Non-Orthogonal Algorithm with Fourier Transform Symmetry for Performance Enhancement of DCO-OFDM Systems

Abstract

The direct current (DC) biased optical orthogonal frequency division multiplexing (DCO-OFDM) technique has been widely used in visible light communication (VLC) systems due to its ease of installation. In this study, the Fourier symmetry (FT) scheme is proposed for the DCO-OFDM systems using BPSK modulation scheme. Furthermore, the proposed FT symmetry scheme is used either for increasing the data rate of the system or for enhancement the bit error rate (BER) system performances. In addition, the non-orthogonal algorithm (NOA) combined with the FT symmetry scheme is proposed for improving the DCO-OFDM system using QPSK modulation scheme. In the proposed NOA algorithm, the successive interference cancellation (SIC) is used at receiver to overcome interfering between real and imaginary parts. In the simulation, different transforms such as Fast Fourier transform (FFT), discrete cosine transform (DCT) and discrete Wavelet transform (DWT) are applied in the proposed schemes. Finally, simulation results show that the proposed schemes can significantly increase the overall system performance compared to the conventional scenario via different measure of performance such as BER, power spectral density (PSD) and peak to average power ratio (PAPR).