Method, apparatus and arrangement for linearizing of a transmitter array

A method comprising:

• feeding back individual response signals at outputs of a plurality of non-linear branches of a transmitter array via respective feedback branches of a feedback circuit;
• controlling phase shift and attenuation of each feedback branch to model a transmission channel of the individual response signals to a receiver in a predetermined direction,
• combining the response signals at the outputs of the feedback branches;
• and
• determining a combined feedback signal to calculate predistortion coefficients for group linearization, wherein the predistortion coefficients are calculated to vary responses of individual ones of the non-linear branches to increase variability of non-linearity of the non-linear branches in their output characteristics.

An arrangement comprising:

• a feedback circuit comprising a plurality of feedback branches for feeding back individual response signals at the outputs of a plurality of non-linear branches of a transmitter array through phase shift and attenuation circuitry of the feedback branches, and for combining the response signals at the outputs of the feedback branches;
• feedback control circuitry configured to control phase shift and attenuation of each feedback branch to model a transmission channel of the individual response signals to a receiver in a predetermined direction;
• and
• measuring circuitry configured to measure a combined feedback signal to calculate predistortion coefficients for group linearization, wherein the predistortion coefficients are calculated to vary responses of individual ones of the non-linear branches to increase variability of non-linearity of the non-linear branches in their output characteristics.