Enhanced Optical OFDM/OQAM for Visible Light Communication Systems
Shuqiang Niu, Ping Wang, Sihui Chi, Zhongyu Liu, Weina Pang, Lixin Guo
Abstract
Orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM) has the advantage of high spectral efficiency due to non-requirement of cyclic prefix (CP) and guard band. However, the high direct current (DC) used in OFDM/OQAM is power inefficient for visible light communication (VLC). In this letter, an enhanced OFDM/OQAM (EO-OFDM/OQAM) scheme is proposed for VLC, which is inspired by the idea of the pulse-amplitude-modulation based hybrid optical OFDM (PHO-OFDM) scheme. In this system, the half of subcarriers of the normal branch carry useful data while the remaining subcarriers are selected to carry negative clipping noise instead of useful data for improving the power efficiency, and a flexible power allocation method is introduced. The simulation results show that compared with the PHO-OFDM, the proposed scheme has a better bit error rate (BER) performance under the same average bit rate without additional operations of interference regeneration and cancellation.