Predistortion apparatus and predistortion method

A predistortion apparatus for compensating for a distortion arising from a non linear property in input to output characteristics of an amplifier, by processing calculation of a plurality of coefficients for a plurality of power series defining the predistortion characteristics for a plurality of power ranges, respectively, so as to apply a reverse property corresponding to the non linear property in the amplifier to input of the amplifier, the predistortion apparatus comprising:

• a coefficient update unit for setting and updating coefficients of the power series to provide the predistortion characteristics for the plurality of power ranges in accordance with a comparison between the input and output of the amplifier;
• and
• a determination unit for determining at least one threshold value defining the plurality of power ranges by shifting the threshold value and operating the coefficient update unit for updating the coefficients for each of the power series corresponding to each of the power ranges defined by the shifted threshold value so as to optimize the predistortion characteristics for each of the power ranges.