A method performed by a radio base station for handling a thermal noise power floor in a thermal noise power floor estimation process, the method comprising: - determining a change or a rate of change of a thermal noise power floor estimate relative to a previous thermal noise power floor estimate; and - performing the following: setting a limitation of the change or the rate of change to be equal to a first threshold, when the change or the rate of change is an increase of the thermal noise power floor estimate and the change or the rate of change exceeds the first threshold; and reducing an estimated time average of Received Total Wideband Power, RTWP, with a quantity dependent on a measured reduction of the thermal noise power floor estimate, when the change or the rate of change is a reduction of the thermal noise power floor estimate and the thermal noise power floor estimate drops below a second threshold, and wherein further at least one of the following actions is performed when the change or the rate of change is a reduction of the thermal noise power floor estimate and the thermal noise power floor estimate drops below the second threshold: re-initiating an estimated probability density function of the thermal noise power floor at a level indicated by the estimated time average of the RTWP, and re-initiating an estimated cumulative probability density function of the thermal noise power floor, at a level indicated by the estimated time average of the RTWP, and wherein the reduction of the estimated thermal noise power floor is measured at each update of the thermal noise power floor estimate. - determining a change or a rate of change of a thermal noise power floor estimate relative to a previous thermal noise power floor estimate; and - performing the following: setting a limitation of the change or the rate of change to be equal to a first threshold, when the change or the rate of change is an increase of the thermal noise power floor estimate and the change or the rate of change exceeds the first threshold; and reducing an estimated time average of Received Total Wideband Power, RTWP, with a quantity dependent on a measured reduction of the thermal noise power floor estimate, when the change or the rate of change is a reduction of the thermal noise power floor estimate and the thermal noise power floor estimate drops below a second threshold, and wherein further at least one of the following actions is performed when the change or the rate of change is a reduction of the thermal noise power floor estimate and the thermal noise power floor estimate drops below the second threshold: re-initiating an estimated probability density function of the thermal noise power floor at a level indicated by the estimated time average of the RTWP, and re-initiating an estimated cumulative probability density function of the thermal noise power floor, at a level indicated by the estimated time average of the RTWP, and wherein the reduction of the estimated thermal noise power floor is measured at each update of the thermal noise power floor estimate. setting a limitation of the change or the rate of change to be equal to a first threshold, when the change or the rate of change is an increase of the thermal noise power floor estimate and the change or the rate of change exceeds the first threshold; and reducing an estimated time average of Received Total Wideband Power, RTWP, with a quantity dependent on a measured reduction of the thermal noise power floor estimate, when the change or the rate of change is a reduction of the thermal noise power floor estimate and the thermal noise power floor estimate drops below a second threshold, and wherein further at least one of the following actions is performed when the change or the rate of change is a reduction of the thermal noise power floor estimate and the thermal noise power floor estimate drops below the second threshold: re-initiating an estimated probability density function of the thermal noise power floor at a level indicated by the estimated time average of the RTWP, and re-initiating an estimated cumulative probability density function of the thermal noise power floor, at a level indicated by the estimated time average of the RTWP, and wherein the reduction of the estimated thermal noise power floor is measured at each update of the thermal noise power floor estimate.