MIMO-OFDM acoustic communication in shallow water

As an alternative to typical single-carrier approaches, multi-carrier Orthogonal Frequency Division Multiplexing (OFDM) communications has been explored in underwater acoustic channels with a large delay spread. In this paper, we investigate multiple-input/multiple-output (MIMO) OFDM communications that effectively can increase the data rate in band-limited underwater channels. The performance of MIMO-OFDM communications is presented using data collected from the KAM11 experiment conducted in shallow water, west of Kauai, Hawaii, which involved multiple transmit and receive arrays with a 10 kHz bandwidth (20–30 kHz) and modulations (QPSK and 16-QAM) at range up to 3 km.