Performance of Zero-Biased NOMA VLC System

Non orthogonal multiple access (NOMA) is used in visible light communication (VLC) to achieve better system capacity. In VLC, unipolar signal is required which is normally achieved using DC-bias, clipping or flipping of negative portion. However, these techniques result in energy and spectral inefficiency. In this work, we proposed NOMA for VLC using zero bias without any clipping. The system is compared with OFDMA VLC for their rate pairs between the users, the spectral efficiency (SE) and energy efficiency (EE). Additionally, the system performance is analyzed for transmit power and bit-error-rate (BER). We further analyzed the performances for static and dynamic power allocation (PA) and outage probability. Simulation results showed the improved performance of zero biased based NOMA VLC. NOMA achieves average rate greater than lOMbps, SE outperformed by 2 bits/sec/Hz and EE improved by 0.4 $\times$ $10^{7}\mathrm{b}\mathrm{i}\mathrm{t}/$Joule compared to OFDMA. NOMA system achieved BER of10-5 at signal to noise ratio (SNR) of about 21dB. The dynamic PA scheme reduces outage probability from 1 to 0.5 compared to static PA especially for the far user target rate of 35-60 Mbps.