  The premise of massive multiple-input multiple-output (MIMO) is based around
coherent transmission and detection. Majority of the vast literature on massive
MIMO presents performance evaluations over simplified statistical propagation
models. All such models are drop-based and do not ensure continuity of channel
parameters. In this paper, we quantify the impact of spatially consistent (SC)
models on beamforming for massive MIMO systems. We focus on the downlink of a
28GHz multiuser urban microcellular scenario. Using the recently standardized
Third Generation Partnership Project 38.901 SC-I procedure, we evaluate the
signal-to-interference-plus-noise ratio of a user equipment and the system
ergodic sum spectral efficiency with zero-forcing, block diagonalization, and
signal-to-leakage-plus-noise ratio beamforming. Our results disclose that at
practical signal-to-noise ratio levels, SC channels yield a significant
performance loss relative to the case without SC due to substantial spatial
correlation across the channel parameters.
