IRS和UAV-IRS共同辅助中继网络公平下行通信方案  

IRS and UAV-IRS co-assisted relay network fair downlink communication scheme

作　　者：许满青 张毅[1] 徐川[1] 徐小涛 XU Manqing;ZHANG Yi;XU Chuan;XU Xiaotao(School of Communications and Information Engineering,Chongqing University of Posts and Telecommunications,Chongqing 400065,P.R.China;College of Information and Communication,National University of Defense Technology,Wuhan 430019,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]国防科技大学信息通信学院,武汉430019

出　　处：《重庆邮电大学学报（自然科学版）》2024年第5期924-934,共11页Journal of Chongqing University of Posts and Telecommunications(Natural Science Edition)

基　　金：国家自然科学基金项目(62171070);重庆市自然科学基金创新发展联合基金重点项目(CSTB2023NSCQ-LZX0129)。

摘　　要：针对长距离中继通信系统中地面用户(ground user,GU)公平性不足和系统灵活性不高的问题,提出一种智能反射面(intelligent reflecting surface,IRS)和机载智能反射面(unmanned aerial vehicle-IRS,UAV-IRS)共同辅助的中继网络多用户公平下行通信传输方案。为实现该中继网络下行链路的通信公平,通过联合优化系统通信调度、系统时隙分配参数、IRS和UAV-IRS反射相移矩阵以及UAV-IRS飞行轨迹来最大化系统用户最小吞吐量。由于该优化问题是非凸问题,将优化问题分解为4个非凸子问题,引入线性规划(linear programming,LP)、松弛变量和连续凸近似(successive convex approximations,SCA)等方法分别对4个子问题进行求解,通过交替优化(alternating optimization,AO)算法得到原非凸问题的近似解。仿真结果表明,所提方案在有效提升系统用户最小吞吐量的同时保障了多用户通信的公平性,并发现系统用户最小吞吐量与IRS和UAV-IRS的反射元件数量、UAV-IRS飞行轨迹以及IRS和中继所处地理位置等因素有关。This paper addresses the issues of insufficient fairness for ground users(GUs)and low system flexibility in long-distance relay communication systems by proposing a downlink communication scheme that utilizes both intelligent reflecting surfaces(IRS)and unmanned aerial vehicle-IRS(UAV-IRS)for multi-user fair communication in relay networks.To achieve communication fairness in the downlink of this relay network,the scheme jointly optimizes system communication scheduling,time slot allocation parameters,IRS and UAV-IRS reflection phase shift matrices,and UAV-IRS flight trajectories to maximize the minimum throughput among system users.Given that the optimization problem is non-convex,it is decomposed into four non-convex subproblems.Methods such as linear programming(LP),relaxed variables,and successive convex approximations(SCA)are used to solve each subproblem,leading to an approximate solution for the original non-convex problem via alternating optimization(AO).Simulation results indicate that the proposed scheme effectively enhances the minimum throughput for system users while ensuring fairness in multi-user communication.It is also observed that the minimum throughput is influenced by factors such as the number of reflecting elements on IRS and UAV-IRS,UAV-IRS flight trajectories,and the geographical locations of the IRS and relays.

关 键 词：智能反射面 无人机 中继通信 时隙分配 

分 类 号：TN925[电子电信—通信与信息系统]