Patent ID: 6853632

Claim:
In a multicarrier communication system in which a signal to be transmitted comprises data bits to be converted into a symbol modulated by each subcarrier of the signal prior to transmission on a channel, a method for minimizing a peak to average power ratio while minimizing introduction of errors into the signal to be transmitted, comprising: sampling the symbols to be transmitted of a frame; compare magnitudes of the samples of the frame to a predetermined threshold to determine whether sample magnitudes in the frame violate the predetermined threshold, the predetermined threshold being selectable to control the number of samples violating the threshold; responsive to determining a sample magnitude does violate the predetermined threshold, applying a differentiable penalty function to the samples having magnitudes exceeding the predetermined threshold; computing a net penalty function value, the net penalty function value responsive to the individual penalty function values computed for the samples having magnitudes exceeding the predetermined threshold; computing a gradient vector responsive to the net penalty function value; determining a direction of the gradient vector; determining an upper limit correction value for each symbol, the upper limit correction value being selectable to control an amount of signal to noise ratio deterioration; applying a correction to the symbols to be transmitted in a direction opposite to the direction of the gradient vector, the magnitude of the correction not exceeding the determined correction values for each symbol; and transmitting the corrected symbols to the channel.