Optimal AP Deployment in Cell-Free Massive MIMO Systems with LoS/NLoS Transmissions:A Stochastic Geometry Approach  

作　　者：Jiang Ling Zhang Qi Zhu Hongbo 

机构地区：[1]Jiangsu Key Laboratory of Wireless Communications,Nanjing University of Posts and Telecommunications,Nanjing 210003,China

出　　处：《China Communications》2024年第9期146-158,共13页中国通信（英文版）

基　　金：supported in part by the National Natural Science Foundation of China under Grant 62171231;in part by the Jiangsu Provincial Key Research and Development Program(No.BE2020084-1)。

摘　　要：Cell-free massive multiple-input multipleoutput(MIMO)is a promising technology for future wireless communications,where a large number of distributed access points(APs)simultaneously serve all users over the same time-frequency resources.Since users and APs may locate close to each other,the line-of-sight(Lo S)transmission occurs more frequently in cell-free massive MIMO systems.Hence,in this paper,we investigate the cell-free massive MIMO system with Lo S and non-line-of-sight(NLo S)transmissions,where APs and users are both distributed according to Poisson point process.Using tools from stochastic geometry,we derive a tight lower bound for the user downlink achievable rate and we further obtain the energy efficiency(EE)by considering the power consumption on downlink payload transmissions and circuitry dissipation.Based on the analysis,the optimal AP density and AP antenna number that maximize the EE are obtained.It is found that compared with the previous work that only considers NLo S transmissions,the actual optimal AP density should be much smaller,and the maximized EE is actually much higher.

关 键 词：cell-free massive MIMO energy efficiency LoS/NLoS transmissions stochastic geometry 

分 类 号：TN929.5[电子电信—通信与信息系统]