In a radio communications system, a plurality of transceivers are each connected to one element of an array of antenna elements. In addition, at least one of the transceivers is additionally connected to a calibration antenna for transmitting or receiving test signals via the antenna elements. At least one calibration processor is provided for determining variations of the test signals in the transceivers. A beamforming processor is provided for taking into account the determined variations for beamforming or determination of direction of arrival of respectively transmitted and received radio signals by the antenna elements.