Abstract: Embodiments herein relate to a method in a radio base station (12) for handling a thermal noise power floor in a thermal noise power floor estimation process. The radio base station (12) determines a change or a rate of change of a thermal noise power floor estimate relative a previous thermal noise power floor estimate. When the change or rate of change exceeds a threshold value, the radio base station (12) performs one or more of the following: setting a limitation of the change or rate of change to be below the threshold; adjusting of a scaling power, and reducing an estimated mean power level with a quantity dependent on a reduction of the thermal noise power floor estimate.