SARIS: Scattering Aware Reconfigurable Intelligent Surface model and Optimization for Complex Propagation Channels

TL;DR

This paper introduces a realistic electromagnetic model for reconfigurable intelligent surfaces (RIS) that accounts for environmental scattering objects, along with an efficient algorithm to optimize RIS and transmitter configurations for improved wireless communication performance.

Contribution

It presents a new electromagnetically consistent RIS channel model incorporating scattering objects and an optimization algorithm for joint RIS and transmitter configuration.

Findings

The proposed model accurately captures interactions with scattering objects.

The optimization algorithm converges reliably and improves system sum-rate.

Numerical results demonstrate significant performance gains over existing methods.

Abstract

The reconfigurable intelligent surface (RIS) is an emerging technology that changes how wireless networks are perceived, therefore its potential benefits and applications are currently under intense research and investigation. In this letter, we focus on electromagnetically consistent models for RISs inheriting from a recently proposed model based on mutually coupled loaded wire dipoles. While existing related research focuses on free-space wireless channels thereby ignoring interactions between RIS and scattering objects present in the propagation environment, we introduce an RIS-aided channel model that is applicable to more realistic scenarios, where the scattering objects are modeled as loaded wire dipoles. By adjusting the parameters of the wire dipoles, the properties of general natural and engineered material objects can be modeled. Based on this model, we introduce a provably convergent and efficient iterative algorithm that jointly optimizes the RIS and transmitter configurations to maximize the system sum-rate. Extensive numerical results show the net performance improvement provided by the proposed method compared with existing optimization algorithms.