First, yes Massive MIMO Can be used in two modes FDD and TDD.  For TDD, Downlink beamforming in Massive MIMO relay on uplink pilot measurements—exploiting reciprocity and TDD operation. For FDD, Massive MIMO uses a predetermined grid of beams with UEs reporting their preferred beams, mostly in FDD operation. The original Massive MIMO concept assumes TDD … Continue reading TDD or FDD is more Better for massive MIMO?