An experiment of the underwater acoustic data transmission in deep sea

Authors have been studying in high-speed acoustic communication for controlling the cable-less ROV. In Aug. 2004, the sea trial of acoustic communication using 32-quadrature amplitude modulation (QAM) were carried out at Suruga Bay in Japan. The carrier frequency is 80 kHz, and symbol rate is 20 kHz (bit rate is 100 kHz). Communication range in the experiment was 50 and 100 m. When the signal-to-noise ratio (SNR) is higher than 20 dB, the error-free communication was carried out for 10,000 symbols data using two-channel decision feed back equalizer (DFE) receiver.