120 research outputs found

    Context-awareness for ubiquitous media service delivery in next generation networks

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    Les rĂ©centes avancĂ©es technologiques permettent dĂ©sormais la fabrication de terminaux mobiles de plus en plus compacts et dotĂ©s de plusieurs interfaces rĂ©seaux. Le nouveau modĂšle de consommation de mĂ©dias se rĂ©sume par le concept "Anytime, Anywhere, Any Device" et impose donc de nouvelles exigences en termes de dĂ©ploiement de services ubiquitaires. Cependant la conception et le developpement de rĂ©seaux ubiquitaires et convergents de nouvelles gĂ©nĂ©rations soulĂšvent un certain nombre de dĂ©fis techniques. Les standards actuels ainsi que les solutions commerciales pourraient ĂȘtre affectĂ©s par le manque de considĂ©ration du contexte utilisateur. Le ressenti de l'utilisateur concernant certains services multimĂ©dia tels que la VoIP et l'IPTV dĂ©pend fortement des capacitĂ©s du terminal et des conditions du rĂ©seau d'accĂšs. Cela incite les rĂ©seaux de nouvelles gĂ©nĂ©rations Ă  fournir des services ubiquitaires adaptĂ©s Ă  l'environnement de l'utilisateur optimisant par la mĂȘme occasion ses resources. L'IP Multimedia Subsystem (IMS) est une architecture de nouvelle gĂ©nĂ©ration qui centralise l'accĂšs aux services et permet la convergence des rĂ©seaux fixe/mobile. NĂ©anmoins, l'Ă©volution de l'IMS est nĂ©cessaire sur les points suivants :- l'introduction de la sensibilitĂ© au contexte utilisateur et de la PQoS (Perceived QoS) : L'architecture IMS ne prend pas en compte l'environnement de l'utilisateur, ses prĂ©fĂ©rences et ne dispose pas d'un mĂ©chanisme de gestion de PQOS. Pour s'assurer de la qualitĂ© fournit Ă  l'utilisateur final, des informations sur l'environnement de l'utilisateur ainsi que ses prĂ©fĂ©rences doivent transiter en cƓur de rĂ©seau afin d'y ĂȘtre analysĂ©s. Ce traitement aboutit au lancement du service qui sera adaptĂ© et optimisĂ© aux conditions observĂ©es. De plus pour le service d'IPTV, les caractĂ©ristiques spatio-temporelles de la vidĂ©o influent de maniĂšre importante sur la PQoS observĂ©e cĂŽtĂ© utilisateur. L'adaptation des services multimĂ©dias en fonction de l'Ă©volution du contexte utilisateur et de la nature de la vidĂ©o diffusĂ©e assure une qualitĂ© d'expĂ©rience Ă  l'utilisateur et optimise par la mĂȘme occasion l'utilisation des ressources en cƓur de rĂ©seau.- une solution de mobilitĂ© efficace pour les services conversationnels tels que la VoIP : Les derniĂšres publications 3GPP fournissent deux solutions de mobilitĂ©: le LTE proposeMIP comme solution de mobilitĂ© alors que l'IMS dĂ©finit une mobilitĂ© basĂ©e sur le protocoleapplicatif SIP. Ces standards dĂ©finissent le systĂšme de signalisation mais ne s'avancent pas sur la gestion du flux mĂ©dia lors du changement d'interface rĂ©seau. La deuxiĂšme section introduit une Ă©tude comparative dĂ©taillĂ©e des solutions de mobilitĂ© dans les NGNs.Notre premiĂšre contribution est la spĂ©cification de l'architecture globale de notre plateforme IMS sensible au contexte utilisateur rĂ©alisĂ©e au sein du projet EuropĂ©en ADAMANTIUM. Nous dĂ©taillons tout d'abord le serveur MCMS intelligent placĂ© dans la couche application de l'IMS. Cet Ă©lĂ©ment rĂ©colte les informations de qualitĂ© de services Ă  diffĂ©rents Ă©quipements rĂ©seaux et prend la dĂ©cision d'une action sur l'un de ces Ă©quipements. Ensuite nous dĂ©finissons un profil utilisateur permettant de dĂ©crire son environnement et de le diffuser en coeur de rĂ©seau. Une Ă©tude sur la prĂ©diction de satisfaction utilisateur en fonction des paramĂštres spatio-temporels de la vidĂ©o a Ă©tĂ© rĂ©alisĂ©e afin de connaĂźtre le dĂ©bit idĂ©al pour une PQoS dĂ©sirĂ©e.Notre deuxiĂšme contribution est l'introduction d'une solution de mobilitĂ© adaptĂ©e aux services conversationnels (VoIP) tenant compte du contexte utilisateur. Notre solution s'intĂšgre Ă  l'architecture IMS existante de façon transparente et permet de rĂ©duire le temps de latence du handover. Notre solution duplique les paquets de VoIP sur les deux interfaces actives pendant le temps de la transition. ParallĂšlement, un nouvel algorithme de gestion de mĂ©moire tampon amĂ©liore la qualitĂ© d'expĂ©rience pour le service de VoIP.The latest advances in technology have already defied Moore s law. Thanks to research and industry, hand-held devices are composed of high processing embedded systems enabling the consumption of high quality services. Furthermore, recent trends in communication drive users to consume media Anytime, Anywhere on Any Device via multiple wired and wireless network interfaces. This creates new demands for ubiquitous and high quality service provision management. However, defining and developing the next generation of ubiquitous and converged networks raise a number of challenges. Currently, telecommunication standards do not consider context-awareness aspects for network management and service provisioning. The experience felt by the end-user consuming for instance Voice over IP (VoIP) or Internet Protocol TeleVision (IPTV) services varies depending mainly on user preferences, device context and network resources. It is commonly held that Next Generation Network (NGN) should deliver personalized and effective ubiquitous services to the end user s Mobile Node (MN) while optimizing the network resources at the network operator side. IP Multimedia Subsystem (IMS) is a standardized NGN framework that unifies service access and allows fixed/mobile network convergence. Nevertheless IMS technology still suffers from a number of confining factors that are addressed in this thesis; amongst them are two main issues :The lack of context-awareness and Perceived-QoS (PQoS):-The existing IMS infrastructure does not take into account the environment of the user ,his preferences , and does not provide any PQoS aware management mechanism within its service provisioning control system. In order to ensure that the service satisfies the consumer, this information need to be sent to the core network for analysis. In order to maximize the end-user satisfaction while optimizing network resources, the combination of a user-centric network management and adaptive services according to the user s environment and network conditions are considered. Moreover, video content dynamics are also considered as they significantly impact on the deduced perceptual quality of IPTV services. -The lack of efficient mobility mechanism for conversational services like VoIP :The latest releases of Third Generation Partnership Project (3GPP) provide two types of mobility solutions. Long-Term Evolution (LTE) uses Mobile IP (MIP) and IMS uses Session Initiation Protocol (SIP) mobility. These standards are focusing on signaling but none of them define how the media should be scheduled in multi-homed devices. The second section introduces a detailed study of existing mobility solutions in NGNs. Our first contribution is the specification of the global context-aware IMS architecture proposed within the European project ADAptative Management of mediA distributioN based on saTisfaction orIented User Modeling (ADAMANTIUM). We introduce the innovative Multimedia Content Management System (MCMS) located in the application layer of IMS. This server combines the collected monitoring information from different network equipments with the data of the user profile and takes adaptation actions if necessary. Then, we introduce the User Profile (UP) management within the User Equipment (UE) describing the end-user s context and facilitating the diffusion of the end-user environment towards the IMS core network. In order to optimize the network usage, a PQoS prediction mechanism gives the optimal video bit-rate according to the video content dynamics. Our second contribution in this thesis is an efficient mobility solution for VoIP service within IMS using and taking advantage of user context. Our solution uses packet duplication on both active interfaces during handover process. In order to leverage this mechanism, a new jitter buffer algorithm is proposed at MN side to improve the user s quality of experience. Furthermore, our mobility solution integrates easily to the existing IMS platform.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF

    Contribution to quality of user experience provision over wireless networks

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    The widespread expansion of wireless networks has brought new attractive possibilities to end users. In addition to the mobility capabilities provided by unwired devices, it is worth remarking the easy configuration process that a user has to follow to gain connectivity through a wireless network. Furthermore, the increasing bandwidth provided by the IEEE 802.11 family has made possible accessing to high-demanding services such as multimedia communications. Multimedia traffic has unique characteristics that make it greatly vulnerable against network impairments, such as packet losses, delay, or jitter. Voice over IP (VoIP) communications, video-conference, video-streaming, etc., are examples of these high-demanding services that need to meet very strict requirements in order to be served with acceptable levels of quality. Accomplishing these tough requirements will become extremely important during the next years, taking into account that consumer video traffic will be the predominant traffic in the Internet during the next years. In wired systems, these requirements are achieved by using Quality of Service (QoS) techniques, such as Differentiated Services (DiffServ), traffic engineering, etc. However, employing these methodologies in wireless networks is not that simple as many other factors impact on the quality of the provided service, e.g., fading, interferences, etc. Focusing on the IEEE 802.11g standard, which is the most extended technology for Wireless Local Area Networks (WLANs), it defines two different architecture schemes. On one hand, the infrastructure mode consists of a central point, which manages the network, assuming network controlling tasks such as IP assignment, routing, accessing security, etc. The rest of the nodes composing the network act as hosts, i.e., they send and receive traffic through the central point. On the other hand, the IEEE 802.11 ad-hoc configuration mode is less extended than the infrastructure one. Under this scheme, there is not a central point in the network, but all the nodes composing the network assume both host and router roles, which permits the quick deployment of a network without a pre-existent infrastructure. This type of networks, so called Mobile Ad-hoc NETworks (MANETs), presents interesting characteristics for situations when the fast deployment of a communication system is needed, e.g., tactics networks, disaster events, or temporary networks. The benefits provided by MANETs are varied, including high mobility possibilities provided to the nodes, network coverage extension, or network reliability avoiding single points of failure. The dynamic nature of these networks makes the nodes to react to topology changes as fast as possible. Moreover, as aforementioned, the transmission of multimedia traffic entails real-time constraints, necessary to provide these services with acceptable levels of quality. For those reasons, efficient routing protocols are needed, capable of providing enough reliability to the network and with the minimum impact to the quality of the service flowing through the nodes. Regarding quality measurements, the current trend is estimating what the end user actually perceives when consuming the service. This paradigm is called Quality of user Experience (QoE) and differs from the traditional Quality of Service (QoS) approach in the human perspective given to quality estimations. In order to measure the subjective opinion that a user has about a given service, different approaches can be taken. The most accurate methodology is performing subjective tests in which a panel of human testers rates the quality of the service under evaluation. This approach returns a quality score, so-called Mean Opinion Score (MOS), for the considered service in a scale 1 - 5. This methodology presents several drawbacks such as its high expenses and the impossibility of performing tests at real time. For those reasons, several mathematical models have been presented in order to provide an estimation of the QoE (MOS) reached by different multimedia services In this thesis, the focus is on evaluating and understanding the multimedia-content transmission-process in wireless networks from a QoE perspective. To this end, firstly, the QoE paradigm is explored aiming at understanding how to evaluate the quality of a given multimedia service. Then, the influence of the impairments introduced by the wireless transmission channel on the multimedia communications is analyzed. Besides, the functioning of different WLAN schemes in order to test their suitability to support highly demanding traffic such as the multimedia transmission is evaluated. Finally, as the main contribution of this thesis, new mechanisms or strategies to improve the quality of multimedia services distributed over IEEE 802.11 networks are presented. Concretely, the distribution of multimedia services over ad-hoc networks is deeply studied. Thus, a novel opportunistic routing protocol, so-called JOKER (auto-adJustable Opportunistic acK/timEr-based Routing) is presented. This proposal permits better support to multimedia services while reducing the energy consumption in comparison with the standard ad-hoc routing protocols.Universidad Politécnica de CartagenaPrograma Oficial de Doctorado en Tecnologías de la Información y Comunicacione

    Empirical studies of Quality of Experience (QoE) : A Systematic Literature Survey

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    Quality of Experience (QoE) is a relatively new phenomenon. The main focus of this thesis has been to conduct a systematic literature survey of research done in the field of QoE over a ten year period. The method, developed by A. Fink, has been used to survey empirical studies. A framework of QoE has been developed, which created the possibility of grouping together and analysing all the studies in a common framework. In total, 44 studies were analysed. 66 per cent of them were studies with human participants and 34 per cent of them were studies without human participants. The majority of the selected empirical studies have analysed the sub-aspect ‘satisfaction’. Among other vital sub-aspects, which were of interest to researches, were ‘usefulness’, ‘ease of use’, ‘communication’, ‘loss/packet loss’, ‘delay’, ‘bandwidth’, and ‘jitter’. The results of this survey show that different sub-aspects depend on different services. It is not enough that one sub-aspect functions very well, because most of sub-aspects are closely related to each other. Therefore, it is very important that sub-aspects, which are dependent on each other, are functioning as one group to achieve higher QoE on user experience. This thesis may contribute to deeper understanding of the phenomenon QoE. Knowledge of QoE can bring in new ideas and new possibilities for developing a new system or products for achieving satisfaction of user experience

    Measuring And Improving Internet Video Quality Of Experience

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    Streaming multimedia content over the IP-network is poised to be the dominant Internet traffic for the coming decade, predicted to account for more than 91% of all consumer traffic in the coming years. Streaming multimedia content ranges from Internet television (IPTV), video on demand (VoD), peer-to-peer streaming, and 3D television over IP to name a few. Widespread acceptance, growth, and subscriber retention are contingent upon network providers assuring superior Quality of Experience (QoE) on top of todays Internet. This work presents the first empirical understanding of Internet’s video-QoE capabilities, and tools and protocols to efficiently infer and improve them. To infer video-QoE at arbitrary nodes in the Internet, we design and implement MintMOS: a lightweight, real-time, noreference framework for capturing perceptual quality. We demonstrate that MintMOS’s projections closely match with subjective surveys in accessing perceptual quality. We use MintMOS to characterize Internet video-QoE both at the link level and end-to-end path level. As an input to our study, we use extensive measurements from a large number of Internet paths obtained from various measurement overlays deployed using PlanetLab. Link level degradations of intra– and inter–ISP Internet links are studied to create an empirical understanding of their shortcomings and ways to overcome them. Our studies show that intra–ISP links are often poorly engineered compared to peering links, and that iii degradations are induced due to transient network load imbalance within an ISP. Initial results also indicate that overlay networks could be a promising way to avoid such ISPs in times of degradations. A large number of end-to-end Internet paths are probed and we measure delay, jitter, and loss rates. The measurement data is analyzed offline to identify ways to enable a source to select alternate paths in an overlay network to improve video-QoE, without the need for background monitoring or apriori knowledge of path characteristics. We establish that for any unstructured overlay of N nodes, it is sufficient to reroute key frames using a random subset of k nodes in the overlay, where k is bounded by O(lnN). We analyze various properties of such random subsets to derive simple, scalable, and an efficient path selection strategy that results in a k-fold increase in path options for any source-destination pair; options that consistently outperform Internet path selection. Finally, we design a prototype called source initiated frame restoration (SIFR) that employs random subsets to derive alternate paths and demonstrate its effectiveness in improving Internet video-QoE

    Distributed control of reconfigurable mobile network agents for resource coordination

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    Includes abstract.Includes bibliographical references.Considering the tremendous growth of internet applications and network resource federation proposed towards future open access network (FOAN), the need to analyze the robustness of the classical signalling mechanisms across multiple network operators cannot be over-emphasized. It is envisaged, there will be additional challenges in meeting the bandwidth requirements and network management...The first objective of this project is to describe the networking environment based on the support for heterogeneity of network components..

    QUALITY-DRIVEN CROSS LAYER DESIGN FOR MULTIMEDIA SECURITY OVER RESOURCE CONSTRAINED WIRELESS SENSOR NETWORKS

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    The strong need for security guarantee, e.g., integrity and authenticity, as well as privacy and confidentiality in wireless multimedia services has driven the development of an emerging research area in low cost Wireless Multimedia Sensor Networks (WMSNs). Unfortunately, those conventional encryption and authentication techniques cannot be applied directly to WMSNs due to inborn challenges such as extremely limited energy, computing and bandwidth resources. This dissertation provides a quality-driven security design and resource allocation framework for WMSNs. The contribution of this dissertation bridges the inter-disciplinary research gap between high layer multimedia signal processing and low layer computer networking. It formulates the generic problem of quality-driven multimedia resource allocation in WMSNs and proposes a cross layer solution. The fundamental methodologies of multimedia selective encryption and stream authentication, and their application to digital image or video compression standards are presented. New multimedia selective encryption and stream authentication schemes are proposed at application layer, which significantly reduces encryption/authentication complexity. In addition, network resource allocation methodologies at low layers are extensively studied. An unequal error protection-based network resource allocation scheme is proposed to achieve the best effort media quality with integrity and energy efficiency guarantee. Performance evaluation results show that this cross layer framework achieves considerable energy-quality-security gain by jointly designing multimedia selective encryption/multimedia stream authentication and communication resource allocation

    Energy-aware routing techniques for software-defined networks

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    Achieving energy efficiency has recently become a key topic of networking research due to the ever-increasing power consumption and CO2 emissions generated by large data networks. This problem is becoming even more concerning and challenging given the drastic traffic increase expected over the next few years. However, the use of efficient energy-aware strategies could overturn this situation reducing the electricity consumption of Internet data transmission networks, as well as contributing to mitigate the environmental impact of other sectors. The existence of redundant network elements with high capacities is a common design practice in current network infrastructures in order to face suddenly failures or peak traffic flows. However, these additional resources remain either unused or barely used most of the time leading to an undesired energy waste. Therefore, putting into sleep mode (i.e. a low-power state) unused elements is an effective and widely-accepted strategy to decrease the consumption of data networks. In this context, SDN can be seen as an attractive solution to achieve the long-awaited energy efficiency in current communications systems, since they allow a flexible programmability suitable for this problem. This doctoral thesis tackles the problem of optimizing the power consumption in SDN through the design of energy-aware routing techniques that minimize the number of network elements required to satisfy an incoming traffic load. Different from existing related works, we focus on optimizing energy consumption in SDN with in-band control traffic in order to close this important gap in the literature and provide solutions compatible with operational backbone networks. Complementing the general aim of improving the energy efficiency in SDN, this research is also intended to cover important related features such as network performance, QoS requirements and real-time operation. Accordingly, this study gives a general perspective about the use of energy efficient routing techniques, which cover integrated routing considerations for the data and control plane traffic in SDN. By using realistic input data, significant values of switched-off links and nodes are reached, which demonstrates the great opportunity for saving energy given by our proposals. The obtained results have also validated the intrinsic trade-off between environmental and performance concerns, considering several performance indicators. These findings confirm that energy-aware routing schemes should be designed considering specific traffic requirements and performance metric bounds. Moreover, it is shown that jointly considering QoS requirements and energy awareness is an effective approach to improve, not only the power consumption, but the performance on critical parameters such as control traffic delay and blocking rate. Similarly, the proposed dynamic traffic allocation with congestion-aware rerouting is able to handle demanding traffic arrival without degrading the performance of higher priority traffic. In general, our proposals are fine-grained, easy to implement and quite balanced and effective in their results looking for a suitable and readily deployment in real-world SDN scenarios. Therefore, the conducted research and contributions reported through this document not only add to what is known about the potential of energy-aware routing techniques, but also stand as a valuable solution on the road to a sustainable networking.L'assoliment de l'eficiĂšncia energĂštica s'ha convertit recentment en un tema clau de recerca de xarxes a causa dels creixents nivells de consum d'energia i emissions de CO2 generats per les xarxes de dades. Aquest problema es torna cada vegada mĂ©s preocupant i desafiant, donat el drĂ stic augment del trĂ nsit esperat en els propers anys. No obstant aixĂČ, l'Ășs d'estratĂšgies energĂštiques eficients podria invertir aquesta situaciĂł, reduint el consum d'electricitat de les xarxes de dades d'Internet i contribuint a mitigar l'impacte ambiental d'altres sectors. L'existĂšncia d'elements de xarxa redundants i amb grans capacitats Ă©s una prĂ ctica de disseny habitual en les infraestructures de xarxes actuals per afrontar fallades sobtades o fluxos de trĂ nsit mĂ©s elevats. Tanmateix, aquests recursos addicionals romanen poc o gens utilitzats la major part del temps, generant un desaprofitament d'energia no desitjat. Per tant, posar en mode de repĂČs (Ă©s a dir, un estat de baixa potĂšncia) elements no utilitzats Ă©s una estratĂšgia efectiva i Ă mpliament acceptada per disminuir el consum en xarxes de dades. En aquest context, les xarxes definides per programari (SDN) es poden considerar una soluciĂł atractiva per aconseguir l'esperada eficiĂšncia energĂštica en els sistemes de comunicacions actuals, ja que permeten una flexible programabilitat idĂČnia per a aquest problema. Aquesta tesi doctoral aborda el problema d'optimitzar el consum d'energia en SDN a travĂ©s del disseny de tĂšcniques d'encaminament conscients de l'energia que minimitzen la quantitat d'elements de xarxa necessaris per satisfer una cĂ rrega de trĂ nsit entrant. Diferent dels treballs existents, aquesta tesi es centra a optimitzar el consum d'energia en SDN amb el control de trĂ fic dins de banda per tancar aquesta important bretxa en la literatura i proporcionar solucions compatibles amb xarxes troncals operatives. Complementant l'objectiu general de millorar l'eficiĂšncia energĂštica en SDN, aquesta recerca tambĂ© pretĂ©n cobrir altres importants parĂ metres relacionats, com ara el rendiment de la xarxa, els requisits de qualitat de servei (QoS) i el funcionament en temps real. En conseqĂŒĂšncia, aquest estudi ofereix una perspectiva general sobre l'Ășs de tĂšcniques d'encaminament eficients energĂšticament, que contempla consideracions integrades per al trĂ fic de dades i del pla de control en SDN. Prenent dades d'entrada realistes, es van aconseguir desconnectar significatives quantitats d'enllaços i nodes, la qual cosa demostra la gran oportunitat d'estalvi d'energia que ofereixen les nostres propostes. Els resultats obtinguts tambĂ© validen el estret compromĂ­s entre les preocupacions ambientals i les qĂŒestions de rendiment de la xarxa, considerant diversos indicadors de rendiment. Aquests resultats confirmen que els esquemes d'encaminament conscients de l'energia s'han de dissenyar tenint en compte els requisits de trĂ fic especĂ­fics i els lĂ­mits desitjats de les mĂštriques de rendiment. A mĂ©s, es demostra que, considerant conjuntament els requisits de QoS i de l'energia necessĂ ria, Ă©s un enfocament eficaç per millorar, no nomĂ©s el consum d'energia, sinĂł tambĂ© el rendiment en parĂ metres crĂ­tics, com la latĂšncia del trĂ fic de control i la probabilitat de bloqueig. De manera semblant, l'assignaciĂł dinĂ mica de trĂ fic proposta, amb re-encaminament conscient de la congestiĂł, permet gestionar grans volums de trĂ nsit sense degradar el rendiment de les demandes de major prioritat. En general, les nostres propostes sĂłn precises, fĂ cils d'implementar i bastant equilibrades i efectives en els seus resultats, buscant un desplegament adequat i fĂ cil en escenaris prĂ ctics de SDN. Per tant, la recerca realitzada i les contribucions contingudes en aquest document no nomĂ©s afegeixen el que es coneix sobre el potencial de les tĂšcniques d'encaminament conscients de l'energia, sinĂł que tambĂ© representen una valuosa soluciĂł en el camĂ­ cap a una xarxa sostenibl
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