Reduced Cost Digital Predistortion Only With In-Phase Feedback Signal

This letter proposes a reduced hardware cost feedback architecture for digital predistortion (DPD) to linearize power amplifiers (PAs). In the proposed DPD, only the in-phase (I) component of PA's output signal is acquired through the feedback path. Based on the statistical regularity of orthogonal frequency division modulation signals, a modified update equation of DPD coefficients with direct learning is derived based on the in-phase component of the feedback signal. The experimental results validate the feasibility of the proposed DPD, which achieves equivalent linearization performances compared to those of the traditional I/Q quadrature demodulation-based technique.