Privacy-Preserving Distributed Edge Caching for Mobile Data Offloading in 5G Networks

Distributed edge caching has drawn great attention with the fast development of smart edge devices. Caching popular contents in the edge can reduce latency and improve the quality of service of edge mobile users. Meanwhile, the data privacy in the edge is critical to preserve the privacy of individual users and devices. How to jointly determine the caching and routing policy in the edge network in a distributed manner and simultaneously design the proper privacy preserving mechanism are challenging. We tackle these challenges in two progressive steps. First, we design a distributed algorithm which can achieve the global optimum. Second, we propose a privacy-preserving mechanism based on differential privacy and prove the privacy guarantee. We conduct extensive numerical simulations based on real-world requests to evaluate the performance of the proposed distributed algorithm and the privacy mechanism. Results highlight a significant improvement of the proposed distributed algorithm while only up to 10.1% of the total serving cost increased by the privacy mechanism.