64-QAM Underwater Acoustic Short Video Communication System for Quasi-Real Time Marine Observation

This letter presents the design of a single-input-single-output (SISO) underwater acoustic (UWA) short video communication system for quasi-real-time marine observation, which employing 64-QAM (Quadrature Amplitude Modulation) to yield a peak data rate of 15 kbps and an adaptive decision feedback equalizer (DA-DFE) with embedded phase-locked loop (PLL) to mitigate multipath interference. Meanwhile, Polar channel encoding and MPEG-4 video compression encoding guarantee the communication performance. Two field tests conducted in different UWA channels demonstrated that the proposed system enables single-element UWA communication of 3.5-second short video clip over a distance of 150 meters with an end-to-end delay on the order of minute. This capability has the potential to be utilized for Internet of Underwater Things (IoUT)-driven quasi-real-time marine observation.