Channel Estimation for Optical IRS-Assisted VLC System via Spatial Coherence

TL;DR

This paper introduces a novel channel estimation method for optical IRS-assisted VLC systems that leverages spatial coherence properties to efficiently estimate the channel without requiring perfect CSI.

Contribution

It unveils the spatial coherence characteristics of OIRS and proposes a sampling-based estimation algorithm that improves channel estimation efficiency in VLC systems.

Findings

Validated the OIRS spatial coherence through simulations

Demonstrated the effectiveness of the proposed estimation algorithm

Achieved accurate channel estimation with reduced complexity

Abstract

Optical intelligent reflecting surface (OIRS) has been considered a promising technology for visible light communication (VLC) by constructing visual line-of-sight propagation paths to address the signal blockage issue. However, the existing works on OIRSs are mostly based on perfect channel state information (CSI), whose acquisition appears to be challenging due to the passive nature of the OIRS. To tackle this challenge, this paper proposes a customized channel estimation algorithm for OIRSs. Specifically, we first unveil the OIRS spatial coherence characteristics and derive the coherence distance in closed form. Based on this property, a spatial sampling-based algorithm is proposed to estimate the OIRS-reflected channel, by dividing the OIRS into multiple subarrays based on the coherence distance and sequentially estimating their associated CSI, followed by an interpolation to retrieve the full CSI. Simulation results validate the derived OIRS spatial coherence and demonstrate the efficacy of the proposed OIRS channel estimation algorithm.