Joint caching and sleep-active scheduling for energy-harvesting based small cells
Dan Xu, Hao Jin, Chenglin Zhao, Dong Liang · 2017
The massive demand of mobile data traffic stimulates the emergence of cache-enabled heterogeneous cellular networks (HetNets). Caching at the network edge can reduce the duplicated transmissions of the contents and improve users' quality of service (QoS), however, the dense deployment of cache-enabled small base stations (SBSs) and relays poses a challenge on energy consumption. Several emerging technologies have been focused on energy savings, such as energy harvesting and dynamic sleep mode operation of base stations (BSs). How to utilize these technologies to optimize energy consumption in cache-enabled HetNet is a hot research topic. Therefore, in this paper, a two-tier caching framework incorporating energy harvesting and sleep mechanism is proposed and joint optimization of energy-efficient sleeping and caching in the energy-harvesting based HetNet is studied. The optimization problem is formulated, aiming at maximizing energy savings in the system, which combines content placement with sleep-active scheduling for self-powered SBSs. To solve the problem, a dynamic energy-harvesting based caching algorithm with sleep-active scheduling mechanism called DECAS is proposed. Simulation results show that by using renewable energy and sleep mechanism, the proposed caching algorithm achieves significant performance gains on energy consumption and maintains high hit ratio, compared with the caching algorithms without joint optimization of energy-harvesting and sleep mechanism.