Orientation of a diffuse reflector for improved coverage in ID-FSOC for vehicular communications

Abstract

Even with no line-of-sight (LoS), stations can optically communicate using Indirect line-of-sight diffused-light free-space optical communications (ID-FSOC). A diffuse reflector in the LoS of the stations reflects diffused light to them. But despite having diffused reflections in almost all directions, the orientation of a flat diffuse reflector defines the communications coverage. Therefore, there is a need for a tool that describes the relationship between the orientation of the diffuse reflector, the coverage, and the achievable data rates for the effective deployment of ID-FSOC. In this paper, we propose a model of the coverage of a diffuse reflector that can allow us to estimate the achievable data rates as a product of the orientation of the diffuse reflector. We use ground-to-vehicle communications as a demanding example scenario. We also propose RISE, a heuristic algorithm that optimizes the horizontal and vertical tilt angles of the reflector to maximize the achievable data rates. We show that 50% or more of the transmitted power of light is reflected, thereby achieving 1 Gbps or higher data rates across the optical local area network.