Phases Calibration of Partially-Connected PSN for UPA-assisted mmWave MIMO Systems

Phase shifter networks (PSNs) are now widely used in massive mmWave MIMO (multi-input multi-output, MIMO) systems for their low cost and high beamforming gain. In practice, however, the real phases of phase shifters may be subject to phase deviations due to temperature drift and aging, which is detrimental to practical communication systems, thus these phase deviations need to be properly estimated and calibrated periodically. To this end, this paper proposes a novel over-the-air (OTA) approach to estimate the phase deviations of the partially-connected PSN (PCPSN) for a uniform planar array (UPA)-assisted mmWave MIMO system, and the simulation results verify the effectiveness of the proposed algorithm by showing that the root mean squared errors (RMSEs) of the phase estimates are close to the Cramer Rao Bounds (CRBs).