Non-line-of-sight Channel Impulse Response Characterisation in Visible Light Communications

One of the important issues in an indoor visible light communication (VLC) system is the multi-path (MP) effect due to reflections. Generally, the MP effect can be characterised by the channel impulse response (CIR). Methods based on ray-tracing/Monte Carlo simulations are primarily used to obtain these impulse responses, but this generally leads to time consuming computer simulations. In this study, an analytical approach is proposed to directly and accurately calculate the non-line-of-sight (NLOS) components of the CIR due to the interior surface reflections in a room. The proposed method could be used in system-level simulations of a networked VLC system (also referred to as a LiFi attocell network), which requires a large number of channels with different transmitter and receiver deployments to be generated in a computationally efficient manner.