Maximization of Visible Light Communication Capacity Employing Quasi-Linear Preequalization with Peak Power Limitation

Abstract

We propose quasi-linear preequalization to be used for high speed visible light communication (VLC) system. Compared with zero-forcing preequalization, this kind of preequalization method is more suitable for a real VLC experimental system with peak power limitation. We carry out simulations and experiments to test the performance of quasi-linear preequalization. With this equalizer, the 3 dB bandwidth of the system can be extended from 17 MHz to 450 MHz. We implement 2.32 Gbit/s phosphorescent white light-emitting diode (LED) VLC transmission over 1 m distance with quasi-linear equalizer, bit and power loading OFDM, differential amplification positive intrinsic negative diode (PIN) receivers, and maximum ratio combining algorithm. To our knowledge, this is the highest transmission data rate based on a phosphorescent white LED VLC system.

Visible light communication system at 3.59 Gbit/s based on c-plane green micro-LED

“…However, full pre-equalization resulted in the decrease of the overall SNR when compensating for the high-frequency components of the signal, thus degrading the system performance [19] . It had been demonstrated that partial pre-equalization can address this contradictory trade-off and achieve a better system performance [20] . In the experiment, we changed the scaling factor α to adjust the ratio of partial pre-equalization.…”