Orthogonal Frequency Division Multiplexing With Index Modulation Based on Discrete Hartley Transform in Visible Light Communications

This paper investigates optical orthogonal frequency division multiplexing (O-OFDM) systems with index modulation (IM) based on discrete Hartley transform (DHT) for visible light communications (VLC). An interesting trade-off between spectral efficiency (SE), energy efficiency, peak-to-average power ratio (PAPR) and bit error rate (BER) performance can be made by using the IM technique. And DHT-based O-OFDM-IM achieve higher SE compared DFT (discrete Fourier transform)-based counterparts. Employing DHT instead of enables removal Hermitian symmetry requirement, which contributes to transmitting more bits results in improvement. To acquire same SE, proposed significantly lower constellation order leading better BER contrast DFT-based We employ DC (direct current) biasing AC (Asymmetrically clipped) techniques investigate this paper. Simulation indicate that SNR gains obtained DCO/ACO-IM comparison also propose a novel reduced-complexity ML (maximum likelihood) detector specifically applicable VLC. The new exhibits as performs than LLR (log-likelihood ratio) reduced computational complexity.