MIMO system implementation with displaced ground antennas for broadband military SATCOM

The Multiple Input - Multiple Output (MIMO) technology is applied to military satellite communication (SATCOM) systems. Superior system performance with respect to channel capacity and data rate is proven utilizing an exemplary communication setup with two antennas at both the ground stations and the geostationary satellite. Contrary to widespread discussed polarization multiplexing SATCOM systems, the approach is suited to fully exploit the multiplexing gain in the spatial domain. This goes along with a linear increase of the channel capacity and the throughput in net data rate depending upon the number of antennas used. Hence, the data rate is almost doubled for the exemplary setup in this paper without the need of higher transmit power or channel bandwidth. Moreover, the system offers improved link availability through antenna diversity. Our approach is based on two ideas: Depending upon the satellite orbit position, distinctly displaced ground antennas grant access to a MIMO channel with maximum spatial multiplexing gain. Nearly optimal data rates are then achieved through maximum likelihood equalization with a low-effort single carrier frequency domain equalizer and a zero-forcing filter. A summary on the robustness of the architecture in respect of capacity degrading influences completes the paper.