PAPR reduction of DC biased optical OFDM using combined clipping and PTS techniques

Visible light communications (VLC) has attracted increasing attention recently from both the industry and academic fields due to its untamed free bandwidth, which can be used to provide ultra-high speed wireless communications. However, high peak to average power ratio (PAPR) is a major issue in VLC system that is based on orthogonal frequency division multiplexing (OFDM) technology. PAPR causes nonlinearities in the transmitted signal and increases the complexity in retrieving the original signal at the receiver. In this paper, a new and hybrid PAPR reduction scheme is proposed for the OFDM-based VLC system using combined signal clipping techniques and partial transmit sequence (PTS). For this proposed hybrid scheme, the signal clipping method is combined with a modified PTS method that is suitable for VLC transmission in order to further reduce the PAPR as well as the bit error rate (BER) of the OFDM-based VLC system. Evaluation of the proposed hybrid scheme has been conducted for different modulation orders and the results has been compared to the clipping methods as well as conventional PTS techniques. The simulation results obtained show that the proposed hybrid scheme provides more than 3 dB PAPR reduction gain as compared to the basic VLC-OFDM signal at a CCDF of 10í1. In comparison with the signal clipping and conventional PTS method, the proposed method obtained PAPR reduction gain of approximately 0.4 dB and 2 dB, respectively. Moreover, the proposed scheme also outperforms the other methods in terms of BER performance for all scenarios