User preference aware hierarchical edge-user cooperative caching strategy

The emergence of various new services has posed a huge challenge to the existing network architecture. To improve the network delay and backhaul pressure, caching popular contents at the edge of network has been considered as a feasible scheme. However, how to efficiently utilize the limited caching resources to cache diverse contents has been confirmed as a tough problem in the past decade. In this paper, considering the time-varying user requests and the heterogeneous content sizes, a user preference aware hierarchical cooperative caching strategy in edge-user caching architecture is proposed. We divide the caching strategy into three phases, that is, the content placement, the content delivery and the content update. In the content placement phase, a cooperative content placement algorithm for local content popularity is designed to cache contents proactively. In the content delivery phase, a cooperative delivery algorithm is proposed to deliver the cached contents. In the content update phase, a content update algorithm is proposed according to the popularity of the contents. Finally, the proposed caching strategy is validated using the MovieLens dataset, and the results reveal that the proposed strategy improves the delay performance by at least 35.3% compared with the other three benchmark strategies.