A radiation power level control scheme for a wireless user equipment (UE) device. In one embodiment, a method comprises determining a time-average transmission power level, comparing the time-average transmission power level with a first time-averaged transmission power limit threshold, the first time-averaged transmission power limit threshold having a value that depends on a transmission power history for the UE device, and responsive to the time-average transmission power level meeting or exceeding the first time-averaged transmission power limit threshold, reducing a transmission power level of the UE device.