Energy-efficient downlink transmission with base station closing in small cell networks

Shutdown of low traffic load base stations (BSs) is recognized as a promising approach to increase energy-efficiency (EE) and reduce total power consumption, especially for small cell networks (SCN). In this paper, we study BS closing strategies for downlink multi-antenna multi-carrier SCN supporting best effort traffics. We formulate the optimization problem of long-term BS closing, BS-user association and subcarrier allocation to maximize EE or minimize total power consumption under the constraints of average sum rate and rate proportion. We obtain an optimal solution for maximizing EE and a suboptimal solution for minimizing total power consumption. Simulation results show that the solutions provide substantial gain both in saving power consumption and increasing EE, and minimizing the total power consumption will not lead to the maximal EE.