A 100Mbps Visible Light Communication System Using Optical Wireless Channel for Indoor Application Based on Composite White Light Generated Using RGB LEDs

This work is based upon the concept of illumination and communication using LEDs. The dependency on wavelength of silicon photodiodes (Si PD) used in optical communications is studied by means of simulation. The sensitivity of the Si PD is compared for three wavelengths corresponding to red (680nm), green (530nm) and blue (460nm). The induced photocurrent in the PD for red wavelength is high as compared to green and blue at low received optical power. The results also affirm that for varying bitrates the red wavelength has better BER performance. The least value of BER achieved here is of the order 10-21. These three wavelengths contribute to form white light compositely. This composite white light is used for visible light communication (VLC) in optical wireless channel (OWC) for indoor applications. The LEDs are intensity modulated at the transmitter and directly detected at the receiver. The OWC length is varied from 1m to 10m with the transmitter and receiver aperture diameter set to 0.5cm and 0.1cm respectively. The results show that using the OOK (on-off keying) the data rate tends to have an upper limit of 100 Mbps, when 680nm wavelength alone is modulated keeping the other two wavelengths unchanged.