Sleep mode implementation issues in green base stations

In this paper, we focus on practical issues when implementing sleep mode in base stations. Our aim being to reduce energy consumption without affecting the Quality of Service (QoS) perceived by users, we expose some problems that my occur when applying sleep mode and propose practical solutions to cope with the resulting QoS degradation. We namely consider activation time issue that may result in blocking new or handover calls, and the ping-pong effect resulting in unnecessary ON/OFF oscillations. We show, using a realistic large-scale simulator, how to choose sleep mode implementation that achieves the best tradeoff between QoS preservation and energy consumption reduction.