2 ms·

Thank you for the support. The case of StarLink (in difference to (indoor) 802.11n/ac) won't give you more than polarization duplex (capped at 2x, in practice

by namibj 7y ago

Thank you for the support. The case of StarLink (in difference to (indoor) 802.11n/ac) won't give you more than polarization duplex (capped at 2x, in practice you'd get up to (iirc) ~30dB isolation) for any individual point-to-point connection. Yes, including the satellite <=> ground-facility "backhaul". Theoretically it _should_ be possible to get like 10x bandwidth via spatial MIMO when using <3μm (likely <1μm) wavelengths, but that might require optical heterodyne detection to get the MIMO streams separated from another in the speckle pattern the atmosphere caused. I'd like to read that paper about optical heterodyne detection spatial MIMO for the link to/from a satellite in an 200~1000km orbit.

Robotbeat 7y ago
One terminal (which has beamforming capability on both ends with hundreds of elements) can connect to multiple satellites with the same frequency band.
- namibj 7y ago
  Oh sure, that's a massive effect. It's just that for a single p2p link, there'd be at most minimal benefit from MIMO. As soon as there are either multiple satellites or multiple user terminals (or dare both), i'd expect nothing worse than the bandwidth scaling with the square root of the antenna count.