Single-FFT Receiver With Pairwise Maximum Likelihood for Layered ACO-OFDM

A single Fourier transform (FFT) receiver with pairwise maximum likelihood (ML) is proposed for layered asymmetrically clipped optical orthogonal frequency division multiplexing (LACO-OFDM). To improve the single-FFT receiver, the pairwise ML detection is made in time domain after a layer diversion in LACO-OFDM. With only one FFT block, the proposed receiver has a low complexity. Simulation results show that the proposed receiver has the better bit error ratio (BER) performance than the conventional iterative scheme for the LACO-OFDM system with 2 layers in additive white Gaussian noise (AWGN) channel. Furthermore, it is proved that compared with the conventional iterative receiver, the proposed receiver is less sensitive to the clipping distortion. As the nonlinearity increased, the proposed scheme can outperform the conventional iterative solution in nonlinearity channel for LACO-OFDM in visible light communications.