Efficient Analytical Calculation of Non-Line-of-Sight Channel Impulse Response in Visible Light Communications

This study provides an analytical method to calculate the non-line-of-sight (NLoS) channel impulse response (CIR) in visible light communication (VLC) systems based on intensity modulation and direct detection (IM/DD). In this method, the NLoS channel is decomposed into a number of components with different propagation categories. These propagation categories are defined according to the number of reflections and the reflective surfaces that the light undergoes. The CIR corresponding to each light propagation category is analysed and the overall NLoS CIR is approximated by the combination of the calculated CIR components in different propagation categories. The proposed method has the major advantage of offering accurate results with very low computational complexity. Typically, a NLoS CIR with a time resolution of 0.1 ns can be generated within a second in MATLAB. Furthermore, the analytical results derived herein could be used as an analytical tool for the VLC channel characterisation study in future research.