Patent ID: 8224265

Claim:
A method of optimizing coefficients for polynomials defining Amplitude Modulation to Amplitude Modulation (AM/AM) and Amplitude Modulation to Phase Modulation (AM/PM) predistortion for a polar modulated transmit signal in a mobile terminal in order to optimize an Output Radio Frequency Spectrum (OFRS) of the mobile terminal, wherein the AM/AM and AM/PM predistortion compensates for AM/AM and AM/PM distortion of a power amplifier in a transmit chain of the mobile terminal, comprising: for each AM/AM coefficient for the polynomial defining the AM/AM predistortion and each AM/PM coefficient for the polynomial defining the AM/PM predistortion, performing a first Error Vector Magnitude (EVM) correction to find a value of the coefficient that provides a minimum EVM; determining values for the AM/AM and AM/PM coefficients to optimize a modulation spectrum of the mobile terminal by varying the AM/AM and AM/PM coefficients according to at least one predetermined rule defining a manner by which the AM/AM and AM/PM coefficients are varied to adjust the modulation spectrum while keeping EVM substantially fixed; and further optimizing the values that optimize the modulation spectrum of the mobile terminal of the AM/AM and AM/PM coefficients in order to optimize a switching spectrum of the mobile terminal such that the values are first optimized for the modulation spectrum of the mobile terminal and are then optimized for the switching spectrum of the mobile terminal.