Fast-Reconfiguring Liquid-Crystal RIS for Pervasive Wireless Networks

TL;DR

LiquiRIS is a novel framework that significantly accelerates phase reconfiguration in liquid crystal RIS, reducing reconfiguration time by up to 71.61%, thus enhancing their practicality for wireless networks.

Contribution

LiquiRIS introduces a dynamic-aware approach that incorporates LC physical properties to enable faster reconfiguration of liquid crystal RIS.

Findings

Achieves up to 71.61% reduction in reconfiguration time.

Validated through experiments on a mmWave LC-RIS prototype.

Improves feasibility of LC-RIS deployment in wireless networks.

Abstract

Reconfigurable intelligent surfaces (RISs) have emerged as a key technology for dynamically reshaping wireless propagation, enhancing coverage and mitigating blockages to enable more pervasive network connectivity. However, implementing RISs at high frequencies remains challenging due to the cost and power demands of semiconductor-based components. To address these critical limitations, liquid crystals (LCs) technology has been identified as a promising low-cost and low-power alternative, giving rise to LC-RIS. The central challenge of this technology, however, lies in its limited responsiveness, as the slow molecular dynamics of LCs lead to long phase-shift reconfiguration times that restrict practicality. This paper presents LiquiRIS, a novel framework that enables substantially faster phase shifting in LC-RIS. By explicitly incorporating the physical dynamics of LC molecules into the phase-shift configuration process, LiquiRIS intelligently selects phase transitions that minimize the overall reconfiguration time. As a result, LiquiRIS achieves up to $ 71.61 \% $ reduction in overall reconfiguration time compared to conventional schemes, significantly improving the feasibility of LC-RIS deployment. The proposed framework is further validated through experiments on a mmWave LC-RIS prototype.