Efficient Data Transmission Using MPPM Dimming Control in Indoor Visible Light Communication

In conventional visible light communication (VLC) dimming control systems utilizing pulse width modulation (PWM), reducing the duty cycle will push up the receiver sensitivity requirement if the transmission rate is kept constant. In this paper, we investigate a dimming control mechanism in indoor VLC to satisfy the receiver sensitivity requirement, which can achieve efficient data transmission while maintaining communication quality. To transmit excess signals, we propose a modification based on a conventional PWM scheme, which combines multi-pulse position modulation (MPPM) dimming control pulses with orthogonal frequency division multiplexing (OFDM) signals. Numerical results show that by utilizing the MPPM pattern effect, excess signals are transmitted, which can reduce the quadrature amplitude modulation (QAM) symbol rate and alleviate the receiver sensitivity requirement under a steadily high data rate and a bit error rate (BER) that is less than 10^-3.