9 research outputs found

    DVB-T2 Simulation Model for OPNET

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    DVB-T2 is offering a new way for broadcasting value-added services to end users, such as High Denition (HD) TV and 3D TV. Thanks to the advances made in digital signal processing, and specically in channel coding, DVB- T2 brings an increased transfer capacity of 50% and a new exibility in services' broadcasting in contrast with the rst generation DVB-T standard. As DVB-T2 is still in deployment's test, simulation model could be an interesting way to evaluate the performance of this network in supporting new value-added services. In this paper, we describe the new features and enhancements we have integrated within the DVB-T2 module in OPNET, and in particular: (i) a realistic physical model;(ii) an MPEG-TS layer with an IP encapsulator;(iii) hierarchical application layer ables to use pcap traces to simulate real video traces. Also, we include an extensive simulation campaign in order to well understand the performance of DVB-T2 networks

    Advanced constellation and demapper schemes for next generation digital terrestrial television broadcasting systems

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    206 p.Esta tesis presenta un nuevo tipo de constelaciones llamadas no uniformes. Estos esquemas presentan una eficacia de hasta 1,8 dB superior a las utilizadas en los Ășltimos sistemas de comunicaciones de televisiĂłn digital terrestre y son extrapolables a cualquier otro sistema de comunicaciones (satĂ©lite, mĂłvil, cableÂż). AdemĂĄs, este trabajo contribuye al diseño de constelaciones con una nueva metodologĂ­a que reduce el tiempo de optimizaciĂłn de dĂ­as/horas (metodologĂ­as actuales) a horas/minutos con la misma eficiencia. Todas las constelaciones diseñadas se testean bajo una plataforma creada en esta tesis que simula el estĂĄndar de radiodifusiĂłn terrestre mĂĄs avanzado hasta la fecha (ATSC 3.0) bajo condiciones reales de funcionamiento.Por otro lado, para disminuir la latencia de decodificaciĂłn de estas constelaciones esta tesis propone dos tĂ©cnicas de detecciĂłn/demapeo. Una es para constelaciones no uniformes de dos dimensiones la cual disminuye hasta en un 99,7% la complejidad del demapeo sin empeorar el funcionamiento del sistema. La segunda tĂ©cnica de detecciĂłn se centra en las constelaciones no uniformes de una dimensiĂłn y presenta hasta un 87,5% de reducciĂłn de la complejidad del receptor sin pĂ©rdidas en el rendimiento.Por Ășltimo, este trabajo expone un completo estado del arte sobre tipos de constelaciones, modelos de sistema, y diseño/demapeo de constelaciones. Este estudio es el primero realizado en este campo

    Understanding Timelines within MPEG Standards

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    (c) 2016 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.Nowadays, media content can be delivered via diverse broadband and broadcast technologies. Although these different technologies have somehow become rivals, their coordinated usage and convergence, by leveraging of their strengths and complementary characteristics, can bring many benefits to both operators and customers. For example, broadcast TV content can be augmented by on-demand broadband media content to provide enriched and personalized services, such as multi-view TV, audio language selection, and inclusion of real-time web feeds. A piece of evidence is the recent Hybrid Broadcast Broadband TV (HbbTV) standard, which aims at harmonizing the delivery and consumption of (hybrid) broadcast and broadband TV content. A key challenge in these emerging scenarios is the synchronization between the involved media streams, which can be originated by the same or different sources, and delivered via the same or different technologies. To enable synchronized (hybrid) media delivery services, some mechanisms providing timelines at the source side are necessary to accurately time align the involved media streams at the receiver-side. This paper provides a comprehensive review of how clock references (timing) and timestamps (time) are conveyed and interpreted when using the most widespread delivery technologies, such as DVB, RTP/RTCP and MPEG standards (e.g., MPEG-2, MPEG-4, MPEG-DASH, and MMT). It is particularly focused on the format, resolution, frequency, and the position within the bitstream of the fields conveying timing information, as well as on the involved components and packetization aspects. Finally, it provides a survey of proofs of concepts making use of these synchronization related mechanisms. This complete and thorough source of information can be very useful for scholars and practitioners interested in media services with synchronization demands.This work has been funded, partially, by the "Fondo Europeo de Desarrollo Regional" (FEDER) and the Spanish Ministry of Economy and Competitiveness, under its R&D&i Support Program in project with ref TEC2013-45492-R.Yuste, LB.; Boronat Segui, F.; Montagut Climent, MA.; Melvin, H. (2015). Understanding Timelines within MPEG Standards. Communications Surveys and Tutorials, IEEE Communications Society. 18(1):368-400. https://doi.org/10.1109/COMST.2015.2488483S36840018

    Network reputation-based quality optimization of video delivery in heterogeneous wireless environments

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    The mass-market adoption of high-end mobile devices and increasing amount of video traffic has led the mobile operators to adopt various solutions to help them cope with the explosion of mobile broadband data traffic, while ensuring high Quality of Service (QoS) levels to their services. Deploying small-cell base stations within the existing macro-cellular networks and offloading traffic from the large macro-cells to the small cells is seen as a promising solution to increase capacity and improve network performance at low cost. Parallel use of diverse technologies is also employed. The result is a heterogeneous network environment (HetNets), part of the next generation network deployments. In this context, this thesis makes a step forward towards the “Always Best Experience” paradigm, which considers mobile users seamlessly roaming in the HetNets environment. Supporting ubiquitous connectivity and enabling very good quality of rich mobile services anywhere and anytime is highly challenging, mostly due to the heterogeneity of the selection criteria, such as: application requirements (e.g., voice, video, data, etc.); different device types and with various capabilities (e.g., smartphones, netbooks, laptops, etc.); multiple overlapping networks using diverse technologies (e.g., Wireless Local Area Networks (IEEE 802.11), Cellular Networks Long Term Evolution (LTE), etc.) and different user preferences. In fact, the mobile users are facing a complex decision when they need to dynamically select the best value network to connect to in order to get the “Always Best Experience”. This thesis presents three major contributions to solve the problem described above: 1) The Location-based Network Prediction mechanism in heterogeneous wireless networks (LNP) provides a shortlist of best available networks to the mobile user based on his location, history record and routing plan; 2) Reputation-oriented Access Network Selection mechanism (RANS) selects the best reputation network from the available networks for the mobile user based on the best trade-off between QoS, energy consumptions and monetary cost. The network reputation is defined based on previous user-network interaction, and consequent user experience with the network. 3) Network Reputation-based Quality Optimization of Video Delivery in heterogeneous networks (NRQOVD) makes use of a reputation mechanism to enhance the video content quality via multipath delivery or delivery adaptation

    Interoperability of semantics in news production

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    Middleware de comunicaçÔes para a internet móvel futura

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    Doutoramento em InformĂĄtica (MAP-I)A evolução constante em novas tecnologias que providenciam suporte Ă  forma como os nossos dispositivos se ligam, bem como a forma como utilizamos diferentes capacidades e serviços on-line, criou um conjunto sem precedentes de novos desafios que motivam o desenvolvimento de uma recente ĂĄrea de investigação, denominada de Internet Futura. Nesta nova ĂĄrea de investigação, novos aspectos arquiteturais estĂŁo ser desenvolvidos, os quais, atravĂ©s da re-estruturação de componentes nucleares subjacentesa que compĂ”em a Internet, progride-a de uma forma capaz de nĂŁo sĂŁo fazer face a estes novos desafios, mas tambĂ©m de a preparar para os desafios de amanhĂŁ. Aspectos chave pertencendo a este conjunto de desafios sĂŁo os ambientes de rede heterogĂ©neos compostos por diferentes tipos de redes de acesso, a cada vez maior mudança do trĂĄfego peer-to-peer (P2P) como o tipo de trĂĄfego mais utilizado na Internet, a orquestração de cenĂĄrios da Internet das Coisas (IoT) que exploram mecanismos de interação Maquinaa-Maquina (M2M), e a utilização de mechanismos centrados na informação (ICN). Esta tese apresenta uma nova arquitetura capaz de simultaneamente fazer face a estes desafios, evoluindo os procedimentos de conectividade e entidades envolvidas, atravĂ©s da adição de uma camada de middleware, que age como um mecanismo de gestĂŁo de controlo avançado. Este mecanismo de gestĂŁo de controlo aproxima as entidades de alto nĂ­vel (tais como serviços, aplicaçÔes, entidades de gestĂŁo de mobilidade, operaçÔes de encaminhamento, etc.) com as componentes das camadas de baixo nĂ­vel (por exemplo, camadas de ligação, sensores e atuadores), permitindo uma otimização conjunta dos procedimentos de ligação subjacentes. Os resultados obtidos nĂŁo sĂł sublinham a flexibilidade dos mecanismos que compoem a arquitetura, mas tambĂ©m a sua capacidade de providenciar aumentos de performance quando comparados com outras soluÇÕes de funcionamento especÍfico, enquanto permite um maior leque de cenĂĄios e aplicaçÔes.The constant evolution in new technologies that support the way our devices are able to connect, as well the way we use available on-line services and capabilities, has created a set of unprecedented new challenges that motivated the development of a recent research trend known as the Future Internet. In this research trend, new architectural aspects are being developed which, through the restructure of underlying core aspects composing the Internet, reshapes it in a way capable of not only facing these new challenges, but also preparing it to tackle tomorrow’s new set of complex issues. Key aspects belonging to this set of challenges are heterogeneous networking environments composed by di↔erent kinds of wireless access networks, the evergrowing change from peer-to-peer (P2P) to video as the most used kind of traffic in the Internet, the orchestration of Internet of Things (IoT) scenarios exploiting Machine-to-Machine (M2M) interactions, and the usage of Information-Centric Networking (ICN). This thesis presents a novel framework able to simultaneous tackle these challenges, empowering connectivity procedures and entities with a middleware acting as an advanced control management mechanism. This control management mechanism brings together both high-level entities (such as application services, mobility management entities, routing operations, etc.) with the lower layer components (e.g., link layers, sensor devices, actuators), allowing for a joint optimization of the underlying connectivity and operational procedures. Results highlight not only the flexibility of the mechanisms composing the framework, but also their ability in providing performance increases when compared with other specific purpose solutions, while allowing a wider range of scenarios and deployment possibilities
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