Delivery Design for Coded Caching Over Wireless Multicast Networks

In wireless multicast networks, different users may have quite different link qualities to the server, which will degrade the multicast performance of the coded caching scheme. In order to effectively handle the asymmetric link qualities and fulfill the fairness delivery requirement by a different user, a parallel delivery scheme is proposed to organize the wireless multicast physical channels into multiple logic parallel partially shared links. Each parallel partially shared link connects the server to a subset of users, and each user can receive coded signals from multiple parallel partially shared links, in which the superposition coding and successive interference cancellation techniques will be utilized to guarantee the recovery of each requested file. Since the parallel partially shared links provide the basis to reasonably balance the traffic load and to allocate the delivery rate among users, this parallel delivery scheme is able to guarantee the fairness transmission requirements and to effectively reduce the required delivery time per bit (DTB), which is defined as the normalized time spent on satisfying all the users' demands, for both the centralized and decentralized placement.