Path Loss Modeling for RIS-Assisted Wireless System with Direct Link and Elevation Factors

TL;DR

This paper develops an analytical path loss model for RIS-assisted wireless systems that incorporates elevation factors and direct links, providing more accurate signal estimation and deployment insights.

Contribution

It introduces a novel analytical model that accounts for elevation and direct link effects in RIS-assisted systems, enhancing existing path loss models.

Findings

Elevation factors significantly impact path loss predictions.

Including direct link improves model accuracy.

Simulation confirms benefits of elevated RIS configurations.

Abstract

The present path loss models for wireless systems employing reconfigurable intelligent surfaces (RIS) do not account for the elevation of the transmitter, receiver, and RIS module. In this paper, we develop an analytical model for path loss of a wireless system utilizing an NxM-element RIS module positioned above the ground surface with elevated transmitter and receiver configurations. Furthermore, we integrate the direct link into the path loss model to enhance its applicability, a crucial aspect often neglected in previous research. We also present simplified analytical expressions for path loss under various configurations, including near-field and far-field scenarios. These expressions elucidate the impact of elevation factors on path loss, facilitating more accurate signal quality estimation at the receiver. Simulation results corroborate that accounting for elevated RIS modules and transceiver units can yield improved deployment strategies for RIS-based wireless systems.