Abstract: Linearizing Power Amplifiers' Outputs in Multi-Antenna System There is provided power efficient and simple structure for linearizing power amplifiers' outputs in multi-antenna beamforming systems. Beamforming factors are obtained for controlling transmission beams of the antennas in an analogue/hybrid beamforming system. At least one power amplifier model is determined on the basis of the power amplifiers' outputs and the beamforming factors. Predistortion parameters, for feeding a predistorted signal to power amplifiers for linearizing the power amplifiers' outputs, are determined such that after the operating parameters of the power amplifiers have been adjusted, errors in power amplifiers' outputs are reduced.

Abstract: Linearizing Power Amplifiers' Outputs in Multi-Antenna System There is provided power efficient and simple structure for linearizing power amplifiers' outputs in multi-antenna beamforming systems. Beamforming factors are obtained for controlling transmission beams of the antennas in an analogue/hybrid beamforming system. At least one power amplifier model is determined on the basis of the power amplifiers' outputs and the beamforming factors. Predistortion parameters, for feeding a predistorted signal to power amplifiers for linearizing the power amplifiers' outputs, are determined such that after the operating parameters of the power amplifiers have been adjusted, errors in power amplifiers' outputs are reduced.

Abstract: It is provided a method for providing feedback to pre-distorters in branches of a MISO system such that the pre-distortion cancels distortions caused by the signal path and the combiner combining the signals from the branches into which input signals are input. The method includes generating uncorrelated noises and mixing them with the input signals, evaluating the output of the combiner based on the input signals and the noises in order to determine a respective contribution of each input signal to the output of the combiner, and accordingly determining an appropriate pre-distortion. The signal path may apply a non-linear and/or dynamic function on the signal.

Abstract: It is provided a method for providing feedback to pre-distorters in branches of a MISO system such that the pre-distortion cancels distortions caused by the signal path and the combiner combining the signals from the branches into which input signals are input. The method includes generating uncorrelated noises and mixing them with the input signals, evaluating the output of the combiner based on the input signals and the noises in order to determine a respective contribution of each input signal to the output of the combiner, and accordingly determining an appropriate pre-distortion. The signal path may apply a non-linear and/or dynamic function on the signal.