Huygens-Fresnel Model Based Position-Aided Phase Configuration for 1-Bit RIS Assisted Wireless Communication

TL;DR

This paper introduces a position-aided phase configuration method for RIS-assisted wireless communication that leverages Fresnel zone properties to reduce CSI overhead and improve signal control.

Contribution

It proposes a novel position-based RIS configuration scheme using Fresnel zones and joint absorption/reflection elements, reducing reliance on complex CSI feedback.

Findings

Effective RIS control without complex CSI

Robustness against position errors and mobility

Validated through simulations

Abstract

Reconfigurable intelligent surface (RIS), composed of nearly passive elements, is regarded as one of the potential paradigms to support multi-gigabit data in real-time. However, in traditional CSI (channel state information) driven frame, the training overhead of channel estimation greatly increases as the number of RIS elements increases to intelligently manipulate the reflected signals. To conveniently use the reflected signal without complex CSI feedback, in this paper we propose a position-aided phase configuration scheme based on the property of Fresnel zone. In particular, we design the impedance based discrete RIS elements with joint absorption mode and reflection mode considering the fabrication complexities, which integrated the property of the Fresnel zone to resist the impact of position error. Then, with joint absorption and 1-bit reflection mode elements, we develop the two-step position-aided ON/OFF states judgement (TPOSJ) scheme and the frame structure to control the ON/OFF state of RIS, followed by analyzing the impacts of mobility and position error on our proposed scheme. Also, we derive the Helmholtz-Kirchhoff integral theorem based power flow. Simulations show that the proposed scheme can manipulate the ON/OFF state intelligently without complex CSI, thus verifying the practical application of our proposed scheme.