A set of power control step size increments are determined such that at least two step size increments differ from one another. The set is sent to a Mobile Station MS. A first power command to the MS informs of a first power for a uplink data transmission on a radio resource (E-DPDCH). To change power on the same radio resource, an offset is computed, the set of step size increments is accessed to determine which one, or combination of them, yield the offset, and the MS is informed of the second power by a second message that identifies those elements of the set that alone or in combination yield the offset. The MS determines the second power as a function of the first power and the step size increment(s) from the second message.