A cross-layer quality-oriented energy-efficient scheme for multimedia delivery in wireless local area networks

Wireless communication technologies, although emerged only a few decades ago, have grown fast in both popularity and technical maturity. As a result, mobile devices such as Personal Digital Assistants (PDA) or smart phones equipped with embedded wireless cards have seen remarkable growth in popularity and are quickly becoming one of the most widely used communication tools. This is mainly determined by the flexibility, convenience and relatively low costs associated with these devices and wireless communications. Multimedia applications have become by far one of the most popular applications among mobile users. However this type of application has very high bandwidth requirements, seriously restricting the usage of portable devices. Moreover, the wireless technology involves increased energy consumption and consequently puts huge pressure on the limited battery capacity which presents many design challenges in the context of battery powered devices. As a consequence, power management has raised awareness in both research and industrial communities and huge efforts have been invested into energy conservation techniques and strategies deployed within different components of the mobile devices. Our research presented in this thesis focuses on energy efficient data transmission in wireless local networks, and mainly contributes in the following aspects: 1. Static STELA, which is a Medium Access Control (MAC) layer solution that adapts the sleep/wakeup state schedule of the radio transceiver according to the bursty nature of data traffic and real time observation of data packets in terms of arrival time. The algorithm involves three phases– slow start phase, exponential increase phase, and linear increase phase. The initiation and termination of each phase is self-adapted to real time traffic and user configuration. It is designed to provide either maximum energy efficiency or best Quality of Service (QoS) according to user preference. 2. Dynamic STELA, which is a MAC layer solution deployed on the mobile devices and provides balanced performance between energy efficiency and QoS. Dynamic STELA consists of the three phase algorithm used in static STELA, and additionally employs a traffic modeling algorithm to analyze historical traffic data and estimate the arrival time of the next burst. Dynamic STELA achieves energy saving through intelligent and adaptive increase of Wireless Network Interface Card (WNIC) sleeping interval in the second and the third phase and at the same time guarantees delivery performance through optimal WNIC waking timing before the estimated arrival of new data burst. 3. Q-PASTE, which is a quality-oriented cross-layer solution with two components employed at different network layers, designed for multimedia content delivery. First component, the Packet/ApplicaTion manager (PAT) is deployed at the application layer of both service gateway and client host. The gateway level PAT utilizes fast start, as a widely supported technique for multimedia content delivery, to achieve high QoS and shapes traffic into bursts to reduce the wireless transceiver’s duty cycle. Additionally, gateway-side PAT informs client host the starting and ending time of fast start to assist parameter tuning. The client-side PAT monitors each active session and informs the MAC layer about their traffic-related behavior. The second component, dynamic STELA, deployed at MAC layer, adaptively adjusts the sleep/wake-up behavior of mobile device wireless interfaces in order to reduce energy consumption while also maintaining high Quality of Service (QoS) levels. 4. A comprehensive survey on energy efficient standards and some of the most important state-of-the-art energy saving technologies is also provided as part of the work

Quality of Experience in Immersive Video Technologies

Over the last decades, several technological revolutions have impacted the television industry, such as the shifts from black & white to color and from standard to high-definition. Nevertheless, further considerable improvements can still be achieved to provide a better multimedia experience, for example with ultra-high-definition, high dynamic range & wide color gamut, or 3D. These so-called immersive technologies aim at providing better, more realistic, and emotionally stronger experiences. To measure quality of experience (QoE), subjective evaluation is the ultimate means since it relies on a pool of human subjects. However, reliable and meaningful results can only be obtained if experiments are properly designed and conducted following a strict methodology. In this thesis, we build a rigorous framework for subjective evaluation of new types of image and video content. We propose different procedures and analysis tools for measuring QoE in immersive technologies. As immersive technologies capture more information than conventional technologies, they have the ability to provide more details, enhanced depth perception, as well as better color, contrast, and brightness. To measure the impact of immersive technologies on the viewersâ QoE, we apply the proposed framework for designing experiments and analyzing collected subjectsâ ratings. We also analyze eye movements to study human visual attention during immersive content playback. Since immersive content carries more information than conventional content, efficient compression algorithms are needed for storage and transmission using existing infrastructures. To determine the required bandwidth for high-quality transmission of immersive content, we use the proposed framework to conduct meticulous evaluations of recent image and video codecs in the context of immersive technologies. Subjective evaluation is time consuming, expensive, and is not always feasible. Consequently, researchers have developed objective metrics to automatically predict quality. To measure the performance of objective metrics in assessing immersive content quality, we perform several in-depth benchmarks of state-of-the-art and commonly used objective metrics. For this aim, we use ground truth quality scores, which are collected under our subjective evaluation framework. To improve QoE, we propose different systems for stereoscopic and autostereoscopic 3D displays in particular. The proposed systems can help reducing the artifacts generated at the visualization stage, which impact picture quality, depth quality, and visual comfort. To demonstrate the effectiveness of these systems, we use the proposed framework to measure viewersâ preference between these systems and standard 2D & 3D modes. In summary, this thesis tackles the problems of measuring, predicting, and improving QoE in immersive technologies. To address these problems, we build a rigorous framework and we apply it through several in-depth investigations. We put essential concepts of multimedia QoE under this framework. These concepts not only are of fundamental nature, but also have shown their impact in very practical applications. In particular, the JPEG, MPEG, and VCEG standardization bodies have adopted these concepts to select technologies that were proposed for standardization and to validate the resulting standards in terms of compression efficiency

Diseño y Desarrollo de un Sistema de Gestión Inteligente de QoE para Redes HD y Estereoscópicas IPTV

[EN] Broadband Internet access connections allow Internet Service Providers (ISP) to offer several types of services to home customers such as data, voice over IP (VoIP), Internet protocol television (IPTV) and now 3D Internet protocol television (3D- IPTV). That is why the number of IPTV service providers is increasing conside- rably in recent years. Thanks to the evolution at many levels of the communication systems, communication networks and devices, to deliver these services is possible, but the maximum quality is not always guaranteed. For this reason, one of the main issues to be considered by the IPTV service providers is to guarantee the Quality of Experience (QoE) perceived by the end user. In order to achieve this goal, in this PhD Thesis we propose an intelligent management system based on inductive prediction methods to guarantee the QoE of the end-user. One of the important aspects to be considered in the development of the management system is to include all the parameters that affect the QoE. With this purpose, we will analyze the parameters that affect the degradation of the video stream received by the end user through the IPTV service. At the network level, we will identify the main parameters which affect the Quality of Service (QoS), such as jitter, delay, lost packets and bandwidth. At the user level, these parameters affect to the subjective perception of the user when watching the video. We also checked that effects derived from the compression, quantization, and bitrate affect this perception too.[ES] Las conexiones de acceso a Internet de banda ancha permiten a los Internet Service Provider (ISP) ofrecer servicios a los hogares tales como datos, Voice on IP (VoIP), Televisión sobre IP (IPTV) y actualmente 3D-TV sobre IP (3D-IPTV). Es por esto que el número de proveedores de servicios de IPTV está aumentando considerable- mente en los últimos años. Gracias a la evolución tanto a nivel de sistemas, como de redes de comunicación como de dispositivos, la entrega de este tipo de servicios es posible pero no siempre con las máximas garantías de calidad. Por este motivo, una de las principales cuestiones a tener en cuenta por parte del proveedor de servicios de IPTV es garantizar la calidad de experiencia (Quality of Experience (QoE)) percibida por el usuario final. Para conseguir este objetivo, en la siguiente tesis doctoral se propone un sistema de gestión inteligente basado en métodos induc- tivos de predicción para garantizar la QoE del usuario final. Uno de los aspectos importantes a tener en cuenta en el desarrollo del sistema de gestión es el incluir los parámetros que afectan a la QoE. Para ello, se analizarán aquellos parámetros que afecten a la degradación del flujo de vídeo recibido por el usuario final a tra- vés del servicio de IPTV. A nivel de red, se identificarán dichos parámetros como aquellos que afectan a la calidad de Servicio (Quality of Service (QoS)) como son el jitter, el retardo, los paquetes perdidos y el ancho de banda principalmente. A nivel de usuario, estos parámetros afectan a la percepción subjetiva del usuario al visualizar el vídeo. Comprobamos como efectos derivados de la compresión, la cuantificación, el bitrate, etc, afectan también a dicha percepción.[CA] Les connexions d'accés a Internet de banda ampla permeten als Proveïdors de Ser- vicis d'Internet (ISP) oferir servicis a les llars com ara dades, veu sobre IP (VoIP), Televisió sobre IP (IPTV) i actualment 3D-TV sobre IP (3D-IPTV). És per açò que el nombre de proveïdors de servicis d'IPTV està augmentant considerablement en els últims anys. Gràcies a l'evolució tant a nivell de sistemes, com de xarxes de comunicació com de dispositius, l'entrega d'este tipus de servicis és possible però no sempre amb les màximes garanties de qualitat. Per este motiu, una de les principals qüestions a tindre en compte per part del proveïdor de servicis d'IPTV és garantir la qualitat d'experiència (Quality of Experience, QoE) percebuda per l'usuari final. Per a aconseguir este objectiu, en la següent tesi doctoral es proposa un sistema de gestió intel·ligent basat en mètodes inductius de predicció per a garantir la QoE de l'usuari final. Un dels aspectes importants a tindre en compte en el desenrotllament del sistema de gestió es incloure els paràmetres que afecten la QoE. Per a això, s'analitzaran aquells paràmetres que afecten la degradació del flux de vídeo rebut per l'usuari final a través del servici d'IPTV. A nivell de xar- xa, s'identificaran dits paràmetres com aquells que afecten la qualitat de Servici (Quality of Service, QoS) com són el jitter, el retard, els paquets perduts i l'ample de banda principalment. A nivell d'usuari, estos paràmetres afecten la percepció subjectiva de l'usuari al visualitzar el vídeo. Comprovem com efectes derivats de la compresió, la quantificació, el bitrate, etc, afecten també a dita percepció.Cánovas Solbes, A. (2016). Diseño y Desarrollo de un Sistema de Gestión Inteligente de QoE para Redes HD y Estereoscópicas IPTV [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/65074TESI