PAPR Reduction for DCO-OFDM Visible Light Communications via Semidefinite Relaxation

This letter considers a direct current-biased optical orthogonal frequency division multiplexing (DCO-OFDM) with intensity-modulated direct-detection modulation for visible light communication systems. The high peak-to-average power ratio (PAPR) is a critical performance-limiting factor for the DCO-OFDM system. To reduce the PAPR, we present a PAPR reduction method by applying a semidefinite relaxation approach to tone injection. With the proposed method, we achieve a significant PAPR reduction as large as 5 dB, which contributes to a noticeable BER performance gain as evidenced by simulation results considering the light emitting diode nonlinearities.