Matlab based platform for the evaluation of modulation techniques used in VLC

In this paper, we describe an experimental evaluation platform, which enables us to obtain the performance of baseband modulation techniques for usage in Visible Light Communication (VLC) applications. For the demonstration of the evaluation platform, we have chosen for Manchester encoding. This choice is exemplary, the described system is able to deal with a large set of analog and digital modulation techniques like Non-Return to Zero (NRZ), Return to Zero (RZ), Pulse Position Modulation (PPM), Binary Frequency Shift Keying, Dual Tone Multi-Frequency (DTMF), Phase Shift Keying (PSK), ... For the Manchester encoding, it is experimentally demonstrated that the statistical distribution of the received signal after matched filter operation, is Gaussian in nature. This allows us to make an estimation of the Bit Error Rate (BER) using Q-functions for Gaussian distributions. Our results demonstrate that the estimated BER strongly depends on the sampling rate at the receiver end. The sampling rate will therefor determine whether or not the receiver can receive NonLine Of Side (NLOS) signals at normal light intensities.