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Advances in Multimedia
Volume 2007, Article ID 94040, 11 pages
Research Article

MAC-Layer QoS Management for Streaming Rate-Adaptive VBR Video over IEEE 802.11e HCCA WLANs

1School of Computer Engineering, Nanyang Technological University, Singapore 639798
2School of Electronics and Information Engineering, Beijing Jiaotong University, Beijing 100044, China

Received 18 January 2007; Revised 17 April 2007; Accepted 15 June 2007

Academic Editor: Mihaela Van Der Schaar

Copyright © 2007 Jianfei Cai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


With the increasing popularity of using WLANs for Internet access, the HCCA mechanism in IEEE 802.11e WLANs has received much more attention due to its efficiency in handling time-bounded multimedia traffic. To achieve high network utilization and good end-to-end QoS in the scenario of VBR video over HCCA is a very challenging task because of the dynamics coming from both the network conditions and the video content. In this paper, we propose a cross-layer framework for efficiently delivering multiclass rate-adaptive VBR video over HCCA. The proposed framework consists of three major modules: the MAC-layer admission control, the MAC-layer resource allocation, and the application-layer video adaptation. Experimental results demonstrate the effectiveness of each individual module and the advantage of dynamic interactions among different modules.