Amplitude Factorization Polynomial Pre-distortion for Nonlinear LED

Abstract

【Objective】Light Emitting Diode (LED) is an important nonlinear optical signal generating device in Visible Light Communication (VLC) systems. The static nonlinearity of LED and the dynamic nonlinear memory effect caused by frequency response can lead to signal distortion and degrade the system performance.【Methods】The nonlinearity of LED can usually be compensated by estimating a pre-distortion model, and the wireless VLC is usually intensity modulated/directly detected.【Results】Therefore, the LED nonlinearity modeling is investigated, and an adaptive pre-distortion device based on Amplitude Factorization Polynomial (AFP) is proposed to compensate LED nonlinearity in this paper. Simulation results show that the proposed scheme exhibits good Bit Error Rate (BER), Amplitude Modulation/Amplitude Modulation (AM/AM) correction and constellation diagram performance with higher modeling accuracy.【Conclusion】The normalized mean square error performance improvement of more than 15 dB compared with the traditional memory polynomial is achieved.

Keywords

• VLC;LED;nonlinear distortion;memory effect;adaptive pre-distortion