CIE x048-PO57 PDF

Visible Light Communication (VLC) requires better optical channel modelling if it is to be used in vehicular applications. Therefore, the radiation transfer between the transmitter and emitter shall be well defined in all circumstances. An important aspect herein is the determination of the Limiting Photometric Distance (LPD), which characterises the transition between near-field and far-field description of the light source. The LPD allows to determine whether simplified equations can be used in the V-VLC channel model. A first step towards this goal is the analysis of a simple, narrow beam, disk-source with uniform luminance. On-axis, analytical solutions exist. Off-axis, however, no closed loop solutions exist. Therefore, a numerical approach is used, which is validated against on-axis measurements and then expanded to off-axis scenarios.  This allows to compute the on- and off-axis LPD of the light source, an important step towards a more accurate description of complex systems for VLC.