Capacity-Driven Low-Interference Fast Beam Synthesis for Next Generation Base Stations

The problem of the low-complexity 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 reformulated as that of matching an ideal “hybrid” pattern fitting
capacity
or
low-interference
constraints along with the angular coordinates. Then, a noniterative 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, the number of transmitters/receivers, and noise levels.