一种基于IRS和UAV辅助通信系统分析

Analysis of IRS and UAV-aided Communication System

为提升智能反射面(IRS)和无人机(UAV)辅助混合通信系统的数据传输速率,提出一种优化用户速率方案。该方案考虑了全双工UAV(FD-UAV)辅助传输模式,IRS辅助传输模式和IRS、FD-UAV辅助混合传输模式(IRS-FD-UAV)。建立联合IRS被动波束形成相位(PBP)和UAV/IRS位置的最大化用户速率的目标问题。考虑目标问题的非凸性,利用块坐标下降法(BCD)将原目标问题分解成2个子问题,分别利用黎曼共轭梯度法和交替求解法求解。性能分析表明,相比于FD-UAV和IRS辅助传输模式,IRS-FD-UAV辅助传输模式具有较高的传输速率。

To improve user’s rate in intelligent reflecting surface(IRS)and unmanned aerial vehicle(UAV)-aided hybrid communication system,an optimized user rate scheme is proposed in this paper.In the scheme three different transmission modes are taken into account,i.e.,①FD-UAV(full duplex-UAV,FD-UAV)-aided transmission;②RIS-aided transmission;③joint RIS-FD-UAV transmission.Firstly,the joint passive beamforming phase and position of UAV/RIS optimization problem is formulated to maximize the user’s rate.Due to the non-convex of the optimization problem,the optimization problem is divided into two sub-problems through block coordinate descent approach.Then,the two sub-problems are solved respectively by Riemannian conjugate gradient method and sequential approach.The performance analysis shows that the joint RIS-FD-UAV transmission mode achieves the best user’s rate among all three modes.At the same time,the PBP has a greater impact on user’s rate than position of UAV/IRS.In addition,we demonstrate the impact of reflecting elements and available transmit power on the system’s performance.