A novel OFDM scheme for VLC systems under LED nonlinear constraints

Abstract

In this paper, a novel optical orthogonal frequency division multiplexing (O-OFDM) scheme based on real-imaginary coefficients separation is proposed for visible light communications (VLCs) to mitigate nonlinear distortion of light-emitting diodes (LEDs). In the proposed scheme, the transmitted signal in the frequency domain does not need to be Hermitian symmetric, and real and imaginary parts are separated. Signals are introduced to keep the clipped information due to the high peak to average power ratio of OFDM, and a procedure to recover the clipped information is proposed. The transmit strategy and receive algorithm of the proposed scheme are presented in detail. Simulation results show that compared with traditional O-OFDM schemes, the proposed scheme can achieve better bit error rate performance under LED nonlinear constraints and reduce the requirement for the linear dynamic range of LEDs.