A Robust Underwater Acoustic Communication System using OFDM-MIMO

The paper will consider the viability of exploiting the spatial diversity that exists in doubly-spread, underwater acoustic communications channels to provide enhanced capacity using an OFDM-MIMO system. The proposed method offers two forms of diversity. First, coded orthogonal frequency-division multiplexing (COFDM) provides frequency diversity by exploiting the frequency selectivity inherent in channels that suffer from multipath propagation. Second, multiple transducers are used to exploit the spatial diversity that exists in underwater acoustic channels, also due to multipath propagation. This allows the multi-transducer communication system to be viewed as a multi-input, multi-output (MIMO) system to provided potential capacity gain.