Performance Analysis of Cluster Content Caching in Cloud-Radio Access Networks

Caching is an energy-efficient method to improve service availability with low cost, and the combination of centralized processing and distributed caching in cloud radio access networks (C-RANs) can reduce redundant traffic. In this paper, a cluster content caching scheme in C-RANs is proposed, which can maintain a balance between the storage volume and the hit ratio of caching, and mitigates the backhaul loadings in C-RANs. By establishing a Poisson point process-based model, the notion of effective capacity is extended into C- RANs, which can capture the maximum content delivery capability of wireless channels with a specific QoS guarantee. Tractable expressions can be obtained in interference limited C-RANs, which show that the content caching scheme outperforms the centralized caching scheme, and provide insights on how to enlarge the the performance gains.