  This paper investigates the impact of the number of antennas (8 to 64) and
the array configuration on massive MIMO channel parameters estimation for
multiple propagation scenarios at 3.5 GHz. Different measurement environments
are artificially created by placing several reflectors and absorbers in an
anechoic chamber. Ground truth channel parameters, e.g, path angles, are
obtained by geometry and trigonometric rules. Then, these are compared to the
channel parameters extracted by the applying Space-Alternating Generalized
Expectation-Maximization (SAGE) algorithm on the measurements. Overall, the
estimation errors for various array configurations and the multiple
environments are compared. This paper will help to determine the appropriate
configuration of the antenna array and the parameter extraction algorithm for
outdoor massive MIMO channel sounding campaigns.
