Design and experiment of post-equalization for OOK-NRZ visible light communication system

Abstract:

Considering that the white LED’s spectral response decreases exponentially with the increase of carrier frequency for the on-off-keying non-return-to-zero (OOK-NRZ) visible light communication (VLC) data links, a first-order RC high-pass filter is designed and fabricated as a post-equalizer (PE) to compensate the LED spectral response. Formulation and simulation are both available for illustrating the VLC performance with and without PE. Experiments are performed in detail for the fabricated OOK-NRZ VLC system integrated with PE. The data transmission results show that by using PE, the measured carrier bandwidth is enhanced from 0.8 (0.4–1.2) MHz to 1.7 (0–1.7) MHz, and the bit-error-rate (BER) is less than 10⁻⁹. It proves the feasibility of the proposed scheme in OOK-NRZ VLC data links.