Performance evaluation of a simplified power-domain NOMA for visible light communications

The performance of a visible light communication (VLC) system based on power-domain nonorthogonal multiple access (PD-NOMA) is experimentally evaluated in this paper. The simplicity of the adopted nonorthogonal scheme is provided by the fixed power allocation method at the transmitter and the single one-tap equalization executed before the successive interference cancellation at the receiver. The experimental results proved the successful transmission of the PD-NOMA scheme with three users in VLC links of up to 2.5 m, after a proper choice of the optical modulation index. All users achieved error vector magnitude (EVM) performances below forward error correction limits in all evaluated transmission distances. At 2.5 m, the user with the best performance reaches an E V M=2.3%.