在超密集部署异构蜂窝网中，由于小小区基站数量的增多，移动网络的能效问题变得尤为突出。为了降低超密集异构网中的能量消耗，实现“绿色蜂窝网络”这一目标，文章提出了一种基于小区休眠的用户关联改进算法来优化系统能效，通过执行基于干扰图的小区休眠准则，使一些满足条件的轻载基站也切换为轻载小区休眠模式，从而减少基站间的干扰并进一步降低了系统能耗。同时，文章对所提算法及对比算法的性能进行了仿真，仿真结果表明，所提算法在能耗和能效方面明显优于原算法，达到了优化系统能效的目的。

In ultra-densely deployed heterogeneous cellular networks,energy efficiency of the network has become prominent due to the increasing number of small cell base stations. In order to reduce the energy consumption and achieve the goal of "green mobile network",an improved user association algorithm based on cell sleeping is proposed to optimize the energy efficiency in this paper.At the same time,some light-loaded base stations which satisfy the cell sleeping criterion according to the interference graph will also switch to the sleeping mode.Finally,the performances of the proposed and conventional algorithms are compared in the simulation.The results show that compared with the conventional alrogithm,the proposed algorithm has much better performance in energy consumption and energy efficiency,achieving the goal of optimizing system energy efficiency.