US Patent 7830783 Method and circuit for reducing the crest factor

The invention relates to a method for reducing the crest factor, comprising the following method steps:(a) IFFT transformation of a data symbol to be transmitted;(b) looking for all peak values within a frame of the IFFT-transformed data symbol the amount of which is above a predetermined threshold;(c) providing a sample correction function;(d) allocating a scaling and phase rotation to the sample correction function according to the amplitude and position of the peak values found;(e) generating a correction signal in the frequency domain from a linear combination of rotated and scaled vectors according to the scaling and position determined;(f) modifying, particularly reducing the peak value of the data symbol to be transmitted by subtracting the correction signal, andIFFT transformation of the peak-value-modified data symbol into the time domain.