The Experts below are selected from a list of 21360 Experts worldwide ranked by ideXlab platform
Rennie Ellie - One of the best experts on this subject based on the ideXlab platform.
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Unintended consequences: Satellite policy and Indigenous television
SAGE Publications Inc., 2013Co-Authors: Rennie EllieAbstract:This article examines two instances of media policy involving Satellite Transmission and Indigenous television: the introduction of the Viewer Access Satellite Television (VAST) platform in 2010 and the introduction of AUSSAT in the mid-1980s. The government’s failure to provide community and Indigenous broadcasters with an access regime at the time of AUSSAT resulted in Australia’s first and only Indigenous commercial television licensee, Imparja. Over a quarter of a century later, Imparja now forms part of the joint-venture company that runs VAST, a key component of Australia’s digital switchover planning. During the passage of the legislative amendments required to establish VAST, the issue of access resurfaced – this time in relation to Australia’s national and community Indigenous television channels. The article recounts the events leading up to the 2010 Bill, and examines the intended and unintended consequences of Satellite policy in relation to Indigenous media, including equalisation and transparency of government funding programs
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Unintended consequences: Satellite policy and Indigenous television
University of Queensland, 2013Co-Authors: Rennie EllieAbstract:This paper examines two instances of media policy involving Satellite Transmission and Indigenous television: The introduction of the Viewer Access Satellite Television (VAST) platform in 2010, and the introduction of AUSSAT in the mid-1980s. The government's failure to provide community and Indigenous broadcasters with an access regime at the time of AUSSAT resulted in Australia's first and only Indigenous commercial television licensee, Imparja. Over a quarter of a century later, Imparja now forms part of the joint venture company that runs VAST, a key component of Australia's digital switchover planning. During the passage of the legislative amendments required to establish VAST through the Houses of Parliament, the issue of access resurfaced, this time in relation to Australia's national and community Indigenous television channels. The paper recounts the events leading up to the 2010 bill and examines the intended and unintended consequences of Satellite policy in relation to Indigenous media, including equalisation and transparency of government funding programs
Fausto Vieira - One of the best experts on this subject based on the ideXlab platform.
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dvb s2 full cross layer design for qos provision
IEEE Communications Magazine, 2012Co-Authors: Angeles Vazquez M Castro, Fausto VieiraAbstract:The second generation of the Digital Video Broadcasting standard for Satellite Transmission, DVB-S2, is the evolution of the highly successful DVB-S Satellite distribution technology. DVB-S2 has benefited from the latest progress in channel coding and modulation such as Low Density Parity Check Codes and higher order constellations to achieve performance that approaches Shannon?s theoretical limit. We present a cross-layer design for Quality-of-Service (QoS) provision of interactive services, which is not specified in the standard. Our cross-layer approach exploits the Satellite channel characteristics of space-time correlation via a cross-layer queueing architecture and an adaptive cross-layer scheduling policy. We show that our approach not only allows system load control but also rate adaptation to channel conditions and traffic demands on the coverage area. We also present the extension of our cross-layer design for mobile gateways focusing on the railway scenario. We illustrate the trade-off between system-wide and individual throughput by means of simulation, and that this trade-off could be a key metric in measuring the service level of DVB-S2 Broadband Service.
Cecile Mallet - One of the best experts on this subject based on the ideXlab platform.
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rainfall measurement from the opportunistic use of an earth space link in the ku band
Atmospheric Measurement Techniques, 2013Co-Authors: Laurent Barthes, Cecile MalletAbstract:Abstract. The present study deals with the development of a low-cost microwave device devoted to the measurement of average rain rates observed along Earth–Satellite links, the latter being characterized by a tropospheric path length of a few kilometres. The ground-based power measurements, which are made using the Ku-band television Transmissions from several different geostationary Satellites, are based on the principle that the atmospheric attenuation produced by rain encountered along each Transmission path can be used to determine the path-averaged rain rate. This kind of device could be very useful in hilly areas where radar data are not available or in urban areas where such devices could be directly placed in homes by using residential TV antenna. The major difficulty encountered with this technique is that of retrieving rainfall characteristics in the presence of many other causes of received signal fluctuation, produced by atmospheric scintillation, variations in atmospheric composition (water vapour concentration, cloud water content) or Satellite Transmission parameters (variations in emitted power, Satellite pointing). In order to conduct a feasibility study with such a device, a measurement campaign was carried out over a period of five months close to Paris. The present paper proposes an algorithm based on an artificial neural network, used to identify dry and rainy periods and to model received signal variability resulting from effects not related to rain. When the altitude of the rain layer is taken into account, the rain attenuation can be inverted to obtain the path-averaged rain rate. The rainfall rates obtained from this process are compared with co-located rain gauges and radar measurements taken throughout the full duration of the campaign, and the most significant rainfall events are analysed.
Angeles Vazquez M Castro - One of the best experts on this subject based on the ideXlab platform.
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dvb s2 full cross layer design for qos provision
IEEE Communications Magazine, 2012Co-Authors: Angeles Vazquez M Castro, Fausto VieiraAbstract:The second generation of the Digital Video Broadcasting standard for Satellite Transmission, DVB-S2, is the evolution of the highly successful DVB-S Satellite distribution technology. DVB-S2 has benefited from the latest progress in channel coding and modulation such as Low Density Parity Check Codes and higher order constellations to achieve performance that approaches Shannon?s theoretical limit. We present a cross-layer design for Quality-of-Service (QoS) provision of interactive services, which is not specified in the standard. Our cross-layer approach exploits the Satellite channel characteristics of space-time correlation via a cross-layer queueing architecture and an adaptive cross-layer scheduling policy. We show that our approach not only allows system load control but also rate adaptation to channel conditions and traffic demands on the coverage area. We also present the extension of our cross-layer design for mobile gateways focusing on the railway scenario. We illustrate the trade-off between system-wide and individual throughput by means of simulation, and that this trade-off could be a key metric in measuring the service level of DVB-S2 Broadband Service.
Laurent Barthes - One of the best experts on this subject based on the ideXlab platform.
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rainfall measurement from the opportunistic use of an earth space link in the ku band
Atmospheric Measurement Techniques, 2013Co-Authors: Laurent Barthes, Cecile MalletAbstract:Abstract. The present study deals with the development of a low-cost microwave device devoted to the measurement of average rain rates observed along Earth–Satellite links, the latter being characterized by a tropospheric path length of a few kilometres. The ground-based power measurements, which are made using the Ku-band television Transmissions from several different geostationary Satellites, are based on the principle that the atmospheric attenuation produced by rain encountered along each Transmission path can be used to determine the path-averaged rain rate. This kind of device could be very useful in hilly areas where radar data are not available or in urban areas where such devices could be directly placed in homes by using residential TV antenna. The major difficulty encountered with this technique is that of retrieving rainfall characteristics in the presence of many other causes of received signal fluctuation, produced by atmospheric scintillation, variations in atmospheric composition (water vapour concentration, cloud water content) or Satellite Transmission parameters (variations in emitted power, Satellite pointing). In order to conduct a feasibility study with such a device, a measurement campaign was carried out over a period of five months close to Paris. The present paper proposes an algorithm based on an artificial neural network, used to identify dry and rainy periods and to model received signal variability resulting from effects not related to rain. When the altitude of the rain layer is taken into account, the rain attenuation can be inverted to obtain the path-averaged rain rate. The rainfall rates obtained from this process are compared with co-located rain gauges and radar measurements taken throughout the full duration of the campaign, and the most significant rainfall events are analysed.
