A method and apparatus for a cellular system is provided. Communication is carried out between a controlling station of a cell and a number of users in said cell, and the controlling station is equipped with a plurality of antennas. The communication can alter between a first and a second mode, and the users in the cell provide the controlling station with feedback information regarding their reception quality. The controlling station alters between said first and second modes of communication as a result of the reliability of the feedback information from the users in the cell, so that if the reliability is above a first threshold, the first mode is used, and if the reliability is equal to or below said first threshold, the second mode is used.