Balancing energy efficiency and hit ratio in social-aware caching: A cross layer approach

Caching is a promising technique that can effectively reduce peak traffic by pushing popular content items proactively to the users during off- peak hours. Two key performance metrics for proactive caching are the energy efficiency and hit ratio. In this paper, we are interested in balancing the hit ratio and energy efficiency in social-aware proactive caching. More specifically, we present a social behavior driven pushing and caching policy that is capable of maximizing the hit ratio while satisfying the power constraint. For two notable schemes, namely uncoded caching and coded caching, we formulate two optimization problems that give the optimal tradeoff between the energy efficiency and caching hit ratio. Furthermore, the optimal solutions present the energy efficient joint pushing and buffer update polices. Our simulation results show that the social-aware pushing and update policies may bring a significant hit ratio gain when the buffer size is far less than the number of items.