<p>Under de senaste åren har Internettelefonin varit på frammarsch, och i takt med att tekniken mognat har fler och fler börjat se den som ett alternativ till att ringa via telefonnätet. Förutom att det är billigare att ringa över det förstnämnda, så erbjuder Internettelefonin också en rad revolutionerande tjänster. Det är dock troligt att telefonnätet kommer att få tjänstgöra i många år till, och det erbjuder fortfarande överlägset bäst stabilitet och har stor acceptans. Om de två telefoninätverken ska existera sida vid sida, med varsina användarbaser är det lämpligt om de kan fås att samverka, så att användare av det ena kan ringa användare av det andra, och vice versa. Detta kan göras med en VoIP/PSTN-gateway, som översätter kontrollinformation och rösttrafik mellan de två nätverken.</p><p>Uppsatsen handlar om det arbete vi har utfört år TietoEnator i Karlstad. Uppgiften bestod i att utveckla en prototyp av en VoIP/PSTN-gateway. Från början var det avsett att systemet skulle klara uppringning från endera en ”vanlig” telefon, eller en så kallad IP-telefon. Därtill skulle rösttrafiken överföras genom ändamålsenlig hårdvara. För att utföra arbetet behövde vi först studera relevanta kommunikationsprotokoll både för telefonnätet och för Internet, för att se hur dessa kunde fås att samverka. Vi behövde också lära oss tillgängliga system, bibliotek och verktyg för att förstå hur vi skulle skapa vårt eget system i den efterkommande implementeringsfasen. På grund av en lång inläsningsperiod och inledande tekniska problem, samt att nödvändig hårdvara för översättning av rösttrafiken inte anlände i tid begränsades arbetet till att innefatta samtal initierade från den vanliga telefonen till ip-telefonen, utan röstöverföring. Likväl har ett resultatgivande arbete utförts, och det beskrivs i detalj i rapporten.</p> / <p>During the past few years Internet telephony has advanced rapidly, and as the technology has evolved, more and more have come to consider it an alternative to making phone calls through the telephone network. Besides being cheaper, Internet telephony also provides several revolutionary services. It is likely though that the telephone network will remain in use for several years to come, and it still offers by far the best stability and is accepted by most people. If the two networks are to coexist, with their respective users, it would be useful if they could be made to interact, so that users of one network can call users of the other, and vice versa. This can be done with a VoIP/PSTN gateway, which translates control information and voice traffic between the two networks.</p><p>Our dissertation is about the work we have performed for TietoEnator in Karlstad. The assignment was to develop a prototype of a VoIP/PSTN gateway. Initially the system was meant to support phone calls initiated either from an “ordinary” phone or from an IP telephone. Also the voice traffic was supposed to be translated with the use of appropriate hardware. To manage this we first needed to study all the relevant protocols for communication used in the telephone network and on the Internet, to get an idea of how these could be made to interact. We also had to learn existing systems, libraries and tools in order to see how we could create our own system. Due to a long learning period and technical problems in the beginning, and because the necessary hardware equipment for translation of voice traffic did not arrive in time, the assignment was limited to include only calls initiated from the ordinary phone to the IP telephone, without voice transmission. Never the less, the efforts have produced results, and our work is explained in detail in this dissertation.</p>

Three dimensional visualisation achieves tremendous savings in time and costs during the design process. Due to these circumstances this methods are gaining in importance. For example improvement in performance and the product security or enabling the operative optimization of a production sequence. By the virtual testing it is possible to validate a product in the whole developing process and product lifecycle. The flight simulator ATILa at Airbus Defence and Space in Friedrichshafen uses these advantages for own products. ATILa is used to test intelligent assistance systems for helicopter pilots. Here the graphic implementation of the virtual earth plays a key role when practicing realistical scenarios. This approach is implemented with the Common Database (CDB) which is enabled by the definition of specifications and standards. Different commercial software packages by Presagis are used to implement the aforementioned database. The software Terra Vista is used for the database generation, including the compilation. For the CDB implementation the software Vega Prime is used to prepare the data with the help of the RTP. The software Vega Prime is not able to display 3D models with LODs, due to a software error. Therefore a third software named Creator is used to modify them. The 3D models are available in the OpenFlight Format. This OpenFlight format consists of different kind of nodes with a complex hierarchical structure. Other software solutions, such as Autodesk or Blender, are not able to provide access to the specific structure. The edited models can be integrated in the virtual environment and have to defined by unambiguous indices. Various settings are used to implement the objects automatically. The compilation of the area of interest takes place by the definition of a geotile with a specific size depending on the latitude. The CDB ouput will be transferred by Vega Prime and with the help of the RTP into the simulator. In addition, there is the possibility to render various CDB databases in the simulator to enable a visualisation of the complete earth. Finally, any errors occurring will be described and methods of resolution explained. The complexity of the generation process of a CDB database could be represented with this thesis. However, the whole workflow of the visualisation of the earth is still in its initial stages, since among other things there are errors in the software. To sum up; the potential of the CDB can be evaluated as above average. / Die 3D Visualisierung vereinfacht den Planungsprozess und geht somit mit einer Zeit- und Kosten- einsparung einher. Aufgrund dieser Sachverhalte gewinnt sie immer weiter an Bedeutung, um zum Beispiel eine verbesserte und sichere Benutzung eines Produktes oder einen optimierten Betrieb einer Produktionskette zu ermöglichen. Durch vorherige virtuelle Erprobung und Vali- dierung eines Produktes können Kosten für den gesamten Entwicklungsprozess und den Pro- duktlebenszyklus gering gehalten werden. Im Flugsimulator für Helikopter namens ATILa in Friedrichshafen (Airbus Defence and Space) versucht man die genannten Vorteile für die eigenen Produkte zu nutzen. Im ATILa werden Assistenzsysteme geprüft, welche die Helikopterpiloten während ihres Fluges unterstützen sollen. Hierbei spielt die grafische Umsetzung der virtuellen Erde in dem Simulator eine entscheidende Rolle, um die Szenarien realitätsnah durchführen zu können. Dies kann mit Hilfe einer sogenannten Common Database (CDB), die durch Spezi- fikationen und Standards definiert ist, umgesetzt werden. Mittels verschiedener kommerzieller Softwarepakete der Firma Presagis lässt sich die oben genannte Datenbank erstellen. Die Gener- ierung und Kompilierung wird mit dem Softwareprogramm Terra Vista vorgenommen. Die Imple- mentierung der CDB in den Flugsimulator erfolgt mit der Software Vega Prime, welche die Daten über einen RTP zur Verfügung stellt. Da dieses Programm durch einen Softwarefehler nicht in der Lage ist, 3D Modelle mit verschiedenen Detaillierungsgraden darzustellen, muss eine dritte Soft- ware namens Creator genutzt werden. Die 3D Modelle liegen im OpenFlight Format vor. Dieses OpenFlight Format weist eine komplexe hierarchische Struktur aus verschiedenen Knoten auf. Andere Softwarelösungen, wie Autodesk oder Blender, sind nicht in der Lage einen Einblick in die spezielle Struktur zu geben. Die bearbeiteten Modelle können dann in der virtuellen Umgebung eingebunden und müssen durch eindeutige Indizes definiert werden. Verschiedene Einstellun- gen werden genutzt, um Objekte automatisch einzubinden. Die Kompilierung des Interessenge- bietes erfolgt über die Definition einer Geokachel mit einer bestimmten Größe, die abhängig vom Breitengrad ist. Die ausgegebene CDB wird mit Vega Prime und mit Hilfe des RTPs in den Simu- lator übertragen. Des Weiteren gibt es die Möglichkeit verschiedene CDB Datenbanken im Sim- ulator simultan zu rendern, was eine vollständige Visualisierung der kompletten Erde ermöglicht. Abschließend werden aufgetretene Fehler näher beschrieben und Lösungsansätze erläutert. Mit der vorliegenden Arbeit konnte die Komplexität der Entstehung einer CDB Datenbank dargestellt werden. Dennoch befindet sich der gesamte Arbeitsablauf der Visualisierung der Erde noch am Anfang, da u.a. Softwarefehler zu bemängeln sind. Zusammenfassend kann das Potenzial einer CDB als überdurchschnittlich bewertet werden.

[pt] Há, nos dias atuais, uma crescente demanda pelo transporte de video sobre IP, i.e., para distribuição de conteúdo pela Internet, por serviços de IPTV em definição padrão e em alta definição e, mesmo para uso interno nas redes de emissoras tradicionais de televisão, que transportam contribuições de elevada qualidade para seus programas. Em tais aplicações, o conteúdo dos programas é transportado usando MPEG-2 ou MPEG-4, sob a forma de MPEG-2 Transport Streams, encapsulados com protocolos tais como RTP, UDP e IP. As redes IP, que são modelizadas como Redes com Apagamento de Pacotes (PEC) não foram, no entanto, concebidas para o transporte de mídias em tempo real, esbarra portanto em problemas comuns como perdas de pacotes e jitter, gerando perturbações que se refletem na recepção do conteúdo. Os métodos tradicionais para superar estas dificuldades, como por exemplo, os que se baseiam em retransmissões usando protocolos ARQ (Automatic Repeat on Request), não são uma solução eficiente para proteger a transmissão de multimídia em tempo real. A proteção de multimídia transmitida em tempo real via IP recorre, neste caso, aos códigos para canal. Há códigos para canal recomendados em RFC s e Padrões, usados amplamente pelos fabricantes de equipamento. Os modernos Códigos Fontanais, possuem características atraentes para o transporte de conteúdos multimídia em tempo real. Neste trabalho, simulações são realizadas, onde o conteúdo encapsulado em Transport Stream, é protegido com Códigos Fontanais antes do encapsulamento para o envio através da rede. A título de comparação, o experimento é realizado também usando outros códigos para canal recomendados. Para realizar a comparação são usadas medições padronizadas do Transport Stream, medições objetivas como artefatos de blocagem e finalmente uma análise subjetiva do conteúdo recebido é usada. O trabalho conclui com a proposta de um Codificador de canal adaptável para Transport Stream. / [en] There is a growing demand for the transport of video over IP today, i.e., for content distribution over the Internet, IPTV services in Standard and High Definition, or even inside traditional broadcasters networks, transporting broadcast quality contributions to the main program. In such applications, the source encoded MPEG-2 or -4 content is transported in the form of MPEG-2 Transport Streams, encapsulated over network protocols. However, IP networks, which can be modeled as Packet Erasure Networks (PEC), were not originally designed for the transport of real time media. There are problems, such as packet drops and jitter, which generate severe impairments in the content that is decoded at the reception. Traditional methods for overcoming these problems, as for example retransmissions performed by Automatic Repeat Request (ARQ) protocols, are not suitable for real-time multimedia protection. Channel coding is the solution of choice for protecting real-time multimedia over IP. There are channel coding schemes specified in open recommendations and Standards, widely adopted by equipment vendors today. Fountain Codes present very attractive characteristics for the transport of real-time multimedia. In the present work, simulations with a Fountain code, protecting Transport Stream contents prior to network encapsulation, are presented. The experiment if repeated with other channel coding techniques commonly employed today. In order to analyze the decoded contents and obtain comparative results, standardized Transport Stream measurements, objective Blocking Artifacts measurements and subjective analysis of the decoded samples are employed. This work is concluded with the proposal of a Transport Stream Adaptive channel encoder, that is explained in Appendix-B.

Under de senaste åren har Internettelefonin varit på frammarsch, och i takt med att tekniken mognat har fler och fler börjat se den som ett alternativ till att ringa via telefonnätet. Förutom att det är billigare att ringa över det förstnämnda, så erbjuder Internettelefonin också en rad revolutionerande tjänster. Det är dock troligt att telefonnätet kommer att få tjänstgöra i många år till, och det erbjuder fortfarande överlägset bäst stabilitet och har stor acceptans. Om de två telefoninätverken ska existera sida vid sida, med varsina användarbaser är det lämpligt om de kan fås att samverka, så att användare av det ena kan ringa användare av det andra, och vice versa. Detta kan göras med en VoIP/PSTN-gateway, som översätter kontrollinformation och rösttrafik mellan de två nätverken. Uppsatsen handlar om det arbete vi har utfört år TietoEnator i Karlstad. Uppgiften bestod i att utveckla en prototyp av en VoIP/PSTN-gateway. Från början var det avsett att systemet skulle klara uppringning från endera en ”vanlig” telefon, eller en så kallad IP-telefon. Därtill skulle rösttrafiken överföras genom ändamålsenlig hårdvara. För att utföra arbetet behövde vi först studera relevanta kommunikationsprotokoll både för telefonnätet och för Internet, för att se hur dessa kunde fås att samverka. Vi behövde också lära oss tillgängliga system, bibliotek och verktyg för att förstå hur vi skulle skapa vårt eget system i den efterkommande implementeringsfasen. På grund av en lång inläsningsperiod och inledande tekniska problem, samt att nödvändig hårdvara för översättning av rösttrafiken inte anlände i tid begränsades arbetet till att innefatta samtal initierade från den vanliga telefonen till ip-telefonen, utan röstöverföring. Likväl har ett resultatgivande arbete utförts, och det beskrivs i detalj i rapporten. / During the past few years Internet telephony has advanced rapidly, and as the technology has evolved, more and more have come to consider it an alternative to making phone calls through the telephone network. Besides being cheaper, Internet telephony also provides several revolutionary services. It is likely though that the telephone network will remain in use for several years to come, and it still offers by far the best stability and is accepted by most people. If the two networks are to coexist, with their respective users, it would be useful if they could be made to interact, so that users of one network can call users of the other, and vice versa. This can be done with a VoIP/PSTN gateway, which translates control information and voice traffic between the two networks. Our dissertation is about the work we have performed for TietoEnator in Karlstad. The assignment was to develop a prototype of a VoIP/PSTN gateway. Initially the system was meant to support phone calls initiated either from an “ordinary” phone or from an IP telephone. Also the voice traffic was supposed to be translated with the use of appropriate hardware. To manage this we first needed to study all the relevant protocols for communication used in the telephone network and on the Internet, to get an idea of how these could be made to interact. We also had to learn existing systems, libraries and tools in order to see how we could create our own system. Due to a long learning period and technical problems in the beginning, and because the necessary hardware equipment for translation of voice traffic did not arrive in time, the assignment was limited to include only calls initiated from the ordinary phone to the IP telephone, without voice transmission. Never the less, the efforts have produced results, and our work is explained in detail in this dissertation.

Organic phosphorescence at room temperature is a strongly growing field of research. Together with fluorescence, it describes the radiative transitions of organic molecules after excitation with light of appropriate wavelength. While fluorescence is a process on the nanosecond timescale, organic phosphorescence is known to show afterglow emission in the lifetime range of microseconds to seconds. These long timescales result from quantum-mechanical restrictions in the transition processes underlying the phosphorescence. Namely, the involved electrons of the molecule have to undergo a spin flip, which is forbidden in zeroth-order approximation due to the necessity of conservation of angular momentum. In consequence, this emission feature of organic materials in general is obstructed at ambient temperature by dominating nonradiative deactivation channels. However, by careful design of the system, efficient phosphorescence at room temperature can be realized. In recent years, the number of publications introducing new organic phosphorescent emitters has continuously increased. However, to that date, the high quantity of described materials is not matched by an adequate amount of proposed applications. In fact, most publications present the synthesis of the substances as well as the morphology of the system, but only briefly address possible subsequent developing steps. In this thesis, as a first step, recent developments in that area are compiled to a broad overview, which includes proposed applications like sensing and optical data storage. Beyond that, a newly detected photophysical effect is introduced and evaluated, which enables the reversible activation of phosphorescence in a thin and transparent film. Since for many emitter materials the presence of adjacent molecular oxygen leads to a complete vanishing of phosphorescence, this emission can locally be tuned by manipulating the respective oxygen concentration. It is shown that a very elegant, non-contact way of achieving that is by using light of different wavelengths only. In detail, radiation in the near UV or blue regime can induce a chemical reaction of the oxygen and its environment, leading to an oxygen depletion at the illuminated regions. By covering the system with suitable barrier layers, no fresh oxygen can refill the system and phosphorescence becomes visible at the respective areas. By that, any luminescent image can be programmed into the transparent layers and be read out on demand. In addition, subsequent illumination with infrared radiation leads to a rise of the overall temperature, which consequently increases the permeability of the oxygen barrier. Therefore, the system is refilled with molecular oxygen and the pattern is erased. In a next step, new images can be written into the device. When not read out by illumination with appropriate light, the system is completely transparent and does not reveal the programmed information. That enables the fabrication of programmable luminescent tags, which allow multiple cycles of writing, reading and erasing, and thus may be used for temporary labeling in logistics or for invisible document security. Prototypes of the mentioned applications are manufactured and tested in this work, revealing the feasibility of their realization. The overall procedure as well as the device structure are part of patent applications. As a further part of the thesis, the characterization of multiple organic emitters and additives reveals that the effect of switchable phosphorescence is not limited to a particular material combination, but is rather a very general behavior. In consequence, device features like emission color, pattern contrast, or wavelength sensitivity are successfully optimized using suitable available organic systems. In order to facilitate a targeted development of new phosphorescent emitters in the future, the decisive demands on the materials to enable programmable tags are defined. Conclusively, more application pathways are depicted, of which one already successfully gained funding by the Federal Ministry of Education and Research of Germany. In this follow-up study, the suitability of the discovered results on sensing of UV radiation will be examined. With two more submitted proposals building up on the presented developments, the results of this thesis open up a broad range of further work both from the scientific and the engineering point of view.:1. Introduction 2. Theory 3. Methods 4. Basic Principles of Programmable Luminescent Tags (PLTs) 5. Characterization of Guest Materials 6. Optimization via Diversification: PLTs with Various Material Systems 7. Conclusions and Outlook / Organische Phosphoreszenz bei Raumtemperatur ist ein aktuell stark wachsendes Forschungsgebiet. Gemeinsam mit der Fluoreszenz beschreibt sie strahlende Übergänge von organischen Molekülen nach der Anregung mit Licht passender Wellenlänge. Während Fluoreszenz ein Prozess auf einer Zeitskala von Nanosekunden ist, zeigt organische Phosphoreszenz typischerweise ein längeres Nachleuchten im Bereich von Mikrosekunden bis Sekunden. Dieses resultiert daraus, dass die Übergangsprozesse, die zur Phosphoreszenz führen, quantenmechanisch nicht erlaubt sind. Die beteiligten Elektronen müssen sich einem Spin-Flip unterziehen, welcher in nullter Näherung aufgrund der Drehimpulserhaltung verboten ist. Infolgedessen wird die Phosphoreszenz organischer Materialien bei Umgebungstemperatur üblicherweise durch dominierende nichtstrahlende Relaxationswege unterdrückt. Durch gezielte Materialentwicklung lässt sich dennoch effiziente Phosphoreszenz realisieren. In den letzten Jahren ist die Zahl der Publikationen, in denen neue organische phosphoreszierende Emitter vorgestellt wurden, kontinuierlich gestiegen. Dieser hohen Auswahl an Materialien steht aktuell jedoch keine ausreichende Anzahl von Vorschlägen potentieller Anwendungen gegenüber. Tatsächlich stellen die meisten Publikationen die Synthese der Substanzen und die Morphologie des Systems vor, gehen aber nur kurz auf mögliche weitere Entwicklungsschritte ein. In dieser Arbeit werden nun zunächst die jüngsten Entwicklungen auf diesem Gebiet zu einem breiten Überblick zusammengestellt, der auch einige der vorgeschlagenen Anwendungen wie Sensorik und optische Datenspeicherung umfasst. Darüber hinaus wird ein neu entdeckter photophysikalischer Effekt vorgestellt und bewertet, der die reversible Aktivierung von Phosphoreszenz in einem dünnen und transparenten Film ermöglicht. Da bei vielen organischen Emittermaterialien die Nähe zu molekularem Sauerstoff zu einem vollständigen Verschwinden der Phosphoreszenz führt, kann diese Emission lokal durch Veränderung der Sauerstoffkonzentration beeinflusst werden. Eine sehr elegante, berührungslose Methode hierfür ist die zielgerichtete Bestrahlung mit Licht verschiedener Wellenlängen. So kann Strahlung im nahen UV- oder im blauen Bereich eine chemische Reaktion des Sauerstoffs mit seiner Umgebung auslösen, die zu einer Abnahme der Sauerstoffmenge in den beleuchteten Bereichen führt. Durch eine zusätzlich aufgebrachte Barriereschicht kann kein frischer Sauerstoff in das System nachströmen, weshalb an den entsprechenden beleuchteten Stellen nach ausreichender Bestrahlung Phosphoreszenz sichtbar wird. Dadurch kann ein beliebiges lumineszentes Muster in die transparenten Schichten einprogrammiert und bei Bedarf ausgelesen werden. Durch die Beleuchtung mit Infrarotstrahlung hingegen wird die Temperatur und damit auch die Durchlässigkeit der Sauerstoffbarriere erhöht. So wird das System mit molekularem Sauerstoff wieder aufgefüllt und die Phosphoreszenz verschwindet. Daraufhin können erneut Bilder in die Folie geschrieben werden. Wenn nicht durch Bestrahlung mit entsprechendem Licht ausgelesen, ist das System völlig transparent und lässt das eingeschriebene Muster nicht erkennen. Dies ermöglicht die Herstellung von programmierbaren lumineszenten Etiketten, die mehrere Schreib-, Lese- und Löschzyklen ermöglichen und somit zur temporären Beschriftung in der Logistik oder zur unsichtbaren Dokumentensicherung eingesetzt werden können. Die Machbarkeit der genannten Anwendungen wird in der Arbeit durch die Herstellung funktionierender Prototypen aufgezeigt. Sowohl das Gesamtverfahren von Aktivierung und Deaktivierung als auch der Aufbau des Systems sind Teil von Patentanmeldungen. Die im Rahmen dieser Arbeit erfolgte Charakterisierung weiterer organischer Emitter und Additive zeigt, dass der Effekt der schaltbaren Phosphoreszenz nicht auf eine bestimmte Materialkombination beschränkt ist, sondern ein sehr allgemeingültiges Verhalten darstellt. Deshalb werden Eigenschaften der Materialsysteme wie die Emissionsfarbe, der Kontrast der Muster oder die Empfindlichkeit gegenüber verschiedenen Lichtwellenlängen mit geeigneten Kombinationen optimiert. Um in Zukunft eine gezielte Entwicklung von organischen phosphoreszierenden Emittern zu ermöglichen, werden die entscheidenden Anforderungen an die Materialien bezüglich ihres Einsatzes in programmierbaren Etiketten dargestellt. Abschließend werden potentielle weitere Entwicklungsrichtungen hin zu weiteren Anwendungen beschrieben, von denen eine bereits Gegenstand von erfolgreich eingeworbener Förderung durch das Bundesministerium für Bildung und Forschung ist. In dieser Folgestudie wird die Eignung der gefundenen Ergebnisse zur Messung von UV-Strahlung untersucht. Mit zwei weiteren eingereichten Anträgen, die auf den vorgestellten Entwicklungen aufbauen, eröffnen die Ergebnisse dieser Arbeit sowohl aus wissenschaftlicher als auch aus technischer Sicht ein breites Spektrum weiterer Forschungsarbeiten.:1. Introduction 2. Theory 3. Methods 4. Basic Principles of Programmable Luminescent Tags (PLTs) 5. Characterization of Guest Materials 6. Optimization via Diversification: PLTs with Various Material Systems 7. Conclusions and Outlook

This diploma thesis focus on transmiting multimedia over computer network. There are detailed informations about protocols RTP and RTPC in a first part because a transmition over a network is realized by using these protocols. Some basic multimedia terms, FFmpeg codecs and SDL library are described in next chapters. A multimedia player using FFmpeg and SDL is implemented in a second part of thesis. The player is console application and it has basic user interface. The player reproduces video and audio from a given file. RTP communication is described in next chapters of the second part. RTP server and client are implemented there too. They are console aplications and they use data coded by Theora or Vorbis. There are summarized results in a conclusion.

Long-Term Evolution (LTE) is the latest development in wide area cellular mobile network technology. In contrast with the earlier generations of circuit-switched mobile networks, LTE is all-IP packet-switched network. Both voice and data are sent inside IP packets. Voice over IP (VoIP) is used to provide voice service to LTE users. The speech frames are encapsulated into real-time protocol (RTP) packets and sent over the network. The underlying UDP and IP layers prepend their headers to this small RTP packet resulting in a relatively high overhead. The small size of the RTP packets containing voice/audio leads to an overhead problem as the protocol overhead is in addition to the large LTE frame overhead, thus wasting network resources. This master’s thesis project proposes to multiplex RTP and data packets at the user’s device as a solution to reduce the overhead. Moreover, the capability of modern user devices to switch between several interfaces (such as LTE and WLAN), is taken into account and the multiplexing of multiple traffic flows or a single traffic flow are studied in the case of a vertical handover. Performance and cost metrics are used to evaluate different potential demultiplexing points, and then the best possible demultiplexing point is identified. The results of this evaluation show that several demultiplexing points can be used based on the operator’s needs. The increased packet payload size increases the energy efficiency of LTE and may avoid the need of the UE to switch to WLAN to save power. In addition, to ensure high quality of service for VoIP traffic, the simultaneous use of multiple interfaces is efficient if the multiplexer is enabled. The multiplexing solution proposed by this thesis is also fully compatible with any virtual private network encapsulation protocol. / Long-Term Evolution (LTE) är den senaste tekniken inom mobil långdistanskommunikation. Jämfört med tidigare generationer av kretskopplade mobila nätverk, är LTE IP paketförmedlande nätverk. Både röstsamtal och datapaket skickas enkapsulerade i IP paket. Voice over IP (VoIP) används för att transportera röstsamtal över IP nätverket. Röstsekvenser enkapsuleras i Real Time Protocol (RTP) paket och skickas över nätverket. De underliggande lagerna som UDP och IP infogar sin huvudinformation i de små RTP paketen vilket gör att kommunikationen blir ooptimerad. De små RTP paketen som innehåller ljudinformation leder till att det blir ooptimerat tillsammans med LTE i och med att man lägger på huvudinformation för varje lager. I det här examensarbetet förslår vi att multiplexa RTP och datapaket tillsammans direkt i användarens enhet för att minska huvudinformationen. Dessutom diskuterar vi möjligheten att byta mellan olika kopplingar (som LTE och WLAN) samt att multiplexa flerfaldig eller singel trafik under en vertikal överlämning. Prestanda och kostnadsmätningar används för att evaluera olika potentiella sammankopplingspunkter, för att kunna ta reda på den bästa sammankopplingspunkten.  Resultatet av detta examensarbete visar på att flera sammankopplingspunkter kan användas beroende på operatörens behov. Den ökade storleken på nyttolasten ökar effektiviteten av LTE nätverken och minskar risken för att behöva byta UE:n till WLAN för att spara energi.  Utöver det ovannämnda kan simultan användning av olika kopplingar användas för att öka kvaliteten på VoIP trafik. Multplexlösningen som föreslås i det här examensarbete är dessutom fullt kompatibel med virtuella privata nätverksenkapsulerande protokoll.

<p>The purpose of this thesis is to examine the possibilities of creating a MPEG-4-compatible set-top box for IP-networks based on open standards. </p><p>Existing alternatives for transporting MPEG-4 over IP are evaluated and ISMA is found to be an important actor within the area. ISMA is a non-profit corporation formed to provide a forum for the creation of specifications that define an interoperable implementation for streaming rich media over IP-networks. </p><p>Two different designs based on ISMA's recommendation are constructed and evaluated. The designs have different levels of complexity and the more complex design is found to be better due to its extended functionality. </p><p>During the design process a number of problems related to this kind of set-top box are discovered. It is believed, however, that many of these problems will be solved within the near future.</p>

<p>The interest for various multimedia services accessed via the Internet has been growing immensely along with the bandwidth available. A similar development has emerged in the 3G mobile network. The focus of this master thesis is on the speech/audio part of a 3G multimedia application. The purpose has been to implement a traffic generating tool that can measure QoS (Quality of Service) in 3G networks. The application is compliant to the 3G standards, i.e. it uses AMR (Adaptive Multi Rate), SIP (Session Initiation Protocol) and RTP (Real Time Transport Protocol). AMR is a speech compression algorithm with the special feature that it can compress speech into several different bitrates. SIP signalling is used so that different applications can agree on how to communicate. RTP carries the speech frames over the network, in order to provide features that are necessary for media/multimedia applications. Issues like perception of audio and QoS related parameters is also discussed, from the perspective of users and developers.</p>

The success of the Internet has brought significant changes to the telecommunication industry. One of the remarkable outcomes of this evolution is Voice over IP (VoIP), which enables realtime voice communications over packet switched networks for a lower cost than traditional public switched telephone networks (PSTN). Nevertheless, security and privacy vulnerabilities pose a significant challenge to hindering VoIP from being widely deployed. The main object of this thesis is to define and elaborate unexplored security and privacy risks on standardized VoIP protocols and their implementations as well as to develop suitable countermeasures. Three research questions are addressed to achieve this objective: Question 1:  What are potential unexplored threats in a SIP VoIP network with regard to availability, confidentiality and privacy by means of unwanted traffic and information disclosure? Question 2:  How far are existing security and privacy mechanisms sufficient to counteract these threats and what are their shortcomings? Question 3:  How can new countermeasures be designed for minimizing or preventing the consequences caused by these threats efficiently in practice? Part I of the thesis concentrates on the threats caused by "unwanted traffic", which includes Denial of Service (DoS) attacks and voice spam. They generate unwanted traffic to consume the resources and annoy users. Part II of this thesis explores unauthorized information disclosure in VoIP traffic. Confidential user data such as calling records, identity information, PIN code and data revealing a user's social networks might be disclosed or partially disclosed from VoIP traffic. We studied both threats and countermeasures by conducting experiments or using theoretical assessment. Part II also presents a survey research related to threats and countermeasures for anonymous VoIP communication.