Thesis (Ph.D.)--University of Melbourne, Dept. of Electrical and Electronic Engineering, 2007. / Typescript. Includes bibliographical references (leaves 139-156).

Thesis (M.App.Sc.) - Carleton University, 2007. / Includes bibliographical references (p. 86-94). Also available in electronic format on the Internet.

Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2007. / Chang, Gee-Kung, Committee Chair ; Zhou, G.Tong, Committee Member ; Copeland, John, Committee Member ; Riley, George, Committee Member ; Ingram, Mary Ann, Committee Member ; Ammar, Mostafa, Committee Member.

Orientador : Helio Waldman / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-04T03:23:02Z (GMT). No. of bitstreams: 1 AlmeidaJunior_RaulCamelodeAndrade_D.pdf: 6394727 bytes, checksum: 56d1667ed2e31b23492071088dcf7edf (MD5) Previous issue date: 2004 / Resumo: A combinação da comutação óptica de pacotes com a multiplexação por divisão de comprimento de onda (WDM) surge como um cenário promissor para as redes ópticas futuras. Um dos requisitos de projeto dessas redes é procurar minimizar a perda de pacotes quando há contendas pelos mesmos recursos. Uma alternativa é a utilização de armazenadores de pacotes ópticos, que fazem uso do domínio temporal para a resolução de contenção. Este trabalho propõe uma modelagem analítica para o desempenho desses dispositivos em redes ópticas assíncronas comutadas por pacote. Devido à inexistência de RAMs ópticas, os armazenadores de pacotes ópticos têm sido atualmente configurados por um conjunto de linhas de atraso capaz de prover um número finito de atrasos fixos. Considerando tal peculiaridade, uma contribuição adicional deste trabalho é a proposição e modelagem de duas políticas capazes de prover diferenciação de serviço em armazenadores de pacotes ópticos. Por fim, objetivando realizar um estudo comparativo entre três possíveis domínios de resolução de contenção, também são abordados os domínios espacial e do comprimento de onda, além da combinação entre eles e entre os domínios temporal e do comprimento de onda / Abstract: The combination of optical packet switching with wavelength division multiplexing (WDM) has emerged as a promising framework for future optical networks. One of the design requirements of these networks is to minimize the packet loss when there are contentions for the same resources. One possibility is to use optical buffers, which exploit the time domain for contention resolution. This work proposes an analytical modeling for the performance of such devices in asynchronous optical packet-switched networks. Due to the non-existence of optical RAMs, optical buffers have been designed using delay line banks that can provide a finite number of fixed delays. Considering such peculiarity, an additional contribution of this work is the proposal and modeling of two policies that can provide service differentiation in optical buffers. Lastly, in order to make a comparative study among three possible contention resolution domains, the space and wavelength domains are also analyzed, as well as their combinations and the combination between the time and wavelength domains / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica

No description available.

Traffic from wireless and mobile devices is predicted to increase 10-fold between 2014 and 2019, surpassing wired data traffic by 2016. Given the expected radio frequency (RF) capacity crunch, this growing wireless demand will have to be met using a variety of new technologies exploiting other parts of the electromagnetic spectrum. Promising research areas include the Millimetre Band as well as Optical Wireless Communications (OWC). Millimetre Band demonstrations have accomplished ultrafast multi-Gigabit links, making use of state-of-the-art fibre transmission systems. However, complex opto-electronic (OE) interfaces are required to convert the optical carrier into Millimetre wireless signals. To avoid these interfaces, an all-optical transparent network is proposed here, spanning over both the fibre and OWC domains, in order to deliver ultrahigh data rates to mobile end-users in indoor environments. This is supported by the recent deployment of fibre-to-the-home (FTTH) networks creating the potential for Terabit aggregate connections at the user's doorstep. Therefore, infrared fibre-wireless-fibre (FWF) links are studied to support data rates over 100 Gb/s in nomadic applications. The link coverage is achieved via narrow beam beamsteering over a wide field-of-view (FOV) using suitable localization and tracking techniques. The proposed model is inherently bidirectional and transparent, i.e. independent of the data rate and modulation format. In this thesis, the potential for ultrafast wide coverage OWCs using SMF-based transceivers and coherent transmission is demonstrated. A record data rate of 418 Gb/s and 209 Gb/s with a wide FOV of θ_FOV=±30° and θ_FOV=±20°, respectively, is shown at a free space range of 3 m. To the best of our knowledge, this is the fastest demonstration of an indoor wireless link that offers practical room-scale coverage. The automated alignment of this FWF link is also demonstrated with the design and implementation a mm-accurate localization and tracking system. Finally, architectures for point-to-multipoint communications are explored in order to adapt the system to multiple users.

Orientadores: Helio Waldman, Moises Renato Nunes Ribeiro / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-12T16:44:15Z (GMT). No. of bitstreams: 1 Fardin_MarconiPereira_M.pdf: 962828 bytes, checksum: b8632419bf2a2ad176b38f5257eceada (MD5) Previous issue date: 2008 / Resumo: A infra-estrutura de transporte da internet está movendo-se para um modelo formado por roteadores de alta velocidade interconectados por um núcleo de redes ópticas inteligentes. A tecnologia WDM (Wavelength Division Multiplex) já está consolidada como meio de incrementar a capacidade de transmissão nessas redes porém, existem poucas propostas de planos de controles distribuídos capazes de lidar dinamicamente com as restrições de Qualidade de Serviço (QoS - Quality of Service) em grandes redes. Neste contexto, informações sobre os estados dos enlaces são constantemente divulgadas pela rede e o mecanismo de inundação se tornou ineficiente para lidar com a disseminação das informações. Este trabalho propõe e analisa uma estrutura sobreposta baseada em tabelas de dispersão distribuídas (DHT - Distributed Hash Table) para dispor informações em um espaço virtual. Uma rede sobreposta virtual endereçada por conteúdo (CAN - Content Addressable Network), com enlaces de longa distância para obter características de mundo pequeno, é utilizada para possibilitar o roteamento com baixa ocupação dos enlaces sem penalizar demasiadamente o atraso inserido. Avaliações analíticas ilustram o ganho de desempenho em grandes redes. / Abstract: The transport layer structure of the Internet is moving towards a model of highspeed routers interconnected by intelligent optical core networks. A consensus has been reached on wavelength division multiplexing (WDM) as the way to increase the transmission capacity. However there are few proposals for distributed control planes under dynamic Quality of Service (QoS) constraints for large networks. In this context, resources availability must be frequently distributed and updated across the network; and flooding may no longer be the best strategy for information dissemination. This work proposes and assesses an overlay structure based on distributed hash tables (DHT) for information indexing over bi-dimensional virtual coordinated spaces. By adding long-distance interconnections to Content-Addressable Networks (CAN), the resulting small-world effect can reduce the number of hops per resource search. Analytical results indicate significant reduction in management traffic over the physical layer of large networks without penalizing to much the inserted delay. / Mestrado / Telecomunicações e Telemática / Mestre em Engenharia Elétrica

Integration of optical wireless communications (OWC) within switched-mode power supplies (SMPS) / Although visible light communication(VLC) systems can provide high density links for use with IoT devices, an energy efficient, high rate method of designing a VLC transmitter is still unclear. Present designs for transmitters such as the bias-T, designs with switch manipulation, and interleaved converters are not commercially viable due to costly and complex designs that sacrifice energy efficiency for data rate. A design allowing for efficient, high rate communications, while maintaining a low cost would allow for widespread adoption of this technology. In this thesis, a novel approach of integrating power converters and VLC systems is explored by replacing commutating diodes with LEDs. By leveraging switched-mode power supply(SMPS) structures, the power dissipated within the converter may be harnessed and used for communications. The result is a simple and energy efficient solution capable of high rate links. Simulation and experimental results demonstrate buck and boost SMPS topologies that simultaneously increase energy efficiency and provide communications at SMPS switching rate without increasing component count. / Thesis / Master of Applied Science (MASc)