1,616 research outputs found
Quality-Oriented Mobility Management for Multimedia Content Delivery to Mobile Users
The heterogeneous wireless networking environment determined by the latest developments in wireless access technologies promises a high level of communication resources for mobile
computational devices. Although the communication resources provided, especially referring to bandwidth, enable multimedia streaming to mobile users, maintaining a high user perceived quality is still a challenging task. The main factors which affect quality in multimedia streaming over wireless networks are mainly the error-prone nature of the wireless channels and the user mobility. These factors determine a high level of dynamics of wireless communication resources, namely variations in throughput and packet loss as well as network availability and delays in delivering the data packets. Under these conditions maintaining a high level of quality, as perceived by the user, requires a quality oriented mobility management scheme. Consequently we propose the Smooth Adaptive Soft-Handover Algorithm, a novel quality oriented handover management scheme which unlike other similar solutions, smoothly transfer the data traffic from one network to another using multiple simultaneous connections. To estimate the capacity of each connection the novel Quality of Multimedia Streaming (QMS) metric is proposed. The QMS metric aims at offering maximum flexibility and efficiency allowing the applications to fine tune the behavior of the handover algorithm. The current simulation-based performance evaluation clearly shows the better
performance of the proposed Smooth Adaptive Soft-Handover Algorithm as compared with other handover solutions. The evaluation was performed in various scenarios including
multiple mobile hosts performing handover simultaneously, wireless networks with variable overlapping areas, and various network congestion levels
Dynamic multimedia content access in a ubiquitous and distributed computing environment
Ubiquitous computing is the concept of embedding many heterogeneous devices within our everyday environment in such a way that they operate seamlessly and become transparent to the person using them. It covers a wide range of applications and services, but of particular interest is multimedia resource adaptation which involves customization and dynamic adaptation of resources according to usage environments and user preferences; this aims to provide consumers with transparent access. This thesis proposes a content negotiation architecture for dynamic adaptation of multimedia content according to usage environment attributes. The architecture shields users from complex configuration details related to the adaptation of multimedia content, while guiding them through user related choices. The architecture also dynamically updates the multimedia content during transmission and consumption when related usage environment attributes are changed. The content negotiation mechanism in the proposed architecture is then extended and deployed in a mobile computing environment to accommodate transfer of multimedia content application session state between devices in a seamless manner. An application session transfer architecture which allows sessions to be directed, stored and transferred through an intermediary session server is proposed. The thesis also considers the foregoing work on the adaptation of multimedia resources applied to sharing in a Peer-to-Peer (P2P) network. It proposes a super peer based dynamic resource adaptation architecture which employs \u27pull\u27 and \u27push\u27 two-stage adaptation approach. This guides users through resource search and configuration details without exposing them to unnecessary technical details; the result is that requested content is transparently adapted to heterogeneous terminal devices. Two separate, but related, modifications are proposed to further improve the performance of the proposed P2P architecture. Firstly, peers are clustered according to registered geographic location information and secondly, based on that registered location information, a locality-based service is introduced which allows users to search services according to their geographic locations. The latter encourages service providers to increase the uptime of their devices and hence provide spare computing power for active adaptation of resources for low-end peers. Resource replication is an important aspect of a P2P system and an adaptive resource replication strategy based on the proposed P2P architecture is presented. It uses resource request rate as the metric to trigger the resource replication process, and proportionally replicates multimedia resources into various configuration states according to the properties of peers and the size of peer clusters. Also, the strategy uses peer related information stored on super peers to determine which peers should be selected to perform adaptive replications and where the resulting replicas should be stored. The proposed adaptive replication strategy demonstrates that the network delays are reduced while resource hit rate is increased in comparison to other replication strategies. Investigation of the deployment of a BitTorrent (BT) - like approach in the proposed P2P resource adaptation architecture is also considered in this thesis. In addition, the architecture\u27s peer selection strategy is adopted and evaluated as a way to enhance the peer selection process in BT. The strategy uses super peers as trackers to intelligently select peers according to their capabilities and shared resource segments and overcome the scalability issue of existing BT implementation. The proposed selection strategy reduces average access time and increases download speed when compared with the existing BT peer selection process with randomly selected peers. Also, the deployment of BT in the proposed P2P architecture shows that it greatly reduces the congested download problem which was previously reported
Dynamic multimedia adaptation and updating of media streams with MPEG-21
The paper discusses media streaming using dynamic resource adaptation and update as a means of facilitating universal multimedia access (UMA): the concept of accessing multimedia content through a variety of possible schemes (Bormans, J. et al., IEEE Sig. Process. Magazine, 2003). As background, the paper summarizes the most common content negotiation approaches and addresses their facets and problems. MPEG-21, the multimedia framework and its relationship to UMA are then explained. Our primary focus is an end-to-end approach to content adaptation which takes advantage of MPEG-21 to facilitate the UMA concept in a media streaming environment. The concept is validated using a media streaming test-bed which provides for wide adaptation according to broad usage descriptions
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Demonstrating Immersive Media Delivery on 5G Broadcast and Multicast Testing Networks
This work presents eight demonstrators and one showcase developed within the
5G-Xcast project. They experimentally demonstrate and validate key technical
enablers for the future of media delivery, associated with multicast and
broadcast communication capabilities in 5th Generation (5G). In 5G-Xcast, three
existing testbeds: IRT in Munich (Germany), 5GIC in Surrey (UK), and TUAS in
Turku (Finland), have been developed into 5G broadcast and multicast testing
networks, which enables us to demonstrate our vision of a converged 5G
infrastructure with fixed and mobile accesses and terrestrial broadcast,
delivering immersive audio-visual media content. Built upon the improved
testing networks, the demonstrators and showcase developed in 5G-Xcast show the
impact of the technology developed in the project. Our demonstrations
predominantly cover use cases belonging to two verticals: Media & Entertainment
and Public Warning, which are future 5G scenarios relevant to multicast and
broadcast delivery. In this paper, we present the development of these
demonstrators, the showcase, and the testbeds. We also provide key findings
from the experiments and demonstrations, which not only validate the technical
solutions developed in the project, but also illustrate the potential technical
impact of these solutions for broadcasters, content providers, operators, and
other industries interested in the future immersive media delivery.Comment: 16 pages, 22 figures, IEEE Trans. Broadcastin
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