Experimental study on the difference between acoustic communication channels in freshwater rivers/lakes and in oceans

Underwater acoustic (UWA) communications and networking have drawn considerable attentions in the last decades, while most of the research effort has been paid to oceanic environment. Given a wide range of potential applications of UWA techniques in freshwater rivers and lakes, it is imperative to understand the acoustic channel characteristics in the above environment. Based on the data sets collected from several field experiments in the Great Lakes region and off the coast of Martha´s Vineyard, Massachusetts, this work characterizes the freshwater river/lake acoustic channels in aspects of sound propagation loss and channel multipath properties, and compares the channel characteristics with those in oceans. Data analysis shows that relative to oceanic channels, freshwater river/lake channels have larger temporal coherence, higher correlation among densely distributed channel paths, and less sound absorption loss. Insights on acoustic transceiver design based on the above channel characteristics are also provided.