Mitigating nonlinearities under average power constraint in visible light communication

The advent of data intensive applications on the mobile devices is putting a strain on the available RF spectrum. Recently, visible light wireless communications has become a desirable alternative due to the low cost of light emitting diode (LED) devices which can offer data rates in the Gigabit per second range while providing lighting. In addition, visible light belongs to the unlicensed part of spectrum which is easily reusable due to the fact that light does not penetrate walls. Various modulation techniques have been adopted for optical wireless because negative signals (or complex signals) cannot be used due to the fact that light intensity is a positive quantity. Orthogonal frequency division multiplexing (OFDM) has been successfully modified for optical wireless but it suffers from high peak-to-average-power ratio (PAPR). High PAPR causes LED to operate in nonlinear region which leads to performance degradation. We discuss a technique to reduce PAPR while keeping averaging power constraint which is important for the purpose of lighting.