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: Interactive Video Coding and Transmission over Heterogeneous Wired-to-Wireless IP Networks Using an Edge Proxy | EURASIP Journal on Applied Signal Processing 2004 2 253-264 2004 Hindawi Publishing Corporation Interactive Video Coding and Transmission over Heterogeneous Wired-to-Wireless IP Networks Using an Edge Proxy Yong Pei Computer Science and Engineering Department Wright State University Dayton OH 45435 USA Email ypei@ James W. Modestino Electrical and Computer Engineering Department University of Miami Coral Gables FL 33124 USA Email jmodestin@ Received 26 November 2002 Revised 19 June 2003 Digital video delivered over wired-to-wireless networks is expected to suffer quality degradation from both packet loss and bit errors in the payload. In this paper the quality degradation due to packet loss and bit errors in the payload are quantitatively evaluated and their effects are assessed. We propose the use of a concatenated forward error correction FEC coding scheme employing Reed-Solomon RS codes and rate-compatible punctured convolutional RCPC codes to protect the video data from packet loss and bit errors respectively. Furthermore the performance of a joint source-channel coding JSCC approach employing this concatenated FEC coding scheme for video transmission is studied. Finally we describe an improved end-to-end architecture using an edge proxy in a mobile support station to implement differential error protection for the corresponding channel impairments expected on the two networks. Results indicate that with an appropriate JSCC approach and the use of an edge proxy FEC-based error-control techniques together with passive error-recovery techniques can significantly improve the effective video throughput and lead to acceptable video delivery quality over time-varying heterogeneous wired-to-wireless IP networks. Keywords and phrases video transmission RTP UDP IP RS codes RCPC codes JSCC edge proxy. 1. INTRODUCTION With the emergence of broadband wireless networks and the increasing demand for multimedia transport over the Internet wireless .
