In a cellular communications network system comprising a plurality of cells including a first cell and second cells different from and present in the neighborhood of the first cell, measurement reports are repeatedly received from user equipments, each including a first signal strength value corresponding to a signal strength measured from the first cell over a short time period and n second signal strength values corresponding to signal strengths measured over the short time period from n second cells, which correspond to the n strongest signal strengths measured from the second cells, n being an integer greater than one. A value of a counter is incremented which corresponds to a potential cooperation area formed by the first cell corresponding to the first signal strength value and the n second cells corresponding to the n second signal strength values.