Joint subcarrier assignment and user association for partial caching-based small cell networks

Caching popular video contents at base stations (BSs) is one promising approach to reduce wireless delivery time and alleviate the backhaul traffic for small cell networks (SCNs). In this work, in contrast to most of existing works that cache the complete video files, a partial caching scheme that caches the front part of video files is proposed. Based on the partial caching scheme, the problem of subcarrier assignment and user association is different, which requires new solutions. Our main goal is minimizing the average wireless delivery time through joint subcarrier assignment and user association optimization and we solve it with two steps. First, we compute the optimal rate of users and satisfy the optimal rate through subcarrier assignment for each cell solving the subcarrier assignment problem. Second, we propose a heuristic method to deal with the user association problem. Simulation results show that the partial caching scheme reduces the average wireless delivery time significantly, especially for the less concentrated file popularity distributions.