  In this paper, we present a fixed mmWave Multi-User Multiple-Input
Multiple-Output (MIMO) system for fixed wireless access with a unique
architecture. A digital MIMO system is combined with an analog multi-beam
antenna array which uses a high-dimension 16x16 Butler matrix to obtain 16
orthogonal beams. A system model of this architecture is presented and used to
simulate its performance comparing to the performance of common-used patch
antennas. Several MIMO precoding techniques are considered and compared with
basic analog beamforming. To verify these results, a prototype is built and a
dedicated measurement campaign is performed. The results show that the system
model is a good approximation and that the use of the multi-beam antenna array
is a good alternative to patch antennas for a large number of users.
