Diffused-Line-of-Sight Communication for Mobile and Fixed Underwater Nodes
Yujian Guo, Meiwei Kong, Omar Alkhazragi, Xiaobin Sun, Mohammed Sait, Tien Khee Ng, Boon S. Ooi
Abstract
The misalignment of mobile underwater wireless optical communication (UWOC) systems, compounded by turbulence in underwater scenarios, is a practical problem that can be resolved through various means. This work describes a pulse-position-modulation-based (PPM-based) diffused-line-of-sight UWOC system that offers a solution to this issue. PPM is found to be power-efficient and, in terms of bit-error-ratio performance, outperforms on-off keying modulation and orthogonal frequency-division multiplexing modulation in complex dynamic underwater channels. Through indoor experiments and outdoor deployment, we validated the robustness of the proposed PPM-based mobile UWOC system. This work sheds light on the practical implementation of UWOC networks for relieving the strict pointing-acquisition-and-tracking requirements when an underwater apparatus is transmitting or receiving signals on the fly.