  Commonly used drop-based channel models cannot satisfy the requirements of
spatial consistency for millimeter-wave (mmWave) channel modeling where
transient motion or closely-spaced users need to be considered. A channel model
having \textit{spatial consistency} can capture the smooth variations of
channels, when a user moves, or when multiple users are close to each other in
a local area within, say, 10 m in an outdoor scenario. Spatial consistency is
needed to support the testing of beamforming and beam tracking for massive
multiple-input and multiple-output (MIMO) and multi-user MIMO in
fifth-generation (5G) mmWave mobile networks. This paper presents a channel
model extension and an associated implementation of spatial consistency in the
NYUSIM channel simulation platform. Along with a mathematical model, we use
measurements where the user moved along a street and turned at a corner over a
path length of 75 m in order to derive realistic values of several key
parameters such as correlation distance and the rate of cluster birth and
death, that are shown to provide spatial consistency for NYUSIM in an urban
microcell street canyon scenario.
