Properties of Space MIMO Communication Channels

— This paper discusses the characteristics of a space-to-space multiple-input, multiple-output (MIMO) communication channel that distinguish it from more common terrestrial MIMO communication channels. These characteristics imply that the channel matrices for space communication channels have a particularly simple structure that leads to statistical characteristics that are both predictable and readily controllable using clusters of satellites as distributed communication nodes. Furthermore, the extremely high cost of launching mass into space introduces a constraint into the channel capacity equation that leads to a spectral-efficiency vs. energy-efficiency tradeoff for space MIMO communication that is fundamentally different from the tradeoff that is generally considered applicable to terrestrial MIMO communication systems.