Bound Analysis of Number Configuration for Reflecting Elements in IRS-Assisted D2D Communications
Dong Li
Abstract
Intelligent reflecting surface (IRS)-assisted communication has emerged as a promising technology for 6G, and has drawn increasing attention in recent years. However, the problem on how to configure the number of reflecting elements has received little attention so far. In this letter, we investigate and analyze the number configuration for IRS-assisted D2D communications, where multiple transmitters send their signals to their corresponding receivers via the IRS. Our goal is to minimize the number of reflecting elements subject to the individual outage performance and the total/individual power consumption constraints. However, the intractable outage performance renders the formulated problem hard to solve. In order to circumvent this problem, we relax the optimization problem and propose two new optimization problems, in which we are able to derive two closed-form expressions for the optimized number of reflecting elements for bound analysis of the original problem. Simulation results demonstrate the derived bounds can be utilized to represent the optimal number configuration under certain noise/power regions or proper placement of the IRS.