Development of Propeller-type Rotary LED Proto-transmitter for Underwater Visible Light Communication

To improve the operational efficiency of remotely operated vehicles (ROVs) used to investigate ocean resources, this paper focuses on underwater visible light communication using a camera as a receiver (i.e., underwater image sensor communication: UISC). UISC can realize wireless communication underwater, where wireless communication using radio waves is difficult. However, due to the limited area of the ROV, it is hard to increase the number of transmitter LEDs installed on the ROV, resulting in a lower communication speed. We have developed a propeller-type rotary LED transmitter (P-RTx) to solve this problem, assuming that the LEDs are attached to the ROV's thruster. P-RTx is a device that increases communication speed by rotating a blinking LED that transmits data and utilizing the receiver's ability to capture their blinking lights as multiple afterimages. As a result of experiments using a prototype P-RTx, we have achieved error-free communications up to a communication distance of 3.0 m at a communication speed of 3.24 kbps, 72 times faster than the conventional method.