  Measurement results for millimeter wave LOS MIMO systems are presented with a
focus on time variation and multipath propagation. Different system setups are
used, including 2x2 and 3x3 MIMO, and involving different synchronization
procedures and front-ends. Furthermore, different propagation scenarios are
evaluated, covering a wide area of applications. The results show that the LOS
component carries significantly more power than the NLOS components, and that
frequency selectivity from front-ends should be taken into account when
designing these high bandwidth systems. Frequency offsets and other phase
variations due to transmit and receive oscillator differences are treated as
part of the channel and thus, depending on the synchronization setup, the MIMO
system exhibits different time variations, particularly in the case of
independent local oscillators. It is also observed that these systems
experience significant non-trivial long-term variations in terms of amplitude
and phase.
