Patent ID: 6175551
Filing Date: 2001-01-16
Classification: H04B,H04J,H04L

Abstract:
A method of reducing a peak-to-average power ratio of a multi-carrier multiplexed signal to be transmitted, said method comprising the steps of:coding a digital input data stream into blocks of N data streams, where N represents a number of subcarriers in said signal;multiplexing data of said N data streams and modulating said subcarriers to provide symbols of modulated data;detecting peak power amplitudes for said symbols and determining whether said peak amplitudes exceed a given threshold; andscaling said peak power amplitudes, if said peak amplitudes exceed said given threshold, wherein said step of scaling includes:generating impulses having phases substantially equal to a peak phase of a corresponding one of said symbols and having an amplitude substantially equal to a peak amplitude of said corresponding one of said symbols minus a desired maximum amplitude;lowpass filtering said impulses on a symbol by symbol basis; andsubtracting a reference function from a corresponding symbol, wherein said subtracted reference function reduces said peak power amplitude of at least one signal sample of said corresponding symbol and said signal to be transmitted.