Published in IET Communications Received on 8th July 2009 Revised on 19th November 2009 doi: 10.1049/iet-com.2009.0422 In Special Issue on Video Communications over Wireless Networks ISSN 1751-8628 Quality of experience-driven adaptation scheme for video applications over wireless networks A. Khan L. Sun E. Jammeh E. Ifeachor Centre for Signal Processing and Multimedia Communication, School of Computing, Communications and Electronics, University of Plymouth, Plymouth PL4 8AA, UK E-mail: asiya.khan@plymouth.ac.uk Abstract: User’s perceived quality of service (QoS) or quality of experience (QoE) is likely to be the major determining factor in the success of new multimedia applications over wireless/mobile networks. The primary aim of this study is to present an adaptation scheme that is QoE-driven for optimising content provisioning and network resource utilisation for video applications over wireless networks. The proposed scheme encompasses the application of a QoE-driven model for optimising content provisioning and network resource utilisation. The content provisioning is optimised by the determination of initial content quality by adapting the video sender bitrate (SBR) according to users’ QoE requirement. By finding the impact of the QoS parameters on end-to-end perceptual video quality, the optimum trade-off between SBR and frame rate is found and the benefits to network providers in maximising existing network resources are demonstrated. The QoE is measured in terms of the mean opinion score. The proposed scheme makes it possible for content providers to achieve optimum streaming (with an appropriate SBR) suitable for the network and content type for a requested QoE. The scheme is also beneficial for network providers for network resource provision and planning, and therefore maximising existing network infrastructure by providing service differentiation. 1 Introduction Content-aware networks have the potential to intelligently and resourcefully link hundreds and thousands of content sources to millions of viewers. It offers service providers a strong service differentiation tool as compared to traditional networks and it can dramatically increase service revenue while increasing user’s quality of experience (QoE). QoE requirements under wireless environments have been gaining importance. QoE or the perceived quality of streamed videos is likely to be the major determining factor in the success of the new multimedia applications. It is therefore important to choose and adapt both the application levels, that is, the compression parameters as well as network settings so that they maximise end-user quality. The prime criterion for quality evaluation of multimedia applications is the user’s perception of service quality [1]. The most widely used metric is the mean opinion score (MOS). Among the various encoding parameters that play a significant role in QoE, the sender bitrate (SBR) and the content dynamics such as the spatial and temporal activity are critical for the final perceptual outcome. The inter-relationships between adapting the video SBR, the activity of the content and QoE are not well understood and relatively less researched. With limited network resources, both content providers and network providers are looking to maximise existing network resources and provide service differentiation to the end customer. Holistically, to provide service differentiation on existing network infrastructure and to provide premium service to end users, it is important to define the user requirement (measured in MOS) for any adaptation to take place, which is the motivation of our study. A QoE-driven adaptation scheme for optimising content provisioning and network planning for video applications over wireless networks is proposed in this paper. Two major research questions for video bitstream adaptation IET Commun., 2010, Vol. 4, Iss. 11, pp. 1337–1347 1337 doi: 10.1049/iet-com.2009.0422 & The Institution of Engineering and Technology 2010 www.ietdl.org