Fig. 1. Block diagram of the proposed adaptive OFDM VLC system (TX: transmitter; RX: receiver).

Fig. 2. Experimental setup for the proposed system.

Fig. 3. Normalized amplitude frequency response of the equivalent channel.

Fig. 4. Measured electrical spectra of the received signals for the (a) 25 MHz case, (b) 12.5 MHz case, and (c) 6.25 MHz case.

Fig. 5. SNR and power allocated results for the (a) 25 MHz case, (b) 12.5 MHz case, and (c) 6.25 MHz case.

Fig. 6. Bits allocated results (BERT=0.001) for the (a) 25 MHz case, (b) 12.5 MHz case, and (c) 6.25 MHz case.

Fig. 7. BER versus spectrum efficiency with and without an adaptive transmission scheme for the (a) 25 MHz case, (b) 12.5 MHz case, and (c) 6.25 MHz case.