Relationship between Signal Retransmission Interval and Communication Quality in Underwater Acoustic Communication Using Time-Diversity and Orthogonal Signal Division Multiplexing

To enable wireless remote control of unmanned underwater vehicles, such as compact underwater drones, it is essential to miniaturize communication systems for underwater acoustic communication (UWA). Unlike previous studies that utilized a single transmitter with multiple receivers, this study introduces a novel approach combining time diversity—repeatedly transmitting and receiving signals with one transmitter and receiver—with Doppler-resilient orthogonal signal division multiplexing (D-OSDM), a modulation method optimized for underwater environments. Experiments explored the relationship between retransmission intervals and performance metrics such as output signal-to-noise ratio and bit error rate. The results indicate that to improve communication quality using time diversity in UWA communication with D-OSDM, it is vital to set an appropriate guard interval and maintain a proper distance between the transmitter and receiver. These findings highlight the effectiveness of time diversity in enhancing the stability of UWA communication systems.