中文摘要：

为了降低无线通信网耗能而引起的二氧化碳排放量和运营商运营资本，提出了一种下行多输人多输出系统能效最优的功率分配方案．根据实际能耗模型与波束赋形建立了系统能效模型，证明了系统存在唯一的全局最优能效，并且给出了最优能效的闭式解，此解与信道状态信息有关．基于此闭式解形成的功率分配方案可以自适应地完成系统最优能效．仿真结果表明，自适应功率分配方案能增加系统的能效和谱效，增加天线数量和减小小区半径是提高系统能效和谱效的重要手段．

英文摘要：

In order to decrease the carbon emission and operator expenditure induced by energy consump- tion of wireless communication networks, a power allocation scheme achieving optimal energy efficiency is proposed for downlink multiple-input muhiple-output system. An energy efficient model is formulated based on realistic power consumption model and beam forming. The existence of unique globally optimal energy efficiency is proved, and the closed-from of the optimal energy efficiency is derived depending on channel state information. Based on the closed-form result, an iterative algorithm achieving optimal ener- gy efficiency adaptively is developed. Simulation shows that the proposed scheme can improve the energy efficiency and spectrum efficiency. Meanwhile, increasing the number of antennas and shrinking cell ra- dius are two important measures to enhance the energy efficiency and the spectrum efficiency.