Modelling and analysis of M-ary variable pulse position modulation for visible light communications

Visible light communication (VLC) is an emerging communication paradigm that supports illumination and data transmission simultaneously. To provide dimming control functionality, a range of dimmable modulation methods have been exploited. Among them, the variable pulse position modulation (VPPM) scheme, which is deployed using the IEEE 802.15.7 VLC standard is very simple and easy to implement. On the other hand, it has a limited data rate because it just uses binary PPM for data transmission. This study proposes the M-ary VPPM (M-VPPM) scheme to increase the data rate of the VPPM scheme. To evaluate the performance of this scheme, the modelling of the transmitter, optical wireless channel and the receiver for M-VPPM are provided. In addition, the error probability according to the dimming ratio and modulation order was analysed mathematically. The simulation results showed that the analytical bounds on the error probability are tight, which provides key insights into the performance trade-off of M-VPPM in a dispersive VLC channel environment.