On the Optimal Evaluation of the Irradiance Angle and the Orientation in OIRS-Aided Vehicle Communication Systems

The characteristics of visible light communication (VLC) make them a potential candidate for beyond fifth generation (5G) cellular standards, specifically for applications related to short-distance and high-throughput indoor communication scenarios. However, in an outdoor environment specifically at the road intersection, VLC faces some challenges such as line-of-sight (LoS) link blockages due to obstacles, and uneven power distribution due to unguided non-line-of-sight (NLoS) reflections, which limits its large-scale deployment in dense scenarios. In this paper, we propose an optical intelligent reflecting surface (OIRS)-aided V2V system with an optimal irradiance angle method to guide the NLoS link towards the desired user in order to maximize the received power at the user. Further, for a given user distribution, we propose a novel algorithm to find the optimal orientation of the OIRS element that will produce the maximum power at the receiver. The proposed algorithm returns the rotational angles which will result in the optimal orientation of the OIRS elements with the time complexity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$O(1)$</tex-math></inline-formula> . In addition, closed-form expression is derived for the obtained optimal irradiance angle, essentially a cosine of the irradiance angle for an element of OIRS based on the location of OIRS and the receiver's (user) position.