Performance analysis for scalar digital predistortion

The scalar digital predistortion (DPD) technology is an attractive linearization method for power amplifier (PA). By using the method, the hardware is simplified greatly because only the out-band distortion power is feedback to train the predistorter. In terms of low cost, the scalar method has obvious advantages over the conventional vector method. However, it is unknown whether there is linearization performance loss in the scalar DPD method. In this paper, the scalar DPD method is modeled and analyzed. The phase rotation phenomenon of the scalar DPD method is revealed. The theoretical analysis results prove the equivalence of the two DPD methods with phase rotation compensation in the memoryless condition. The equivalence is verified by using the numerical simulation.