Mitigating Sea Surface Fading with D-MIMO: Experimental Validation

The performance of wireless communications at sea are often limited by fading caused by reflections at the sea surface. The reliability could potentially be improved by employing multiple antennas. We have conducted massive multiple-input multiple-output (MIMO) measurements at sea in order to evaluate the performance. The measurements were conducted at 5.6 GHz with 64 dual-polarized antennas, which were distributed vertically in groups of eight antennas. We evaluated the CDF of the maximum-ratio combined channel gain for different number of antennas, and compared distributed and co-located antenna configurations. We conclude that having distributed antennas is key to reduce the channel fading by a significant amount. Additionally, optimizing antenna spacing can significantly minimize fading without requiring a large number of antennas. In our scenario, the channel fading could be reduced by 15 dB by employing only three distributed antennas, showing the potential of distributed MIMO systems to improve reliability in maritime communications.