EPCache: In-network video caching for LTE core networks

Video traffic is becoming the dominant form of traffic over mobile networks, challenging the ongoing standardization and deployment of Next generation mobile networks (4G). Currently, as the mainstream design of evolution to 4G, LTE networks provide high data-rate communication tunnels between mobile users and the Internet. However, this generic tunneling communication introduces at least 3 external hops for any request over the network, which results in high latency as well as operating expense, especially for video traffic with high bandwidth requirement. In this work, we propose EPCache, a novel in-network video caching framework for LTE core networks, which addresses the following key questions: (1)what to cache, i.e., how to select in-system video library; (2)how to cache, i.e., how to distribute the selected video library. We prove that the formulated problem is NP-hard. Together with the investigation into characteristics of online video requests, we then propose a fast algorithm for the problem. Extensive simulations are carried out to study the framework. Numerical results show that our algorithm reaches 97 - 99% of optimal. We also discuss critical issues of EPCache implementation in current LTE systems.