ORIS allocation to minimize the outage probability in a multi-user VLC scenario

Visible Light Communication (VLC) is a promising solution to address the growing demand for wireless data, leveraging the widespread use of light-emitting diodes (LEDs) as transmitters. However, its deployment is challenged by link blockages that cause connectivity outages. Optical reconfigurable intelligent surfaces (ORISs) have recently emerged as a solution to mitigate these disruptions. This work considers a multi-user VLC system and investigates the optimal association of ORISs to LEDs and users to minimize the outage probability while limiting the number of ORISs used. Numerical results from our proposed optimization algorithm demonstrate that using ORISs can reduce the outage probability by up to 85% compared to a no-ORIS scenario.

On Using Curved Mirrors to Decrease Shadowing in VLC

Visible light communication (VLC) complements radio frequency in indoor environments with large wireless data traffic. However, VLC is hindered by dramatic path losses when an opaque object is interposed between the transmitter and the receiver. Prior works propose the use of plane mirrors as optical reconfigurable intelligent surfaces (ORISs) to enhance communications through non-line-of-sight links. Plane mirrors rely on their orientation to forward the light to the target user location, which is challenging to implement in practice. This paper studies the potential of curved mirrors as static reflective surfaces to provide a broadening specular reflection that increases the signal coverage in mirror-assisted VLC scenarios. We study the behavior of paraboloid and semi-spherical mirrors and derive the irradiance equations. We provide extensive numerical and analytical results and show that curved mirrors, when developed with proper dimensions, may reduce the shadowing probability to zero, while static plane mirrors of the same size have shadowing probabilities larger than 65%. Furthermore, the signal-to-noise ratio offered by curved mirrors may suffice to provide connectivity to users deployed in the room even when a line-of-sight link blockage occurs.