RIS辅助的无小区大规模MIMO系统中信道估计及谱效分析  

Channel estimation and spectral efficiency analysis for RIS-aided cell-free massive MIMO systems

作　　者：刘梦源 景小荣[1,2,3] LIU Mengyuan;JING Xiaorong(School of Communications and Information Engineering,Chongqing University of Posts and Telecommunications,Chongqing 400065,P.R.China;Chongqing Key Laboratory of Mobile Communications Technology,Chongqing 400065,P.R.China;Engineering Research Center of Mobile Communications,Ministry of Education,Chongqing 400065,P.R.China)

机构地区：[1]重庆邮电大学通信与信息工程学院,重庆400065 [2]移动通信技术重庆市重点实验室,重庆400065 [3]移动通信教育部工程研究中心,重庆400065

出　　处：《重庆邮电大学学报（自然科学版）》2023年第6期1028-1037,共10页Journal of Chongqing University of Posts and Telecommunications(Natural Science Edition)

基　　金：上海星思半导体有限责任公司横向课题(XS-CQ-001)。

摘　　要：无小区大规模多输入多输出(cell-free massive multiple input multiple output,Cell-Free mMIMO)技术打破传统蜂窝小区边界,从根本上解决了小区间干扰问题,从而大幅度提高系统吞吐量;同时,基于超材料的可重构智能表面(reconfigurable intelligent surface,RIS)可实现对无线电磁环境的智能操控。针对RIS辅助的无小区mMIMO系统,基于叠加导频(superimposed pilot,SP)复用模式,提出了一种基于吉洪诺夫正则化(Tikhonov regularization,TR)的迭代信道估计方法,在此基础上,从理论上推导了系统上行频谱效率(spectral efficiency,SE)的闭合表达式,通过最大化系统SE研究了SP复用模式的最优功率分配因子。仿真结果表明,采用该信道估计方法可有效提升系统SE。Cell-Free massive multiple input multiple output(Cell-Free mMIMO)technique breaks the traditional cellular cell boundaries and fundamentally solves the inter-cell interference problem,thus significantly improving the system throughput.Meanwhile,the reconfigurable intelligent surface(RIS)made of metamaterials can achieve intelligent control of the radio-magnetic environments.An iterative channel estimation method based on tikhonov regularization(TR)is proposed for the RIS-aided Cell-Free mMIMO system based on the superimposed pilot(SP)multiplexing mode.Based on it,the theoretical derivation of the system uplink spectral efficiency(SE)is performed.The optimal power allocation factor of the SP multiplexing mode is then investigated by maximizing the system SE.Simulation results show that the channel estimation method can effectively improve the system SE.

关 键 词：无小区大规模多输入多输出 可重构智能表面 吉洪诺夫正则化 叠加导频 频谱效率 

分 类 号：TN929[电子电信—通信与信息系统]