tailieunhanh - báo cáo hóa học:" Research Article Optimization of Hierarchical Modulation for Use of Scalable Media"

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 Optimization of Hierarchical Modulation for Use of Scalable Media | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2010 Article ID 942638 12 pages doi 2010 942638 Research Article Optimization of Hierarchical Modulation for Use of Scalable Media Yongheng Liu1 and Conor Heneghan2 1 Department of Electronic and Electrical Engineering University College Dublin Dublin Ireland 2 Communication Digital Signal Processing Group National University of Ireland Dublin Ireland Correspondence should be addressed to Yongheng Liu Received 2 August 2009 Revised 3 January 2010 Accepted 13 January 2010 Academic Editor Ling Shao Copyright 2010 Y. Liu and C. Heneghan. 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. This paper studies the Hierarchical Modulation a transmission strategy of the approaching scalable multimedia over frequency-selective fading channel for improving the perceptible quality. An optimization strategy for Hierarchical Modulation and convolutional encoding which can achieve the target bit error rates with minimum global signal-to-noise ratio in a single-user scenario is suggested. This strategy allows applications to make a free choice of relationship between Higher Priority HP and Lower Priority LP stream delivery. The similar optimization can be used in multiuser scenario. An image transport task and a transport task of an MPEG4 AVC video embedding both QVGA and VGA resolutions are simulated as the implementation example of this optimization strategy and demonstrate savings in SNR and improvement in Peak Signal-to-Noise Ratio PSNR for the particular examples shown. 1. Introduction Recent developments in media source coding have evolved from consideration not only of compression efficiency in terms of rate-distortion curves but also on methods for providing easy-to-use scalability features. .