With advances in wireless technology and mobile devices, the number of mobile users using multimedia services has increased significantly in recent years. Mobile devices can be connected and roam on heterogeneous wireless networks. The IEEE 802.21 group has designed a Media Independent Handover (MIH) standard to ensure seamless Vertical Handover (VHO) in heterogeneous networks. However, the standard currently depends on features of the network (e.g. the type of network and available bandwidth) to achieve seamless VHO. This approach is limited, as it does not consider how a Quality of Experience (QoE) can be provided and maintained for customers when delivering multimedia services in heterogeneous wireless networks. The aim of the project is to develop a novel QoE-driven VHO management framework for providing and maintaining an appropriate level of QoE of multimedia services as the mobile user’s actual requirements in heterogeneous wireless networks. A QoE-driven VHO algorithm is more efficient for maintaining this acceptable QoE of multimedia services than traditional network-based or QoS-based VHO algorithms. There are three main contributions during this project. Firstly, A thorough evaluation of the performance of voice and video services via Skype was carried out in terms of the QoE metric (i.e. MOS). This work identified the impact of video content and packet loss on the QoE metric for voice and video communication services over wireless networks. Secondly, a QoE-driven VHO algorithm was developed to provide and maintain an acceptable QoE of mobile video services for mobile users. Compared to a traditional network-based VHO algorithm, this algorithm can provide better QoE and maintain acceptable QoE. Lastly, the User-centric QoE-driven (UCQoE) VHO framework to provide satisfactory QoE of multimedia services according to the mobile user’s requirements. The framework allows users to set their own preferences (e.g. quality-guarantee or cost-free) and carry out VHO operations accordingly. The evaluation showed that the proposed framework can provide a better QoE for delivered video services than QoS-based and network-based VHO algorithms. Furthermore, the proposed framework can be used to avoid unnecessary cost of mobile data when the option of cost-free is preferred by the user. During this project, three international conference papers had been published and a journal paper has been submitted to IEEE Transactions on Mobile Computing. The main contribution-UCQoE VHO management framework can be developed to maintain QoE of all mobile services in the future.

Ce travail a origine dans le contexte du projet européen Napa-Wine et son premier but est de rendre les applications pair-a-pair conscientes du réseau qui est au dessous. Cette information (e.g. capacité du chemin, latence, etc.) aide a optimiser le trafic P2P et ses bénéfices sont duplices : d'un coté les operateurs peuvent limiter le trafic sur les " peering links " en le confinant dans leur Autonomous System. De l'autre coté les utilisateurs peuvent connaître une meilleure qualité du service due à la proximité des autres noeds. Pour maitriser le problème, nous analysons les applications existantes d'abord, et nous évaluons leur niveau de conscience du réseau : comme plusieurs systèmes sont " closed source ", nous les étudions comme des boites noires au moyen d'une analyse purement passive, puis nous mettons en place un banc d'essai complètement contrôlé et finalement nous utilisons des sondes actives en parallèle pour déduire les propriétés dynamiques du voisinage. Dans une seconde étape, nous vérifions l'état de l'art des algorithmes de diffusion des morceaux vidéo dans un simulateur réaliste où nous modelons latences et débit d'accès selon résultats académiques. Dans un tel scenario, nous étudions comment la diffusion des morceaux vidéo subit une dégradation de performance en présence d'erreurs de mesure et une connaissance obsolète de l'état du système. Finalement nous développons un scenario d'émulation dans lequel nous pouvons tester des vraies applications. Notre banc d'essai peut gérer jusqu'à 200 instances d'applications réelles et émuler la topologie du réseau de recherche existant Abilene ; il permet aussi de exécuter algorithmes d'ingénierie du trafic que nous exploitons pour analyser phénomènes de couplage entre couche IP et routage applicatif.

In the revolutionary world of Telecommunications industry, costumer’s satisfaction with the product plays a pivotal role. The QoE is affected by the quality of service of a network provided by the service providers. Generic relationship between Quality of Experience and Quality of Service aids to the evolution of smarter ways of regulating the network performance. Accordingly, several studies have engrossed on classifying the relationships between QoE and QoS, seldom noticing the exponential and logarithmic relationships. Correspondingly, investigating the influence of diverse parameters such as stalls, delays, losses on QoE and analyzing whether the additive model or multiplicative model fits the best. In this work, the aim is to investigate the relationships between multi-dimensional QoE space and multi-dimensional QoS parameters. In order to build the subtlety in the sector of multi-dimensional QoE models for multi factor QoS parameters, this study has been conducted.Since the demand for high quality videos is rising tremendously, it has been a necessity for the service and network providers to ensure the best service. In this study a statistical analysis was performed based on quality assessment method. The videos were streamed using the VLC Player and the user’s reactions were logged. A questionnaire was prepared with questions regarding quality and disturbances observed Figure 14. A total of 15 users participated in the study. The data collected in the study was analyzed using averages, correlations and regression analysis. Comparisons were made between the additive modelling approach and multiplicative modelling approach by linear regression. In conclusion, proposing that the multiplicative model is the best fit for resolutions vs stalls w.r.t mean opinion score (MOS).

Recent years the research focus began on “Quality of Experience” (QoE) that addresses user satisfaction level and improvement of service. The notation sustainable throughput, sometimes also called reliable throughput, ensures user satisfaction level at the same time requires an optimum resource to provide the service. In the context of communication, it becomes important to analyze user behavior with respect to network performance.             Since the user is closer to the transport layer than the network layer, there opens a new domain to relate “QoE aware sustainable throughput” and “TCP throughput”. There is a need to further investigation of “QoE aware sustainable throughput” as it the one which sufficiently QoE, while “TCP throughput” is the result of a control process on a layer. Moreover, it is essential to estimate the QoE aware sustainable throughput based on HTTP streaming on the server and client application may result in a closer understanding of the nature of TCP in terms of user expectation.                In this study, we evaluated the performance of video streaming considering the TCP throughput in the presence of network disturbances, packet loss, and delay. The TCP packet behavior is observed in the experimental test setup. The quality assessment at which the QoE problems can still be kept at the desired level is determined. Mean opinion scores of the preferred use cases for the dash and non-dash server is used to estimate the relationship factor between “TCP throughput” and “QoE aware sustainable throughput”.

Applications that can change their behaviour based on the user’s contextual appearance are called context-aware applications. Applications developed for smart phones, which carry a multitude of different sensors, and actuators have gained a huge penetration within the market. Frequent usage of mobile applications such as home automation, friend finder, car accident notification and tracking etc; have seen an increased growth from the user’s perspective. However, for such applications, it is necessary to have knowledge of the performance and cost parameters, which directly affect the QoE of the application users.  This thesis investigates possible context aware behaviours in real time situations and measures the Quality of Experience (QoE) as well as identifying the Packet Delay Variation (PDV). The background and some state-of-the-art technologies are studied, and based on these studies, three scenarios are designed and implemented and based on their QoE, results and conclusions are presented, with the  results obtained  shown by means of   graphical representations of the QoE and PDV values.

We report on our experiences from two user studies (lab experiments) with nearly 300 participants for QoE evaluation using real mobile services and devices in our WiFi network emulation testbed. We briefly introduce our principles for integrating real services in these studies: how we selected relevant services, how we investigated their testability and how we tested them with high efficiency.

Få verktyg är riktade uttryckligen till fjärråtkomst och fjärrskrivbordprestanda. De få verktyg som gör det är utvecklade specifikt till det användarområde som de var utformade för och är därför begränsade i sin tillämpning. Eftersom upplevelsekvalitet är en problematisk term att sätta fingret på, eftersom det är, per definition, subjektivt och kommer därför skilja sig mellan användare, uppmuntrar användandet av ett verktyg som kan mäta prestandan. I detta papper undersökts om ett universellt verktyg kan användas för att jämföra fjärrskrivbordsprogram från en användares perspektiv. Genom att fokusera på vad användare ser på skärmen från fjärrskrivbordsprogrammet, så försäkrar denna vinkel att mätningarna tagna är oberoende av vad för fjärrskrivbords protokoll, eller vad för fjärrskrivbordprogram som används. Med målet att kunna mäta en skillnad mellan två tester, så användes två applikationer, TeamViewer och RealVNC, för att ansluta till en maskin och utföra en rad förprogrammerade handlingar. Tester med varierande nätverksfördröjning spelades in i form av skärmklipp, som därefter analyserades av ett program som kan upptäcka färgskillnader på pixlar mellan två tester. Resultatet visar att det finns en mätbar skillnad mellan de två olika fjärrskrivbordsprogrammen, vilket ger hopp om att i framtiden så kan en universal metod tas fram för att mäta upplevelsekvalitet på fjärrskrivbord. / Few tools are targeted explicitly to remote access and remote desktop performance, those who do, are highly specified to the scenarios they were designed for and are therefore limited in their application. Since Quality of Experience (QoE) is a problematic term to pinpoint, as it is, by definition, subjective and will therefore differ between users, it encourages the use of a tool that can measure performance. This paper examines whether a universal tool can be used to compare remote desktop applications from a QoE perspective. By focusing on what is displayed, rather than how the remote desktop application displays it, this angle ensures that the measurements taken are independent of what remote desktop protocol or application are used. With the goal to able to measure a difference between two tests, two applications, TeamViewer and RealVNC, were used to connect to a machine and perform a series of pre-scripted actions. Tests with varying network latency were recorded in the form of screenshots, which were then analysed by a program that can detect colour differences in pixels between two tests. The results show that there is a measurable difference between the two different remote desktop applications, which gives hope that in the future a universal method can be developed to measure the Quality of Experience of remote desktop applications.

We report on our experiences from two user studies (lab experiments) with nearly 300 participants for QoE evaluation using real mobile services and devices in our WiFi network emulation testbed. We briefly introduce our principles for integrating real services in these studies: how we selected relevant services, how we investigated their testability and how we tested them with high efficiency.

The number of Information and Communication Technologies (ICTs) used in organizations is increasing. Without careful management, this trend can have sever consequences for organizations as it easily can fragment the business communication. A promising approach to manage these ICTs is to integrate them into a single medium so to ease the communication within and between organizations. The open source project Janus introduces new ways to communicate between legacy protocols and the real-time communication API Web Real-Time Communication (WebRTC). This master thesis addresses how this WebRTC-based implementation can communicate with an IP video door system. In particular, a minimal front-end solution has been implemented and evaluated. The implementation allows the user to make a call, get notified in the communication tool (both visually and auditory), have a two-way audio call, and see the video stream from the video door system. An objective WebRTC-based quality assessment, focusing on Quality of Experience (QoE), has been conducted on the implementation. As part of this assessment, we used the WebRTC-internals tool to collect receiver-relevant video attributes. A QoE-focused comparison to a light-weight Kurento client implementation was also performed. The results show that our Janus implementation and setting is feasible, aside from the periodic bandwidth drops, and outperforms Kurento in the defined QoE attributes.

Adaptive video streaming is perpetually influenced by unpredictable network conditions, whichcauses playback interruptions like stalling, rebuffering and video bit rate fluctuations. Thisleads to potential degradation of end-user Quality of Experience (QoE) and may make userchurn from the service. Video QoE modelling that precisely predicts the end users QoE underthese unstable conditions is taken into consideration quickly. The root cause analysis for thesedegradations is required for the service provider. These sudden changes in trend are not visiblefrom monitoring the data from the underlying network service. Thus, this is challenging toknow this change and model the instantaneous QoE. For this modelling continuous time, QoEratings are taken into consideration rather than the overall end QoE rating per video. To reducethe user risk of churning the network providers should give the best quality to the users. In this thesis, we proposed the QoE modelling to analyze the user reactions change over timeusing machine learning models. The machine learning models are used to predict the QoEratings and change patterns in ratings. We test the model on video Quality dataset availablepublicly which contains the user subjective QoE ratings for the network distortions. M5P modeltree algorithm is used for the prediction of user ratings over time. M5P model gives themathematical equations and leads to more insights by given equations. Results of the algorithmshow that model tree is a good approach for the prediction of the continuous QoE and to detectchange points of ratings. It is shown that to which extent these algorithms are used to estimatechanges. The analysis of model provides valuable insights by analyzing exponential transitionsbetween different level of predicted ratings. The outcome provided by the analysis explains theuser behavior when the quality decreases the user ratings decrease faster than the increase inquality with time. The earlier work on the exponential transitions of instantaneous QoE overtime is supported by the model tree to the user reaction to sudden changes such as video freezes.