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Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Efficient Transmission of H.264 Video over Multirate IEEE 802.11e WLANs | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2008 Article ID 480293 14 pages doi 10.1155 2008 480293 Research Article Efficient Transmission of H.264 Video over Multirate IEEE 802.11e WLANs Yaser Pourmohammadi Fallah 1 Panos Nasiopoulos 1 and Hussein Alnuweiri2 1 Department of Electrical and Computer Engineering The University of British Columbia 2332 Main Mall Vancouver Canada V6T1Z4 2 Department of Electrical and Computer Engineering Texas A M University at Qatar P. O. Box 23874 Doha Qatar Correspondence should be addressed to Yaser Pourmohammadi Fallah yjallah@ieee.org Received 12 August 2007 Revised 17 December 2007 Accepted 2 March 2008 Recommended by Chi Ko The H.264 video encoding technology which has emerged as one of the most promising compression standards offers many new delivery-aware features such as data partitioning. Efficient transmission of H.264 video over any communication medium requires a great deal of coordination between different communication network layers. This paper considers the increasingly popular and widespread 802.11 Wireless Local Area Networks WLANs and studies different schemes for the delivery of the baseline and extended profiles of H.264 video over such networks. While the baseline profile produces data similar to conventional video technologies the extended profile offers a partitioning feature that divides video data into three sets with different levels of importance. This allows for the use of service differentiation provided in the WLAN. This paper examines the video transmission performance of the existing contention-based solutions for 802.11e and compares it to our proposed scheduled access mechanism. It is demonstrated that the scheduled access scheme outperforms contention-based prioritized services of the 802.11e standard. For partitioned video it is shown that the overhead of partitioning is too high and better results are achieved if some partitions are .
