OFDM-Based Underwater Acoustic Communication System Designing for Under-Ice and Cold-Water Applications

Cold sea and ocean places of our planet hide a lot resources and secrets. But its exploring cannot be done without help of proper technical means. Ones of the most enabling of them are underwater unmanned vehicles and sensor networks, which rely on underwater communication systems. The paper presents a research dedicated to issues of providing underwater vehicles and networks with communication and navigation in conditions of cold water and ice covered seas and oceans. We consider problems of adaptation of OFDM underwater acoustic communication systems to conditions of under-ice hydroacoustic channel. For that purpose we propose noncoherent OFDM demodulation techniques complemented by transducer beam swinging approach. This complex of measures was tested during in situ experiments on the distances up to 3 km with different underwater bottom landscapes, transmitter and receiver mooring depths. The results were analyzed and visualized.