Energy Efficiency Fairness in Heterogeneous Cellular Networks with Wireless Power Transfer

This paper studies the fairness for energy efficient in multi-tier downlink heterogeneous cellular networks (HCNs), where user equipments (UEs) can receive information and harvest energy from wireless power transfer. To balance the UEs received information and harvested energy in HCNs, we proposed an energy-efficiency-based proportionally fairness utility function. Based on the analysis for transmission rate and harvested energy of UEs, we show the energy-efficiency-based proportionally fairness is concave function for received threshold when association probability is fixed. Exploiting alternative programming for joint association probability and received threshold, we propose an efficient iterative algorithm for obtaining the suboptimal solution. Simulation results demonstrate the energy efficiency of multi-tier downlink HCNs improvement brought by the proposed suboptimal association probability and received threshold compared to the scheme that received threshold is low.