  We study the uplink performance of massive multiple-input multiple-output
(MIMO) when users are equipped with multiple antennas. To this end, we consider
a generalized channel model that accounts for line-of-sight propagation and
spatially correlated multipath fading. Most importantly, we employ the
Weichselberger correlation model, which has been shown to alleviate the
deficiencies of the popular Kronecker model. The main contribution of this
paper is a rigorous closed-form expression for the uplink spectral efficiency
using maximum-ratio combining and minimum mean square error channel estimation.
Our result is a non-trivial generalization of previous results on massive MIMO
with spatially correlated channels, thereby enabling us to have suitable
designs for future massive MIMO systems. Numerical simulations corroborate our
analysis and provide useful insights on how different propagation conditions
affect system performance.
