Performance of the OFDM underwater acoustic communication system with high-rank subcarrier modulation and active beam pattern control

Underwater acoustic communication is the most suitable approach for underwater data transmission and navigation due to its substantial achievable transmission range of up to tens of kilometers and reasonable data throughput up to 20 kbit/s. But such a performance faces a lot of problems of the underwater acoustic channel, the main of which is strongly pronounced multipath propagation. One way to get around this problem is to use an underwater acoustic communication system, which combines the orthogonal frequency division multiplexing (OFDM) and the ability to steer the directional pattern on the transmitting device using a phased antenna array based on coaxially located piezo ceramic cylinder antennas. OFDM combined with high-rank subcarrier modulation allows it to have good data throughput, while beam steering (BS) allows choosing the optimal inclination angle of directional pattern to reduce the multipath effects. The paper presents an overview of system design and the conditions of experiments and the analysis of its results.