  The problem of the real-time multiple-input multiple-output (MIMO) array
control when requirements on capacity performance, out-of-cell interference,
and computational efficiency are simultaneously enforced is addressed by means
of an innovative hybrid beamforming technique. The synthesis of the excitations
of the MIMO system is first re-formulated as that of matching an ideal "hybrid"
pattern fitting capacity or low-interference constraints along the angular
coordinates. Then, a non-iterative processing scheme is derived for each MIMO
beam where numerically-efficient synthesis techniques are profitably combined.
Representative results, from an extensive numerical validation, are discussed
to show, also comparatively, the advantages and the current limitations of the
proposed synthesis method when dealing with different propagation scenarios,
number of transmitters/receivers, and noise levels.
