Underwater Acoustic Communication Modems: Recent Trends in Technology

Abstract

Underwater communication is critical for various applications e.g. oceanographic research, underwater biological monitoring, military operations, seismic survey and offshore oil and gas exploration. Over the past few years, there have been significant advancements in underwater communication modems, enhancing their reliability, range, data rate, and adaptability to the challenging underwater environments. This article provides a technical overview of these recent developments and serves as a valuable reference for researchers in the field. The paper is focused on previous research and surveys in the field of designing underwater modems according to modulation techniques and signal processing methods. It reviews the state-of-the-art underwater acoustic (UWA) communication modems into two categories, namely Software-defined UWA modems and Digital-signal-processor-based UWA modems. The advanced networking techniques associated with underwater modems are being implemented for high-end applications. Underwater signal transmission is integrated by machine learning with highly developed signal-processing techniques nowadays. The study discusses various modem designs, including those for a small autonomous unmanned vehicle (AUV), hybrid optical-acoustic modem, a reconfigurable/flexible UWA modem, and a real-time UWA modem.  Additionally, the challenges faced by the researchers from academia as well as from industry in designing the UWA communication modem are also highlighted.