MIMO performance evaluation for airborne wireless communication systems

This paper presents a characterization of the practical performance gains of a multiple-input/multiple-output (MIMO) system with respect to a traditional single-input/single-output (SISO) system in an air-to-ground environment. Analysis of these performance gains is based on actual data throughput and channel-state measurements of an airborne 4×4 MIMO-enabled orthogonal frequency division multiplexing (OFDM) system. Practical realization of these performance gains with a coded-OFDM wideband system was accomplished through airborne field trials across multiple flight profiles. We show through experimental validation that average MIMO throughput gains in excess of 2× can be achieved relative to a SISO system. These field trials also indicate that MIMO processing can deliver a 1.6× increase in the range of the link. Additionally, if channel-state information (CSI) is available at the transmitter - which enables MIMO eigen beamforming - the average throughput gain can be further increased to 4.5× and the link range can be increased by as much as 3.6x. It is also shown that for a 4×4 MIMO system to deliver the same throughput performance as a conventional SISO system in an air-to-ground environment, a relative TX power savings of up to 21 dB can be realized.