Joint predistortion of IQ impairments and PA nonlinearity in concurrent dual-band transmitters

Abstract

I/Q impairments of the I/Q modulator can adversely affect the performance of wireless transmitters. When employing digital predistortion (DPD) to linearize the transmitters, the linearization performance would be limited as well. For the concurrent dual-band transmitters which include two I/Q modulators, I/Q impairments show cross-modulation effects between the two signals in each band. This paper proposes a joint predistorter to compensate for I/Q impairments and power amplifier (PA) nonlinearity in concurrent dual-band transmitters in a joint manner. In comparison with the state-of-the-art work used for linearize concurrent dual-band transmitters, the proposed joint predistorter show significant improvement of linearization performance. Measurement results for a concurrent dual-band PA operating at 1.9 GHz and 2 GHz prove the effectiveness and superiority of the joint predistorter.