MPPM Aided Dimmable Reverse Polarity Optical OFDM for Visible Light Communication

Zixian Yang, Ming Jiang, Lin Zhang

Abstract: In this paper, we propose a multiple pulse position modulation (MPPM) aided reverse polarity optical orthogonal frequency division multiplexing (RPO- OFDM) scheme that aims to enhance the spectral efficiency (SE) for dimmable visible light communication (VLC) systems. In this scheme, we exploit the MPPM patterns to transmit the extra information bits without the increase of the signal bandwidth, and thus improving the SE. Specifically, for each frame, the binary information stream is divided into two parallel groups, where the first group is used to select the patterns of MPPM symbols, while the other is modulated by optical OFDM. Then the time-domain OFDM signal is accommodated by both the 'on' and 'off' slots of MPPM symbols for transmissions over the VLC channel. Theoretical analysis on the frame error probability (FEP) is provided and validated by simulation results, showing that the proposed system with extended dimming control achieves the highest effective spectral efficiency (ESE) in most of the scenarios compared with a few reference systems, without substantially increasing the computational complexity.