Energy-efficient mode switching mechanism with flexible functional splitting in energy harvesting cloud radio access networks

In energy harvesting cloud radio access networks, the sleep mode switching of small radio remote head (SRRH) and the functional splitting between SRRH and baseband unit are two important challenges for improving energy efficiency and throughput. In this paper, we propose an energy-efficient mode switching mechanism (E²MSM) with flexible functional splitting in which a controller determines the modes of SRRHs and functional splitting level by considering the renewable energy levels and populations of SRRHs. To optimize the performance of E²MSM, a constraint Markov decision process problem is formulated and a joint optimal policy on the sleep scheduling and the functional splitting level is obtained by a linear programming. Evaluation results demonstrate that E²MSM with the optimal policy can achieve comparable throughput to the throughput-oriented scheme while consuming no non-renewable energy.