Joint broadcast scheduling and user's cache management for efficient information delivery

In information delivery through broadcasting, a server continuously pushes information in a broadcast channel and the users access it by tuning in and waiting until the information they are interested in is transmitted. The server follows a schedule that attempts to match the user access statistics in order to reduce the access latency. In case of inhomogeneous user populations with several different access profiles, the users have local cache to smooth out the mismatches of their profile with the broadcast schedule statistics. In this work we propose a method for joint design of the server broadcast schedule and the user caching strategy such that the access delay is minimized. We identify a fluid model of the joint problem on which the joint optimization is performed and subsequently the dynamic schedule is designed to match the optimal fluid model parameters. It turns out that with joint design of the broadcast schedule and the user cache management policy significant performance improvement is achieved, particularly for inhomogeneous user populations.