Research On The Wireless Channel Distortion Based On Progressive Fine Granularity Scalability Coding

With the rapid development of wireless network, multimedia communication on wireless network has become possible. Based on two major research projects: "The Key Techniques of Modern Distance Education: Interactive Real-time Education Software Tools"(Key Science and Technology Item Foundation of China National Education Ministry No.2000175) and "Joint Source and Channel Encoding in the Mobile Communication System"(subproject of "Digital Video and Audio Coding, Transmission and Application System", National 863 Project), the distortion of the multimedia stream over wireless channel is researched in this dissertation.This dissertation first introduces the characteristics of the wireless channel, and lists some wireless channel models, indicates the advantage of the multimedia stream over wireless channel, then emphasis was put on one of the multimedia stream——PFGS(Progress Fine Granularity Scalable). At the same time, the three different frameworks are discussed, some important parameters of the PFGS are analyzed, and these relations are indicated.Based on the scalability of the streams from PFGS coding, indicates error concealment's shortage in the PFGS coding, and a simple and effective algorithm is proposed. By analyzing channel distortion based on this error concealment technique, an equation which is used to predict channel distortion accurately is given, and then overall distortion is got.Final, non-real-time part (Eden system) of the Distance Learning System is introduced in this dissertation. Eden system is a multimedia courseware-on-demand network system. Students can use this system to teach themselves and improve their study efficiency. And teachers can also use it to make their own multimedia network courseware, and publish them on the Internet. Student then can point out what they want on the Internet. Thus the system releases the teachers' burden and improves the efficiency of the teaching resource. Eden system takes full advantage of multimedia compression coding and transmission techniques, which not only can be used in Distance Learning but also in video-on-demand.