Evolução ADSL para GPON e 4G: aspectos de planeamento e dimensionamento

Mestrado em Engenharia Electrónica e TelecomunicaçõesEsta dissertação aborda alguns dos desafios que se impõem aos operadores de telecomunicações em virtude das novas dinâmicas de consumo de serviços e ao aumento dos volumes de dados que fluem nas redes. Neste contexto, o foco da dissertação centra-se nos aspectos de planeamento e dimensionamento de capacidade, particularmente no desenvolvimento de um modelo de dimensionamento de capacidade de redes GPON – a evolução mais comum das redes fixas baseadas em cobre e tecnologia ADSL- tomando em consideração a natureza aleatória da actividade e a intensidade de consumo dos utilizadores.This dissertation addresses some of the challenges that are imposed on telecommunications operators due to the new dynamics of service consumption and increased volumes of data flowing on the networks. In this context, this dissertation focuses on the aspects of capacity dimensioning and planning, in particular, through the development of a method for the GPON networks – The common evolution of the fixed lines is based on ADSL copper technology - That consider the random nature of users’ activity and intensive consumption

Efeitos cruzados em serviços de vídeo sobre redes óticas passivas

Mestrado em Engenharia Electrónica e TelecomunicaçõesA evolução das redes óticas passivas é uma tendência natural para lidar com o aumento da largura de banda nas redes de acesso. Atualmente, o requisito básico para a próxima geração destas redes (NG-PON2) passa por ter uma infraestrutura única capaz de facultar um ambiente de coexistência com as tecnologias antecessoras. Neste contexto, são necessárias novas alocações no especto da fibra para ir em frente em termos de inovação. Os efeitos não lineares, em particular o espalhamento de Raman estimulado (SRS), pode ter uma influência considerável na definição dos comprimentos de onda a serem usados nesta evolução, de modo a preservar intactos os sistemas legados, em especial o sistema de distribuição de vídeo que é particularmente suscetível a esse fenómeno. Neste âmbito, o presente documento, apresenta um estudo sobre o impacto causado pelo SRS sobre o vídeo em ambientes de convivência com sinais modulados. Primeiramente faz-se uma análise em simulação do impacto causado pela componente estática do fenómeno. Posteriormente, é introduzido o estudo em laboratório do impacto causado pela componente dinâmica (X-talk) desse mesmo fenómeno. Várias dependências são avaliadas, como a frequência de modulação dos canais de vídeo, separação entre canais óticos, potência dos sinais modulados, número de canais modulados e formato de modulação.The evolution of passive optical networks is a natural tendency to handle increased bandwidth in access networks. Currently, the basic requirement for the next generation of these networks (NG-PON2) is to have a single infrastructure capable of providing an environment of coexistence with the technologies predecessors. In this context, new wavelength allocations of the spectrum has to be done . The nonlinear effects, Stimulated Raman Scattering (SRS) in particular, can have a considerable influence on the definition of which wavelengths to use in this development, so as to preserve intact the legacy systems, particularly video distribution systems which is particularly susceptible to these phenomena. In this context, this paper presents a study on the impact caused by SRS on the video signal in environments where modulated signals coexist. Firstly, an analysis is made by simulating the impact caused by the static component of this phenomenon. It is then introduced the laboratory study of the impact caused by the dynamic component (X-talk) of the same phenomenon. Several dependencies are evaluated, such as the modulation frequency of the video channels, separation channels, optical power of modulated signals, number of modulated channels and their modulation format

Orthogonal frequency division multiplexing for next generation optical networks

Next generation optical networks will be required to provide increased data throughput on a greater number of optical channels and will also have to facilitate network flexibility in order to adapt to dynamic traffic patterns. Furthermore, the potentially wide deployment of optical Access and Metropolitan networks in particular require that these challenges are met in a cost effect manner. This thesis examines the use of Orthogonal Frequency Division Multiplexing (OFDM) as a means of helping to meet these requirements for next generation optical systems with a high market volume. OFDM is a multi–carrier modulation technique which exhibits high spectral efficiency and a tolerance to chromatic dispersion making it an excellent candidate for use in next generation optical networks. The work presented in this thesis shows how the use of OFDM in conjunction with novel laser devices and direct detection can be used to construct cost effective, low footprint optical systems. These systems are capable of providing >10Gb/s per optical channel and are suitable for implementation as optical access networks. Furthermore, OFDM is shown to be a realistic candidate for use in an optical switching environment where external modulation is employed and, as such, can be considered for use in next generation metropolitan networks

Radio over fiber enabling PON fronthaul in a two-tiered cloud

Avec l’avènement des objets connectés, la bande passante nécessaire dépasse la capacité des interconnections électriques et interface sans fils dans les réseaux d’accès mais aussi dans les réseaux coeurs. Des systèmes photoniques haute capacité situés dans les réseaux d’accès utilisant la technologie radio sur fibre systèmes ont été proposés comme solution dans les réseaux sans fil de 5e générations. Afin de maximiser l’utilisation des ressources des serveurs et des ressources réseau, le cloud computing et des services de stockage sont en cours de déploiement. De cette manière, les ressources centralisées pourraient être diffusées de façon dynamique comme l’utilisateur final le souhaite. Chaque échange nécessitant une synchronisation entre le serveur et son infrastructure, une couche physique optique permet au cloud de supporter la virtualisation des réseaux et de les définir de façon logicielle. Les amplificateurs à semi-conducteurs réflectifs (RSOA) sont une technologie clé au niveau des ONU(unité de communications optiques) dans les réseaux d’accès passif (PON) à fibres. Nous examinons ici la possibilité d’utiliser un RSOA et la technologie radio sur fibre pour transporter des signaux sans fil ainsi qu’un signal numérique sur un PON. La radio sur fibres peut être facilement réalisée grâce à l’insensibilité a la longueur d’onde du RSOA. Le choix de la longueur d’onde pour la couche physique est cependant choisi dans les couches 2/3 du modèle OSI. Les interactions entre la couche physique et la commutation de réseaux peuvent être faites par l’ajout d’un contrôleur SDN pour inclure des gestionnaires de couches optiques. La virtualisation réseau pourrait ainsi bénéficier d’une couche optique flexible grâce des ressources réseau dynamique et adaptée. Dans ce mémoire, nous étudions un système disposant d’une couche physique optique basé sur un RSOA. Celle-ci nous permet de façon simultanée un envoi de signaux sans fil et le transport de signaux numérique au format modulation tout ou rien (OOK) dans un système WDM(multiplexage en longueur d’onde)-PON. Le RSOA a été caractérisé pour montrer sa capacité à gérer une plage dynamique élevée du signal sans fil analogique. Ensuite, les signaux RF et IF du système de fibres sont comparés avec ses avantages et ses inconvénients. Finalement, nous réalisons de façon expérimentale une liaison point à point WDM utilisant la transmission en duplex intégral d’un signal wifi analogique ainsi qu’un signal descendant au format OOK. En introduisant deux mélangeurs RF dans la liaison montante, nous avons résolu le problème d’incompatibilité avec le système sans fil basé sur le TDD (multiplexage en temps duplexé).With the advent of IoT (internet of things) bandwidth requirements triggered by aggregated wireless connections have exceeded the fundamental limitation of copper and microwave based wireless backhaul and fronthaul networks. High capacity photonic fronthaul systems employing radio over fiber technology has been proposed as the ultimate solution for 5G wireless system. To maximize utilization of server and network resources, cloud computing and storage based services are being deployed. In this manner, centralized resources could be dynamically streamed to the end user as requested. Since on demand resource provision requires the orchestration between the server and network infrastructure, a smart photonic (physical layer)PHY enabled cloud is foreseen to support network virtualization and software defined network. RSOAs (Reflective Semiconductor Optical Amplifier) are being investigated as key enablers of the colorless ONU(Optical Network Unit) solution in PON (Passive Optical Network). We examine the use of an RSOA in radio over fiber systems to transport wireless signals over a PON simultaneously with digital data. Radio over fiber systems with flexible wavelength allocation could be achieved thanks to the colorless operation of the RSOA and wavelength reuse technique. The wavelength flexibility in optical PHY are inline with the paradigm of software defined network (SDN) in OSI layer 2/3. The orchestration between optical PHY and network switching fabric could be realized by extending the SDN controller to include optical layer handlers. Network virtualization could also benefit from the flexible optical PHY through dynamic and tailored optical network resource provision. In this thesis, we investigate an optical PHY system based on RSOA enabling both analog wireless signal and digital On-Off Keying (OOK) transportation within WDM (Wavelength Division Multiplexing) PON architecture. The RSOA has been characterized to show its potential ability to handle high dynamic range analog wireless signal. Then the RF and IF radio over fiber scheme is compared with its pros and cons. Finally we perform the experiment to shown a point to point WDM link with full duplex transmission of analog WiFi signal with downlink OOK signal. By introducing two RF mixer in the uplink, we have solved the incompatible problem with TDD (Time Division Duplex) based wireless system

Next generation passive optical networks based on orthogonal frequency division multiplexing techniques

In recent decades, the industry of communications has acquired huge significance, and nowadays constitutes an essential tool for the society information. Thus, the exponential growth in demand of broadband services and the increasing amount of information to be transmitted have spurred the evolution of the access network infrastructure to effectively meet the user needs in an effective way in terms of costs of both installation and maintenance. Passive optical networks (PON) are currently considered the most efficient and least costly alternative to deploy fiber to the home environment. In order to allow many users simultaneously coexist PONs based on time multiplexing (TDMA) have been developed. Looking ahead, however, it is expected that these techniques do not meet the requirements on access networks. In consequence, other multiple access techniques such as Wavelength Division Multiplexing Access (WDMA) or Orthogonal Frequency Division Multiplexing Access (OFDMA) are currently under study and development for use in the next generation of PONs. Particularly, in recent years OFDM has stood out among the scientific community to be considered a solution with great potential on future implementation of PONs. This is especially true due to the capacity of OFDM to work with multilevel modulations, its high tolerance to chromatic dispersion, and its high flexibility and granularity in terms of bandwidth management. Given the above, the aim of this Thesis is to study deeply the advantages and challenges of implementing the standard OFDM as an access network solution; likewise, it offers solutions to improve its performance. In order to evaluate the main structures and strategies for OFDM-based PON, a comparative analysis of all of them is performed firstly, highlighting their sensitivity levels, maximum range and number of users. A key aspect for network providers is the cost of operation, deployment and maintenance of networks. As a low-cost solution, this Thesis proposes a network model called Statistical-OFDMA-PON based on intensity modulation and direct detection. In addition, dynamic bandwidth management strategies are applied into this model getting an improvement in the power balance which in turn, allows to increase the maximum range and the scalability in number of users. One of the main OFDM problems is the Peak-to-Average Power Ratio (PAPR) which increases with the number of carriers. This thesis proposes a new algorithm based on folding the signal and transmitting auxiliary information in order to compensate the PAPR effect and thus increase the sensitivity of the optical system. On the other hand, OFDMA requires a large number of operations in the digital domain resulting in a high computational effort, which in turn results in an increased cost. For this reason, this Thesis presents a study on the optimization of the required resolution in the Digital-to-Analog / Analog-to-Digital Converters (DAC/ADCs) maintaining the transmission quality. The optimization of the computation time may make the OFDMA-based optical network more attractive for future PONs. Finally, another problem concerning the OFDM optical networks is their sensitivity to Phase Noise (PN). In this regard, this Thesis presents a study of the effect of the laser linewidth and its dependence on signal bandwidth. A mitigation technique based on pilot tones is implemented and the limiting values for the laser linewidth are found to be within the reach of present low-cost light sources.En estas últimas décadas, la industria de las comunicaciones ha adquirido gran importancia y hoy en día, constituye una herramienta imprescindible para el funcionamiento en la sociedad de la información. Así pues, el crecimiento exponencial en la demanda de servicios de banda ancha y la carga de información cada vez mayor que se necesita transmitir ha estimulado la evolución de las infraestructuras del tramo de acceso a la red para poder satisfacer las necesidades del usuario de forma efectiva en términos de costes de instalación y de mantenimiento. Las redes ópticas pasivas (Passive Optical Networks, PON) son actualmente consideradas la alternativa más eficiente y de menor coste para desplegar fibra hasta los hogares. Con el fin de permitir que muchos usuarios coexistan simultáneamente se han desarrollado PONs basadas en multiplexación en tiempo (Time Division Multiplexing Access, TDMA). De cara al futuro, sin embargo, se prevé que estas técnicas no permitan cubrir las exigencias sobre las redes de acceso. En consecuencia, otras técnicas de acceso múltiple al medio como el acceso múltiple por división de longitud de onda (Wavelength Division Multiplexing Access, WDMA) o el acceso múltiple por división de frecuencia ortogonal (Orthogonal Frequency Division Multiplexing Access, OFDMA) se encuentran actualmente en proceso de estudio y desarrollo para su uso en la futura generación de PONs. En concreto, en los últimos años OFDM se ha destacado entre la comunidad científica al considerarse una solución con gran potencial para su futura implantación en redes de acceso pasivas. Esto es especialmente cierto debido a la capacidad que el OFDM para trabajar con modulaciones multinivel, así como su alta tolerancia a la dispersión cromática y a la gran flexibilidad y granularidad que posibilita en términos de gestión del ancho de banda. Por todo lo anterior, el objetivo de esta Tesis es estudiar con profundidad las ventajas y los retos de aplicar el estándar OFDM como solución de red de acceso; del mismo modo, ofrece soluciones para mejorar su rendimiento. Con el objetivo de evaluar las principales estructuras basadas en OFDM-PON, en primer lugar se realiza un análisis comparativo de todas ellas destacando sus niveles de sensibilidad, máximo alcance y número de usuarios. Un aspecto fundamental para los proveedores de red es el coste de operación, despliegue y mantenimiento de las redes. Como solución de bajo coste, esta Tesis propone un modelo de red llamado Statistical-OFDMA-PON que se basa en modulación de intensidad y detección directa. Además, este modelo se completa con estrategias de gestión dinámica del ancho de banda de los usuarios que conforman la estructura de red propuesta consiguiendo una mejora en el balance de potencias que permite aumentar distancia y número de usuarios. Uno de los principales problemas del OFDM es el alto nivel de la relación de potencia de pico a potencia media (Peak-to-Average Power Ratio, PAPR) creciente con el número de portadoras. Esta Tesis propone un nuevo algoritmo basado en el pliegue de la señal y la transmisión de información auxiliar para compensar el efecto del PAPR aumentando así la sensibilidad del sistema óptico. Por otro lado, OFDMA requiere un número elevado de operaciones en el dominio digital resultando en un alto esfuerzo computacional que a su vez se traduce en un aumento del coste. Por esta razón, esta Tesis presenta un estudio sobre la optimización de la resolución requerida en los conversores analógicodigital (Digital-to-Analog/Analog-to-Digital Converters, DAC/ADCs) manteniendo la calidad de transmisión. La optimización del tiempo de cómputo requerido puede dotar de un mayor atractivo la solución de red óptica basada en OFDMA. Finalmente, otro de los problemas que presentan las redes ópticas OFDM es su sensibilidad frente al ruido de fase (Phase Noise, PN). En este aspecto, esta Tesis presenta un estudio del efecto del ancho de línea del láser y su dependencia con el ancho de banda de la señal. Técnicas de mitigación basadas en tonos piloto han sido implementadas y se han encontrado los valores limitantes del ancho de línea dentro del alcance de los láseres de bajo coste

Multimode fibre broadband access and self-referencing sensor networks

Future Internet Access technologies are supposed to bring us a very performing connection to the main door of our homes. At the same time, new services and devices and their increase use will require data transfers at speeds exceeding 1Gbps inside the building or home at the horizon 2012. Both drivers lead to the deployment of a high-quality, futureproof network inside buildings and homes. This environment may end up taking advantage of optical cabling solutions as an alternative to more traditional copper or pure wireless approaches. Related to this latter fact, the objectives of this work are: • The achievement of a full convergence scenario between optical networks from the telecommunication services providers to the end users underscores the necessity of accurate and realistic fibre models in assessing the performance of broadband access networks with the premises of high-capacity and total compatibility. Silicabased MMFs and PF GIPOFs are the most promising candidates for such a convergence within the in-building/home scenario. Contributions to a better understanding of the possibilities of signal transmission outside the baseband of such fibres are investigated, in order to extend their capabilities, together with the evaluation of current fibre frequency response theoretical models by means of an extensive set of measurements. • The achievement of a full convergence scenario between optical networks from the telecommunication services providers to the end users is also contingent on research and development in the field of optical fibre sensors, mainly driven by the growing demand of fully building/home and industry automation, leading to a reliable integration of the optical networks. Related to this, development of multiplexing and measurement techniques for fibre-optic intensity-based sensors are analyzed and experimentally investigated. In the sensor network topology proposed, by replacing the fibre delay line with an electronic delay in the reception stage, it is possible to avoid long fibre delay coils in the remote sensing points and achieving a compact, flexible and re-configurable self-referencing technique. Applications in both scenarios can be considered, on the one hand the in-building/home network and on the other hand the WDM-PON access network topology through which operators provision the different services. -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------La demanda e incursión en la sociedad de nuevos servicios multimedia, tales como televisión por Internet (IPTV, Internet Protocol Television) o video-bajo-demanda (VoD, Video on Demand) junto con el incremento del tráfico de datos requerido para nuevas aplicaciones como la televisión por alta definición (HDTV, High-Definition Television) y transferencias P2P (Peer-to-Peer) exigen un aumento de la capacidad de las redes de datos desplegadas hoy en día. Para hacer frente a este aumento de la demanda de capacidad de las redes de acceso, los proveedores de estos servicios multimedia están reemplazando las infraestructuras de las redes de acceso basadas en cable coaxial, tales como xDSL (x- Digital Subscriber Line), por otras nuevas de mayor capacidad desplegadas en fibra óptica, permitiendo la interconexión de los nodos de red con los múltiples hogares y negocios de los abonados, constituyendo el núcleo de lo que es conocido como “fibra hasta el hogar/nodo/edificio” o redes FTTx. Tradicionalmente el despliegue de las redes ópticas se ha realizado mediante fibra óptica monomodo de sílice (SMF, Singlemode Fibre). Ello es debido a su gran ancho de banda que permite una gran capacidad de transporte de servicios y datos. Es por ello que en base a este tipo de fibra se ha realizado el despliegue de redes de distribución y metropolitanas y, de un tiempo a esta parte, incluso penetrando su instalación en las redes de acceso. Junto con lo anteriormente expuesto, existe una necesidad de convergencia de servicios e infraestructuras dentro de las redes de acceso. Actualmente, cables coaxiales, par trenzado de cobre e incluso señales inalámbricas se encuentran entremezcladas dentro del hogar proporcionando servicios diferentes con apenas cooperación entre ellos. Una infraestructura común dentro del hogar en el que una gran cantidad de servicios pudieran ser integrados y soportados por la misma sería un aspecto deseable. Y es más, frente a las desventajas de infraestructuras basadas en cable de cobre (cable coaxial y par trenzado) como son susceptibilidad a interferencias electromagnéticas, presencia de crosstalk y relativa baja capacidad de transporte de datos, las fibras ópticas (tanto en su versión monomodo como multimodo) presentan las ventajas de un menor volumen, mayor flexibilidad y menor peso junto con una capacidad mayor de transmisión de datos sobre distancias mayores. Es por esto que éstas últimas constituyen la base para las futuras redes de acceso en el hogar

Determinación del camino óptimo de migración hacia una AON de un operador de telecomunicaciones en Colombia

El sector de las Telecomunicaciones como elemento transversal en el desarrollo de la sociedad moderna está en su fase dorada gracias a fenómenos como la globalización, la automatización y las fuerzas del mercado que han establecido un ritmo en el crecimiento de tráfico en las redes de acceso y la disminución de precio del ancho de banda; escenario que ha obligado a los operadores a fortalecer las redes de transmisión con modelos de migración y arquitecturas de altas prestaciones que mejoren la relación costo ¿ beneficio y les permita prestar ¿el mejor servicio¿ con grandes utilidades. En Colombia los inicios de estas redes de transmisión datan de la época en que fue autorizada para prestar el primer servicio de telefonía de larga distancia la firma belga ¿Mourlon and Co¿, desde entonces, las tecnologías FDM1, TDM2/PDH3 fundamentaron el crecimiento de las actuales redes ópticas WDM4. Sin alejarse de desarrollos globales, los operadores regionales y nacionales han mantenido una dinámica de fortalecimiento periódico de sus redes en sintonía con los rápidos cambios tecnológicos globales (crecimiento de tráfico en las redes de acceso, redes IP móviles 3G y 4G, abaratamiento del ancho de banda, ampliación de canales dedicados a grandes empresas, creación de servicios para las entidades gubernamentales, entre otros).MaestríaMAGISTER EN INGENIERÍA ÉNFASIS EN INGENIERÍA ELECTRÓNIC

Análise técnico-económica de redes de acesso : ferramentas de decisão

Mestrado em Engenharia Electrónica e TelecomunicaçõesO recente crescimento de consumo de internet e televisão por cabo desencadeou a necessidade de novas redes de acesso. O mundo das telecomunicações tornou-se num negócio competitivo entre as operadoras. As estratégias de competitividade são agora com baseadas em qualidade do serviço e na acessibilidade dos preços a todas as categorias da população. Para garantir estes requisitos é necessário inovar em equipamentos e meios de distribuição. A implantação de novas redes de acesso tornou-se crucial na sociedade, mas a recente crise económica mundial forçou um dimensionamento cuidado para garantir o máximo lucro possível no negócio. Portanto esta dissertação apresenta uma análise económica e financeira da implementação de uma rede HFC. Mostra a estrutura da rede e as suas características tecnológicas, além disso explica como lidar com problemas no dimensionamento da rede: a incerteza espacial associada ao processo de adesão dos utilizadores e como lidar com consumo em excesso de largura de banda, também causado pelos utilizadores. Por fim realiza o estudo da instalação da rede HFC em três tipos diferentes de cenários e expondo os resultados económicos obtidos, permitindo a conclusão sobre a viabilidade destes projetos.The recent growth in Data Traffic and Cable Tv consumption triggered the need for new access networks and the world of Telecommunications has become a very competitive business among service providers. The strategies of competitiveness are now based on quality of services and affordable prices to all classes of the population. To guarantee these requirements, an equipment and distribution facilities innovation was necessary. The deployment of Next Generation Access Networks (NGA) has become crucial in society, but the recent world economic crisis has forced a careful dimensioning to produce the most profit possible with small investments. This dissertation presents a techno-economic analysis of a HFC network implementation. The network structure and technologic characteristics are presented, along with explanation of how to deal with problems in the network dimensioning: as spatial uncertainty associated with the adhesion process of the users and the surplus consumption of bandwidth by them. Finally, the study of the network implementation in three different sorts of areas is shown and the economic results obtained are exposed, providing the viability of these projects

Semiconductor Optical Amplifiers and mm-Wave Wireless Links for Converged Access Networks

Future access networks are converged optical-wireless networks, where fixed-line and wireless services share the same infrastructure. In this book, semiconductor optical amplifiers (SOA) and mm-wave wireless links are investigated, and their use in converged access networks is explored: SOAs compensate losses in the network, and thereby extend the network reach. Millimeter-wave wireless links substitute fiber links when cabling is not economical