Master Thesis - 2008

At present, video distribution systems for movies or some TV programs are expected to emerge with a large demand for on-demand services with an aggressive and effective utilization of the high speed B-ISDN. In particular, those kinds of services are more desirable such that viewers can request their own favorite programs at their convenient time with more various personal ways of life today. Existing Video on Demand (VoD) systems such as Full-VoD and Near-VoD, haven't spread widely yet because of their inefficient cost of resources for communication and storage. In our research, we aim at an efficient VoD system based on high speed network. We focus on the forms of data trasmission, and propose a new VoD system. In our proposed system, distribution time for a service is devided into some periods. In the first period, service is started in a on-demand way on a request by certain user as much as possible. After that period, users who had started to receive the same program from the same period are mereged into a group of multicast and they share the communication bandwidth. The proposed system aggressively utilizes multicast and devides the program resource data into mass block files and transmits them to the viewer treminals as a burst traffic via high speed network periodically. Those mass blocks enable individual video controls such like rewindings, halt on the playback etc. in the range of one block size. The user terminal has a buffer with a size of two blocks to increase a flexibility of individual video controls. We also consider the scheduling for burst data distribution to each user, and show an effectiveness of our proposed system by comparing it with the traditional system. Also request blocking rate, utilization rate of a communication link, user ratio who are included into multicast are evaluated.