Abstract
Intelligent reflecting surface (IRS) has emerged as an innovative and disruptive solution to boost the spectral and energy efficiency and enlarge the coverage of wireless communication systems. However, the existing literature on IRS mainly concentrates on wireless communication systems assisted by single or multiple distributed IRSs, which are not always effective. In view of this issue, this paper considers a special double-IRS-assisted wireless communication system, where IRS1 and IRS2 are deployed near the base station (BS) and the user, respectively, and the transmitted signals reach the user via the cascaded BS-IRS1-IRS2-user channel only. We cooperatively optimize transmit and passive beamforming on the two IRSs based on the particle swarm optimization (PSO) algorithm to maximize the received signal power. Simulation indicates that despite no direct line-of-sight (LoS) path from the BS to the user, an excellent signal-to-noise ratio (SNR) is available at the receiver with the aid of two IRSs, which demonstrates that it is feasible to assist communication by double reflection links composed of two IRSs. Additionally, we unexpectedly find that when the positions of the two IRSs are fixed, by exchanging the positions of the BS and the user, the obtainable SNRs are similar.
Highlights
Due to its ability to smartly control signal reflection with low-cost passive reflecting elements, intelligent reflecting surface (IRS) ( referred to as reconfigurable intelligent surface (RIS) or large intelligent surface (LIS)) is an innovative and disruptive paradigm that can boost the spectral and energy efficiency and effectively enlarge the coverage of wireless communication systems [1,2,3]
The reflecting elements are typically made of thin materials, which are light with low power, so Intelligent reflecting surface (IRS) can be freely mounted on related objects in the environment to cater to diverse application scenarios
By cooperatively optimizing the transmit and passive beamforming on the two IRSs based on the particle swarm optimization (PSO) algorithm, the received signal-to-noise ratio (SNR) at the user are derived
Summary
Due to its ability to smartly control signal reflection with low-cost passive reflecting elements, intelligent reflecting surface (IRS) ( referred to as reconfigurable intelligent surface (RIS) or large intelligent surface (LIS)) is an innovative and disruptive paradigm that can boost the spectral and energy efficiency and effectively enlarge the coverage of wireless communication systems [1,2,3]. The existing literature on IRS mainly focuses on wireless communication systems assisted by single or multiple distributed IRSs (e.g., [6,7,8,9,10] [11,12,13,14,15]), with each IRS independently serving related users in range through one-time signal reflection For IRS to play a vital role in the above scenario, two or more IRSs could be exploited to cooperatively serve various terminals with the aid of multihop signal reflection to avoid scattered obstacles
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
