Band-Limited Nyquist Pulse Design for Visible Light Communication Systems With Signal-Dependent Noise

This paper explores the impact of signal-dependent noise (SDN) on the band-limited Nyquist pulse design in visible light communication (VLC) systems. We provide a bandlimited signal transmission model with SDN, and also extend the transmission scheme with time-varying bias in the existing work. We analyze the noise features of the band-limited VLC systems with SDN, and show that the SDN strength after receive filtering is determined by both transmitter and receiver pulses. For the inter-symbol interference (ISI)-free transmission with sampling receiver and time-varying bias, we provide a bandlimited Nyquist pulse design method to maximize the low bound of output signal-to-noise ratio (SNR) after receiver filtering, and the designed pulses are unrelated to channel condition and SDN strength. For the ISI-free transmission with matched filter, we prove that there is no theoretical optimal band-limited Nyquist pulse, and provide the Nyquist pulse design methods for the two transmission schemes without bias and with time-varying bias, respectively. Numerical results demonstrate that the designed pulses outperform the existing pulses for different excess bandwidth factors and modulation formats in VLC systems with SDN.