LAUSR

In this letter, we focus on energy efficiency in small cell networks where a large number of small cells are spatial deployed in dense urban area. We optimize the energy efficiency by sleep mechanism under average connection ratio (ACR) and average user rate constrains. First, we derive the average rate in 3-D small cell networks by Matern Hardcore point process. Then, based on monotonicity analysis, the optimal small cell sleep probability is calculated to satisfy both ACR and average rate constrains. In addition, we also formulate an optimal maximum connection number of small cell that minimizes the energy consumption subject to the joint constraint of ACR and average rate. Numerical results show that with the sleep strategy, the small cell networks energy consumption can be reduce about 21% of the total. Our optimal sleep probability and maximum connection number can be effectively applied to design small cell sleep strategy for 3-D small cell networks.