A method for simplifying calculations for pre-whitening in a G-RAKE receiver, comprising receiving at least two signals with at least two antennas via a channel, where each one of said received signals comprises time delayed and attenuated versions of the original signals. Each received signal forms a corresponding vector of received signal versions and the vectors form a matrix of received signals, where, due to correlation between the antennas, the received signals are correlated. Each version also comprises a certain amount of colored noise. The correlating effect of the antennas is estimated and formulated in matrix form and used to acquire essentially uncorrelated received signal vectors in an essentially uncorrelated received signal matrix. A calculated inverse of a covariance matrix of the calculated essentially uncorrelated signal vectors is used to pre-whiten the noise. A G-RAKE receiver arranged for applying the method above.