In-network caching and content placement in cooperative small cell networks

Anticipating multimedia file requests via caching at the small cell base stations (SBSs) has emerged as a promising technique for enhancing the quality-of-service (QoS) of cellular user equipments (UEs). Nevertheless, in traditional caching approaches, files are retrieved from evolved packet core (EPC) of the network, and without coordination among SBSs, which introduces new challenges of content duplication and unbalanced traffic load on the backhaul. In this paper, we propose a collaborative framework in which the SBSs can access files from the caches of other SBSs within the same network domain (i.e., connected to the same service gateway). We design a cost model for the content retrieval of contents across SBSs and from the EPC, and we propose a cost-aware decentralized algorithm, based on which the SBSs devise individual caching strategies (i.e., which files to cache, and from where). Simulation results show that the proposed cooperative caching scheme yields significant gains in terms of in-network content availability, reaching up to 21% improvement compared to a traditional approaches based on geographical distribution of the UEs.