Radio Communications

In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modified our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the field of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks

A Survey on Non-Geostationary Satellite Systems: The Communication Perspective

The next phase of satellite technology is being characterized by a new evolution in non-geostationary orbit (NGSO) satellites, which conveys exciting new communication capabilities to provide non-terrestrial connectivity solutions and to support a wide range of digital technologies from various industries. NGSO communication systems are known for a number of key features such as lower propagation delay, smaller size, and lower signal losses in comparison to the conventional geostationary orbit (GSO) satellites, which can potentially enable latency-critical applications to be provided through satellites. NGSO promises a substantial boost in communication speed and energy efficiency, and thus, tackling the main inhibiting factors of commercializing GSO satellites for broader utilization. The promised improvements of NGSO systems have motivated this paper to provide a comprehensive survey of the state-of-the-art NGSO research focusing on the communication prospects, including physical layer and radio access technologies along with the networking aspects and the overall system features and architectures. Beyond this, there are still many NGSO deployment challenges to be addressed to ensure seamless integration not only with GSO systems but also with terrestrial networks. These unprecedented challenges are also discussed in this paper, including coexistence with GSO systems in terms of spectrum access and regulatory issues, satellite constellation and architecture designs, resource management problems, and user equipment requirements. Finally, we outline a set of innovative research directions and new opportunities for future NGSO research

D 3. 3 Final performance results and consolidated view on the most promising multi -node/multi -antenna transmission technologies

This document provides the most recent updates on the technical contributions and research challenges focused in WP3. Each Technology Component (TeC) has been evaluated under possible uniform assessment framework of WP3 which is based on the simulation guidelines of WP6. The performance assessment is supported by the simulation results which are in their mature and stable state. An update on the Most Promising Technology Approaches (MPTAs) and their associated TeCs is the main focus of this document. Based on the input of all the TeCs in WP3, a consolidated view of WP3 on the role of multinode/multi-antenna transmission technologies in 5G systems has also been provided. This consolidated view is further supported in this document by the presentation of the impact of MPTAs on METIS scenarios and the addressed METIS goals.Aziz, D.; Baracca, P.; De Carvalho, E.; Fantini, R.; Rajatheva, N.; Popovski, P.; Sørensen, JH.... (2015). D 3. 3 Final performance results and consolidated view on the most promising multi -node/multi -antenna transmission technologies. http://hdl.handle.net/10251/7675

Proceedings of the Mobile Satellite Conference

A satellite-based mobile communications system provides voice and data communications to mobile users over a vast geographic area. The technical and service characteristics of mobile satellite systems (MSSs) are presented and form an in-depth view of the current MSS status at the system and subsystem levels. Major emphasis is placed on developments, current and future, in the following critical MSS technology areas: vehicle antennas, networking, modulation and coding, speech compression, channel characterization, space segment technology and MSS experiments. Also, the mobile satellite communications needs of government agencies are addressed, as is the MSS potential to fulfill them

Smart antennas for strategic environment

The objective of this Thesis consists in presenting in a concise and effective way the results achieved during researches and studies on satellite systems interference sources, advanced antenna arrays for satellite systems to mitigate the increasing anti-interference needs and on an innovative way to generates inhomogeneous wave in lossless media for contributing to the design of a novel type of antenna for deep penetrating lossy media

A Vision and Framework for the High Altitude Platform Station (HAPS) Networks of the Future

A High Altitude Platform Station (HAPS) is a network node that operates in the stratosphere at an of altitude around 20 km and is instrumental for providing communication services. Precipitated by technological innovations in the areas of autonomous avionics, array antennas, solar panel efficiency levels, and battery energy densities, and fueled by flourishing industry ecosystems, the HAPS has emerged as an indispensable component of next-generations of wireless networks. In this article, we provide a vision and framework for the HAPS networks of the future supported by a comprehensive and state-of-the-art literature review. We highlight the unrealized potential of HAPS systems and elaborate on their unique ability to serve metropolitan areas. The latest advancements and promising technologies in the HAPS energy and payload systems are discussed. The integration of the emerging Reconfigurable Smart Surface (RSS) technology in the communications payload of HAPS systems for providing a cost-effective deployment is proposed. A detailed overview of the radio resource management in HAPS systems is presented along with synergistic physical layer techniques, including Faster-Than-Nyquist (FTN) signaling. Numerous aspects of handoff management in HAPS systems are described. The notable contributions of Artificial Intelligence (AI) in HAPS, including machine learning in the design, topology management, handoff, and resource allocation aspects are emphasized. The extensive overview of the literature we provide is crucial for substantiating our vision that depicts the expected deployment opportunities and challenges in the next 10 years (next-generation networks), as well as in the subsequent 10 years (next-next-generation networks).Comment: To appear in IEEE Communications Surveys & Tutorial

Towards automated structure determination

Der erste Teil dieser Arbeit beschäftigte sich mit der konventionellen strukturellen und dynamischen Charakterisierung von gefaltenen und intrinsisch ungefaltenen Proteinen mittels NMR Spektroskopie. ICln ist ein hochkonserviertes und essentielles 27kDa protein und ist in verschiedenen Signaltransduktionswegen wie Zellvolumsregulation, Angiogenese, oder RNA Prozessierung involviert. Basierend auf Rekonstitutionsexperimente in Membranlipiden und anderen Ergebnissen chloridkanalbildende Funktion von ICln vorgeschlagen. Obwohl knock-down Experimente eine direkte funktionelle Eigenschaft dieses Proteins in der Zellvolumsregulation anzeigten, wurde durch näheren Vergleich der biophysikalischen Charakteristika von Chloridstromen aus Zellen unter hypoosmotischen Bedingungen (die in allen bislang untersuchten Zelltypen praktisch gleich sind) mit jenen erhalten aus ICln Überexpression in Xenopus oocyten einige deutliche Unterschiede sichtbar. Weiters zeigten Immunofluorenszenzexperimente unter normalen Bedingungen eine primare zytoplasmatische Lokalisation des Proteins an, das erst durch hypoosmotische Induktion in oder nahe zur Plasmamembran translokalisier wird. Diese Ergebnisse ließen einige Zweifel an einer porenbildenden Kanalfunktion von ICln aufkommen und viele Forschern ordneten dem Protein in diesem Zusammenhang daraufhin eine rein regulatorische Rolle zu. Nichtsdestoweniger ist die Identifizierung oder der Ausschluß potentieller chloridkanalbildender Kanditaten enorm wichtig, da physiologische Veranderungen in der Chloridepermeabilitat die Grundlage vieler schwerer Erkrankungen, wie der Osteopetrosis, der Dent'sche Krankheit oder des Bartter Syndroms sind. Zur diesem Zweck wurde die tertiäre Struktur von ICln in Lösung bestimmt. Dabei zeigte sich das der N-terminale Teil des Proteins in eine Pleckstrin Homologiedoman-analoge Struktur faltet (ein Strukturmotif das bereits in vielen signaltranduktionsregulatorischen Protein identifiziert wurde), wohingegen der C-terminale Abschnitt intrinisch unfaltet ist mit einigen wenigen Sequenzbereichen mit schwach ausgepragter Sekundarstrukturpreferenz. Des weiteren konnten Interaktionen mit dem membrannahen cytoplasmatischen Teil des Blutplatchen alpha2beta-Integrinprotein und mit dem Faktor LSm4 (einem funktionellen Protein in der snRNP Biogenese) nachgewiesen werden. Eine weitere manuelle Strukturanalyse befaßte sich mit der Bestimmung der Lösungskonformation von Cyclophilin D, einem Mitglied der Immunophilin Familie, das an den mitochondrialen Permeabilitatsporenapparat bindet, und ein interessantes Zielprotein bei der Behandlung von neurodegenerativen Erkrannkungen darstellt. Nebenbei wurde eine bereits publizierte NMR-Struktur der LIM1 Domane aus CRP2 verfeinert. Weitere NMR Analysen beschäftigten sich mit den intrinsisch ungefaltenen Proteinen BASP1 and Osteopontin (OPN), beide sehr vielversprechende Zielproteine für die Krebsforschung. In Anlehnung zur Bewaltigung des enormen Aufwands eines structural genomic Projekts wurde im zweitem Teil dieser Arbeit eine einfache sogenannte direkte Methode zur raschen Strukturcharakterisierung in dieser Arbeit entwickelt und anhand experimenteller Daten getestet. Zuletzt wurde das Leistungsvermogen eines von unserem Gruppenleiter verfaßtem Programm für die automatische Vorhersage der Ligandbindungstelle anhand verschiedener Protein-Ligand Komplexe aus der Datenbank evaluiert