A downlink power control algorithm for long-term energy efficiency of small cell network

Recently, small cells have been densely deployed in hot spots and overlaid with macro cells in order to guarantee the quality of service for voluminous multimedia data. For a small cell network (SCN), the long-term energy efficiency is one of the most challenging issues for conserving energy while achieving link capacity over the air-interface. In this paper, we present a novel downlink power control scheme to maximize the long-term energy efficiency over a time division multiple access system, which includes multiple small cells and a central controller. Toward this goal, we formulate a long-term energy efficiency optimization problem by defining a long-term energy efficiency metric and performing an iterative algorithm to obtain optimal solutions in real-time via fast convergence. The simulation results show that the proposed metric is very effective at improving the long-term energy efficiency and conserving 8.1 % of the energy on average when compared to a conventional metric. In addition, it is verified that the proposed metric is more effective for an SCN, in particular, when the link capacity is severely degraded due to inter-cell interference.