Energy-Optimal Edge Content Cache and Dissemination: Designs for Practical Network Deployment

Cloud storage and computing, although it empowers ubiquitous and global information acquisition, analysis, and management, the latency performance and heavy traffic burdens at fronthaul/ hackhaul links have emerged as critical concerns due to the scalability issue, which consequently drives the development of edge content cache and dissemination. Despite ample research on latency and traffic load reduction, an effective design of edge content cache and dissemination from the perspective of energy efficiency is imperative. Noting the fact that wireless service demands are inherently unbalanced over geographic regions, a practical cell planning strategy of operators' basic interests should deploy base stations massively in hot spot areas and sparsely in rural areas. A mobile user is therefore able to acquire desired contents through multiple base stations in a hot spot, while performing autonomous content cache and dissemination with other mobile users in rural areas. Taking this practical constraint into consideration, this article offers energy-optimal edge content cache and dissemination designs for hot spot and rural areas. Exploiting Lyapunov optimization and optimum control theory, we demonstrate analytical foundations and principles of the proposed optimum designs. Engineering insights are also revealed through practical simulation investigations to extend the research frontier of energy-efficient edge content cache and dissemination.