On the Sparsity and Aperiodicity of a Base Station Antenna Array in a Downlink MU-MIMO Scenario

An application study into irregular sparse arrays (ISAs) is proposed to function as base station antennas (BSAs) in a mm-wave multi-user multiple-input multiple-output (MU-MIMO) system. The results show that the sum rate capacity of ISAs can be increased relative to regularly-spaced BSA arrays with half a wavelength element separation, especially for a high number of users. This is due to the narrower beams formed by the larger antenna apertures of sparse arrays. Furthermore, the aperiodic distribution of antenna elements alleviates the problem of grating lobes in sparse arrays and is seen to improve the average power consumption of power amplifiers at the same time.