Abstract

Abstract—Locally caching contents at the network edge con-stitutes one of the most disruptive approaches in 5G wireless networks. Reaping the benefits of edge caching hinges on solv-ing a myriad of challenges such as how, what and when to strategically cache contents subject to storage constraints, traffic load, unknown spatio-temporal traffic demands and data sparsity. Motivated by this, we propose a novel transfer learning-based caching procedure carried out at each small cell base station. This is done by exploiting the rich contextual information (i.e., users’ content viewing history, social ties, etc.) available from device-to-device (D2D) interactions, referred to as source domain. This prior information is incorporated in the so-called target domain where the goal is to optimally cache strategic contents at the small cells as a function of storage, estimated content popularity, traffic load and backhaul capacity. It is shown that the proposed approach overcomes the notorious data sparsity and cold-start problems, yielding significant gains in terms of users ’ quality-of-experience (QoE) and backhaul offloading, with gains reaching up to 22 % in a setting consisting of four small cell base stations. Index Terms—caching, transfer learning, collaborative filter-ing, data sparsity, cold-start problem, 5G I.