On Capacity of 2-by-2 Underwater Wireless Optical MIMO Channels

In this paper, we consider the channel capacity of underwater wireless optical communication (UWOC) multiple-input multiple-output (MIMO) links. We develop a 2-by-2 UWOC MIMO channel model over which two sources transmit data to two detectors in the presence of inter-symbol-interference (ISI) and apply this channel model to evaluate the UWOC MIMO channel capacity in terms of mutual information. Numerical examples are carried out to investigate the impacts of seawater type, attenuation length, symbol baud rate, detector field of view (FOV) and transmit power on the channel capacity. Simulation results suggest that the 2-by-2 UWOC MIMO channel capacity decreases as the symbol baud rate increases and can be enhanced by increasing average transmit power or adjusting detector FOV.