Yes, MU-MIMO is supported in NR as well as in LTE Rel 12 onwards. Beamforming is a technique to change the phase and amplitude of the signal using multiple antennas at the transmitter, so that upon reaching the receiver, it is appeared to be arriving from a single antenna. Beamforming can be used for SU-MIMO, which is also referred as generalized beamforming (e.g. TM7 based beamforming using 4 transmit antennas). When there are high number of transmit antennas (e.g. 64T64R antenna array), MU-MIMO can be employed serving several users using same time-frequency resources, where each user is served by a sub-array of antennas.
