4 ms·

MU-MIMO implies a phased array no?

• lxgr 3y ago
  They are conceptually related, and the more antennas you add ("massive MIMO"), the more you get into the "phased array" domain, especially on the base station side, which is where MU-MIMO is exploited. But on common mobile devices, you only have two or four antennas, so the beamforming gain is much more limited. Having more than one antenna there is mostly done to leverage multipath propagation in a non-line-of-sight environment for capacity gains as far as I understand it, and in a line-of-sight environment, you only get very moderate steering gains of a few dB (and practically no steering/beamforming effect). Satellite communication is primarily line-of-sight, though. So while the satellite can steer its beams towards a given mobile device (both for transmit and receive), and this allows for higher spectral efficiency and better use of the satellite's transmit power and better noise rejection, the mobile device can't do the same and will easily be overwhelmed by a jammer at least in the downlink path, as far as I understand.