Analysis of nonline-of-sight visible light communications

We analyze the channel properties of a nonline-of-sight (NLOS) ceiling-to-device and device-to-device visible light communication systems by considering various receivers' orientation and variable fields of view (FOVs). Analyses based on the recursive indoor channel model show that for a particular transmitter configuration, the pure NLOS path can offer higher 3-dB channel bandwidth (up to 14 MHz) compared with the link with LOS and NLOS components. We also show how the receiver rotation (orientation) influences the probability of receiving signals via the NLOS path compared with the LOS and NLOS paths. Moreover, based on the experimental campaign, we demonstrate that shadowing observed at the receiver due to people's movement results in decreased received power level (up to 1.8 dB), thus resulting in reshaping of the probability density function of received power.