  This paper investigates the impacts of Inter-Channel Interference (ICI)
effects on a shallow underwater acoustic (UWA) orthogonal frequency-division
multiplexing (OFDM) communication system. Considering both the turbulence of
the water surface and the roughness of the bottom, a stochastic geometry-based
channel model utilized for a wide-band transmission scenario has been exploited
to derive a simulation model. Since the system bandwidth and the sub-carrier
spacing is very limited in the range of a few kHz, the channel capacity of a
UWA system is severely suffered by the ICI effect. For further investigation,
we construct the signal-to-noise-plus-interference ratio (SINR) based on the
simulation model, then evaluate the channel capacity. Numerical results show
that the various factors of a UWA-OFDM system as subcarriers, bandwidth, and
OFDM symbols affect the channel capacity under the different Doppler
frequencies. Those observations give hints to select the good parameters for
UWA-OFDM systems.
