342 research outputs found

    Deep Space Network information system architecture study

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    The purpose of this article is to describe an architecture for the Deep Space Network (DSN) information system in the years 2000-2010 and to provide guidelines for its evolution during the 1990s. The study scope is defined to be from the front-end areas at the antennas to the end users (spacecraft teams, principal investigators, archival storage systems, and non-NASA partners). The architectural vision provides guidance for major DSN implementation efforts during the next decade. A strong motivation for the study is an expected dramatic improvement in information-systems technologies, such as the following: computer processing, automation technology (including knowledge-based systems), networking and data transport, software and hardware engineering, and human-interface technology. The proposed Ground Information System has the following major features: unified architecture from the front-end area to the end user; open-systems standards to achieve interoperability; DSN production of level 0 data; delivery of level 0 data from the Deep Space Communications Complex, if desired; dedicated telemetry processors for each receiver; security against unauthorized access and errors; and highly automated monitor and control

    WDM/TDM PON bidirectional networks single-fiber/wavelength RSOA-based ONUs layer 1/2 optimization

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    This Thesis proposes the design and the optimization of a hybrid WDM/TDM PON at the L1 (PHY) and L2 (MAC) layers, in terms of minimum deployment cost and enhanced performance for Greenfield NGPON. The particular case of RSOA-based ONUs and ODN using a single-fibre/single-wavelength is deeply analysed. In this WDM/TDM PON relevant parameters are optimized. Special attention has been given at the main noise impairment in this type of networks: the Rayleigh Backscattering effect, which cannot be prevented. To understand its behaviour and mitigate its effects, a novel mathematical model for the Rayleigh Backscattering in burst mode transmission is presented for the first time, and it has been used to optimize the WDM/TDM RSOA based PON. Also, a cost-effective, simple design SCM WDM/TDM PON with rSOA-based ONU, was optimized and implemented. This prototype was successfully tested showing high performance, robustness, versatility and reliability. So, the system is able to give coverage up to 1280 users at 2.5 Gb/s / 1.25 Gb/s downstream/upstream, over 20 Km, and being compatible with the GPON ITU-T recommendation. This precedent has enabled the SARDANA network to extend the design, architecture and capabilities of a WDM/TDM PON for a long reach metro-access network (100 km). A proposal for an agile Transmission Convergence sub-layer is presented as another relevant contribution of this work. It is based on the optimization of the standards GPON and XG-PON (for compatibility), but applied to a long reach metro-access TDM/WDM PON rSOA-based network with higher client count. Finally, a proposal of physical implementation for the SARDANA layer 2 and possible configurations for SARDANA internetworking, with the metro network and core transport network, are presented

    Customer premise service study for 30/20 GHz satellite system

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    Satellite systems in which the space segment operates in the 30/20 GHz frequency band are defined and compared as to their potential for providing various types of communications services to customer premises and the economic and technical feasibility of doing so. Technical tasks performed include: market postulation, definition of the ground segment, definition of the space segment, definition of the integrated satellite system, service costs for satellite systems, sensitivity analysis, and critical technology. Based on an analysis of market data, a sufficiently large market for services is projected so as to make the system economically viable. A large market, and hence a high capacity satellite system, is found to be necessary to minimize service costs, i.e., economy of scale is found to hold. The wide bandwidth expected to be available in the 30/20 GHz band, along with frequency reuse which further increases the effective system bandwidth, makes possible the high capacity system. Extensive ground networking is required in most systems to both connect users into the system and to interconnect Earth stations to provide spatial diversity. Earth station spatial diversity is found to be a cost effective means of compensating the large fading encountered in the 30/20 GHz operating band

    10 Gigabit-capable Passive Optical Network Transmission Convergence layer design

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    Uusien laajakaistaisten tietoliikennepalvelujen ja kasvavan tiedonsiirtokapasiteetin tarpeen myötä kiinteiden liityntäverkkojen infrastruktuuri on muuttumassa sähköisestä optiseksi. Euroopan komission rahoittamassa Scalable Advanced Ring-based passive Dense Access Network Architecture (SARDANA)-tutkimusprojektissa tutkitaan seuraavan sukupolven passiivisten optisten liityntäverkojen teknologioita. Projektin päätavoitteena on pienentää passiivisiin optisiin liityntäverkkoihin liittyviä kustannuksia. Tämä diplomityö käsittelee SARDANA-testiverkon standardoimattoman 10 Gigabit-capable Passive Optical Network (XGPON) Transmission Convergence (TC)-kerroksen suunnittelua ja ensimmäistä toteutusta optisessa verkkopäätteessä (ONU:ssa). TC-kerros toteuttaa Medium Access Control (MAC)-protokollan. SARDANA XGPON TC (SXGTC)-kerros perustuu standardoituun ITU-T G.984.3 Gigabit-capable Passive Optical Network (GPON) TC (GTC)-kerroksen [ITU08] tarjoamaan ratkaisuun mutta eroaa tästä yksityiskohdiltaan. Kaikki SXGTC-kerroksen oleelliset yksityiskohdat peilataan GTC-kerrokseen. Suunniteltu SXGTC-protokolla tukee maksimissaan 9.95328 Gbps:n symmetrisiä tiedonsiirtonopeuksia. SXGTC-protokolla on optimoitu käsittelemään dataa 8 tavun sanoissa. Ensimmäinen ONU SXGTC-kerroksen toteutus ohjelmoitavassa Field Programmable Gate Array (FPGA)-piirissä esitellään funktionaalisten lohkojen avulla. Tämän implementaation tiedonsiirtonopeus alasuunnassa on 9.95328 Gbps 98 %:n kaistatehokkuudella ja yläsuunnassa 2.48832 Gbps 94.5 %:n kaistatehokkuudella SARDANA-testiverkkokonfiguraation tapauksessa.With the emergence of new broadband telecommunication services and constantly increasing bandwidth demand, fixed access network infrastructure is evolving from electrical to optical. The European Commission funded research project Scalable Advanced Ring-based passive Dense Access Network Architecture (SARDANA) researches the next-generation passive optical access network technologies. The main goal of the project is to reduce expenses that are related to passive optical access networks. This master's thesis discusses the design of the non-standardized 10 Gigabit-capable Passive Optical Network (XGPON) Transmission Convergence (TC) layer and its first implementation version for Optical Network Unit (ONU) for the SARDANA test network. The SARDANA XGPON TC (SXGTC) layer implements the Medium Access Control (MAC) protocol. The SXGTC layer is based on the standardized solution offered by the ITU-T G.984.3 Gigabit-capable Passive Optical Network (GPON) TC (GTC) layer recommendation [ITU08] but differs from it in many details. All the SXGTC layer features are compared to those of the GTC layer. As a result, the SXGTC protocol is able to support operation on up to 9.95328 Gbps symmetrical transmission rates. The SXGTC layer is optimized for the 8-byte-word-based data processing. The first ONU SXGTC layer Field Programmable Gate Array (FPGA) implementation is presented in terms of functional blocks. The implementation supports operation on 9.95328 Gbps in the downstream offering 98 % bandwidth efficiency and on 2.48832 Gbps in the upstream offering 94.5 % bandwidth efficiency for the SARDANA test network configuration

    Communications with guaranteed bandwidth and low latency using frequency-referenced multiplexing

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    Emerging cloud applications such as virtual reality and connected car fleets demand guaranteed connections, as well as low and stable latency, to edge data centres. Currently, user–cloud communications rely on time-scheduled data frames through tree-topology fibre networks, which are incapable of providing guaranteed connections with low or stable latency and cannot be scaled to a larger number of users. Here we show that a frequency-referenced multiplexing method can provide guaranteed bandwidth and low latency for time-critical applications. We use clock and optical frequency synchronization, enabled by frequency comb and signal processing techniques, to provide each user with dedicated optical bandwidth, creating scalable user–cloud upstream communications. As a proof of concept, we demonstrate a frequency-division multiplexing system servicing up to 64 users with an aggregate bandwidth of 160 GHz, exhibiting a data rate of up to 4.3 Gbps per user (240.0 Gbps aggregated capacity considering a 200 GHz wavelength band) with a high receiver sensitivity of –35 dBm

    A flexible readout board for HEP experiments

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    This thesis will present my contributions to the development of the PiLUP board along with a general overview of its features and capabilities. The PiLUP board is a general-purpose FPGA-based readout board for data acquisition systems under development by the University of Bologna and the Instituto Nazionale Fisica Nucleare (INFN) and intended for high energy physics experiments, where the sheer amount of data generated by detectors often requires custom hardware solutions. This board was initially proposed for the next upgrade of the ATLAS Pixel detector. In this context its purpose would be to interface the Front-End readout chip RD53A with the FELIX card and provide advanced testing features such as an emulator for the RD53A that will help the development of the other parts of the data acquisition chain. Nonetheless, since the early stages of development, the hardware has been designed to offer great flexibility so that the same hardware platform could be directly used in other applications. To this purpose an important feature of the board is the great extendibility offered by the presence of different interfaces, such as and 3 FMC connectors (two low density and one high density), a PCI Express x8 interface, gigabit ethernet and an integrated SFP connector. The computing power of the PiLUP is provided by of two FPGAs, a Zynq-7 SoC and a Kintex-7 produced by Xilinx, intended to be used in master-slave configuration. In this case the Zynq, with its dual-core ARM processor and the possibility to run an embedded linux distribution, would be used as main interface with the other functionalities in the board. The main objective of this thesis is the development of such software and firmware control infrastructure, starting from the firmware solutions for the inter-FPGA communication to the low-level software to control the system

    Advanced Technique and Future Perspective for Next Generation Optical Fiber Communications

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    Optical fiber communication industry has gained unprecedented opportunities and achieved rapid progress in recent years. However, with the increase of data transmission volume and the enhancement of transmission demand, the optical communication field still needs to be upgraded to better meet the challenges in the future development. Artificial intelligence technology in optical communication and optical network is still in its infancy, but the existing achievements show great application potential. In the future, with the further development of artificial intelligence technology, AI algorithms combining channel characteristics and physical properties will shine in optical communication. This reprint introduces some recent advances in optical fiber communication and optical network, and provides alternative directions for the development of the next generation optical fiber communication technology

    The DUNE Far Detector Interim Design Report, Volume 3: Dual-Phase Module

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    The DUNE IDR describes the proposed physics program and technical designs of the DUNE far detector modules in preparation for the full TDR to be published in 2019. It is intended as an intermediate milestone on the path to a full TDR, justifying the technical choices that flow down from the high-level physics goals through requirements at all levels of the Project. These design choices will enable the DUNE experiment to make the ground-breaking discoveries that will help to answer fundamental physics questions. Volume 3 describes the dual-phase module's subsystems, the technical coordination required for its design, construction, installation, and integration, and its organizational structure

    Analog radio over fiber solutions for multi-band 5g systems

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    This study presents radio over fiber (RoF) solutions for the fifth-generation (5G) of wireless networks. After the state of the art and a technical background review, four main contributions are reported. The first one is proposing and investigating a RoF technique based on a dual-drive Mach-Zehnder modulator (DD-MZM) for multi-band mobile fronthauls, in which two radiofrequency (RF) signals in the predicted 5G bands individually feed an arm of the optical modulator. Experimental results demonstrate the approach enhances the RF interference mitigation and can prevail over traditional methods. The second contribution comprises the integration of a 5G transceiver, previously developed by our group, in a passive optical network (PON) using RoF technology and wavelength division multiplexing (WDM) overlay. The proposed architecture innovates by employing DD-MZM and enables to simultaneously transport baseband and 5G candidate RF signals in the same PON infrastructure. The proof-of-concept includes the transmission of a generalized frequency division multiplexing (GFDM) signal generated by the 5G transceiver in the 700 MHz band, a 26 GHz digitally modulated signal as a millimeter-waves 5G band, and a baseband signal from an gigabit PON (GPON). Experimental results demonstrate the 5G transceiver digital performance when using RoF technology for distributing the GFDM signal, as well as Gbit/s throughput at 26 GHz. The third contribution is the implementation of a flexible-waveform and multi-application fiber-wireless (FiWi) system toward 5G. Such system includes the FiWi transmission of the GFDM and filtered orthogonal frequency division multiplexing (F-OFDM) signals at 788 MHz, toward long-range cells for remote or rural mobile access, as well as the recently launched 5G NR standard in microwave and mm-waves, aiming enhanced mobile broadband indoor and outdoor applications. Digital signal processing (DSP) is used for selecting the waveform and linearizing the RoF link. Experimental results demonstrate the suitability of the proposed solution to address 5G scenarios and requirements, besides the applicability of using existent fiber-to-the-home (FTTH) networks from Internet service providers for implementing 5G systems. Finally, the fourth contribution is the implementation of a multi-band 5G NR system with photonic-assisted RF amplification (PAA). The approach takes advantage of a novel PAA technique, based on RoF technology and four-wave mixing effect, that allows straightforward integration to the transport networks. Experimental results demonstrate iv uniform and stable 15 dB wideband gain for Long Term Evolution (LTE) and three 5G signals, distributed in the frequency range from 780 MHz to 26 GHz and coexisting in the mobile fronthaul. The obtained digital performance has efficiently met the Third-Generation Partnership Project (3GPP) requirements, demonstrating the applicability of the proposed approach for using fiber-optic links to distribute and jointly amplify LTE and 5G signals in the optical domain.Agência 1Este trabalho apresenta soluções de rádio sobre fibra (RoF) para aplicações em redes sem fio de quinta geração (5G), e inclui quatro contribuições principais. A primeira delas refere-se à proposta e investigação de uma técnica de RoF baseada no modulador eletroóptico de braço duplo, dual-drive Mach-Zehnder (DD-MZM), para a transmissão simultânea de sinais de radiofrequência (RF) em bandas previstas para redes 5G. Resultados experimentais demonstram que o uso do DD-MZM favorece a ausência de interferência entre os sinais de RF transmitidos. A segunda contribuição trata da integração de um transceptor de RF, desenvolvido para aplicações 5G e apto a prover a forma de onda conhecida como generalized frequency division multiplexing (GFDM), em uma rede óptica passiva (PON) ao utilizar RoF e multiplexação por divisão de comprimento de onda (WDM). A arquitetura proposta permite transportar, na mesma infraestrutura de rede, sinais em banda base e de radiofrequência nas faixas do espectro candidatas para 5G. A prova de conceito inclui a distribuição conjunta de três tipos de sinais: um sinal GFDM na banda de 700 MHz, proveniente do transceptor desenvolvido; um sinal digital na frequência de 26 GHz, assumindo a faixa de ondas milimétricas; sinais em banda base provenientes de uma PON dedicada ao serviço de Internet. Resultados experimentais demonstram o desempenho do transceptor de RF ao utilizar a referida arquitetura para distribuir sinais GFDM, além de taxas de transmissão de dados da ordem de Gbit/s na faixa de 26 GHz. A terceira contribuição corresponde à implementação de um sistema fibra/rádio potencial para redes 5G, operando inclusive com o padrão ―5G New Radio (5G NR)‖ nas faixas de micro-ondas e ondas milimétricas. Tal sistema é capaz de prover macro células na banda de 700 MHz para aplicações de longo alcance e/ou rurais, utilizando sinais GFDM ou filtered orthogonal frequency division multiplexing (F-OFDM), assim como femto células na banda de 26 GHz, destinada a altas taxas de transmissão de dados para comunicações de curto alcance. Resultados experimentais demonstram a aplicabilidade da solução proposta para redes 5G, além da viabilidade de utilizar redes ópticas pertencentes a provedores de Internet para favorecer sistemas de nova geração. Por fim, a quarta contribuição trata da implementação de um sistema 5G NR multibanda, assistido por amplificação de RF no domínio óptico. Esse sistema faz uso de um novo método de amplificação, baseado no efeito não linear da mistura de quatro ondas, que vi permite integração direta em redes de transporte envolvendo rádio sobre fibra. Resultados experimentais demonstram ganho de RF igual a 15 dB em uma ampla faixa de frequências (700 MHz até 26 GHz), atendendo simultaneamente tecnologias de quarta e quinta geração. O desempenho digital obtido atendeu aos requisitos estabelecidos pela 3GPP (Third-Generation Partnership Project), indicando a aplicabilidade da solução em questão para distribuir e conjuntamente amplificar sinais de RF em enlaces de fibra óptica
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