Karel De Vogeleer

The effects of Packet Delay Variation on the perceptual quality of video

The satisfaction of end-users is important when evaluating services and products. Visualizing the network behavior in mobile streaming as well as modeling the correlation between Quality of Service (QoS) and Quality of Experience (QoE) is expected to improve user satisfaction of services on the Internet. Given that network and human factors are the elements that affect the final output of the measurements, it is important to take the Packet Delay Variation (PDV) into consideration. In this paper we observe the PDV during a series of real-life experiments on a 3rd Generation (3G) network while streaming videos. User Rating (UR) values from user input are recorded accordingly. With this aim, we implemented a QoE assessment tool that measures network metrics in kernel space, while simultaneously logging user ratings with regards to the perception of an ongoing realtime video on an Android phone. The primary goal is to identify a clear trend in the QoE modeling, so that we can assess the satisfaction of a user by deriving the QoE from measurable QoS metrics. We find that PDV degrades user perception. Observations show that, during the experiments, sudden breaks and restarts in the packet flow exist. Even though the use of Exponentially Weighted Moving Average (EWMA) assists in finding a model that shows the relationship between PDV and UR, on-off flushing is a major threat affecting this relationship. The results show that correlations with different quality can be reached with various modifications of the proposed matching model.

Providing an User Centric Always Best Connection

Although Quality of Experience (QoE) is perceived as a subjective measure of a user’s experience, it is the only measure that actually counts to a user of a service. It is essential to identify, quantify and ultimately improve the perception of QoE for a user. The PERIMETER project improves the user’s experience by identifying a more user-centric network selection, based on QoE calculations and user preferences. PERIMETER defines a generic QoE model which forms the basis for QoE signalling and QoE based content adaptation support. This paper provides an insight into how user centric seamless mobility is being achieved by PERIMETER, beginning with an explanation of QoE and the need for preferences. Next, more details of the complete system, including QoE management, user feedback and the final delivery, are provided. Finally, an outlook is given on PERIMETER’s future plans and its contributions to research in the Future Internet.

An application layer architecture for seamless roaming

The paper advances a new architecture for seamless roaming, which is implemented at the application layer. This architecture is subject for the research projects PERIMETER and MOBICOME, recently granted by the EU STREP FP7 and EUREKA, respectively. The research challenges are on mobility management, security, QoE management, overlay routing, node positioning, mobility modeling and prediction, middleware and handover. The foundation of seamless handover is provided by several components, the most important ones being the handover, mobility management, connectivity management and Internet mobility. The paper provides an analysis of these components as well.

PERIMETER: A user-centric mobility framework

This demo shows a prototype of a user-centric mobility framework that provides handover for macro-mobility on handheld devices. The framework is designed for mobile-controlled handover and does not require modification of the Internet infrastructure. The end-users are so able to control the roaming process governed by user considerations in addition to business objectives. To achieve seamless mobility UDP tunneling is used as a basis for the handover process. Additionally, measurements are performed on the tunnels to acquire Quality of Service (QoS) metrics and hence serve for roaming decision making processes.

Content dependency of the traffic control in the darwin streaming server

The Darwin Streaming Server employs stream thinning and transmission rate adaptation for traffic and congestion control. We investigate the relation of video content with the stream thinning and transmission rate adaptation process under 3GPP-adaptation. We observe that stream thinning is not only initiated upon fluctuation of network properties or the jitter buffer, but sometimes also upon the content of the streamed video. Moreover, we show that in extreme situations the video transmission is halted based merely on content dependent properties reflected in the RTSP feedback. This may have adverse consequences for the user experience. We put forward alterations to the 3GPP-adaptation traffic control of the Darwin Streaming Server that controls the stream thinning process. The alterations aim to avoid video freezes as a result of video content dependent properties. The results show that the probability of an interrupt-free playback is higher for the alterations than for the default streaming server algorithms.

ROMA: a middleware framework for seamless handover

The chapter reports on a new middleware architecture suggested for seamless handover. The middleware is part of an architectural solution suggested by Blekinge Institute of Technology (BTH) for seamless handover, which is implemented at the application layer. This architecture is subject for the PERIMETER STREP and MOBICOME projects, granted by the EU FP7 and EUREKA, respectively. The suggested middleware, called ROMA, represents a software system with two sets of Application Programmer Interface (API), one for application writers and another one for interfacing various overlay and underlay systems. ROMA thus provides a transport-agnostic platform for future Internet applications. The paper provides a short description of the ROMA middleware, with particular focus on API design and address translation.

A Lightweight Macro-mobility Framework

This paper presents the design of a lightweight framework to provide vertical handover for macro-mobility on handheld devices. The framework is designed for mobile-controlled handover and does not require modification of the Internet infrastructure. The framework enables users to control the entire vertical handover process so handover decisions are driven by user preferences rather than ISP considerations. UDP tunneling is used as the basis for seamless roaming. Support nodes participate in mobility management by keeping track of the mobile users. We elaborate on a proof-of-concept implementation targeted to be deployed on the Android platform.

Seamless roaming: developments and challenges

The chapter reports on recent developments and challenges focused on seamless handover. These are subject for the research projects MOBICOME and PERIMETER, recently granted by the EU EUREKA and EU STREP FP7, respectively. The research projects are considering the recently advanced IP Multimedia Subsystem (IMS), which is a set of technology standards put forth by the Internet Engineering Task Force (IETF) and two Third Generation Partnership Project groups, namely 3GPP and 3GPP2. The foundation of seamless handover is provided by several components, the most important ones being the handover, mobility management, connectivity management and Internet mobility. The paper provides an intensive analysis of these components

Evaluation of swarm video streaming

IPTV has been hailed as a “killer app” of the Internet for a long time, but it has yet to really make a major breakthrough, due to various technical and political reasons. The recent influx of community-driven video distribution has re-actualized the research into efficient distribution methods for streaming video. In this paper, we suggest a number of modifications and extensions to the BitTorrent distribution and replication system to make it suitable for use in providing a streaming video delivery service, and implement parts of these in a simulator. Also, we report on a simulation study as well as a large-scale real-world study of the extensions on PlanetLab. Results show that BitTorrent can be used as a bandwidth-efficient alternative to traditional IPTV solutions.