The present invention relates to a device for calculating an indication of power of a received radio signal, said device comprising: a receiver (102) for receiving a plurality of logarithmic values representing a sequence of measurements of power of the received radio signal; circuitry (104) for determining a sum of the plurality of logarithmic values; wherein said circuitry (104) comprises: an adder (106) for pairwise summing of two logarithmic values, and a plurality of memory registers (108), which are arranged to store intermediate sums of logarithmic values, wherein the circuitry is arranged to control the adder (106) to sum the plurality of logarithmic values by a recursive procedure such that the first and the second logarithmic value in individual summations of the recursive procedure represent substantially same number of power measurements.