Patent ID: 9692627
Date: 2017-06-27
CPC Classifications: H04B,H04L

Claim:
1. A signal processing circuit, in an orthogonal frequency division multiplexing (OFDM) transmitter, for reducing a peak-to-average power ratio (PAPR) of a modulated signal, the signal processing circuit comprising: a peak detector configured to detect peaks having sizes above a threshold value from an in-phase/quadrature (IQ) baseband signal of the modulated signal and to output information on a position, a size and a phase of each of the peaks; a memory configured to store a reference peak in time domain, the reference peak indicating a peak of a maximum size that is removable in the OFDM transmitter; a peak generator configured to generate an inverse peak signal for canceling a part of an amplitude of the IQ baseband signal from the reference peak based on the information on the position, the size and the phase of each of the detected peaks; and a signal processing unit having a delayer and an adder, and configured to add the inverse peak signal to the IQ baseband signal to constrain the amplitude of the IQ baseband signal; wherein the peak generator is configured to calculate a removal ratio for each of the detected peaks, wherein a size of each of the peaks is reduced by the respective removal ratio, to multiply the reference peak by the respective removal ratio calculated for each of the peaks to generate a peak signal for cancellation, and to add the peak signal for cancellation to the corresponding peak taking into account the phase and position of the peak, to generate the inverse peak signal.