Title: Opportunistic Content Delivery in Fading Broadcast Channels,
Abstract: We consider content delivery over fading broadcast channels. A server wants
to transmit K files to K users, each equipped with a cache of finite size.
Using the coded caching scheme of Maddah-Ali and Niesen, we design an
opportunistic delivery scheme where the long-term sum content delivery rate
scales with K the number of users in the system. The proposed delivery scheme
combines superposition coding together with appropriate power allocation across
sub-files intended to different subsets of users. We analyze the long-term
average sum content delivery rate achieved by two special cases of our scheme:
a) a selection scheme that chooses the subset of users with the largest
weighted rate, and b) a baseline scheme that transmits to K users using the
scheme of Maddah-Ali and Niesen. We prove that coded caching with appropriate
user selection is scalable since it yields a linear increase of the average sum
content delivery rate.