Visible light communication sensors with adaptive hysteretic circuits for automotive applications

摘要

As communication-based safety applications are developed for the next generation of vehicle active safety systems, this article focuses on the benefits of using adaptive hysteresis circuits toward the development of environmental-adaptive VLC sensors with significantly enhanced performances. Thus, analytical and numerical approaches to analyze hysteresis systems with noisy input are discussed and the benefits of adaptive hysteresis are presented. Furthermore, a linear relation between optimal hysteresis thresholds and noise strengths is determined. The experimental validation of the theoretical results is performed by using a Schmitt Trigger with threshold values adjusted by digital potentiometers controlled by an embedded microcontroller. Significant BER improvement is obtained by the hysteresis threshold adjustment.