Proceedings of the Third International Mobile Satellite Conference (IMSC 1993)

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial cellular communications services. While the first and second International Mobile Satellite Conferences (IMSC) mostly concentrated on technical advances, this Third IMSC also focuses on the increasing worldwide commercial activities in Mobile Satellite Services. Because of the large service areas provided by such systems, it is important to consider political and regulatory issues in addition to technical and user requirements issues. Topics covered include: the direct broadcast of audio programming from satellites; spacecraft technology; regulatory and policy considerations; advanced system concepts and analysis; propagation; and user requirements and applications

RADGIS - an improved architecture for runtime-extensible, distributed GIS applications

A number of GIS architectures and technologies have emerged recently to facilitate the visualisation and processing of geospatial data over the Web. The work presented in this dissertation builds on these efforts and undertakes to overcome some of the major problems with traditional GIS client architectures, including application bloat, lack of customisability, and lack of interoperability between GIS products. In this dissertation we describe how a new client-side GIS architecture was developed and implemented as a proof-of-concept application called RADGIS, which is based on open standards and emerging distributed component-based software paradigms. RADGIS reflects the current trend in development focus from Web browser-based applications to customised clients, based on open standards, that make use of distributed Web services. While much attention has been paid to exposing data on the Web, there is growing momentum towards providing “value-added” services. A good example of this is the tremendous industry interest in the provision of location-based services, which has been discussed as a special use-case of our RADGIS architecture. Thus, in the near future client applications will not simply be used to access data transparently, but will also become facilitators for the location-transparent invocation of local and remote services. This flexible architecture will ensure that data can be stored and processed independently of the location of the client that wishes to view or interact with it. Our RADGIS application enables content developers and end-users to create and/or customise GIS applications dynamically at runtime through the incorporation of GIS services. This ensures that the client application has the flexibility to withstand changing levels of expertise or user requirements. These GIS services are implemented as components that execute locally on the client machine, or as remote CORBA Objects or EJBs. Assembly and deployment of these components is achieved using a specialised XML descriptor. This XML descriptor is written using a markup language that we developed specifically for this purpose, called DGCML, which contains deployment information, as well as a GUI specification and links to an XML-based help system that can be merged with the RADGIS client application’s existing help system. Thus, no additional requirements are imposed on object developers by the RADGIS architecture, i.e. there is no need to rewrite existing objects since DGCML acts as a runtime-customisable wrapper, allowing existing objects to be utilised by RADGIS. While the focus of this thesis has been on overcoming the above-mentioned problems with traditional GIS applications, the work described here can also be applied in a much broader context, especially in the development of highly customisable client applications that are able to integrate Web services at runtime

Proceedings of the Fifth International Mobile Satellite Conference 1997

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial communications services. While previous International Mobile Satellite Conferences have concentrated on technical advances and the increasing worldwide commercial activities, this conference focuses on the next generation of mobile satellite services. The approximately 80 papers included here cover sessions in the following areas: networking and protocols; code division multiple access technologies; demand, economics and technology issues; current and planned systems; propagation; terminal technology; modulation and coding advances; spacecraft technology; advanced systems; and applications and experiments

Systematic Design of Multiport Antennas for MIMO-enabled Mobile Wireless Terminals

Mobile wireless communication systems have undergone a tremendous development in the past decade. One of the major advancements is the widespread use of MIMO transmission schemes beginning with the introduction of the 3rd Generation Partnership Project (3GPP) standard LTE and being extended in LTE Advanced. So as to support MIMO transmission schemes mobile terminals must be equipped with multiport antenna systems. The term refers to an arrangement of two or more antenna elements operating in the same frequency range and mounted on the same mobile wireless platform. Reduced volume per antenna element and strong interaction between all antenna elements are major design challenges and require for new systematic design approaches beyond classical single antenna design. The ongoing miniaturization of mobile terminals, the extension of the mobile spectrum and in particular the opening of new mobile communication bands at the lower end of the spectrum exacerbate these challenges. Design and characterization of multiport antennas have therefore become subject of high interest and of numerous research projects in both academia and industry. This dissertation contributes to the development of systematic design procedures for multiport antennas with emphasis on accounting for the restrictions and side conditions which apply when designing multiport antennas for actual consumer equipment. The dissertation has developed along an industry funded research project, with a focus on electrically small devices where antenna design is constantly faced with fundamental physical limits. Chapter 1 gives an overview of the state of the art in antenna characterization and design techniques applicable to multiport antennas for MIMO. Chapter 2 introduces into the analysis of multiport antennas in terms of their radiation modes. Modal analysis, based on spectrum of the radiation matrix, allows for unambiguous characterization of a multiport antenna by means of invariant properties. Modal descriptive quantities are defined which are basic to the design approach followed in this dissertation. Analyzing a multiport antenna with respect to its radiation modes is possible only after a design concept has been conceived. More fundamental from a design point of view is the question for the space of feasible radiation modes and their realization under the constraint of a given chassis form factor. Chapter 3 addresses this question based on the theory of characteristic modes for conducting bodies. The relevant properties of characteristic modes on the chassis of mobile terminals are reviewed. The excitation of characteristic modes by means of capacitive and inductive coupling elements is investigated in detail. Finally, a systematic design approach for multiport antennas is presented in which the antenna’s radiation modes are constructively derived from the usable characteristic chassis modes. Chapter 4 deals with design of matching networks for N-port antennas. Starting from the general expression for the scattering matrix of an ideal 2N-port matching network different topologies and alternative implementations are discussed. As a solution of particular interest in cases where some radiation modes feature insufficient bandwidths, special attention is given to systematic design of MDN which maps radiation modes to external ports of the antenna system. Chapter 5 focuses on the particular problems encountered in the design of antenna systems for extremely small mobile wireless terminals. After a review of applicable fundamental limits bandwidth estimation and approaches to maintain a decent total efficiency are discussed. The combination of electrical switching in the antenna structure with electrical tuning in an external matching network is suggested in this context. The DL-MIMO concept is introduced as a system level measure to cope with insufficient bandwidth. The different aspects are exemplified with the design of a 2-port MIMO antenna for a USB dongle. Chapter 6 describes in detail design, fabrication and measurement of four antenna prototypes. The validity of the design approach described in the previous chapters is confirmed. In conclusion, a systematic design approach, which combines the theory of characteristic chassis modes for conducting bodies with modal analysis of a multiport antenna, i.e. considers the spectrum of its radiation matrix is presented. The approach is successfully applied to a number of practically relevant design problems. The design technique permits identification of near optimum antenna solutions which approach the fundamental limits of attainable bandwidth and total efficiency.Systematischen Entwurf von Multiport-Antennen für MIMO-fähigen Mobilfunkendgeräte Die Mobilkommunikation hat in den letzten Jahren eine enorme Entwicklung durchlaufen. Eine der wesentlichen technischen Weiterentwicklungen ist der Übergang zu MIMO Übertragungsverfahren, in großem Maßstab beginnend mit der Einführung des 3GPP Standards LTE und in grÖßerem Umfang noch im zukünftigen LTE-Advanced. Mobile Endgeräte müssen dazu mit Mehrtorantennen ausgestattet sein. Der Begriff Mehrtorantenne bezeichnet eine Anordnung von zwei oder mehr Antennenelementen, die im gleichen Fequenzbereich betrieben werden und auf einer gemeinsamen Plattform angeordnet sind. Die Verringerung des je Antennenelement zur Verfügung stehenden Volumens und die starke Kopplung zwischen den Antennenelementen führen auf neue Herausforderungen für den Entwurf. Neue, systematische Entwurfsmethoden jenseits der klassischen Methoden für den Entwurf von Einzelantennen sind gefordert. Die fortschreitende Miniaturisierung mobiler Endgeräte, die Erweiterung des für den Mobilfunk genutzten Spektrums und insbesondere die Öffnung neuer Bander am unteren Ende des Spektrums für den Mobilfunk verschärfen die Anforderung an die Entwurfsmethodik. Entwurf und Charakterisierung von Mehrtorantennen sind deswegen heute Themen von großem Interesse und Gegenstand zahlreicher industrieller und akademischer Forschungsprojekte. Die vorliegende Dissertation liefert einen Beitrag zur Entwicklung systematischer Entwurfsverfahren für Mehrtorantennen unter besonderer Berücksichtigung der Einschränkungen und Randbedingungen die beim Entwurf von kommerziellen Endgeräten vorliegen. Zahlreiche Fragestellungen ergaben sich aus einem vom Verfasser bearbeiteten industriellen Forschungs- und Entwicklungsprojekt mit Schwerpunkt auf elektrisch kleinen Endgeräten, bei denen der Entwurf stets mit fundamentalen physikalischen Schranken konfrontiert ist. Kapitel 1 gibt einen Überblick über den Stand der Technik auf dem Gebiet des Entwurfs und der Charakterisierung von Mehrtorantennen für MIMO Anwendungen. Kapitel 2 führt in die Analyse von Mehrtorantennen mit Hilfe ihrer Strahlungsmoden ein. Die modale Betrachtung auf Grundlage des Spektrums der Strahlungsmatrix gestattet es, Mehtorantennen mit Hilfe ihrer invarianten Eigenschaften eindeutig zu charakterisieren. Es werden die modalen Beschreibungsgrössen definiert auf denen der in dieser Arbeit verfolgte Entwurfsansatz basiert. Die Strahlungsmoden einer Mehtorantenne können jedoch erst betrachtet werden, wenn ein Entwurf bereits vorliegt. Die vom Standpunkt der Entwurfsmethodik wichtigere Frage ist die nach Raum der unter den Einschränkungen eines gegebenen Geräte-Formfaktors realisierbaren Strahlungsmoden. Sie wird in Kapitel 3 auf Grundlage der Theorie Charakteristischer Moden leitender Körper behandelt. Die relevanten Eigenschaften charakteristischer Moden auf dem Gehäuse elektrisch kleiner mobiler Endgeräte werden betrachtet. Die Anregung charakteristischer Moden mit Hilfe von kapazitiven und induktiven Koppelelementen wird ausführlich untersucht. Abschließend wird ein Entwurfsansatz für Mehtorantennen beschrieben, in welchem die Strahlungsmoden der Antenne konstruktiv aus den nutzbaren charakteristischen Moden des Gehäuses abgeleitet werden. In Kapitel 4 werden Anpassnetzwerke für N-Tor Antennen behandelt. Ausgehend von der allgemeinen Formulierung für die Streumatrix des benötigten 2N-Tor Netzwerkes werden verschiedene Topologien und Realisierungsalternativen diskutiert. Gesondert betrachtet werden noch einmal MDNs, welche die Strahlungsmoden einer Mehtorantenne unmittelbar auf die Speisetore abbilden, da sie in Falle unzureichender modaler Bandbreiten, von besonderem Interesse sind. Kapitel 5 fokussiert auf die besonderen Probleme bei beim Entwurf extrem kleiner Antennensysteme. Nach Betrachtung in die maßgeblichen physikalischen Beschränkungen werden die Abschätzung erreichbarer Bandbreiten und Maßnahmen zur Sicherstellung eines akzeptablen Wirkungsgrades diskutiert. Vorgeschlagen wird in diesem Zusammenhang die Kombination von elektrisch rekonfigurierbaren Antennenstrukturen mit elektrisch abstimmbaren Anpass-Netzwerken. Die verschiedenen Aspekte werden am Beispiel des Entwurfs eines 2-Tor MIMO Antennensystems für einen USB Dongle erläutert. pKapitel 6 beschreibt im Detail den Entwurf, die Herstellung und die messtechnische Charakterisierung vier unterschiedlicher Prototypen von Mehrtorantennen. Anhand der Beispiele wird der in den vorherigen Kapiteln entwickelte Entwurfsansatz validiert. Insgesamt wird mit dieser Arbeit ein systematischer Entwurfsansatz vorgeschlagen, der auf der Kombination der Theorie charakteristische Moden leitender Körper mit der modalen Analyse von Mehrtorantennen, d.h. der Betrachtung des Spektrums der Strahlungsmatrix aufbaut. Der Ansatz wird erfolgreich auf eine Reihe praktisch relevanter Entwurfsaufgaben angewandt. Er führt auf ein systematisches Entwurfsverfahren, das es gestattet, Lösungen in der Nähe der physikalischen Grenzen für die erreichbare Bandbreite und den Wirkungsgrad aufzufinden

Future of the Internet--and how to stop it

vi, 342 p. : ill. ; 25 cmLibro ElectrónicoOn January 9, 2007, Steve Jobs introduced the iPhone to an eager audience crammed into San Francisco’s Moscone Center.1 A beautiful and brilliantly engineered device, the iPhone blended three products into one: an iPod, with the highest-quality screen Apple had ever produced; a phone, with cleverly integrated functionality, such as voicemail that came wrapped as separately accessible messages; and a device to access the Internet, with a smart and elegant browser, and with built-in map, weather, stock, and e-mail capabilities. It was a technical and design triumph for Jobs, bringing the company into a market with an extraordinary potential for growth, and pushing the industry to a new level of competition in ways to connect us to each other and to the Web.Includes bibliographical references (p. 249-328) and index Acceso restringido a miembros del Consorcio de Bibliotecas Universitarias de Andalucía Electronic reproduction. Palo Alto, Calif. : ebrary, 2009 Modo de acceso : World Wide Webpt. 1. The rise and stall of the generative Net -- Battle of the boxes -- Battle of the networks -- Cybersecurity and the generative dilemma -- pt. 2. After the stall -- The generative pattern -- Tethered appliances, software as service, and perfect enforcement -- The lessons of Wikipedia -- pt. 3. Solutions -- Stopping the future of the Internet : stability on a generative Net -- Strategies for a generative future -- Meeting the risks of generativity : Privacy 2.0. Index32

Modelling of reliable service based operations support system (MORSBOSS)

Philosophiae Doctor - PhDThe underlying theme of this thesis is identification, classification, detection and prediction of cellular network faults using state of the art technologies, methods and algorithms

A Network of One’s Own: Struggles to Domesticate the Internet

This thesis is a design research practice-led inquiry into the domesticated Internet. It first seeks to complicate simplistic corporate and academic visions by naming some of the struggles it encounters – not least to assert a private home and network of one's own. It is argued that a century of domestic technologies has emphasised invisibility, ubiquity, and automation in ways that obscure a network of exploited people and finite resources. Furthermore, these technological ambitions are met through machine surveillance, in ways newly enabled by the domesticated Internet, that threaten the privacy of the home. In response, this thesis seeks some practical ways to design alternatives that assert a network of one's own and makes the work it implicates visible. The methodological approach is broadly Research Through Design supplemented by a practice described as designerly hacking through which hidden technical potential is revealed and given meaning. Two empirical studies are described that together make an account of the technical possibility and social reality of the networked home: an autobiographical technical exploration of the author's home and network with the making of hacks and Research Products privately and in public; and a cultural probe engagement with six rented households surfacing contemporary accounts of the domesticated Internet and in particular the challenges and opportunities of wireless networking. Together this yields a series of technical and social insights for design and two forms are offered to communicate these: a framework for understanding change in the networked home (The Stuff of Home) and a set of 30 design patterns for a network of one's own; each invites different analyses. The conclusion then draws together the multiple threads developed through this thesis and offers some reflection on the complexity of doing contemporary technical design work

Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression