Tiia Sutinen

QoS-Aware real-time video encoding How to Improve the User Experience of a Gaming-on-Demand Service

The advances in multimedia and network technologies have created novel services (e.g. Video-on-Demand, IPTV and Gaming-on-Demand), which set high Quality of Service (QoS) requirements. There are various existing QoS support technologies for networks, but these are used and controlled by network operators and single service providers have no possibility to control the whole end-to-end path from their server to the user. Instead the service providers can use various application level solutions to improve the user-perceived quality of video services. One possibility is to monitor the network status end-to-end and change the video encoding parameters accordingly. This paper considers dynamic video encoding adaptation focusing to improve the user-perceived service quality of a Gaming-on-Demand service, which is a highly demanding interactive multimedia application based on a client-server infrastructure and video streaming.

Dynamic Cross-Layer Adaptation of Scalable Video in Wireless Networking

The recent trend in Internet traffic indicates the proliferation of usage of multimedia services where a substantial part is related to some sort of video transmission. Moreover, an increasing number of Internet users employ wireless access technologies. High-quality video streaming over wireless access in unison with great mobility brings challenges to sustain the mobile user perceived video quality high. Capacities of wireless links vary due to, for instance, coverage area limitations, multipath propagation, and fading. However, novel video codecs utilize a layered encoding/decoding mechanism, which conveniently allows adapting the video quality, and thus the bitrate, by adjusting the number of layers transmitted. In this study, we exploit an extensive cross-layer signaling framework for a dynamic scalable video adaptation in varying network capacity. We focus on comparing a fast and fair MAC-layer packet scheduling with a relatively slow and long-term adaptivity taken place already at the application layer using a real H.264/SVC video. Our results attest the advantages of adaptation through the use of feedback signaling, which enables continuing the use of the current network access despite its capacity variation.

Cross-layer architecture for adaptive real-time multimedia in heterogeneous network environment

Despite the interest, the utilization of todays networking environment including a variety of access technologies and various services and capabilities is still minimal. Multiaccess mobile devices already on the market provide a capability to hand over the heterogeneous networks but so far there has not been any commonly approved way to efficiently capitalize on this feature. Media Independent Handover Services standard specified by the IEEE 802.21 working group is expected to establish the basis for heterogeneous handovers. Although IEEE 802.21 has usage also beyond heterogeneous handovers, its capabilities do not fulfill all the requirements of adaptive multimedia transmission. For example, upper layer events and end-to-end traffic control communication are outside the scope of IEEE 802.21. In this study, we introduce an information service architecture for adaptive multimedia which enables to collect and disseminate events and information from the different layers of the protocol stack locally and also between network entities regardless of their location in the network. Our architecture presents a Triggering Engine on top of the IEEE 802.21 services in order to introduce upper layer events, flexibility to event distribution, and end-to-end event based signaling to adaptive multimedia transmission.

Cross-Layer Enhanced Mobility Management in Heterogeneous Networks

The criteria used by state-of-the-art mobility protocols in their handover decision-making are very limited. The protocols typically rely on routing advertisements or signal strength measurements in mobility detection but these criteria fail to reflect the actual transmission conditions in the networks. Instead, more extensive information originating from both the mobile nodes local stack and the network should be employed to achieve more informed handover decision-making. This paper introduces a framework and a prototype implementation for improving the handover performance of Mobile IP based on a variety of cross-layer and cross-domain triggers. The paper also presents the first results obtained from testing the prototype that show the usefulness of the approach.

An architecture for adaptive multimedia streaming to mobile nodes

We describe the ADIMUS architecture which addresses the problem of maintaining the subjective quality of multimedia streaming for a mobile user. In contrast to other works, the entire end-to-end path of the video stream is considered. Adaptation mechanisms for maintaining quality include time-critical handovers, overlay routing and network estimation techniques. Our architecture is built on overlays that provides the necessary functionality for a video streaming service. The paper highlights the key components that ADIMUS advocates to support quality streaming from server to mobile client.

Distributed information service architecture for overlapping multiaccess networks

Multimedia delivery in mobile multiaccess network environments has emerged as a key area within the future Internet research domain. When network heterogeneity is coupled with the proliferation of multiaccess capabilities in mobile handheld devices, one can expect many new avenues for developing novel services and applications. New mechanisms for audio/video delivery over multiaccess networks will define the next generation of major distribution technologies, but will require significantly more information to operate according to their best potential. In this paper we present and evaluate a distributed information service, which can enhance media delivery over such multiaccess networks. We describe the proposed information service, which is built upon the new distributed control and management framework (DCMF) and the mobility management triggering functionality (TRG). We use a testbed which includes 3G/HSPA, WLAN and WiMAX network accesses to evaluate our proposed architecture and present results that demonstrate its value in enhancing video delivery and minimizing service disruption in an involved scenario.

Chronicle Recognition for Mobility Management Triggers

An optimally working mobile system requires tight cooperation and an information stream that flows impeccably between its components. This, however, is not the current state of the art, as applications and system components must each, in isolation, acquire data, create a knowledge base, and maintain it with diligence. We introduce chronicle recognition to our trigger management framework and present the advantages of generating synthetic triggers based on events and measurements, establishing the theoretical foundation. We explain how, by using a time point algebra, we can reason with reified logic and obtain triggers that are unavailable otherwise. These triggers can be generated efficiently, as our results indicate, and are reliable in terms of event temporal correlation.

Towards ubiquitous video services through scalable video coding and cross-layer optimization

Video content as one of the key features of future Internet services should be made ubiquitously available to users. Moreover, this should be done in a timely fashion and with adequate support for Quality of Service (QoS). Although providing the required coverage for ubiquitous video services, wireless networks, however, pose many challenges especially for QoS-sensitive video streaming due to their inadequate or varying capacity. In this article, we propose a cross-layer video adaptation solution, which may be used for optimizing network resource consumption and user experienced quality of video streaming in wireless networks; thus improving the availability of video services to mobile users. Our solution utilizes the flexibility of the Scalable Video Coding (SVC) technology and combines fast and fair Medium Access Control (MAC) layer packet scheduling with long-term application layer adaptation. The proposed solution both improves the usage of network resources by dropping video data based on its priority when the network is congested but also reduces efficiently the number of useless packet transfers in a congested network. We evaluate our solution with a simulation study under varying network congestion conditions. We find that already application layer adaptation gains over 60% less base layer losses, momentous for SVC video decodability and quality, than in the case without any adaptation. When our MAC layer scheduling is enabled, nearly a zero loss situation with respect to packet losses carrying base layers can be attained, resulting in peak-signal-to-noise ratio values very close to the original.

Scalable Video Coding Impact on Networks

This paper describes the CELTIC project on ”Scalable Video Coding Impact on Networks” with the focus of designing a streaming system based on the Scalable Video Coding extension of the H.264/AVC standard. The system is designed to cope with streaming scenarios that can be classified in four use cases: session handover, network congestion, receiver heterogeneity and user driven adaptation. A complete overview of the architecture of the system is given. Two demonstration scenarios are described in detail, which point out the advantages of scalable video coding compared to single layer approaches in multimedia transmission and adaptation scenarios. A concluding section summarizes the work and provides an outlook to future work items.

MAC layer QoS architecture for optimized and fair transmission of scalable video

The increasing demand for mobile video delivery has boosted the development of mechanisms which improve the Quality of Service (QoS) of video transmission through bitstream adaptation. In this paper, we study adapting H.264/SVC streams in the MAC layer. We introduce a generic QoS architecture for implementing both inter- and intra-traffic class QoS for scalable video streams, and verify the solution with OPNET simulations in the context of IEEE 802.11e EDCA. The results show that our two-tier hierarchical scheduling approach provides for optimized SVC delivery in. 11e networks without hampering the channel access of the other traffic types.