5,484 research outputs found

    System level performance of ATM transmission over a DS-CDMA satellite link.

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    PhDAbstract not availableEuropean Space Agenc

    A Roadmap Toward a Unified Space Communication Architecture

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    In recent years, the number of space exploration missions has multiplied. Such an increase raises the question of effective communication between the multitude of human-made objects spread across our solar system. An efficient and scalable communication architecture presents multiple challenges, including the distance between planetary entities, their motion and potential obstruction, the limited available payload on satellites, and the high mission cost. This paper brings together recent relevant specifications, standards, mission demonstrations, and the most recent proposals to develop a unified architecture for deep-space internetworked communication. After characterizing the transmission medium and its unique challenges, we explore the available communication technologies and frameworks to establish a reliable communication architecture across the solar system. We then draw an evolutive roadmap for establishing a scalable communication architecture. This roadmap builds upon the mission-centric communication architectures in the upcoming years towards a fully interconnected network or InterPlanetary Internet (IPN). We finally discuss the tools available to develop such an architecture in the short, medium, and long terms. The resulting architecture cross-supports space agencies on the solar system-scale while significantly decreasing space communication costs. Through this analysis, we derive the critical research questions remaining for creating the IPN regarding the considerable challenges of space communication.Peer reviewe

    Design and Implementation of a Narrow-Band Intersatellite Network with Limited Onboard Resources for IoT

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    Satellite networks are inevitable for the ubiquitous connectivity of M2M (machine to machine) and IoT (internet of things) devices. Advances in the miniaturization of satellite technology make networks in LEO (Low Earth Orbit) predestined to serve as a backhaul for narrow-band M2M communication. To reduce latency and increase network responsivity, intersatellite link capability among nodes is a key component in satellite design. The miniaturization of nodes to enable the economical deployment of large networks is also crucial. Thus, this article addresses these key issues and presents a design methodology and implementation of an adaptive network architecture considering highly limited resources, as is the case in a nanosatellite (≈10 kg) network. Potentially applicable multiple access techniques are evaluated. The results show that a time division duplex scheme with session-oriented P2P (point to point) protocols in the data link layer is more suitable for limited resources. Furthermore, an applicable layer model is defined and a protocol implementation is outlined. To demonstrate the technical feasibility of a nanosatellite-based communication network, the S-NET (S band network with nanosatellites) mission has been developed, which consists of four nanosatellites, to demonstrate multi-point crosslink with 100 kbps data rates over distances up to 400 km and optimized communication protocols, pushing the technological boundaries of nanosatellites. The flight results of S-NET prove the feasibility of these nanosatellites as a space-based M2M backhaul.BMWi, 50YB1225, S-Band Netzwerk für kooperierende SatellitenBMWi, 50YB1009, SLink - S-Band Transceiver zur Intersatelliten-Kommunikation von NanosatellitenDFG, 414044773, Open Access Publizieren 2019 - 2020 / Technische Universität Berli

    Third Conference on Artificial Intelligence for Space Applications, part 2

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    Topics relative to the application of artificial intelligence to space operations are discussed. New technologies for space station automation, design data capture, computer vision, neural nets, automatic programming, and real time applications are discussed

    Second year technical report on-board processing for future satellite communications systems

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    Advanced baseband and microwave switching techniques for large domestic communications satellites operating in the 30/20 GHz frequency bands are discussed. The nominal baseband processor throughput is one million packets per second (1.6 Gb/s) from one thousand T1 carrier rate customer premises terminals. A frequency reuse factor of sixteen is assumed by using 16 spot antenna beams with the same 100 MHz bandwidth per beam and a modulation with a one b/s per Hz bandwidth efficiency. Eight of the beams are fixed on major metropolitan areas and eight are scanning beams which periodically cover the remainder of the U.S. under dynamic control. User signals are regenerated (demodulated/remodulated) and message packages are reformatted on board. Frequency division multiple access and time division multiplex are employed on the uplinks and downlinks, respectively, for terminals within the coverage area and dwell interval of a scanning beam. Link establishment and packet routing protocols are defined. Also described is a detailed design of a separate 100 x 100 microwave switch capable of handling nonregenerated signals occupying the remaining 2.4 GHz bandwidth with 60 dB of isolation, at an estimated weight and power consumption of approximately 400 kg and 100 W, respectively

    COST EFFICIENT PROVISIONING OF MASS MOBILE MULTIMEDIA SERVICES IN HYBRID CELLULAR AND BROADCASTING SYSTEMS

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    Uno de los retos a los que se enfrenta la industria de las comunicaciones móviles e inalámbricas es proporcionar servicios multimedia masivos a bajo coste, haciéndolos asequibles para los usuarios y rentables a los operadores. El servicio más representativo es el de TV móvil, el cual se espera que sea una aplicación clave en las futuras redes móviles. Actualmente las redes celulares no pueden soportar un consumo a gran escala de este tipo de servicios, y las nuevas redes de radiodifusión móvil son muy costosas de desplegar debido a la gran inversión en infraestructura de red necesaria para proporcionar niveles aceptables de cobertura. Esta tesis doctoral aborda el problema de la provisión eficiente de servicios multimedia masivos a dispositivos móviles y portables utilizando la infraestructura de radiodifusión y celular existente. La tesis contempla las tecnologías comerciales de última generación para la radiodifusión móvil (DVB-H) y para las redes celulares (redes 3G+ con HSDPA y MBMS), aunque se centra principalmente en DVB-H. El principal paradigma propuesto para proporcionar servicios multimedia masivos a bajo coste es evitar el despliegue de una red DVB-H con alta capacidad y cobertura desde el inicio. En su lugar se propone realizar un despliegue progresivo de la infraestructura DVB-H siguiendo la demanda de los usuarios. Bajo este contexto, la red celular es fundamental para evitar sobre-dimensionar la red DVB-H en capacidad y también en áreas con una baja densidad de usuarios hasta que el despliegue de un transmisor o un repetidor DVB-H sea necesario. Como principal solución tecnológica la tesis propone realizar una codificación multi-burst en DVB-H utilizando códigos Raptor. El objetivo es explotar la diversidad temporal del canal móvil para aumentar la robustez de la señal y, por tanto, el nivel de cobertura, a costa de incrementar la latencia de la red.Gómez Barquero, D. (2009). COST EFFICIENT PROVISIONING OF MASS MOBILE MULTIMEDIA SERVICES IN HYBRID CELLULAR AND BROADCASTING SYSTEMS [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/6881Palanci

    Trade-off analysis of modes of data handling for earth resources (ERS), volume 2

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    For abstract, see N75-26470
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