Practical Performance and Prospect of Underwater Optical Wireless Communication ——Results of Optical Characteristic Measurement at Visible Light Band under Water and Communication Tests with the Prototype Modem in the Sea——

Takao SAWA  Naoki NISHIMURA  Koji TOJO  Shin ITO  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E102-A   No.1   pp.156-167
Publication Date: 2019/01/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E102.A.156
Type of Manuscript: INVITED PAPER (Special Section on Wideband Systems)
Category: 
Keyword: 
chlorophyll,  LD,  turbidity,  UOWC,  VLC,  

Full Text: FreePDF

Summary: 
Underwater optical wireless communication has been merely a theory for a long time because light sources are too weak to use them as emitters for communications. In the past decade, however, underwater optical wireless communications have used laser diodes or light emitting diodes as emitters with visible light in high brightness with low power consumption. Recently, they have become practical. As described in this paper, recent trends of underwater optical wireless communication study, practical modems and prospective uses of underwater optical wireless communication are presented first. Next, optical characteristics of the seawater in various conditions are explained based on the experimental data measured using the profiler for underwater optics produced especially for this study. Then the prototype underwater optical wireless communication modem developed by our team is introduced. It was tested in several sea areas, which confirmed bi-directional communication in the 120m range at 20Mbps and a remote desktop connection between under water vehicles at 100m range. In addition, one modem was set in air; other was set in water. The modems mutually communicated directly through the sea surface.