Impact of dimming and aperture on the optical wireless performance in public street lighting

Visible light communication (VLC) is an emerging technology for public street lighting. The paper comprises two parts. A spatial scaled simulation model for Signal to Noise Ratio (SNR) analysis and a spatial scaled experiment are elaborated to evaluate the VLC propagation channel model in an inhomogeneous street lighting channel. As a first result, a minor improved non Line of Sight (NLoS) ceiling bounce simulation substantially agrees with the measurement. The model is sufficient adequate for a path loss estimation in a larger spatial dimension. As a second result, the receiver requires a huge aperture of 10 to 30 cm diameter for a communication performance of wireless sensor networks between the lights. The Line of Sight (LoS) link requires nearly a quarter of the surface but pointing errors are likely due to the rural outdoor environment. Furthermore, the spatial simulation resolution considering a small Field of View (FOV) influences the gain of up to 5 dB and has therefore been identified as a new error source in the NLoS propagation model whereby the influence is negligible at medium distances.