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 Cross-Layer Design for Video Transmission over Wireless Rician Slow-Fading Channels Using an Adaptive Multiresolution Modulation and Coding Scheme | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2007 Article ID 86915 12 pages doi 2007 86915 Research Article Cross-Layer Design for Video Transmission over Wireless Rician Slow-Fading Channels Using an Adaptive Multiresolution Modulation and Coding Scheme Yong Pei1 and James W. Modestino2 1 Computer Science and Engineering Department Wright State University Dayton OH 45435 USA 2 Electrical and Computer Engineering Department University of Miami Coral Gables FL 33124 USA Received 22 August 2006 Accepted 13 April 2007 Recommended by Alex Kot We describe a multilayered video transport scheme for wireless channels capable of adapting to channel conditions in order to maximize end-to-end quality of service QoS . This scheme combines a scalable video source coder with unequal error protection UEP across layers. The UEP is achieved by employing different channel codes together with a multiresolution modulation approach to transport the different priority layers. Adaptivity to channel conditions is provided through a joint source-channel coding JSCC approach which attempts to jointly optimize the source and channel coding rates together with the modulation parameters to obtain the maximum achievable end-to-end QoS for the prevailing channel conditions. In this work we model the wireless links as slow-fading Rician channel where the channel conditions can be described in terms of the channel signal-to-noise ratio SNR and the ratio of specular-to-diffuse energy z . The multiresolution modulation coding scheme consists of binary rate-compatible punctured convolutional RCPC codes used together with nonuniform phase-shift keyed PSK signaling constellations. Results indicate that this adaptive JSCC scheme employing scalable video encoding together with a multiresolution modulation coding approach leads to significant improvements in delivered video quality for specified channel conditions. In particular the approach results
