NEC has demonstrated stable two-way, long-distance communication underwater using an underwater acoustic communication module. This communication module is realized by combining the company’s sonar-related technologies such as transducer technology and watertight technology with NTT’s space-time equalization technology.
With the cooperation of NTT and Mitsubishi Heavy Industries, a communication module has been incorporated into an experimental underwater unmanned exploration vehicle, and the underwater unmanned exploration vehicle can be remotely controlled as it navigates at 2-3 knots in an ocean area 2.5 kilometers away. They demonstrated a use case for two-way communication to receive data collected by the spacecraft.
NEC will continue to miniaturize the communication module and conduct demonstration experiments with various partners, aiming for commercialization in 2024.
　
As the use of the ocean continues to advance, including offshore wind power generation and blue carbon, there is a growing need to operate underwater IoT devices, autonomous unmanned vehicles (AUVs), underwater drones, etc. for equipment management and underwater surveys. In order to operate these systems effectively, the realization of stable underwater communications has become an urgent issue.
Underwater acoustic communication is a technology that can realize stable communication underwater, but due to its characteristics, communication to moving objects is affected by the Doppler effect, and in the horizontal direction, it is subject to reflections from the sea surface, the seabed, etc. Because of the effects of multipath waves caused by refraction, communication with moving devices and horizontal communication has been a problem.