RIS辅助去蜂窝大规模MIMO系统低复杂度预编码算法设计
Low Complexity Precoding Algorithm Design for RIS-aided Cell-free Massive MIMO Systems
胡亚婷 1史恩宇 1许柏恺 1郑家康 1章嘉懿 1艾渤1
作者信息
- 1. 北京交通大学电子信息工程学院,北京 100044
- 折叠
摘要
构思了一种智能超表面(Reconfigurable Intelligent Surface,RIS)辅助去蜂窝大规模多输入多输出(Cell-free Massive Multiple-Input Multiple-Output,CF mMIMO)通信系统,提出了一种低复杂度预编码和 RIS反射相位交替优化(Alternating Optimization,AO)算法.对于传统正则化迫零(Regularized Zero Forcing,RZF)预编码算法复杂度过高的问题,利用共轭梯度(Conjugate Gradients,CG)法,提出一种低复杂度的RZF-CG预编码算法,将RZF预编码的逆矩阵转换为线性方程组最小化问题,推导算法的残差以更新搜索方向,迭代求解逆矩阵.以最大化系统用户的总频谱效率为目标,推导了RIS相位闭合表达式,基于统计的信道状态信息提出一种低复杂度的投影梯度上升(Projected Gradient Ascent,PGA)算法.仿真结果表明,所提的AO算法能有效地提升系统性能,算法复杂度降低了约 73.2%.
Abstract
In this paper,we consider a Reconfigurable Intelligent Surface(RIS)-aided Cell-free massive Multiple-Input Multiple-Output(CF mMIMO)communication system,and propose a low-complexity precoding and RIS reflection phase shifts Alternating Opti-mization(AO)algorithm.In order to solve the problem that traditional Regularized Zero Forming(RZF)precoding algorithm is too complex,we propose a low-complexity RZF-CG precoding algorithm using the Conjugate Gradients(CG)method,which converts the in-verse matrix of RZF precoding into a linear equation system minimization problem,derives the residuals of the algorithm to update the search direction,and iteratively solves the inverse matrix.With the goal of maximizing the total spectral efficiency of the system user,we derive the RIS phase closed-form expression and then propose a low-complexity Projected Gradient Ascent(PGA)algorithm based on statistical channel state information.Simulation results show that the proposed AO algorithm can not only effectively improve system per-formance,but also reduce the algorithm complexity by about 73.2%.
关键词
智能超表面/去蜂窝大规模多输入多输出通信系统/预编码/低复杂度Key words
RIS/CF mMIMO systems/precoding/low-complexity引用本文复制引用
出版年
2024
国家科技期刊平台
NSTL
万方数据