada uno de los escenarios. Para ello se parte de una primera fase de investigación teórica sobre la tecnología LTE, las estrategias ICIC, la herramienta de planificación radio utilizada y las zonas de estudio. En la siguiente fase se realizan todos los estudios necesarios para su posterior análisis y comparación, de manera que se puedan sacar conclusiones del efecto de la estrategia ICIC y su eficacia en cada entorno. El consum massiu de dades que existeix actualment arreu de tot el món requereix que les xarxes d’accés compleixin amb les expectatives dels usuaris, proporcionant una ràpida descàrrega de les dades i una bona qualitat de la xarxa. La tecnologia prèvia al denominat 4G és LTE (Long Term Evolution), actualment és una de les tecnologies més utilitzades en gran part del món i aconsegueix altes velocitats de descàrrega comparantla amb tecnologies anteriors. A l’entorn de les comunicacions mòbils o cel·lulars, el territori es divideix en cel·les o cèl·lules a les quals donar servei, que reutilitzen l’espectre radioelèctric. Amb l’objectiu de mitigar la interferència entre aquestes cel·les, es requereixen tècniques avançades de comunicacions sense fils. Una d’aquestes tècniques és la Coordinació d’Interferències entre Cel·les (ICIC, Inter-Cell Interference Coordination). En aquest projecte es pretén estudiar l’efecte de l’estratègia ICIC amb els seus diferents tipus i en diversos escenaris amb l’objectiu de fer una comparació qualitativa dels resultats obtinguts en cadascun dels escenaris. Per això es parteix d’una primera fase de recerca teòrica sobre la tecnologia LTE, les estratègies ICIC, l’eina de planificació radio utilitzada i les zones d’estudi. En la següent fase es realitzen tots els estudis necessaris pel posterior anàlisis i comparació, de manera que es puguin extreure conclusions de l’efecte de la estratègia ICIC i la seva eficàcia a cada entorn.

Traditionally, wireless cellular systems have been designed to operate in Frequency Division Duplexing (FDD) paired bands that allocates the same amount of spectrum for both downlink (DL) and uplink (UL) communication. Such design is very convenient under symmetric DL/UL traffic conditions, as it used to be the case when the voice transmission was the predominant service. However, with the overwhelming advent of data services, bringing along large asymmetries between DL and UL, the conventional FDD solution becomes inefficient. In this regard, flexible duplexing concepts aim to derive procedures for improving the spectrum utilization, by adjusting resources to the actual traffic demand. In this work we review these concepts and propose the use of unpaired Time Division Duplexing (TDD) spectrum on the unused resources for small eNBs (SeNB), so that user equipment (UEs) associated to those SeNB could be served either in DL or UL. This proposal alleviates the saturated DL in FDD-based system through user offloading towards the TDD-based system. The flexible duplexing concept is analyzed from three points of view: a) regulation, b) Long Term Evolution (LTE)standardization, and c) technical solutions., submitted to IEEE Communications Magazine

M.Ing. The increase of interest in the development of radio communications, both terrestrial and satellite is reaching far and beyond the most optimistic expectations. There has been an accelerated emergence of newer technologies, all claiming highly coveted radio frequency spectrum resources. With the push for the development of location based services, utilizing satellite com- communications for military purposes and later for civilian use; there has been a parallel development in terrestrial communications technology making it possible to implement cost efficient reliable user systems for voice and data services ...

This paper aims to find patterns of knowledge from physical layer data coming from Heterogeneous Long Term Evolution (LTE) networks. We discuss how the collected data is employed in such a manner that improves Minimization of Drive Tests (MDT) functionality in LTE networks. In particular we aim to predict Quality of Service (QoS) expressed in terms of throughput of the User Datagram Protocol (UDP) traffic flow. We propose regression models to estimate QoS, by extrapolating information independently of the user’s physical location. In particular our approach allows to estimate the QoS in any location, based on measurements collected at anytime in the past, or anywhere in the network. This will allow to significantly reduce costs of future network deployments, even in complex and heterogeneous scenarios, such as those foreseen in stadiums, events, etc. We identify three feasible regression models, and we compare results in terms of prediction accuracy.

©2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Carrier Aggregation is an important feature in Long Term Evolution Advanced (LTE-A). It allows operators to provide larger operational bandwidths without the need of having a contiguous, large piece of spectrum. However, an increased bandwidth also needs a larger channel sounding to obtain channel state information (CSI), required for frequency domain scheduling and link adaptation. This constitutes a serious challenge for the uplink since wideband sounding reference signals cannot be transmitted by cell edge (power limited) users and hopped sounding requires a long time to sweep the entire transmission band, thus leading to outdated and less reliable CSI. Also, average interference and its variation in time can seriously jeopardize the CSI at the eNodeB. In this paper, we present an integration of inter cell interference coordination with CSI reporting by reducing the interference variability through controlled allocations. Results show that the entire CSI accuracy can be improved and so does the overall cell performance.

We consider a distributed SON (D-SON) architecture where the interaction of different self-organizing network (SON) functions negatively affect the performances of the system. This is referred to in 3rd Generation Partnership Project (3GPP) as a SON conflict, which needs to be handled by means of a self-coordination framework. We focus on a functional architecture and a theoretical framework based on the theory of Markov decision process (MDP) for the self-coordination of different actions taken by different SON functions. In order to cope with the complexity of the overall SON problem, we subdivide the global MDP modeling the long-term evolution (LTE)-enhanced node base station (eNB) onto simpler subMDPs modeling the different SON functions. Each sub-problem is defined as a subMDP and solved independently by means of reinforcement learning (RL), and their individual policies are combined to obtain a global policy. This combined policy can execute several actions per state but can introduce policy conflicts. We focus on the specific SON conflict generated by the concurrent execution of coverage and capacity optimization (CCO) and inter-cell interference coordination (ICIC) SON functions, which may require to update the same parameter, i.e., the transmission power level. The coordination among the different actions selected by the conflicting use cases is achieved by means of a coordination game where the players are the subMDPs and the actions and rewards are those provided by means of a RL approach. Performance evaluation is carried out in a ns3 release 8 compliant LTE system simulator, and it shows that our self-coordination approach provides satisfying solutions in terms of system performances for both the conflicting SON functions.

In a self-organized Long Term Evolution (LTE) network, different Self-Organizing Network (SON) functions or different instances of the same SON function can execute parallel actions, which interact or collide among each other. When the effect of the interaction negatively affects the performances of the system, this is referred to in 3rd Generation Partnership Project (3GPP) as a SON conflict, which needs to be handled by means of a self-coordination framework. We focus on the self-coordination of different actions taken by two SON functions in a distributed SON (D-SON) architecture, which implements the SON functions at the edges of the network. We propose a multi-agent framework where each Enhanced Node Base station (eNB), is an autonomous agent modeled by means of a Markov Decision Process (MDP). We subdivide this global Markov Decision problem onto simpler subMDPs modeling the different SON functions. Each sub-problem is defined as an MDP and solved independently, and their individual policies are combined to obtain a global policy. This combined policy can execute several actions per state in parallel, but can introduce policy conflicts, which model the mentioned SON conflicts. Each subMDP is solved by means of a Reinforcement Learning (RL) approach. We focus on the SON conflict generated by the concurrent execution of Coverage and Capacity Optimization (CCO) and Inter-Cell Interference Coordination (ICIC) SON functions, which may require to update the same parameter, i.e. the transmission power level. Coordination among different actions is achieved by means of a coordination game where the players are the subMDPs and the actions and rewards are those provided by the independent RL solutions. Performance evaluation is carried out in a ns3 release 10 compliant LTE system simulator and it shows that our self-coordination approach provides satisfying solutions in terms of system performances for both the conflicting SON functions.

The widespread adoption of wireless technologies is leading to an ever increasing demand for the Radio Frequency (RF) spectrum that supports mobile communication. A Cognitive Radio (CR) can increase the amount of a radio frequency spectrum that is usefully employed by authorizing unlicensed users to connect to licensed spectrum spaces when they are idle. Long Term Evolution (LTE) is a technology that has developed to support next generation multimedia applications coupled with high data rates. To overcome the spectrum scarcity issue and to multiply capacity, dynamic spectrum access is deployed in LTE. Dynamic Spectrum Access (DSA) identifies the possibilities of utilizing the spectrum wisely. (As cited in abstract.)

The explosive growth of cellular networks makes their deployment and maintenance more and more complex, time consuming, and expensive. Self-Organizing Networks have been recognized as a promising way to alleviate this problem by minimizing human intervention in such processes. This paper introduces a novel multiobjective framework, based on evolutionary optimization, aiming at improving network performance and users Quality of Service. By tuning the transmitted power at each cell, average intercell interference levels are minimized. The design of the proposed scheme is feasible for distributed implementations in Long Term Evolution (LTE) and LTE-Advanced networks and its operation is compatible with current specifications. The framework is able to provide effective network-specific optimization and obtained results show that gains in terms of network capacity and cell edge performance are 5 and 10 %, respectively. Energy savings always accompanied such enhancements with reductions up to 35 %.

Long term Evolution is the recent telecommunication technology proposed by 3GPP. It is boasts to have low latency, high data rates and higher spectral efficiency which occurs by having Packet switched architecture for both voice and data. For this altered architecture, testing LTE in real network would be too expensive. OMNET++ provides a cheapest and effective way of testing LTE network before implementing it in real network. OMNET++ is open source simulation platform. It implements the user plane of LTE-network. The main objective behind this work is to test how well LTE-network is implemented and what further changes can be made in it. The effectiveness of current LTE package (Sim-LTE) is tested by performing several simulations.

This project focuses on the implementation of the LTE Listen Mode functionality for a femtocell. The Listen Mode functionality is part of any LTE femtocell capabilities. The Listen Mode Functionality is the functionality by which a femtocell obtains information about all the LTE base stations that lie in the neighborhood.

Analysis of QoS mechanisms and prioritization in LTE environments with consideration of a public safety communication.

To assure a good channel state information (CSI) in the uplink users need to send sounding reference signals along the entire bandwidth. This task is challenging in a Carrier Aggregation framework, as the time period between two consecutive measurements will rise due to the increased available bandwidth. This leads to outdated information about the radio channels, and as a consequence a poorer link adaptation is carried out. In order to avoid this situation a inter cell interference coordination method to improve the CSI reliability is presented. This is particularly important for power limited users. On the one hand the interference variability perceived in reception is reduced by allocating resources in a controlled manner, and on the other hand by reducing the available bandwidth sounding measurements are more frequent. Results show that the entire CSI accuracy can be improved and so does the overall cell performance.

LTE (Long Term Evolution) is a fourth generation cellular network technology that provides improved performance related to data rate, coverage and capacity compared to legacy cellular systems. In this context, one of the main goals of LTE is to provide fast and seamless handover from one cell to another to meet a strict delay requirement while simultaneously keeping network management simple. Hence, the decision to trigger a handover is a crucial component in the design process of handover, since the success and the efficiency, to a large extent, depends on the accuracy and timeliness of the decision. The design of an efficient and successful handover requires a careful selection of HO parameters and the optimal setting of these. The LTE standard supports two parameters to trigger the handover and select the target cell: hysteresis margin and Time-to-Trigger (TTT) The research topic of this thesis which is “LTE Handover Performance Evaluation Based on Power Budget Handover Algorithm”, focuses on different combinations or settings of HOM and TTT values to evaluate the handover performance based on Reference Signal Received Power (RSRP) measurement within certain deployment scenarios, such as different UE speeds, system loads and cell sizes. The Power Budget Handover Algorithm (PBHA) picks the best hysteresis and time-to-trigger combinations to evaluate the system performance in terms of number of handovers, signal-to-interference plus noise ratio (SINR), throughput, delay and packet lost for UE's which are about to perform the handover.

Current state-of-the-art approaches are evaluated for the downlink (DL) of an LTE-based wireless network when multiple Small-Cells (SC) eNBs coexist in the same area. With the aim of increasing data-rate performance of users, we consider that all SCeNBs reuse the same resources. In this situation, inter-cell interference (ICI) becomes the main impairment in the communication. One of the solution may be the use of time domain eICIC (TDM muting), allowing to avoid the ICI. An alternative strategy is to employ multiple-input multiple-output (MIMO) techniques if channel state information (CSI) at the transmitter (CSIT) can be exploited. Nevertheless, CSI reported by User Equipments (UEs) may suffer large delays, even higher than the channel coherence time, and non-perfect accuracy, where the errors are due to the adopted feedback schemes: digital or analog. In this context, the approach in [1] for the interference channel (IC), and assuming imperfect delayed CSIT is considered, getting insight into the benefits of the MIMO-based over the eICIC-based schemes.

The future network architecture towards heterogeneous, it would be converged many different types of network, such as cellular network, femtocell network, ad-hoc network, MANET, VANET and wireless sensor network. With new network service type and service demanding are emerging, it would cause the huge number of mobile terminal accesses to network. Hence, it makes big trouble for managing mobility, and brings forward challenge.The handover is the most important part in the mobility management, because the handover is frequently occurred when UE is moving, hence the handover number directly affects the system performance, and network QoS. A sophisticated HO decision algorithm can improve the performance of system, although in current literature there are many HO decision algorithms proposed and every algo- rithm owns dramatical advantages, but they also have limitations or drawbacks. In this report, we will survey the HO decision algorithms, and summarise them. Based on some current algorithms propose a new HO decision algorithm.

Interference management has been recognized by the industry as a key enabler for 4G systems. Emerging technologies include multicarrier systems such as LTE and WiMAX for which effective management of intercell interference is of utmost importance in order to improve the Quality of Service (QoS) at cell edges. Static Intercell Interference Coordination (ICIC) techniques such as Soft Frequency Reuse (SFR) are aimed at alleviating this problem; however the usage of baseline SFR designs (schemes without optimization) only offers tradeoffs between cell edge performance and spectral efficiency and performance is indeed far from optimal as results herein confirm. Thus, this paper presents a novel multiobjective algorithm in order to address this problem and achieve effective optimization of SFR implementations. Results show that the proposed algorithm succeeds in finding good-quality SFR configurations enhancing simultaneously network capacity and cell edge performance while reducing energy consumption with respect to baseline designs and previous proposals.

Against previous Long Term Evolution (LTE) re-leases, LTE-Advanced (LTE-A) allows the use of non-contiguous resource allocation in the uplink (UL). This feature leads to an increase in spectral efficiency thanks to link performance gains obtained from frequency diversity. At the same time noncontiguous allocations bring higher peak to average power ratio (PAPR) and so potentially higher inter-modulation and adjacent channel leakage-power ratio (ACLR). Power de-rating has been proposed as a means to avoid this problem and thus user equipments (UEs) must reduce their maximum transmitted power. However, the additional link loss on power limited UEs partially counteracts the gain brought by multi-cluster allocation. In this sense, this paper proposes to include Maximum Power Reduction (MPR) information in opportunistic scheduling decisions. The new scheduling proposal is able to determine whether multi-clustering leads to a net gain in instantaneous throughput or if localized allocation is preferred. Results show that this method improves cell throughput and allows making a smarter use of clustered transmission.

Densifying the Macro-cellular network by deploying Pico eNodeBs with CRE to enhance system performance and meet future expected demands. [ANGLÈS] Deploying low power nodes within a macro cell layout, also known as heterogeneous networks (HetNets), is a promising solution to enhance the global performance of LTE mobile communication systems and particularly the performance in cell-edges and indoor areas. In this sense, Range expansion (RE) in low power nodes is mandatory in areas not covering hotspots, otherwise there is no significant offload from the macro cell and gains are poor. This technique allows attracting more users and thus achieving performance improvement. However, RE causes extra downlink interference which becomes severe for higher bias values and so the benefits translate into important degradation. For that, RE should be jointly designed with advanced interference coordination schemes to overcome these issues. This thesis discusses LTE-Advanced as evolution of LTE release 8/9, and describes the concept of HetNets, RE, the major technical challenges and interference coordination schemes. Finally, results are presented related to HetNets (Macro-Pico scenario) using system level simulation to evaluate the impact on system performance for different configurations. [CASTELLÀ] El despliegue de nodos de baja potencia dentro de la capa macro celular, también conocido como redes heterogéneas (HetNets), es una solución prometedora para mejorar el rendimiento global de los sistemas de telefonía móvil Long Term Evolution (LTE) y en particular, el rendimiento en los bordes de celda y áreas interiores. En este sentido, la expansión de rango (RE) en los nodos de baja potencia es obligatoria en áreas que no cubren hotspots, ya que de otro modo no habría un traspaso significativo de usuarios desde la macro celda y las ganancias serían pobres. Esta técnica permite atraer a más usuarios y así conseguir una mejora de rendimiento. Sin embargo, RE causa interferencia adicional en el enlace descendente que se vuelve grave para los valores de ampliación rango mayores y ello da como resultado una degradación importante. Por lo tanto, RE debe ser diseñado conjuntamente con esquemas de coordinación de interferencia para superar estos problemas. Esta tesis discute LTE-Advanced como evolución de LTE Release 8/9, y describe el concepto de HetNets, la expansión del rango, los retos técnicos más importantes y los esquemas de coordinación de interferencia. Finalmente, se presentan resultados mediante simulación de un despliegue HetNet (escenario Macro-Pico) que evalúan el impacto en el rendimiento del sistema para distintas configuraciones. [CATALÀ] El desplegament de nodes de baixa potència dins de la capa macro cel·lular, també conegut com xarxes heterogènies (HetNets), és una solució prometedora per millorar el rendiment global dels sistemes de telefonia mòbil Long Term Evolution (LTE) i, en particular, el rendiment a les vores de cel·les i àrees interiors. En aquest sentit, l'expansió de rang (RE) en els nodes de baixa potència és obligatòria en àrees que no cobreixen hotspots, ja que d'una altra manera no hi hauria un traspàs significatiu d'usuaris des de la macro cel·la i els guanys serien pobres. Aquesta tècnica permet atreure més usuaris i així aconseguir una millora de rendiment. No obstant això, RE causa interferència addicional a l'enllaç descendent que es torna greu pels valors d'ampliació rang majors i això dóna com a resultat una degradació important. Per tant, RE ha de ser dissenyat conjuntament amb esquemes de coordinació d'interferència per superar aquests problemes. Aquesta tesi discuteix LTE-Advanced com a evolució de LTE Release 8/9, i descriu el concepte de HetNets, l'expansió del rang, els reptes tècnics més importants i els esquemes de coordinació d'interferència. Finalment, es presenten resultats mitjançant simulació d'un desplegament HetNet (escenari Macro-Pico) que avaluen l'impacte en el rendiment del sistema per a diferents configuracions.

Best paper award of the 6th Joint IFIP Wireless and Mobile Networking Conference (WMNC'2013) Effective intercell interference (ICI) mitigation has been identified as a key challenge for emerging OFDMA cellular technologies such as Long Term Evolution (LTE). In order to address this issue, mobile operators have adopted static Intercell Interference Coordination (ICIC) strategies, including Fractional Frequency Reuse (FFR), given their low complexity and easy implementation. However, recent results made evident the need for additional research efforts as the performance of FFR is poor in realistic cellular deployments. Thus, this paper presents a solution to this problem by means of a novel multiobjective optimization framework able to adapt FFR to any realistic cellular layout. By tuning the operational parameters of FFR at cell level, the proposed scheme succeeds in finding solutions outperforming reference schemes and baseline designs in terms of network capacity and cell edge performance while keeping energy consumption as low as possible. Peer Reviewed Award-winning

Transmitted power in Long Term Evolution - Advanced (LTE-A) uplink (UL) is strongly related to the number of physical resource blocks (PRBs) allocated. As the transmitted bandwidth increases power does so. However, this rise in power is also required to increase throughput. It is necessary to create efficient techniques that allows sending more information (bits) with the same power requirements. Against previous LTE releases, LTE-A allows the use of non-contiguous resource allocation in the UL together with the simultaneous transmission along multiple component carriers named, carrier aggregation. These features lead to an increase in spectral efficiency thanks to ling performance gains obtained from frequency diversity. This work studies the effect of scheduling techniques on the throughput performance and power consumption of users. Results show that cell edge performance is very sensitive to the scheduling decisions, therefore, limitations in bandwidth are introduced in order to reduce power consumption and improve throughput. Carrier Aggregation turns out to be more efficient as users can be classified and improve spectral and energy efficiency.

Advanced (LTE-A) allows for non-contiguous resource allocation in the uplink. The aim is to increase the spectral efficiency by exploiting users’ frequency diversity gain. This feature implies that clustered-DFT-S-OFDM must be used in the uplink, no longer preserving the single carrier property of previous releases. Multi-cluster transmission brings an increase in the signal’s Peak-to-Average Power Ratio (PAPR) and so power de-rating must be introduced to control out-of-band emissions. Maximum power Reduction (MPR) can counteract the frequency gain and bring losses to the users’ performance. This paper proposes a novel scheduler that considers the MPR information. The packet scheduler’s main task is to evaluate the gain or loss in throughput of the multi-cluster transmission over a conventional contiguous one. Based on the Sounding Reference Signals (SRSs) channel estimation, the eNB can predict the multi- cluster transmission’s performance. Results show that enabling the MPR information in the scheduler adapts the transmission mode to each particular case, enhancing the system throughput

This paper presents the FPGA design of an interference-aware digital front end tailored for heterogeneous multi-cell LTE-based systems. A resource-optimized RTL architecture has been implemented and validated under realistic operating conditions using the GEDOMIS® testbed. The parallelization and concurrent resource utilization of the joint synchronization and interference detection processing blocks is covered with low-level details.

Orientador: Michel Daoud Yacoub Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação Resumo: Este projeto de pesquisa objetiva responder a algumas questões sistêmicas levantadas por ocasião do início do desenvolvimento do sistema LTE-450, parte integrante do projeto RASFA - Redes de Acesso Sem Fio Avançadas, conduzido pelo CPqD - Fundação Centro de Pesquisa e Desenvolvimento em Telecomunicações, com recursos do FUNTTEL - Fundo para o Desenvolvimento Tecnológico das Telecomunicações. Esse projeto visa, como um de seus objetivos, o desenvolvimento de um sistema de rádio acesso sem fio LTE-450, operando na faixa de 450 a 470 MHz, baseado na tecnologia LTE - Long Term Evolution. A faixa de 450 a 470 MHz está atribuída em base global desde 2007 para o Serviço Móvel, conforme identificado pela União Internacional de Telecomunicações na World Radiocommunication Conference 2007. A Anatel - Agência Nacional de Telecomunicações - publicou a nova destinação de uso para a faixa de 450 a 470 MHz em 20 de dezembro de 2010, através da Resolução n º 558. Várias ações vêm sendo empreendidas em apoio ao uso da faixa 450 a 470 MHz, para a prestação de serviços banda larga sem fio para áreas rurais, como consta do Programa Nacional de Telecomunicações Rurais, publicado pela Portaria 431/2009 do Ministério das Comunicações, e do Plano Nacional de Banda Larga, publicado em 13 de maio de 2010. Entende-se que a faixa de 450 a 470 MHz é ideal para a implantação de serviços de banda larga sem fio em áreas rurais, devido às suas características de propagação. Por outro lado, a base de conhecimento sobre o canal rádio em sistemas de rádio acesso móvel banda larga considera o uso, em áreas urbanas, de faixas de frequências situadas entre 850 MHz e 3500 MHz. São notórias as diferenças entre as características de propagação nessas faixas e nas faixas de UHF, principalmente quando a área de prestação do serviço deixa de ser a urbana e passa a ser a rural. Nesse sentido, alguns requisitos sistêmicos podem ser questionados e mesmo redimensionados. Esses requisitos foram aqui endereçados através de levantamento de dados em campo e posterior análise crítica contra a base de conhecimento disponível. São questões como a amplitude do desvanecimento seletivo e por despolarização, a intensidade do ruído impulsivo, os modelos de propagação aplicáveis à área rural e à faixa de UHF, a variação da perda de percurso com a altura da antena do terminal e a discriminação de polarização da antena do terminal Abstract: This research project aims to answer some systemic issues raised during the early development of the LTE-450 radio access system, part of a project RASFA - Advanced Wireless Networks Access, led by CPqD Foundation - Center for Research and Development in Telecommunications with resources of FUNTTEL - Technological Development of Telecommunications Fund. This project aims, as one of its objectives, the development of a LTE-450 wireless system, operating in the 450-470 MHz band, based on LTE - Long Term Evolution technology. The 450-470 MHz band is allocated, on a global basis, since 2007 for Mobile Service, as identified by the International Telecommunication Union in the World Radiocommunication Conference 2007. Anatel - The Brazilian National Telecommunications Agency has published a new destination for the 450-470 MHz band on December 20, 2010, through Resolution No. 558. Several actions have been undertaken in support of the use of the 450-470 MHz band, to provide wireless broadband services to rural areas, as set out in the National Rural Telecommunications Plan, published by the Decree 431/2009 of the Ministry of Communications and the National Broadband Plan (PNBL), published on May 13, 2010. It is understood that the 450-470 MHz band is ideal for deploying wireless broadband services in rural areas, due to its propagation characteristics. On the other hand, the base of knowledge about the mobile broadband access radio systems channel, considering the use in urban areas, situated between 850 MHz and 3500 MHz bands have notable differences between the propagation characteristics of these bands and the UHF bands, especially when the area of service provision ceases to be the urban and goes to the rural areas. Thus, some systemic requirements can be questioned and even resized. These requirements are addressed here through field data gathering and subsequent critical analysis against the knowledge base available. These issues are such as the extent of selective fading and depolarization, the intensity of the impulse noise, the propagation models applicable to the rural area and the UHF band, the variation of the path loss with the height of the terminal antenna and of terminal antenna polarization discrimination Mestrado Telecomunicações e Telemática Mestre em Engenharia Elétrica

The technology moves fast and the wireless systems tend to be software defined radio (SDR). The new wireless standards increase the efficiency of communications, also its complexity, which demand more processing. The FlexNets is an open source project that explores the new possibilities of flexible radio communications. It provides some tools to develop SDR. In recent years, graphical processors have evolved and expanded to the market of high performance computing. These processors (GPUs) are cheaper and consume less power per floating point operation than classical CPUs. It is therefore quite interesting to study wether these processors are suitable for application in the SDR. This work is aimed at analyzing the feasibility of this technology to implement systems based on SDR radio. Català: La tecnologia avança molt ràpid, i cada vegada més en el desenvolupament de sistemes sense fils es tendeix al disseny de sistemes ràdio definits per software (SDR). Els nous estàndards de comunicacions sense fils incrementen la seva eficiència però també la seva complexitat, la qual demanda més processament. El projecte FlexNets és una iniciativa per a la investigació en SDR. La missió de FlexNets és proporcionar les eines necessaries per al desenvolupament de SDR d’una forma senzilla i flexible. Durant els darrers anys, els processadors gràfics (GPUs) han evolucionat, s’han estès en el mercat de les aplicacions de gran cost computacional. Les GPUs tenen un preu reduït i són de baix consum per a una alta capacitat computacional. Per tant, resulta força interessant estudiar si aquests processadors són aptes per a la aplicació en SDR. Aquest treball està orientat a l’anàlisi de la viabilitat d’aquesta tecnologia per implementar sistemes ràdio basats en SDR sobre la plataforma de FlexNets.

Long Term Evolution (LTE) es una tecnología de comunicación móvil que permite garantizar tanto la alta demanda de transmisión de datos requerida en la actualidad como la calidad del servicio ofrecido, para ello se sirve de un conjunto de funcionalidades que gestionan los recursos radio disponibles. Una de estas funcionalidades es el control de admision de usuarios, el cual regula la entrada de usuarios en función de la calidad de servicio requerida por este usuario que desea conectarse y de la calidad de servicio requerida por todos los usuarios ya conectados a la base. Este proyecto parte de un simulador LTE creado en el lenguaje de programacion C# que dispone de todas las funcionalidades RRM excepto el AC. A causa de ello, todos los usuarios estan conectados y transmiten información durante toda la simulacion. Por lo tanto, con el objetivo de implementar el control de admisión se han modificado tanto las funcionalidades de gestion de recursos radio como los usuarios conectados al sistema, a los cuales se les evaluara ciertas condiciones de transmisión como la cantidad de datos que poseen en el buffer o la tasa binaria garantizada. En el proyecto también se ha implementado un gestor de recursos que permita la estimación del canal a un gran numero de usuarios.

In moderm OFDMA-based cellular networks, intercell interference is the main issue limiting the capacity of these systems. Recently, intensive research work has been focused on intercell interference coordination as it has been recognized as an important element to achieve seamless levels of quality of service. However, in most of the cases, this issue is addressed as a standalone issue. In this work, a novel channel state information feedback mechanism is proposed aiming at improving the system performance when static interference coordination techniques are also considered. By means of the proposed scheme, gains in terms of (1) users throughput, (2) cell edge performance and (3) energy efficiency are achieved with respect to existing aperiodic LTEbased mechanisms. Moreover, given the low complexity of the proposed solution, feasibility aspects are also discussed and a possible LTE implementation alternative is suggested.

This paper presents a novel methodology to assess the downlink performance of static intercell interference coordination techniques in the context of OFDMA-based cellular networks. In the last few years, interference mitigation techniques have been considered a research topic of utmost importance since intercell interference is the main issue limiting the capacity of modern cellular technologies such as LTE and WiMAX. The methodology presented in this paper should be understood not only as an analytical shortcut to foresee overall network interference conditions but also a mean to properly establish bounds to parameters associated to static intercell interference techniques operation. Moreover, the analysis allows to take into account both local large scale fading particularities and mobile operators’ preferences. In this sense, results show how the resulting set of preferred operational points is in general operatordependent and hence, the usefulness of the proposed framework is established.

Intercell Interference is the main issue limiting the capacity of modern OFDMA-based cellular networks. Recently, extensive research work has been focused on intercell interference coordination since it has been recognized as a key concept to achieve seamless levels of quality of service. Nevertheless, very often this problematic is addressed as a standalone issue. In this work, a novel channel state information feedback scheme is proposed aiming at improving the overall system performance when both channel state information and static interference coordination are jointly considered. By means of the proposed scheme, gains in terms of users throughput, cell edge performance and energy efficiency are achieved with respect to existing aperiodic LTE-based mechanisms without additional complexity.

Effective interference management is a technical challenge of utmost importance for emerging OFDMA-based technologies such as Long Term Evolution (LTE) and Worldwide Interoperability for Microwave Access (WiMAX). Static Intercell Interference Coordination techniques including Soft Frequency Reuse (SFR) have enjoyed acceptance among mobile operators as a solution to deal with this problem mainly due to their low complexity and easy implementability. However, recent results indicate that the performance of default SFR settings directly applied to realistic cellular deployments is quite suboptimal and hence optimization is mandatory. This paper addresses this issue by presenting a novel multiobjective framework able to achieve accurate fine tuning of SFR and hence, enhance system capacity and cell edge performance while reducing energy consumption.

This article focuses on the investigation of the Admission Control techniques in order to assure Quality of Service (QoS) in Long Term Evolution (LTE) systems. So as to estimate the users bandwidth requirement, Sounding Reference Signals (SRS) bandwidth are allocated to each user in order to have accurate up-to-date channel state information at the evolved Node B (eNB). Since User Equipments (UEs) are power limited, several SRS are required to scan the full bandwidth for UEs with high path loss. Therefore, in order to own reliable information the eNB must trade-off up-to-date information and accuracy of the measurement. This paper investigates a novel way in which the eNB measures the users radio requirements in order to accomplish QoS, using the information on the SRS already known by the eNB. This measurement technique is compared against two models presented in [1], first a reference AC model in which users are accepted up to a cell bit-rate limit, and a second one proposed by the authors in which the users requirements are estimated using the power control formula and the Shannon capacity. The methodology followed is based on system level simulations. Results show that the SRS based AC is more optimist when estimating users channel conditions and therefore more users are accepted to the system, increasing the overall cell throughput when compared to the power control based algorithm.