A Differential Multiple Single Carrier Modulation Scheme for Underwater Acoustic Communications and Its Actual Evaluation Results

This paper discusses actual evaluation results of a differential multiple single carrier (MSC) modulation scheme for underwater acoustic communications (UWACs). UWACs suffer from severe doubly-selective channels and inter-carrier interference due to non-uniform frequency offset. In addition, assuming image data communications, UWACs require improved frequency efficiency. To resolve these issues, this paper proposes a wireless transmission scheme that employs differential MSC modulation scheme. Next, this paper investigates the parameters for 8kbps-UWACs and 64kbps-UWACs aiming at wireless control of autonomous underwater vehicles and image data communications, respectively. Finally, two actual evaluation results in an acoustic experimental pool and an actual shallow-sea environment confirm that the UWAC MODEMs have excellent performance on severe doubly-selective channels.