An Enhanced DCO-OFDM Scheme for Visible Light Communication Systems

In visible light communication (VLC) systems, optical orthogonal frequency division multiplexing (O-OFDM) is an appealing modulation scheme. Recently, a number of O-OFDM schemes have been proposed. Direct current optical orthogonal frequency-division multiplexing (DCO-OFDM) is one of the known O-OFDM schemes for its high spectral efficiency and low-complexity. Since VLC involves a combination of illumination and communication, different optical power is often required to achieve a certain illumination level. However, the performance of DCO-OFDM will severely degrade when a relatively high or low optical power constraint is imposed. To solve this problem, an enhanced DCO-OFDM (eDCO-OFDM) scheme is proposed in this paper. By introducing a piecewise function with adaptive slopes according to the required optical power, eDCO-OFDM is able to demonstrate significant performance advantages over conventional DCO-OFDM in terms of spectral efficiency and bit-error rate. Comprehensive simulations were conducted to verify the efficiency of the proposed scheme.