A communication apparatus and method are provided for predicting effects of changes in at least one radio network parameter on a cellular network which comprises a processor which is adapted to: (a) select a source cell in a cellular network; (b) select from among a first plurality of cells being neighbors of that source cell, a second plurality of neighboring cells and define a reference cluster that includes the source cell and the second plurality of cells; and (c) use the reference cluster to predict the effects of carrying out one or more changes in at least one radio network parameter on at least one network performance indicator of the reference cluster, and based on that prediction, establishing an expected impact of the one or more changes in the at least one radio network parameter on a cellular network performance.