Patent ID: 8724721

Claim:
A method for reducing the crest factor of an input signal related to a symbol, the method performed in a part of a transmitter and comprising: creating a clipped signal by clipping the input signal using a predetermined clipping threshold; subtracting the clipped signal from the input signal to create a peak signal; selecting only a predetermined number of data points of the peak signal, wherein the predetermined number of data points are the predetermined number of data points of the peak signal with the highest magnitudes; convoluting the selected data points of the peak signal with the inverse Fourier transform of a filtering mask defined in the frequency domain to create a filtered signal; and creating a subtraction signal by subtracting the filtered signal from the input signal; wherein an initial peak signal is created prior to receipt of all data points of the input signal relating to the symbol and wherein said convolution is started based on the initial peak signal; and wherein further data points are added to the initial peak signal as the further data points are received as part of the input signal relating to the said symbol, thereby creating an updated initial peak signal and wherein said convolution is continued based on the updated initial peak signal.