Capacity Analysis of Ship-to-Shore HF MIMO Systems Employing a Single-Hop Ionospheric Channel

We examine the capacity of a ship-to-shore high-frequency (HF) multiple-input multiple-output (MIMO) communication system that uses a single-hop ionospheric channel between the transmitter and the receiver. Our operating hypothesis is that using platform-based HF antennas in such systems allows for exploiting both polarization and spatial diversity in HF MIMO systems. An analytic model is presented and used to calculate the single-hop MIMO channel capacity. The model takes into account the polarization and spatial diversity, the characteristics of the transmit and receive antennas, as well as the statistical behavior of the ionosphere in response to the ordinary and extraordinary modes of propagation through the ionosphere. The possibility of using the characteristic modes of the platform as radiating elements of such a MIMO system is explored and a procedure for designing platform-based antennas that maximize the HF MIMO channel capacity is presented.