ERPO-OFDM for data transmission and brightness control in visible light communication system

Visible light communication system using orthogonal frequency division multiplexing (OFDM), a multicarrier modulation supports information transmission through light emitting diodes (LEDs). The proposed framework coalesce the asymmetrically clipped optical OFDM (ACO-OFDM) and the brightness control sequence (BCS) signal. The BCS signal is generated using digital dimming technique. The technique used is variable delta sigma modulation (vDSM). The BCS sequence controls the LEDs brightness with its varying duty cycle. The proposed system supports both data transmission and illumination control simultaneously. The deployed digital dimming technique avoids flickering and blinking while dimming. The simulation results shows better bit error rate performance for the proposed scheme, enhanced reverse polarity optical OFDM (ERPO-OFDM) which combines inverted ACO-OFDM and vDSM.