Content caching and scheduling in wireless broadcast networks with elastic and inelastic traffic

The rapid growth of wireless content access implies the need for content placement and scheduling at wireless base stations. We study a system under which clients are divided into clusters based on their channel conditions, and their requests are represented by different queues at logical frontends. Requests might be elastic (implying no hard delay constraint) or inelastic (requiring that a delay target be met). Correspondingly, we have request queues that indicate the number of elastic requests, and deficit queues that indicate the deficit in inelastic service. Caches are of finite size, and can be refreshed periodically from a media vault. We design provably optimal policies that stabilize the request queues (hence ensuring finite delays) and reduce average deficit to zero (hence ensuring that the QoS target is met). We illustrate our approach through simulations.