Analysis of the Multichannel WDM-VLC Communication System

Visible light communication (VLC) systems can achieve a higher data rate by increasing the number of channels using wavelength division multiplexing (WDM) technology. In this paper, we investigate the maximum number of channels and possible data rate in a WDM-VLC system based on light emitting diode (LED). Channel crosstalk from the spectral overlap of LEDs is analyzed by modeling LED spectra and the formula for crosstalk is derived from VLC link, including optical filter transmittance and detector spectral response. An experimental setup with different wavelength of LEDs is used to confirm the validity of the crosstalk analysis. The number of channels and data rate are determined by the SNR, including signal power, channel crosstalk, and detector noise. The results indicate that for indoor illumination standard with ON-OFF keying modulation and 33 nm channel spacing to achieve a BER of 10(-6), the maximum and optimal numbers of channels are 12 and 10, respectively. Additionally, the achievable data rate is 5.1 Gb/s which is about 9.3 times than that of the single channel system.