Energy Efficiently Caching and Transmitting Scalable Videos in HetNets

In order to solve the issue of repeated content deliveries, caching is proposed as the potential technique in the fifth generation communication networks. In this paper, we propose the energy- efficient caching scheme in heterogeneous networks, i.e., scalable video coding-based fractional caching, which aims at providing on-demand videos with different perceptual qualities. We derive the expressions for successful transmission probabilities and ergodic service rates, then establish the power consumption model. Based on the above derivations, the energy efficiency (EE) maximization problem is formulated, which is subject to the cache size restriction of each small cell base station. After some approximations, the proposed EE problem is efficiently solved by the standard gradient projection method. Finally, numerical results validate theoretical analysis and demonstrate the superiority of the proposed caching scheme.