Joint optimization of spectral efficiency and energy efficiency with low-precision ADCs in cell-free massive MIMO systems  

作　　者：Han WANG Chang SUN Jiamin LI Pengcheng ZHU Dongming WANG Xiaohu YOU 

机构地区：[1]National Mobile Communications Research Laboratory,Southeast University,Nanjing 210096,China [2]Purple Mountain Laboratories,Nanjing 211111,China

出　　处：《Science China(Information Sciences)》2022年第5期165-179,共15页中国科学（信息科学）（英文版）

基　　金：supported in part by National Key Research and Development Program(Grant No.2020YFB1806600);National Natural Science Foundation of China(Grant Nos.61971127,61871465,61871122);Fundamental Research Funds for the Central Universities。

摘　　要：In cell-free massive multiple-input multiple-output(MIMO)systems,it is beneficial to apply low-precision analog-to-digital converters(ADCs)to reduce power consumption,hardware cost,and the load on backhaul link.However,low-precision ADCs will result in serious degradation in spectral efficiency(SE).It is important to achieve a good tradeoff between SE and energy efficiency(EE)for cell-free massive MIMO systems with low-precision ADCs.In this paper,we first derive the closed-form expressions of uplink achievable rates with maximal ratio combining(MRC)receiver and zero-forcing(ZF)receiver in cell-free massive MIMO systems.Then we analyze the EE model of cell-free massive MIMO systems.Based on the above analysis,the tradeoff between SE and EE is studied.Moreover,we propose two quantization bit allocation algorithms to optimize the SE and EE jointly from the perspective of multi-objective optimization.One algorithm is based on the deep Q-network(DQN)and the other one is based on the non-dominated sorting genetic algorithmⅡ(NSGA-Ⅱ).The proposed algorithms provide more feasible solutions and achieve better system performance than equal quantization bit allocation algorithm.Numerical results verify the accuracy of the derived closed-form expressions and the effectiveness of the proposed optimization algorithms.

关 键 词：cell-free massive MIMO low-precision ADC spectral efficiency energy efficiency multi-objective optimization 

分 类 号：TN929.5[电子电信—通信与信息系统]