摘要

In this paper, the energy efficiency and the spectral efficiency for orthogonal frequency division multiplexing (OFDM)-based visible light communication schemes are studied, which is crucial for practical application with limited energy resources. The conventional schemes, including asymmetrically clipped optical OFDM (ACO-OFDM), pulse-amplitude-modulated discrete multitone, and direct current biased optical OFDM, are compared in terms of energy efficiency and spectral efficiency relationship. The influence of power allocation for asymmetrically clipped dc biased optical OFDM and hybrid ACO-OFDM is also investigated. The energy efficiency and spectral efficiency of layered ACO-OFDM with a variable layer number are calculated and their relationship is also formulated. These conventional and hybrid modulation schemes are analyzed and compared through computer simulations, which should be considered in practice according to the requirements of illumination and transmission.