Transmitting a signal from a power amplifier

A computer program product for limiting peak-to-average power of a signal transmitted from a power amplifier, the computer program product comprising code embodied on a non-transient computer-readable medium and configured so as when executed on a processing apparatus to:

• generate a first signal;
• apply a pulse-shape filter to the first signal, thereby generating a second signal being a filtered version of the first signal;
• output the second signal for transmission from a power amplifier;
• apply each of a plurality of predictor filters to a respective instance of the first signal, each predictor filter approximating the application of the pulse-shape filter to the first signal based on a different respective set of filter coefficients, and each thereby generating a respective third signal;
• determine an indicator of amplitude of each of the third signals;
• select the indicator corresponding to the largest of said amplitudes;
• generate a modifier based on the selected indicator;
• and
• use the modifier to limit the first signal prior to applying the pulse-shape filter.

A transmission system comprising:

• a signal processing apparatus configured to generate a first signal and to apply a pulse-shape filter to the first signal, thereby generating a second signal being a filtered version of the first signal;
• and
• a power amplifier arranged to transmit the second signal for transmission from a power amplifier;
• wherein the signal processing apparatus is further configured to:
• apply each of a plurality of predictor filters to a respective instance of the first signal, each predictor filter approximating the application of the pulse-shape filter to the first signal based on a different respective set of filter coefficients, and each thereby generating a respective third signal;
• determine an indicator of amplitude of each of the third signals;
• select the indicator corresponding to the largest of said amplitudes;
• generate a modifier based on the selected indicator;
• and
• use the modifier to limit the first signal prior to applying the pulse-shape filter.