MIMO for airborne communications [Industry Perspectives]

MIMO technology has been widely applied in terrestrial wireless communications due to its high spectral efficiency in the presence of rich multi-paths. The benefits of MIMO in airborne communications, however, have not been fully recognized. The lack of scattering in the airborne environment may lead one to incorrectly believe that the spectral efficiency gain of an airborne MIMO is rather limited. In this article, we describe how spatial multiplexing gain can be obtained in airborne environments by antenna system design rather than natural scattering. In particular, we will focus on two techniques: the use of dual polarized antennas and the choice of antenna separation relative to the carrier wavelength. We present both field test results and computer simulations demonstrating the benefits of MIMO in airborne environments.