Impulses injection for PAPR reduction in visible light OFDM communications

Orthogonal frequency division multiplexing (OFDM) in visible light communications (VLC) inherits the disadvantage of high peak-to-average power ratio (PAPR) from OFDM in radio frequency (RF) communications. VLC-OFDM differs from RF-OFDM in that there are two PAPRs to be reduced, namely upper PAPR and lower PAPR. In this paper, we propose a distortion-based impulse injection method to achieve PAPR reduction in bit-loaded VLC-OFDM systems. To minimize the in-band constellation-wise error vector magnitude (EVM), a quadratically constrained linear optimization problem is formulated. This scheme is advantageous over simple clipping and prior works in that it can wisely allocate less distortions to higher order constellations with a few more variables.