Sparse Indexed OFDM Modulation Technique For Visible Light Communication (VLC) With reduced Peak-to-Average Power Ratio (PAPR)

Abstract

In this paper, diversity sparse activated subcarriers OFDM index modulation (DSASOFDM-IM) is proposed to improve the Energy Efficiency (EE) of interpolated sparse activated subcarriers OFDM index modulation (ISAS-OFDM-IM), which was proposed to improve spectrum efficiency (SE) and bite error rate (BER) of the OFDM modulation technique in visible light communication (VLC) systems. The EE improvement using DSAS-OFDM-IM resulted from improving the peak to average power ratio (PAPR) for the transmitted signal. DSAS-OFDM-IM and ISAS-OFDM-IM are considered as time domain interpolated version of the sparse activated subcarriers OFDM index modulation (SAS-OFDM-IM). SAS-OFDM-IM, improves the SE of the classical index modulation OFDM (IM-OFDM). Unfortunately this is done on the cost of degrading the BER due to burst errors. ISAS-OFDM-IM solves for the problem of burst errors by introducing zeros between samples in the time domain signal, which leads to a good improvements in BER at low values of signal to noise ratio (SNR). ISAS-OFDM-IM solves for the problem of the burst errors but degrading the PAPR due to the reduction in the average power. The proposed DSAS-OFDM-IM solves for the problem of burst errors and reducing the BER without affecting the PAPR of the SAS-OFDM-IM as was occurred by ISAS-OFDM-IM. Results indicate good improvements in SE, EE and BER of OFDM, which are considered as important requirements for VLC as a new trend in optical wireless communication. An improvement about 6 dB in BER was achieved by using DSAS-OFDM-IM technique.