ADO-OFDM Based Visible Light Communication Impaired by Side Effect Modulation

Visible light communication (VLC) schemes provide high data rate communication using orthogonal frequency division multiplexing (OFDM). VLC can be impaired by side effect modulation (SEM) which is the unintended modulation caused by the power supply to manage the LED luminaires. In the literature, the impact of SEM has already been illustrated for DC-biased optical OFDM (DCO-OFDM) and asymmetrically clipped optical OFDM (ACO-OFDM). However, the impact has not been analyzed for any hybrid optical OFDM formats. This paper evaluates the influence of SEM for a hybrid optical OFDM termed as asymmetrically clipped DC-biased optical OFDM (ADO-OFDM). Our results show that a very small amount of SEM can remarkably decline the bit error rate (BER) performance of ADO-OFDM. It is found that the degradation due to SEM is more in ADO-OFDM compared to DCO-OFDM and ACO-OFDM. In the mitigation process, we estimated the SEM signal by subtracting the transmitted signal from the random average received signal, and then deducting the estimated SEM from the sampled received signal. Results show that the mitigation process greatly improves the BER performance of ADO-OFDM based VLC systems.