25 research outputs found

    SARDANA: an all-optical access-metro WDM/TDM-PON

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    A new optical access network, named “Scalable Advanced Ring-based passive Dense Access Network Architecture” (SARDANA), is presented. It transparently integrates WDM metro and TDM PON access technologies, implementing ring protection, 100 km reach and up to 1024 users served at 10 Gb/s, with passive highly-shared infrastructure. The introduced innovations are hybrid ring/tree WDM/TDM Passive Optical Network (PON) architecture; a resilient remote node (RN), which is distantly pumped from the Optical Line Terminal (OLT); and a reflective ONU (Optical Network Unit); as well as an enhanced Medium Access Control (MAC) protocol.Postprint (published version

    A Comparative Study of Asynchronous and Synchronous OCDMA Systems

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    New trends on Optical Access Networks: DBAs for 10G EPON and Long-Reach PON

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    The access network infrastructure plays an important role in the overall performance of the network, next generation access networks (NGA) must be able to access diverse services, and should incorporate adequate architectures that include mechanisms for the integration of different technologies. New optical access technologies trends are: WDM, 10 Gb/s, and longer reach/higher splits. It is also important to take into account the evolution of the installed legacy PONs to the next generation optical access networks. The present paper goes through such topics, focusing on the research being carried out to develop dynamic bandwidth algorithms for the 10 Gb/s new EPON standard (IEEE 802.3av). We summarize results and point out issues that will require further investigation.Postprint (published version

    Sistemas de teste automáticos para transceivers NG-PON2

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    Optical communications have had a fundamental role in conecting people worldwide. More than ever, there has been an incessant necessity to turn technology more ubiquitous With recent advancements in optical technology, it has become possible to keep up with the demand for higher transmission rates in upstream or downstream, higher bandwidth e still guaranteeing Quality of Service (QoS) among inumerous users This emerging necessity has taken telecommunication companies to inovate in the area of development regarding optical equipment and also dealing with the referred necessities. For this to happen, good quality control, calibration e testing of produced parts is of paramount importance. The work cut out for this dissertation is focused on the improvement and addition of funtionalities to a test-board designed to perform measurements of BER levels, calibration and maintenance of parts according to the newest optical standard(New Gigabit Passive Optical Network 2 (NGPON2)) that operates in maximum rates of 10Gb/s per channel. In the rst part of this work, emphasis is given to the development of a slave Inter Integrated Circuit (I2C) module that ensures connection between the test board and the user, supplying BER values measured through a block dedicated to measure BER levels. Later the same module will allow to access all micro-controlers of the test-board, ensuring calibration functions. On a second part, a characterization of different transceivers of different Field Programmable Gate Array (FPGA)s is performed, consisting of an eye diagram analysis of the transceivers and if possible, to test 10Gb/s continuous mode through BER curves assessing their response. Finally, a comparison is made between all transceivers, the obtained response along with all the respective results, will contribute to the source project of the automatic test board developed at PICadvanced with the intent on evaluating 10 Gigabit Small Form Factor Pluggables (XFP) production.As comunicações têm vindo a ter um papel fundamental em interligar todas as pessoas do mundo. Mais do que nunca, tem havido uma incessante necessidade de tornar a tecnologia mais ubíqua. Com o recente avanço e desenvolvimento da tecnologia Optica, tem sido possível acompanhar a demanda por altas taxas de transmissão em upstream ou downstream, maior largura de banda e ainda garantir Quality of Service (QoS) entre ínumeros utilizadores, etc. . . Esta necessidade emergente tem levado empresas de telecomunicações a inovar na área de desenvolvimento de equipamento óptico e por consequente, comaltar as necessidades referidas. Para isto acontecer tem de haver um bom controlo, calibração e teste de peças produzidas. O trabalho desta dissertação dedica-se ao melhoramento e acrescento de funcionalidades a uma placa de testes desenhada para desempenhar medições de níveis de Bit Error Ratio (BER), calibração e manutenção de peças para o novo standard óptico (New Gigabit Passive Optical Network 2 (NGPON2)) que recorre ao uso de taxas máximas de transmissão de 10Gb/s por canal Na primeira parte do trabalho é dado foco ao desenvolvimento de um módulo escravo Inter Integrated Circuit (I2C) que visa estabelecer o contacto entre a placa de calibração e o utilizador fornecendo os valores de BER medidos através de um bloco dedicado a medir o nível de BER. Mais tarde este módulo servirá para poder aceder aos micro-circuitos da placa de testes podendo realizar funções de calibração. Numa segunda parte, é realizada uma caracterização de diferentes transceivers de diferentes Field Programmable Gate Array (FPGA)s, a caracterização consiste numa análise do diagram de olho de transceivers e ainda sendo possível, testar o modo contínuo nas mesmas, através curvas de BER para avaliar a sua resposta. Por fim, é feita uma comparação entre os mesmos transceivers, além de que todos os resultados obtidos irão contribuir para a o projecto fonte da placa de testes automatizada desenvolvida pela PICadvanced com o intuito de avaliar a produção de 10 Gigabit Small Form Factor Pluggables (XFP).Mestrado em Engenharia Eletrónica e Telecomunicaçõe

    A Low Cost Migration Path Towards Next Generation Fiber-To-The-Home Networks

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    Abstract: A highly-scalable access architecture achieving high-user-density and enabling resiliency, centralized light-generation control, remote amplification and colorless ONU with Reflective Semiconductor Optical Amplifier (RSOA) is presented as the bridge between the already deployed Fiber-to-theHome infrastructures and the advanced optical access networks. A technoeconomical comparison of these optical access networks is done, depicting the proposed solution -SARDANA-as the most cost effective migration path towards the Next Generation Passive Optical Networks

    Arquitectura WDM-PON baseada em componentes sintonizáveis

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    Mestrado em Engenharia Electrónica e TelecomunicaçõesO tema principal abordado neste trabalho é a tecnologia WDM-PON como próxima geração de redes de acesso. Começou por ser feita uma abordagem geral a este tópico, servindo esta como ponto de partida para a parte experimental. Foi proposta e demonstrada uma arquitectura WDM-PON bidirecional directamente modulada baseada em lasers sintonizáveis e receptores sintonizáveis no terminal do utilizador, e um divisor de potência no nó de acesso. Foram também apontados possíveis melhoramentos ao hardware desta arquitectura. Dois formatos de modulação avançados – QPSK e Duobinário – foram abordados, no contexto dos sistemas WDM-PON. Assim sendo, foram testados um sistema coerente QPSK e um sistema UDWDM-QPSK e foram apresentados os resultados obtidos.The main topic of this work is WDM-PON as a technology for next generation access networks. It was first made a general approach to this topic, serving as starting point to the experimental part. It was proposed and demonstrated a bidirectional directly modulated WDM-PON architecture based on tunable lasers and tunable receivers at the users’ end, and a splitter at the Remote Node. Possible improvements to this architecture’s hardware were also pointed out. Two advanced modulation formats – QPSK and Duobinary – were addressed, in the context of WDM-PON systems. Thus, we tested a coherent QPSK and a UDWDM QPSK system and present the obtained results

    Architectures and dynamic bandwidth allocation algorithms for next generation optical access networks

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    HFR Networks: New concepts and technologies

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    To study the main trends which drive the merging of fiber and wireless technologies in access networks. As the hybrid radio networks constitute a new and emerging field of knowledge it is difficult to get a clear picture of their main building blocks and basic technologies and concepts. Due to the lack of reference texts with a basic entry level, in this PFC we aim at carrying out a thorough study of the related literature in order to establish a clear classification of systems and techniques, to clarify the basic terms and to study the specific transmission characteristics of hybrid radio links, both from a point to point as well as from a networks management perspective. • Steaming from the above, the main physical effects and phenomena around optical and wireless technologies will be reviewed and the basic analytical as well as computer and simulation tools will be presented along with some simulation examples showing relevant fiber-radio transmission effects and techniques. • The main driver will be to help newcomers to the field to get a fast understanding of the basic related ideas and analysis techniques for hybrid fiber-radio networks. • In this regard the key building blocks to implement the HFR's networks will be identified. These should include underlying concepts such as working frequencies, general structure for the coexistence of wireless and fiber technologies, the network components and topologies proposed, as well as the hybrid link's features, characterizing parameters and main impairments that degrade the quality of transmission

    Wavelength reconfigurability for next generation optical access networks

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    Next generation optical access networks should not only increase the capacity but also be able to redistribute the capacity on the fly in order to manage larger variations in traffic patterns. Wavelength reconfigurability is the instrument to enable such capability of network-wide bandwidth redistribution since it allows dynamic sharing of both wavelengths and timeslots in WDM-TDM optical access networks. However, reconfigurability typically requires tunable lasers and tunable filters at the user side, resulting in cost-prohibitive optical network units (ONU). In this dissertation, I propose a novel concept named cyclic-linked flexibility to address the cost-prohibitive problem. By using the cyclic-linked flexibility, the ONU needs to switch only within a subset of two pre-planned wavelengths, however, the cyclic-linked structure of wavelengths allows free bandwidth to be shifted to any wavelength by a rearrangement process. Rearrangement algorithm are developed to demonstrate that the cyclic-linked flexibility performs close to the fully flexible network in terms of blocking probability, packet delay, and packet loss. Furthermore, the evaluation shows that the rearrangement process has a minimum impact to in-service ONUs. To realize the cyclic-linked flexibility, a family of four physical architectures is proposed. PRO-Access architecture is suitable for new deployments and disruptive upgrades in which the network reach is not longer than 20 km. WCL-Access architecture is suitable for metro-access merger with the reach up to 100 km. PSB-Access architecture is suitable to implement directly on power-splitter-based PON deployments, which allows coexistence with current technologies. The cyclically-linked protection architecture can be used with current and future PON standards when network protection is required

    Real-time digital signal processing for new wavelength-to-the-user optical access networks

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    Nowadays, optical access networks provide high capacity to end users with growing availability of multimedia contents that can be streamed to fixed or mobile devices. In this regard, one of the most flexible and low-cost approaches is Passive Optical Network (PON) that is used in Fiber-to-the-Home (FTTH). Due to the growing of the bandwidth demands, Wavelength Division Multiplexing (WDM), and later on ultra-dense WDM (udWDM) PON, with a narrow channel spacing, to increase the number of users through a single fiber, has been deployed. The udWDM-PON with coherent technology is an attractive solution for the next generation optical access networks with advanced digital signal processing (DSP). Thanks to the higher sensitivity and improved channel selectivity in coherent detection with efficient DSP, optical networks support larger number of users in longer distances. Since the cost is the main concern in the optical access networks, this thesis presents DSP architectures in coherent receiver (Rx), based on low-cost direct phase modulated commercial DFB lasers. The proposals are completely in agreement with consept of wavelength-to-the-user, where each client in optical network is dedicated to an individual wavelength. Next, in a 6.25 GHz spaced udWDM grid with the optimized DSP techniques and phase-shift-keying (PSK) modulation format, the high sensitivity is achieved in real-time field-programmable-gate-array (FPGA) implementations. Moreover, this thesis reduces hardware complexity of optical carrier recovery (CR) with two various strategies. First, based on differential mth-power frequency estimator (FE) by using look-up-tables (LUTs) and second, LUT-free CR architecture, with optimizing the power consumption and hardware resources, as well as improving the channel selectivity in terms of speed and robustness. Furthermore, by designing very simple but efficient clock recovery, a symbol-rate DSP architecture, which process data using only one sample per symbol (1-sps), for polarization diversity (POD) structure, becomes possible. It makes the DSP independent from state-of-polarization (SOP), even in the case of low-cost optical front-end and low-speed analog-to-digital converters (ADCs), keeps the performance high as well as sensitivity in real-time implementations on FPGA.Avui en dia, les xarxes d'accés òptic proporcionen una alta capacitat als usuaris finals amb una creixent disponibilitat de continguts multimèdia que es poden transmetre a dispositius fixos o mòbils. En aquest sentit, un dels enfocaments més flexibles i de baix cost és la Xarxa Òptica Passiva (PON) que s'utilitza a Fibra-fins-la-Llar (FTTH). A causa del creixent requeriment de l'ample de banda, s'ha desplegat la multiplexació de divisió d'ona (WDM) i, posteriorment, el PON amb WDM d'alta densitat (udWDM), amb un espaiat estret de canals, per augmentar el nombre d'usuaris a través d'una sola fibra. L'udWDM-PON amb tecnologia coherent és una solució atractiva per a les xarxes d'accés òptic d'última generació amb processament avançat de senyal digital (DSP). Gràcies a la major sensibilitat i a la selectivitat millorada del canal en la detecció coherent amb DSP eficient, les xarxes òptiques suporten un nombre més gran d'usuaris a distàncies més llargues. Atès que el cost és la principal preocupació en les xarxes d'accés òptic, aquesta tesi presenta arquitectures DSP en receptor coherent (Rx), basades en làsers DFB comercials modulats en fase directa de baix cost. Les propostes estan d'acord amb la asignació de la longitud d'ona a l'usuari, on a cada client de la xarxa òptica se li dedica a una longitud d'ona individual. A continuació, en una graella udWDM espaciada de 6,25 GHz amb les tècniques de DSP optimitzades i el format de modulació de fase (PSK), s'aconsegueix l'alta sensibilitat en implementacions field-programable-gate-array (FPGA) en temps real. A més, aquesta tesi redueix la complexitat del maquinari de recuperació òptica de portadors (CR) amb dues estratègies diverses. Primer, basat en un estimador de freqüència de potència diferencial (FE) mitjançant l'ús de taules de cerca (LUTs) i, en segon lloc, l'arquitectura CR sense LUT, amb l'optimització del consum d'energia i els recursos de maquinari, a més de millorar la selectivitat del canal en termes de velocitat i robustesa. A més, al dissenyar una recuperació de rellotge molt simple, però eficaç, es fa possible una arquitectura DSP a la velocitat dels símbols, que processa dades utilitzant només una mostra per símbol (1-sps) per a l'estructura de la diversitat de polarització òptica (POD). Fa que el DSP sigui independent de l'estat de polarització (SOP), fins i tot en el cas dels analog-to-digital converters (ADC) de front-end òptics de baix cost, i manté el rendiment alt i la sensibilitat en les implementacions en temps real de FPGA.Postprint (published version
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