I. Introduction
With THE RAPID development of signal processing, communication, and networking technologies, video-over-IP applications become more and more popular and have attracted millions of users over the Internet [1], [2]. One simple solution to video streaming over Internet is the client-server service model [3], [4], where the video is streamed directly from a server to clients. However, with the client-server service model, the upload bandwidth of the server grows proportionally with the number of clients [5], which makes the large-scale video streaming impractical.