A Downlink Scheduler for Multicasting Wireless Video-on-Demand

We consider a video delivery problem in which a server multicasts a video to several users over a wireless broadcast channel. Users arrive and depart asynchronously, and when a user arrives, he/she wishes to watch the video from the beginning. Existing approaches for this problem assume that the server is either completely aware of the state of the users or is completely oblivious to their states, the former being most useful for small numbers of users and the latter being most useful for large networks. We propose a dynamic-programming-based scheduler that can operate in both of these regimes, as well as the intermediate regime in which feedback is available but incomplete. The scheduler is validated both numerically and experimentally.