A cellular multiple-input and multiple-output (MIMO) system has a base station. The base station has a plurality of antennas. To control a signal transmission in the MIMO system, the base station monitors at least one indicator which indicates whether a spatial resolution of the plurality of antennas allows signals received from at least two terminals to be distinguished. The base station selectively activates a multiple access transmission and reception for the at least two terminals as a function of the at least one indicator. The multiple access transmission and reception causes the at least two terminals to share a common channel.