HMM-Based Signal Characterization and Detection for VLC under Weak Illuminance

Visible light communication (VLC) under weak illuminance includes both regular peak light emitting diode (LED) transmission power with low duty cycle and low LED transmission peak power with regular duty cycle. In this work, we address the signal characterization and transmission rate of VLC with low transmission power and regular duty cycle. We first characterize the LED nonlinear effect via a state transition model based on the experimental measurement. Then we adopt hidden Markov model (HMM) to characterize the LED transmission under low peak power. Based on the HMM, we propose a Viterbi detection method to detect the state of signals. Numerical results based on the HMM are presented.