  In this paper, stochastic channel models for massive MIMO (M-MIMO) and
extreme large MIMO (XL- MIMO) system applications are described, evaluated and
systematically compared. This work aims to cover new aspects of massive MIMO
stochastic channel models in a comprehensive and systematic way. For that, we
compare different models, presenting graphically and intuitively the behavior
of each model. Each massive MIMO channel model emulates the environment using
different methodologies and properties. Using metrics such as capacity, SINR,
singular values decomposition (SVD), and condition number, one can understand
the influence of each characteristic on the modelling and how it differentiates
from other models. Moreover, in new XL-MIMO scenarios, where the near-field and
visible region (VR) effects arise, our finding demonstrate that for the two
assumed schemes of clusters distribution, the clusters location influences the
performance of the conjugate beamforming and zero-forcing (ZF) precoding due to
the correlation effect, which have been analysed from the geometric massive
MIMO channel models.
