Embodiments of a method in a network node for controlling a radio transmitter. In each one of a plurality of consecutive control steps spanning a predetermined control window, determining a first limit representing a number of physical resource blocks, PRBs, that can be scheduled in each one of a plurality of consecutive future slots of a current control step, based at least in part on an allowable average output power of the radio transmitter. The control window comprises a plurality of control steps, and each control step comprises a plurality of slots. When the determined first limit is less than or equal to a pre-configured second limit representing a number of PRBs that can be scheduled in a single slot, scheduling PRBs in a proportion of the plurality of consecutive future slots of the current control step, the proportion being calculated such that an averaged fraction of scheduled PRBs in the current control step is less than or equal to the first limit.