An intelligent radio access network selection and optimisation system in heterogeneous communication environments

PhDThe overlapping of the different wireless network technologies creates heterogeneous communication environments. Future mobile communication system considers the technological and operational services of heterogeneous communication environments. Based on its packet switched core, the access to future mobile communication system will not be restricted to the mobile cellular networks but may be via other wireless or even wired technologies. Such universal access can enable service convergence, joint resource management, and adaptive quality of service. However, in order to realise the universal access, there are still many pending challenges to solve. One of them is the selection of the most appropriate radio access network. Previous work on the network selection has concentrated on serving the requesting user, but the existing users and the consumption of the network resources were not the main focus. Such network selection decision might only be able to benefit a limited number of users while the satisfaction levels of some users are compromised, and the network resources might be consumed in an ineffective way. Solutions are needed to handle the radio access network selection in a manner that both of the satisfaction levels of all users and the network resource consumption are considered. This thesis proposes an intelligent radio access network selection and optimisation system. The work in this thesis includes the proposal of an architecture for the radio access network selection and optimisation system and the creation of novel adaptive algorithms that are employed by the network selection system. The proposed algorithms solve the limitations of previous work and adaptively optimise network resource consumption and implement different policies to cope with different scenarios, network conditions, and aims of operators. Furthermore, this thesis also presents novel network resource availability evaluation models. The proposed models study the physical principles of the considered radio access network and avoid employing assumptions which are too stringent abstractions of real network scenarios. They enable the implementation of call level simulations for the comparison and evaluation of the performance of the network selection and optimisation algorithms

MediaSync: Handbook on Multimedia Synchronization

This book provides an approachable overview of the most recent advances in the fascinating field of media synchronization (mediasync), gathering contributions from the most representative and influential experts. Understanding the challenges of this field in the current multi-sensory, multi-device, and multi-protocol world is not an easy task. The book revisits the foundations of mediasync, including theoretical frameworks and models, highlights ongoing research efforts, like hybrid broadband broadcast (HBB) delivery and users' perception modeling (i.e., Quality of Experience or QoE), and paves the way for the future (e.g., towards the deployment of multi-sensory and ultra-realistic experiences). Although many advances around mediasync have been devised and deployed, this area of research is getting renewed attention to overcome remaining challenges in the next-generation (heterogeneous and ubiquitous) media ecosystem. Given the significant advances in this research area, its current relevance and the multiple disciplines it involves, the availability of a reference book on mediasync becomes necessary. This book fills the gap in this context. In particular, it addresses key aspects and reviews the most relevant contributions within the mediasync research space, from different perspectives. Mediasync: Handbook on Multimedia Synchronization is the perfect companion for scholars and practitioners that want to acquire strong knowledge about this research area, and also approach the challenges behind ensuring the best mediated experiences, by providing the adequate synchronization between the media elements that constitute these experiences

Multimedia player implementation on embedded systems

Thesis (Master)--Izmir Institute of Technology, Electronics and Communication Engineering, Izmir, 2008Includes bibliographical references (leaves: 85-88)Text in English; Abstract: Turkish and Englishxi, 90 leavesThere has been a surge in the number of digital audio and video content in recent years. Advances in the compression and storage technologies and improvements in the speed of internet connection have enabled widespread use of multimedia content. A wide variety of devices have been introduced to decode and play these media contents.Initially designed as a mere voice communication device, the mobile phones nowadays come equipped with a variety of multimedia capabilities including media players despite their limited system resources.Nowadays, huge servers host dramatically increased audio and video contents Users prefer to watch these contents while streaming rather than downloading them first. So, streaming media players are responsible to present multimedia contents without annoying interrupts.This thesis firstly introduces challenges in design and implementation of a streaming media player and then proposes solutions. Main challenges are keeping audio-video synchronization and server-client synchronization and detecting stream type, handling of multithreaded operations and buffer management. Audio-video synchronization problem is solved by using audio as master stream. Server-client synchronization problem is solved by designing a playback mechanism that keeps synchronization with the server by tuning the playback rate of a streaming media without losing lip-sync between audio and video. The proposed streaming player also has a feature of identifying the type of a media stream very rapidly without using a discrete stream inspector module. The presented design is heavily multithreaded which is implemented on Linux platform, moreover it is also convenient for and implementable on any multithreaded platform

Authoring objektbasierter AV-Anwendungen

This thesis is focused on the authoring process of object-based AV applications according to the object and scene concept of MPEG-4. The object-based approach embraces the extended interactive opportunities of multimedia applications as well as the distribution opportunities of audiovisual media. Producing of object-based AV applications has profound effects on the whole digital media chain. The existence of efficient authoring tools and systems is an important requirement for the success of such applications. The goal of this work was the development of concepts and components for an authoring system for object-based AV applications that supports collaborative work of several authors. The development was divided into three fields: authoring formats, authoring servers, and authoring tools. Authoring formats store all of the resulting information for the description of object-based AV applications during the authoring process. They describe a scene on a well adapted abstraction level and enable the exchange of scene data with other authors and systems. Some special authoring formats were developed which fulfill the requirements of concrete applications regarding abstraction level and function range. Authoring tools are the interfaces of the authoring system to the authors. In focus are interactive graphic tools for the support of an intuitive work during the authoring process. The authoring server is the technical basis for the collaborative work of several authors in the production of object-based AV applications. A flexible data management was developed on the basis of a native XML database. It controls the access at the level of nodes within the scene graph and enables the collaboration of many authors in a novel way. The authoring server is also the interface between the producers of media objects and the authors. Furthermore, it enables the reusability of scenes and elements in different projects. The developed concepts are oriented towards the possibilities of MPEG-4, but they are transferable to other multimedia applications which are based on a scene graph. With these concepts and components both can be realized, universally applicable as well as specialized authoring systems and tools. Several exemplary applications show the operability of the developed components.Die vorliegende Dissertation beschäftigt sich mit dem Authoring-Prozess objektbasierter AV-Anwendungen auf Basis des Objekt- und Szenenkonzeptes von MPEG-4. Diese moderne Beschreibungsform vereint die interaktiven Nutzungsmöglichkeiten digitaler Medien mit den Distributionsmöglichkeiten audiovisueller Medien. Die Umsetzung des Objekt- und Szenenkonzeptes hat tief greifende Auswirkungen auf die gesamte digitale Medienkette. Die Schaffung leistungsfähiger Autorensysteme ist eine wichtige Voraussetzung für die Verbreitung solcher Anwendungen. Das Ziel der Arbeit war die Entwicklung von Konzepten und Komponenten für ein Autorensystem mit Unterstützung eines auf mehrere Autoren verteilten Authoring-Prozesses. Authoring-Formate speichern alle anfallenden Informationen zur Beschreibung einer objektbasierten AV-Anwendung. Es wurden Authoring-Formate entwickelt, welche an die Anforderungen konkreter Anwendungen hinsichtlich Abstraktionsebene und Funktionsumfang angepasst sind. Autorenwerkzeuge sind die Schnittstellen des Autorensystems zu den Autoren. Im Fokus stehen grafisch-interaktive Werkzeuge zur Unterstützung eines intuitiven Arbeitens während des Authoring-Prozesses. Der Authoring-Server ist die technische Grundlage des Autorensystems für die verteilte Erstellung objektbasierter AV-Anwendungen. Er verwaltet alle anfallenden Daten und stellt diese den Autoren unter Berücksichtigung ihrer individuellen Berechtigungen zur Verfügung. Der Authoring-Server bildet die Schnittstelle zwischen den Produzenten der Medienobjekte und den Autoren. Er ermöglicht eine Wiederverwendung von Szenen und Szenenelementen über Produktionsgrenzen hinweg. Der Authoring-Server erlaubt es Autoren und auch Medienproduzenten, gemeinsam an der Erstellung einer AV-Anwendung zu arbeiten. Dafür wurde ein flexibles Datenmanagement auf Basis einer XML-Datenbank entworfen. Die entwickelten Konzepte orientieren sich an den Möglichkeiten von MPEG-4, sind aber auch auf andere multimediale Anwendungen übertragbar, die auf einem Szenengraphen beruhen. Auf dieser Basis können sowohl universell einsetzbare als auch spezialisierte Autorensysteme und Werkzeuge realisiert werden. Mehrere exemplarische Umsetzungen belegen die Funktionsfähigkeit der entwickelten Komponenten

Self-organizing Network Optimization via Placement of Additional Nodes

Das Hauptforschungsgebiet des Graduiertenkollegs "International Graduate School on Mobile Communication" (GS Mobicom) der Technischen Universität Ilmenau ist die Kommunikation in Katastrophenszenarien. Wegen eines Desasters oder einer Katastrophe können die terrestrischen Elementen der Infrastruktur eines Kommunikationsnetzwerks beschädigt oder komplett zerstört werden. Dennoch spielen verfügbare Kommunikationsnetze eine sehr wichtige Rolle während der Rettungsmaßnahmen, besonders für die Koordinierung der Rettungstruppen und für die Kommunikation zwischen ihren Mitgliedern. Ein solcher Service kann durch ein mobiles Ad-Hoc-Netzwerk (MANET) zur Verfügung gestellt werden. Ein typisches Problem der MANETs ist Netzwerkpartitionierung, welche zur Isolation von verschiedenen Knotengruppen führt. Eine mögliche Lösung dieses Problems ist die Positionierung von zusätzlichen Knoten, welche die Verbindung zwischen den isolierten Partitionen wiederherstellen können. Hauptziele dieser Arbeit sind die Recherche und die Entwicklung von Algorithmen und Methoden zur Positionierung der zusätzlichen Knoten. Der Fokus der Recherche liegt auf Untersuchung der verteilten Algorithmen zur Bestimmung der Positionen für die zusätzlichen Knoten. Die verteilten Algorithmen benutzen nur die Information, welche in einer lokalen Umgebung eines Knotens verfügbar ist, und dadurch entsteht ein selbstorganisierendes System. Jedoch wird das gesamte Netzwerk hier vor allem innerhalb eines ganz speziellen Szenarios - Katastrophenszenario - betrachtet. In einer solchen Situation kann die Information über die Topologie des zu reparierenden Netzwerks im Voraus erfasst werden und soll, natürlich, für die Wiederherstellung mitbenutzt werden. Dank der eventuell verfügbaren zusätzlichen Information können die Positionen für die zusätzlichen Knoten genauer ermittelt werden. Die Arbeit umfasst eine Beschreibung, Implementierungsdetails und eine Evaluierung eines selbstorganisierendes Systems, welche die Netzwerkwiederherstellung in beiden Szenarien ermöglicht.The main research area of the International Graduate School on Mobile Communication (GS Mobicom) at Ilmenau University of Technology is communication in disaster scenarios. Due to a disaster or an accident, the network infrastructure can be damaged or even completely destroyed. However, available communication networks play a vital role during the rescue activities especially for the coordination of the rescue teams and for the communication between their members. Such a communication service can be provided by a Mobile Ad-Hoc Network (MANET). One of the typical problems of a MANET is network partitioning, when separate groups of nodes become isolated from each other. One possible solution for this problem is the placement of additional nodes in order to reconstruct the communication links between isolated network partitions. The primary goal of this work is the research and development of algorithms and methods for the placement of additional nodes. The focus of this research lies on the investigation of distributed algorithms for the placement of additional nodes, which use only the information from the nodes’ local environment and thus form a self-organizing system. However, during the usage specifics of the system in a disaster scenario, global information about the topology of the network to be recovered can be known or collected in advance. In this case, it is of course reasonable to use this information in order to calculate the placement positions more precisely. The work provides the description, the implementation details and the evaluation of a self-organizing system which is able to recover from network partitioning in both situations

Enhanced Quality of Experience Based on Enriched Network Centric and Access Control Mechanisms

In the digital world service provisioning in user satisfying quality has become the goal of any content or network provider. Besides having satisfied and therefore, loyal users, the creation of sustainable revenue streams is the most important issue for network operators [1], [2], [3]. The motivation of this work is to enhance the quality of experience of users when they connect to the Internet, request application services as well as to maintain full service when these users are on the move in WLAN based access networks. In this context, the aspect of additional revenue creation for network operators is considered as well. The enhancements presented in this work are based on enriched network centric and access control mechanisms which will be achieved in three different areas of networks capabilities, namely the network performance, the network access and the network features themselves. In the area of network performance a novel authentication and authorisation method is introduced which overcomes the drawback of long authentication time in the handover procedure as required by the generic IEEE 802.1X process using the EAP-TLS method. The novel sequential authentication solution reduces the communication interruption time in a WLAN handover process of currently several hundred milliseconds to some milliseconds by combining the WPA2 PSK and the WPA2 EAP-TLS. In the area of usability a new user-friendly hotspot registration and login mechanisms is presented which significantly simplifies how users obtain WLAN hotspot login credentials and logon to a hotspot. This novel barcode initiated hotspot auto-login solution obtains user credentials through a simple SMS and performs an auto-login process that avoids the need to enter user name and password on the login page manually. In the area of network features a new system is proposed which overcomes the drawback that users are not aware of the quality in which a service can be provided prior to starting the service. This novel graceful denial of service solution informs the user about the expected application service quality before the application service is started

Audio module integration into high quality video transmission software

El projecte tracta d'afegir noves funcionalitats al sistema de transmissio HD, basat en software lliure, UltraGrid. El projecte consistira en l'integracio d'un modul d'audio tant en captura des d'una mateixa font, audio i video, com desde una font independent de forma sincronitzada, per cada usuari. Aixo donara lloc a un sistema complet de videoconferencia adaptable. A mes en una segona fase del projecte, l'alumne adaptara el modul d'audio per a entorns multiusuari (multiconferencia), en els modes, N:1 i N:N, afegint les millores d'audio aconseguides. Per ultim, s'estudiara la viabilitat de desenvolupar un cancel?ladors d'eco basat en software i un modul de deteccio d'activitat per donar posicio preferent al usuari que esta parlant a la multi- conferenci

Linux-Box: DVB and VoD streaming over local area networks

Aquest treball tracta sobre un projecte comú anomenat Linux-Box portat a terme per diferents persones al departament de Telecomunicacions (IET) de la Universitat de Pisa. Linux-Box és un sistema dotat amb targetes TDT (DVB-T) i de televisió per satèl·lit (DVB-S) que permet transmetre aquests senyals fins a un àmbit domèstic. Més endavant podria ser utilitzat en àmbits privats com les cases de clients o en institucions públiques com escoles, universitats, biblioteques i també seria possible en àmbits empresarials. El projecte està dividit en 4 apartats: 1. Ubuntu 6.06 LTS. Explica perquè s’utilitza Ubuntu en el projecte. A més també s’explica de forma breu que és Linux i les distribucions més utilitzades. 2. Multimedia Network Protocols: s’expliquen els diferents protocols desde la capa de xarxa fins la capa d’aplicació que s’utilitzen en el projecte Linux-Box. Aquests protocols són utilitzats tant en streaming, com en anunciació, unicast/multicast, encapsulat de vídeo i codecs. Els diversos temes tractats aquí es fan amb el propòsit de comparar i no només com a recerca teòrica. A la fi es veuen els programes utilitzats en el projecte per analitzar el tràfic de la xarxa. 3. Linux-Box: s’explica el funcionament i els objectius globals del projecte. Es dedica un sub-apartat a “VideoLan - VLC” part important a nivell de sofware. Més endavant es parla de les característiques de la Linux-Box de forma acurada: streaming de VoD i senyals de TV i s’analitzen els problemes coneguts i les seves solucions proposades. A la fi s’enumeren els llenguatges de programació utilitzats al projecte i en quina part s’utilitzen. Observarem que és una aplicació on diversos llenguatges de programació estan contínuament solapats. 4. Developed Part: es posa en pràctica la teoria estudiada a la resta del treball. Està dividida en 4 seccions: Desenvolupar una aplicació en codi C per convertir la llista de Canals (tant terrestre com de satèl·lit) en format XML. Una secció dedicada al streaming de Canals de TV a la pàgina web principal. Un anàlisis profund dels paquets creats per la Linux-Box i la seva activitat a la xarxa. Finalment s’analitzen els diferents scripts i les seves configuracions. Alguns són útils per a un futur desenvolupament i d’altres s’utilitzen en seccions prèvies. 5. Conclusions: conté les conclusions i línies futures. El projecte compta amb diverses opcions que encara poden ser implementades i estudiades. Aquí exposem les nostres interpretacions i possibles línies futures d’estudi