多小区大规模分布式天线系统中下行链路能效研究

分析了多小区远程接入单元（RAU）个数、用户天线数、小区个数及发射功率等参数与系统下行链路能效（EE）最优时的关系.根据RAU与用户之间的距离，推导出系统吞吐量的解析式；根据具有路径损耗、阴影衰落、多径衰落特征的复合信道与多个实际功耗参数间的关系，建立了系统下行链路EE的优化模型；推导出系统EE与小区RAU个数、用户天线数、小区个数及发射功率的变化关系，并用算法得到了系统EE最优的理论值.理论分析和仿真结果验证了系统EE与影响其取值的多参数间关系的正确性，提出的系统EE优化算法具有迭代次数低的优点.

Research on Downlink Energy Efficiency of Multi-Cell Massive Distributed Antenna System

In multi-cell massive distributed wireless communication system, the relationship between the optimal downlink energy efficiency (EE) and the number of remote access units (RAUs), the number of user antennas, the number of cells and the transmitting power of multiple cells is studied. First, according to the distance between RAU and user, the analytic formula of system throughput is derived. Then, the downlink EE optimization model is established based on the relationship between the actual power consumption parameters and the composite channel, which includes path loss, shadow fading and multipath fading. Finally, based on this, the relationship between the EE and some impact factors including the number of RAUs, the number of user antennas, the number of cells and the transmitting power is deduced, meanwhile the corresponding algorithm is proposed to maximize the EE. Theoretical analysis and simulation results verify that the correctness of the relationship between system EE and multiple related parameters, and the proposed system EE optimization algorithm also has the advantage of low iteration times.