  Optical intelligent reflecting surface (OIRS) offers a new and effective
approach to resolving the line-of-sight blockage issue in visible light
communication (VLC) by enabling redirection of light to bypass obstacles,
thereby dramatically enhancing indoor VLC coverage and reliability. This
article provides a comprehensive overview of OIRS for VLC, including channel
modeling, design techniques, and open issues. First, we present the
characteristics of OIRS-reflected channels and introduce two practical models,
namely, optics model and association model, which are then compared in terms of
applicable conditions, configuration methods, and channel parameters. Next,
under the more practically appealing association model, we discuss the main
design techniques for OIRS-aided VLC systems, including beam alignment, channel
estimation, and OIRS reflection optimization. Finally, open issues are
identified to stimulate future research in this area.
