BEAMFORMING IN ANTENNA SYSTEMS

Apparatuses, methods, and systems for beamforming in antenna systems are disclosed. A method includes determining an unconstrained analog precoding matrix (FRF,UC), wherein the unconstrained analog precoding matrix (FRF,UC) is determined based on M dominant eigenvectors of the sum of spatial channel covariance matrices of K users, and wherein K indicates a number of users communicating with a base station. The method further includes determining a constrained analog precoding matrix (FRF) based on the unconstrained analog precoding matrix (FRF,UC), determining a compensation matrix (FCM), digitally multiplying K inputs with a multiple-input multiple-output (MIMO) precoding matrix (FMU) generating M outputs, digitally multiplying the M outputs with the compensation matrix (FCM) generating M compensation outputs, generating M analog frequency-up-converted signals based on the M compensation outputs, and analog multiplying the M analog frequency-up-converted signals with the analog precoding matrix (FRF) generating N output signals for transmission, wherein N is greater than M.