Abstract: A method of assigning frequencies in a cellular telephone system in which a first group of the available frequencies is assigned to a first cell, and then distinct groups are assigned to adjacent cells, leaving at least one distinct group of frequencies free for later re-use. This system is applied to each cell in the system, so that for any cell, it and its adjacent cells do not use all of the frequencies in the system. For a first stage of cell splitting, frequencies are assigned from at least one non-adjacent cell (using the frequency re-use groups) to at least one part of the cell being split, while maintaining coverage of the cell from the same cell site.