Multi-User Allocation Using Multi-Band OFDM-NOMA in Visible Light Communications

The modulation bandwidth limitations and high frequency fading severely restrict the potential of multiple access technique in VLC systems. In this paper, the capacity of a multi-user VLC system is boosted by sub-band division of OFDM modulation and power allocation optimization of NOMA. Notably, the allocation of users in different sub-bands can be configured according to their SNRs. A capacity enhancement of over 21% is experimentally achieved compared to the traditional OFDM-NOMA scheme.