Methods and apparatus for performing radio resource management measurements in a heterogeneous network are provided in an effort to prevent failure of RRM measurement procedures in a dominant interference scenario. The near end radio link node is connected to a far end radio link node via a radio link. When the fan is rotated to cause an amount of fluid to flow through the outlet of the frame, the fluid control elements provided in the frame are adapted to control a flow direction of the fluid flown out of the outlet.