Cooperation-Based Probabilistic Caching Strategy in Clustered Cellular Networks

This letter will discuss the probabilistic caching strategies in spatially clustered cellular networks. Thanks to the content preference of mobile users, proactive caching can be adopted as a promising technique to diminish the backhaul traffic and to decrease the content delivery latency. However, basically there are two obstacles to accomplish the caching policy, i.e., the limited storage capacity of small cells to cache large amount of multimedia contents, and the too small number of users under each base station to imply the content aggregation effect. Traditional caching strategies of the base station only concern its local requests from the connected users through wireless links, but neglect the potential benefit from the cluster feature of the network infrastructure and user traffic demand. In this letter, we proposed a new policy called "Caching as a Cluster", where small cells can exchange content with each other to fulfill every user request within the cluster of base stations. Intuitively, this cooperation between base stations makes a difference to decrease the content delivery latency of mobile users in clustered cellular networks as testified in our numerical simulation.