Enhanced tolerance against optical background noise in VLC link by using line coded signal with receiver filter

Abstract

The performance of visible light communication (VLC) link is significantly affected by optical background noises generated by fluorescent light or AC driven light emitting diode (LED) and eventually degrades the data rate due to the in-band interference between signal and noise. Here, bandwidth efficient 8b10b dc-balanced line coding and post-detection electrical filter based VLC link is demonstrated to improve the system tolerance against the optical background noises. The 8b10b coded signal with low frequency components near DC ensure that the crosstalk noise is effectively minimized by spectral separation of signal and noise contributions. Moreover, the use of post detection filter for 8b10b coded signal gives an additional attenuation of noise frequency to further improve the system tolerance against optical background noise. The proposed VLC link is investigated thoroughly in several noise power levels as well as different noise frequencies, where the results indicate improved system tolerance against noise power by about 6.5 dB in compare to conventional data signal. The demonstration also shows that the proposed scheme maintains a low BER for the noise frequency up to 500 kHz for 10 Mb/s data modulation having a good eye opening.