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Systems of small distributed satellites in low Earth orbit (LEO) transmittingcooperatively to a multiple antenna ground station (GS) are investigated. Thesesatellite swarms have the benefit of much higher spatial separation in thetransmit antennas than traditional big satellites with antenna arrays,promising a massive increase in spectral efficiency. However, this wouldrequire instantaneous perfect channel state information (CSI) and strongcooperation between satellites. In practice, orbital velocities around 7.5 km/slead to very short channel coherence times on the order of fractions of theinter-satellite propagation delay, invalidating these assumptions. In thispaper, we propose a distributed linear precoding scheme and a GS equalizerrelying on local position information. In particular, each satellite onlyrequires information about its own position and that of the GS, while the GShas complete positional information. Due to the deterministic nature ofsatellite movement this information is easily obtained and no inter-satelliteinformation exchange is required during transmission. Based on the underlyinggeometrical channel approximation, the optimal inter-satellite distance isobtained analytically. Numerical evaluations show that the proposed scheme is,on average, within 99.8% of the maximum achievable rate for instantaneous CSIand perfect cooperation

Beamspace MIMO for Satellite Swarms