Optimized Combination of Conventional and Constrained Massive MIMO Arrays

A combination of low cost constrained massive multiple-input-multiple-output (MIMO) and conventional arrays for constructing receiver signal points is investigated. The constrained radio frequency (RF) front ends are limited to on/off switching of antenna elements. A few full RF frontends are shown to compensate for the signal errors of the constrained RF frontends for various scenarios. An algorithm for such a hybrid RF (HRF) system is developed that optimizes the performance with respect to the mean square error of the constructed receiver signals for a Rayleigh fading channel model.