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De Gaudenzi R.,European Space Agency | Del Rio Herrero O.,European Space Agency | Gallinaro G.,Space Engineering
International Journal of Satellite Communications and Networking | Year: 2014

This paper describes the key design and performance aspects of the Enhanced Spread Spectrum Aloha (E-SSA) physical layer, which represents an essential component of the S-band Mobile Interactive Multimedia European Telecommunication Institute standard. Thanks to advanced signal processing at the gateway side, the E-SSA random access protocol allows to achieve unprecedented spectral efficiency in a pure asynchronous random access mode with high robustness against received packets power unbalance. The E-SSA physical layer is closely derived from the Third Generation PartnershipWideband Code Division Multiple Access random access channel physical layer with some adaptation to best operate in the Land Mobile Satellite channels. Particular emphasis is devoted to the E-SSA physical layer system design drivers as well to the packet transmission control policies, which are of high relevance for S-band Mobile Interactive Multimedia. The demodulator architectural design is also illustrated jointly with some of the key detection performance. Finally, the E-SSA random access protocol performance are reported for Additive White Gaussian Noise and satellite mobile channels. Copyright © 2014 John Wiley & Sons, Ltd. Source


Alamanac A.B.,European Space Agency | Chan P.M.L.,University of Bradford | Duquerroy L.,European Space Agency | Hu Y.F.,University of Bradford | And 3 more authors.
International Journal of Satellite Communications and Networking | Year: 2010

This article presents an overview of the DVB-RCS system addressing mobile scenarios (DVB-RCS+M). It analyses the challenges linked to the mobility support and it summarizes some of the techniques to cope with those challenges. The focus of this article will be on the technical solutions analyzed within the framework of ESA studies and contracts. In particular, this article will address in detail the proactive retransmission technique and the seamless handover mechanisms including beam, satellite, gateway and gap-filler handovers. Copyright © 2010 John Wiley & Sons, Ltd. Source


Tronc J.,Airbus | Angeletti P.,European Space Agency | Song N.,TU Ilmenau | Haardt M.,TU Ilmenau | And 2 more authors.
International Journal of Satellite Communications and Networking | Year: 2014

The objective of this paper is to review state-of-the-art techniques of beamforming in mobile satellite systems and evaluate the potential benefits/drawbacks of on-ground beamforming compared with on-board beamforming approach. The paper also provides a short analysis of beamforming error sources in on-ground beamforming such as propagation effects at feeder link level, on-board degradations at payload level, differential atmospheric perturbations, and Doppler shift effect. An investigation of signal processing techniques is also performed to provide a preliminary assessment of the interest for employing adaptive beamforming and precoding techniques in multi-spots mobile satellite systems. Copyright © 2013 John Wiley & Sons, Ltd. The objective of this paper is to review state-of-the-art techniques of beam forming in mobile satellite systems and evaluate the potential benefits/drawbacks of on-ground beam forming (OGB) compared with on-board beam forming approach. The paper also provides a short analysis of beam forming error sources in OGB and an investigation of signal processing techniques to evaluate the interest for employing adaptive beam forming and pre-coding techniques in multi-spots mobile satellite systems. Copyright © 2013 John Wiley & Sons, Ltd. Source


Angeletti P.,European Space Agency | Toso G.,European Space Agency | Ruggerini G.,Space Engineering
8th European Conference on Antennas and Propagation, EuCAP 2014 | Year: 2014

A deterministic algorithm based on simple analytical equations for designing planar circular sparse array antennas is presented. The positions and the dimensions of the radiating elements are jointly exploited and optimized using simple analytical equations. The algorithm permits solving one of the main limitations associated to sparse arrays, i.e. the poor aperture efficiency especially when patterns with low sidelobe levels are obtained using only the density of the elements avoiding any amplitude tapering. © 2014 European Association on Antennas and Propagation. Source


Doumanis E.,Queens University of Belfast | Goussetis G.,Queens University of Belfast | Kosmopoulos S.A.,Space Engineering
IEEE Microwave and Wireless Components Letters | Year: 2011

A new inline coupling topology for narrowband helical resonator filters is proposed that allows to introduce selectively located transmission zeros (TZs) in the stopband. We show that a pair of helical resonators arranged in an interdigital configuration can realize a large range of in-band coupling coefficient values and also selectively position a TZ in the stopband. The proposed technique dispenses the need for auxiliary elements, so that the size, complexity, power handling and insertion loss of the filter are not compromised. A second order prototype filter with dimensions of the order of 0.05λ, power handling capability up to 90 W, measured insertion loss of 0.18 dB and improved selectivity is presented. © 2011 IEEE. Source

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