A Low-Complexity Digital Predistortion Technique For Digital I/Q Transmitters

This paper presents an advanced yet simple digital pre-distortion (DPD) technique for digital I/Q transmitters (DTXs). Exploiting the I/Q orthogonality, an effective 2×1-D DPD procedure is proposed to bypass the exhaustive 2-D search of the entire constellation diagram. Utilizing this technique, a four-way Doherty DTX is linearized. Measurement results demonstrate that for a non-contiguous six-carrier OFDM-QAM signal with aggregated bandwidth of 150MHz, the ACPR is better than -47.3dBc, and EVM is better than -41/-40dB for channel-1/-6, respectively.