Energy Efficiency Optimization with Statistical QoS Provisioning for Energy Harvesting Networks

In this paper, we develop statistical quality of service (QoS)-driven power control policies to maximize the effective energy efficiency (EEE), which is defined as the spectrum efficiency under given specified QoS constraints per unit harvested energy, for energy harvesting based wireless networks. In particular, first, we analyze the long-term available energy constraints and formulate the EEE maximization problem. Then, we derive the closed-form solutions of optimal power control policies to the EEE maximization problem under the battery capacity dominated constraint, the average harvested energy constraint, and both the battery capacity and average harvested energy constraints, respectively. Furthermore, we derive the threshold to judge whether the optimal power control policy is limited by the battery capacity. The obtained numerical results validate our analyses and show that our developed optimal power control policies can optimize the EEE with statistical QoS provisioning over energy harvesting based wireless networks.