Experiment on MIMO Communications in Seawater by RF Signals

This paper gives evaluation on MIMO communications by RF signals in seawater thorough analysis on channel capacity, simulations, and experiment in shallow water. The analysis on channel capacity reveals that near-bound capacity in MIMO communications is achieved by interference cancellation based on ZF by setting antenna spacing of more than a half of wavelength in seawater. Simulation results show that expected bitrate reaches at more than 10 bps/Hz and 20 bps/Hz by employing 2x2 and 4x4 MIMO communications, respectively, with 64QAM in frequency band of 10 MHz. Experiment in shallow water has been conducted on 2x2 MIMO communications with 64QAM, and 10-Mbps data transmission has been achieved, which is expected bitrate in wireless communications in seawater by RF signals.