System for compensating the non-linear distortion introduced by a radio power amplifier based on harmonic analysis

Abstract

Digital predistortion systems aim to reduce the impact of the non-linear response of radio power amplifiers, usually for improving the spectral performance of wireless telecommunication networks. The present invention pertains to such a system having increased robustness and rapidity. Rather than analyzing the ongoing error between the intended and actual amplifier output in the background during normal operation, or performing iterative adaptations, the response of the amplifier is rapidly probed in the foreground by applying a sinusoidal tone having a variable frequency and amplitude according to a predetermined sequence. The harmonics generated due to the non-linear response of the amplifier are extracted from its output signal. By establishing an approximate correspondence between their amplitudes and the individual parameters of an algebraic relationship suitable for compensating the non-linear response of the amplifier, the present invention enables the direct calculation of said parameters. The possibility of ongoing adjustment of said parameters based on additional transducers is also described.

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