It is disclosed a method and a network node (502, 70, 90) for selecting a candidate cell (14, 44, 06) to be combined with a target cell (12, 42, 502) having a radio equipment (76) connected to a radio equipment controller (74). The method comprises identifying (612, 82) at least two candidate cells where a time delay in communication between any two of: said at least two candidate cells and the target cell, is below a pre-determined time threshold, selecting (614, 84) the one (44) having the highest connection activity with the target cell; and combining (616, 86) the selected candidate cell (14, 44) and said target cell (12, 42) into a logical cell. Embodiments of the present invention have the advantage that the logical cells being defined provides have a high overall mobile network connectivity improvement.