Iterative Clipping for PAPR Reduction in Visible Light OFDM Communications

摘要

Visible light communications (VLC) rely on white light emitting diodes (LEDs) to transmit information and provide illumination. White LEDs act as low pass filters and thus place a limitation on achievable data rates in VLC. Orthogonal frequency division multiplexing (OFDM) has been applied to VLC to best make use of the available modulation bandwidth through bit loading. However, VLC-OFDM waveforms exhibit high peak-to-average power ratio (PAPR). This drawback makes VLC-OFDM signals very sensitive to nonlinerarity of LEDs and requires large biasing. We propse an iterative clipping method to reduce upper PAPR and lower PAPR of over sampled VLC-OFDM signals without introuducing in-band distortions. Theoretical analysis of PAPRs distributions, and simulations of PAPR reduction scheme are presented in this paper.