47 research outputs found

    Convergence-analysis of the internet and the telecommunication architectures

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    The convergence of the Internet and Telecommunication Architectures is a key issue in today’s telecommunication world. It is foreseen that future versions of UMTS will be all-IP based, and therefore the interest in this area is increasing. The focus in this paper is to show how to access IN-services from the Internet and other IP-based networks. Previous research of the interworking between PSTN and IP-networks will be discussed. The respective advantages of different architectures are presented and some solutions of building a bridge between the protocols used in these networks are described. Further, this paper presents some of the performance problems that may occur in such systems

    Investigation of an intelligent personalised service recommendation system in an IMS based cellular mobile network

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    Success or failure of future information and communication services in general and mobile communications in particular is greatly dependent on the level of personalisations they can offer. While the provision of anytime, anywhere, anyhow services has been the focus of wireless telecommunications in recent years, personalisation however has gained more and more attention as the unique selling point of mobile devices. Smart phones should be intelligent enough to match user’s unique needs and preferences to provide a truly personalised service tailored for the individual user. In the first part of this thesis, the importance and role of personalisation in future mobile networks is studied. This is followed, by an agent based futuristic user scenario that addresses the provision of rich data services independent of location. Scenario analysis identifies the requirements and challenges to be solved for the realisation of a personalised service. An architecture based on IP Multimedia Subsystem is proposed for mobility and to provide service continuity whilst roaming between two different access standards. Another aspect of personalisation, which is user preference modelling, is investigated in the context of service selection in a multi 3rd party service provider environment. A model is proposed for the automatic acquisition of user preferences to assist in service selection decision-making. User preferences are modelled based on a two-level Bayesian Metanetwork. Personal agents incorporating the proposed model provide answers to preference related queries such as cost, QoS and service provider reputation. This allows users to have their preferences considered automatically

    Network sharing through service outsourcing in inter-domain IMS frameworks

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    Includes abstract.Includes bibliographical references (leaves 161-167).Resource sharing can be used as a short-term solution to the imbalance between the supply and demand of network resources. Resources sharing enables operators to provide services to their subscribers using networks belonging to other operators. Resource sharing in mobile networks is increasingly becoming an option for operators to provide service to their subscribers. In this thesis we explore a mechanism for sharing access network resources that utilises negotiable short-term Service Level Agreements (SLA) that can easily adapt to changing network conditions. Through this mechanism operators of resource constrained networks may use near real time dynamic SLAs to negotiate network access services for their subscribers. We refer to this form of resource sharing as 'Service Outsourcing'

    OSA/PARLAY on a SIP network

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    I-centric User Interaction

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    Die Vision I-centric Communications bedeutet, einen uneingeschränkten Blick auf das menschliche Kommunikationsverhalten zu werfen, um Kommunikationssysteme entsprechend daran angepasst zu entwickeln. Diese Vision definiert einen benutzerorientierten Ansatz zur Erstellung von Diensten und Anwendungen. Dies setzt zunächst eine Analyse der Benutzeranforderungen voraus, um geeignete Systeme und Dienste zu entwerfen. Anstatt Technologie-fokussierte Lösungen ohne jegliche Anpassung an die jeweiligen Personen anzubieten, sollte ein I-centric System seine Dienste ohne sichtbare technische Details und unter Berücksichtigung von Benutzerpräferenzen sowie der Benutzerumgebung darbieten. Der Vision von I-centric Communications folgend, stellt die vorliegende Arbeit einen Ansatz zur Realisierung der Idee von I-centric User Interaction vor. Dieser Ansatz erweitert und vervollständigt die Vision durch verbesserte Benutzerinteraktionsfähigkeiten. Diese Dissertation zeigt, dass es möglich ist, Kommunikationssysteme zu realisieren, die die Interaktion zwischen Benutzern und Diensten ohne Einschränkung auf bestimmte Technologien für Benutzerschnittstellen sowie in personalisierter und umgebungsberücksichtigende Art und Weise unterstützen. Derartig verbesserte Benutzerinteraktion wird die Akzeptanz und die Benutzung von Diensten erhöhen. Einerseits soll die Benutzerinteraktion verschiedene Arten von Technologien für Benutzerschnittstellen unterstützen, durch die die Geräte-Unabhängigkeit und der ständige Zugang zu den Diensten ermöglicht werden. Entsprechend dem aktuellem Kontext und der Absicht können die Benutzer die bevorzugte und geeignete Art der Interaktion wählen. Andererseits soll die Interaktion selbst den Benutzerpräferenzen sowie der jeweiligen Umgebung angepasst werden. Dementsprechend diskutiert die vorliegende Arbeit diese unterschiedlichen Problembereiche, identifiziert die notwendigen Funktionen und bietet entsprechende Lösungsansätze jeweils. Die Arbeit präsentiert und analysiert zunächst die Vision I-centric Communications mit Hinblick auf den Aspekt der Benutzerinteraktion. Basierend auf den identifizierten Anforderungen wurde ein Ansatz zur Realisierung von I-centric User Interaction entwickelt. Dieser Ansatz, der in dieser Arbeit vorgestellt wird, spezifiziert ein Service Adaptation Framework und einzelne Modelle für Generische Benutzerinteraktion , für Personalisierung sowie für Ambient Awareness , die sich jeweils auf die identifizierten Problembereiche konzentrieren. Abschließend präsentiert die vorliegende Arbeit Ergebnisse einer prototypischen Realisierung des dargelegten Ansatzes. Die Ergebnisse demonstrieren die Einsetzbarkeit der entwickelten Konzepte und die Erfüllung der Vision von I-centric User Interaction . Die Forschungsarbeit im Bereich I-centric Communications wurde in Kooperation zwischen dem Lehrstuhl für Offene Kommunikationssysteme (OKS) der Technischen Universität Berlin (TUB) und dem Fraunhofer Institut FOKUS durchgeführt. Die Vision sowie das Referenzmodell für I-centric Communications , die in der vorliegenden Arbeit vorgestellt werden, sind Ergebnisse dieser Kooperation. Die Forschungsschwerpunkte der Kooperation zwischen TUB und FOKUS waren das Generelle Modell für I-centric Dienste , die Dienstplattform für I-centric Dienste sowie ein Ansatz zur Interaktion zwischen Nutzern und I-centric Dienste . Die vorliegende Arbeit konzentriert sich auf den Ansatz I-centric User Interaction , der die Interaktion zwischen Nutzern und den Diensten betrachtet. Die Aspekte der I-centric Dienste werden in der vorliegenden Arbeit nicht betrachtet. Diese Aspekte wurden in einer zweiten Dissertation von Stefan Arbanowski, Fraunhofer FOKUS, analysiert und ausgearbeitet. Die Ergebnisse dieser Arbeit wurden in verschiedenen nationalen und internationalen Forschungsprojekten (BMBF LiveFutura, BMBF PI-AVIda, BMBF VHE-UD, IST WSI, IST WWRI), Standardisierungsgremien (OMG, WWRF), Konferenzpapieren sowie Zeitschriften eingebracht, um die Vision von I-centric Communications einem größeren Auditorium vorzustellen.The vision of I-centric Communications means to take an unlimited look at human communication behavior and to adapt the activities of communication systems to it. This vision defines a user-centered approach for the realization of services and applications. It requires to start analyzing user demands to design suitable systems and services. Instead of just providing technology-focused solutions without any adaptation to individuals, an I-centric system should provide services hiding technical details and considering the individual s preferences as well as the individual s environment. Following the vision of I-centric Communications, this thesis introduces an approach to realize I-centric User Interaction. This approach enhances and completes the vision by providing advanced user interaction capabilities. It answers the question whether it is possible to realize a communication system, which allows the interaction between user and services without any restriction to specific user interface technologies and in a personalized as well as ambient aware manner. Such enhanced user interaction will lead to a higher acceptance and increased usage of services. On the one hand, the user interaction shall support different kinds of user interface technologies enabling Device Independence and ubiquitous access to the services. According to their current context and intended action, users can select the preferred and suitable way of interaction. On the other hand, the user interaction shall be adapted to the user s preferences and to the user s environment. Accordingly, this work discusses these different areas of concern, identifies necessary functions, and provides suitable solutions for each. First, the thesis introduces and analyses the vision of I-centric Communications with special regard to the aspect of user interaction. Based on the identified requirements and areas of concern, an approach to realize I-centric User Interaction was developed. The approach, presented in this thesis, specifies a Service Adaptation Framework and individual models for Personalization, for Ambient Awareness, and for Generic User Interaction focusing on the respective areas of concern. Finally, the thesis illustrates the results from the prototypical implementation of the presented approach, which has been pursued in several projects in parallel. These results demonstrate the applicability of the developed concepts and the fulfillment of the vision of I-centric User Interaction. The work in the area of I-centric Communications was carried out in cooperation of the Department for Open Communication Systems (OKS) at the Technical University Berlin (TUB) and the Fraunhofer Institute FOKUS. The vision and the reference model for I-centric Communications, introduced in this thesis, are results of this cooperation. The main research directions for the cooperation between TUB and FOKUS have been a general model for I-centric services, the service platform for I-centric services, and an approach for the interaction of users with I-centric services. This thesis focuses on an approach for I-centric User Interaction. The general aspects of I-centric services as defined by the vision are out of scope of this thesis. Nevertheless, these aspects have been analyzed by Stefan Arbanowski, researcher at Fraunhofer FOKUS, in a second PhD thesis in parallel. The results of this work have been contributed to different national and international projects (BMBF LiveFutura, BMBF PI-AVIda, BMBF VHE-UD, IST WSI, IST WWRI), standardization bodies (OMG, WWRF), conferences papers, and journals by introducing the vision of I-centric Communications to a larger auditorium, and by exploiting parts of the developed I-centric systems

    IEEE 802.21 in heterogeneous handover environments

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    Mestrado em Engenharia de Computadores e TelemáticaO desenvolvimento das capacidades tecnológicas dos terminais móveis, e das infra-estruturas que os suportam, potenciam novos cenários onde estes dispositivos munidos com interfaces de diferentes tecnologias vagueiam entre diferentes ambientes de conectividade. É assim necessário providenciar meios que facilitem a gestão de mobilidade, permitindo ao terminal ligar-se da melhor forma (i.e., optando pela melhor tecnologia) em qualquer altura. A norma IEEE 802.21 está a ser desenvolvida pelo Institute of Electrical and Electronics Engineers (IEEE) com o intuito de providenciar mecanismos e serviços que facilitem e optimizem handovers de forma independente da tecnologia. A norma 802.21 especifica assim um conjunto de mecanismos que potenciarão cenários como o descrito acima, tendo em conta a motivação e requerimentos apresentados por arquitecturas de redes futuras, como as redes de quarta geração (4G). Esta dissertação apresenta uma análise extensiva da norma IEEE 802.21, introduzindo um conjunto de simulações desenvolvidas para estudar o impacto da utilização de mecanismos 802.21 em handovers controlados por rede, numa rede de acesso mista composta por tecnologias 802.11 e 3G. Os resultados obtidos permitiram verificar a aplicabilidade destes conceitos a ambientes de próxima geração, motivando também uma descrição do desenho de integração de mecanismos 802.21 a arquitecturas de redes de quarta geração. ABSTRACT: The development of the technological capabilities of mobile terminals, and the infra-structures that support them, enable new scenarios where these devices using different technology interfaces roam in different connectivity environments. This creates a need for providing the means that facilitate mobility management, allowing the terminal to connect in the best way possible (i.e., by choosing the best technology) at any time. The IEEE 802.21 standard is being developed by the Institute of Electrical and Electronics Engineers (IEEE) to provide mechanisms and services supporting Media Independent Handovers. The 802.21 standard specifies a set of mechanisms that enable scenarios like the one described above, considering the motivation and requirements presented by future network architectures, such as the ones from fourth generation networks (4G). This thesis presents an extensive analysis of the IEEE 802.21 standard, introducing a set of simulations developed for studying the impact of using 802.21 mechanisms in network controlled handovers, in a mixed access network composed of 802.11 and 3G technologies. The obtained results allow the verification of the applicability of these concepts into next generation environments, also motivating the description of the design for integration of 802.21 mechanisms to fourth generation networks

    Cooperative & cost-effective network selection: a novel approach to support location-dependent & context-aware service migration in VANETs

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    Vehicular networking has gained considerable interest within the research community and industry. This class of mobile ad hoc network expects to play a vital role in the design and deployment of intelligent transportation systems. The research community expects to launch several innovative applications over Vehicular Ad hoc Networks (VANETs). The automotive industry is supporting the notion of pervasive connectivity by agreeing to equip vehicles with devices required for vehicular ad hoc networking. Equipped with these devices, mobile nodes in VANETs are capable of hosting many types of applications as services for other nodes in the network. These applications or services are classified as safety-critical (failure or unavailability of which may lead to a life threat) and non-safety-critical (failure of which do not lead to a life threat). Safety-critical and non-safety-critical applications need to be supported concurrently within VANETs. This research covers non-safety-critical applications since the research community has overlooked this class of applications. More specifically, this research focuses on VANETs services that are location-dependent. Due to high speed mobility, VANETs are prone to intermittent network connectivity. It is therefore envisioned that location-dependence and intermittent network connectivity are the two major challenges for VANETs to host and operate non-safety-critical VANETs services. The challenges are further exacerbated when the area where the services are to be deployed is unplanned i.e. lacks communication infrastructure and planning. Unplanned areas show irregular vehicular traffic on the road. Either network traffic flows produced by irregular vehicular traffic may lead to VANETs communication channel congestion, or it may leave the communication channel under-utilized. In both cases, this leads to communication bottlenecks within VANETs. This dissertation investigates the shortcomings of location-dependence, intermittent network connectivity and irregular network traffic flows and addresses them by exploiting location-dependent service migration over an integrated network in an efficient and cost-effective manner
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