智能超表面辅助多用户系统的通用低复杂度波束成形设计  

General Low-complexity Beamforming Designs for Reconfigurable Intelligent Surface-aided Multi-user Systems

作　　者：陈晓[1] 施建锋 朱建月 潘存华 CHEN Xiao;SHI Jianfeng;ZHU Jianyue;PAN Cunhua(School of Artificial Intelligence/School of Future Technology,Nanjing University of Information Science and Technology,Nanjing 210044,China;School of Electronic and Information Engineering,Nanjing University of Information Science and Technology,Nanjing 210044,China;National Mobile Communications Research Laboratory,Southeast University,Nanjing 210096,China)

机构地区：[1]南京信息工程大学人工智能学院(未来技术学院),南京210044 [2]南京信息工程大学电子与信息工程学院,南京210044 [3]东南大学移动通信国家重点实验室,南京210096

出　　处：《电子与信息学报》2025年第1期128-137,共10页Journal of Electronics & Information Technology

基　　金：国家自然科学基金(62101273,62201274);江苏省自然科学基金(BK20210641,BK20220439)。

摘　　要：针对可重构智能超表面(RIS)辅助多用户系统中基站和RIS联合波束成形设计问题,该文提出通用低复杂度联合波束成形设计方案。首先,分析RIS辅助多用户系统以最大化和数据速率为目标的联合波束成形非凸优化问题。其次,利用波束导向矢量近似正交性设计RIS反射矩阵,进一步利用迫零方法设计基站发射波束成形,并对多用户进行功率分配优化。最后,讨论该方案适用性并对比该方案的计算复杂度相比现有方案降低了一个数量级。仿真结果表明,所提通用低复杂度波束成形设计可以获得较高和数据速率,并且采用最优功率分配可以进一步提高和数据速率。此外,仿真结果和理论分析都表明系统和数据速率随RIS位置的变化而变化,该结论为RIS位置的选择提供参考依据。Objective Reconfigurable Intelligent Surface(RIS),an innovative technology for 6G communication,can effectively reduce hardware costs and energy consumption.Most researchers examine the joint BeamForming(BF)design problem in RIS-assisted Multiple-Input Single-Output(MISO)systems or single-user Multiple-Input Multiple-Output(MIMO)systems.However,few investigate the non-convex joint BF optimization problem for RIS-assisted multi-user MISO systems.The existing joint BF design approaches for these systems primarily rely on iterative algorithms that are complex,and some methods have a limited application range.Methods To address the issue,general low-complexity joint BF designs for RIS-assisted multi-user systems are considered.The communication system consists of a Base Station(BS)with an M-antenna configuration utilizing a Uniform Rectangular Array(URA),a RIS with N reflecting elements also arranged in a URA,and K single-antenna User Equipment(UEs).It is assumed that the transmission channel between the BS and UEs experiences blocking due to fading and potential obstacles in a dynamic wireless environment.The non-convex optimization challenge of joint BF design is analyzed,with the goal of maximizing the sum data rate for RIS-aided multi-user systems.The design process involves three main steps:First,the RIS reflection matrix${\boldsymbol{\varTheta}}$is designed based on the perfect channel state information obtained from both the BS-RIS and RIS-UE links.This design exploits the approximate orthogonality of the beam steering vectors for all transmitters and receivers using the URA(as detailed in Lemma 1).Second,the transmit BF matrix W at the BS is derived using the zero-forcing method.Third,the power allocation at the BS for multiple users is optimized using the Water-Filling(WF)algorithm.The proposed scheme is applicable to both single-user and multi-user scenarios,accommodating Line-of-Sight(LoS)paths,Rician channels with LoS paths,as well as Non-LoS(NLoS)paths.The computational complexity of the proposed joint B

关 键 词：智能超表面 波束成形 和数据速率 低复杂度 

分 类 号：TN929.5[电子电信—通信与信息系统]