A radio communication network (1) comprises at least a radio base station (10) serving an active cell (15) and a radio base station (20, 30, 40) having a passive cell (25, 35, 45) and does not transmit any cell-defining information for the passive cell (25, 35, 45). User equipment (100) receives random access enabling information applicable to the passive cell (25, 35, 45) from the radio base station (10) serving the active cell (15). The user equipment (100) uses this information for compiling and transmitting a random access to the radio base station (20, 30, 40) of the passive cell (25, 35, 45). Upon reception of the random access, the radio base station (20, 30, 40) activates its passive cell (25, 35, 45) and starts transmission of cell-defining information for the now activated cell (25, 35, 45) to assist user equipment (10) in finding the cell (25, 35, 45) for radio communication service.