Digital PreDistortion for Concurrent Dual-Band Transmitter with a Single Feedback Path

A new digital pre-distortion technique to linearize power amplifiers (PAs) is being proposed for concurrent dual-band transmitters. In the considering system, dual-band signals are combined and amplified by a single wideband PA. The PA output signal is distorted by the cross-modulation between different band signals as well as their own inter-modulation. In conventional dual-band DPD techniques, two independent dualfeedback paths are required to convert the dual band PA outputs into baseband signals, respectively. However, it increases hardware complexity and expense. In this paper, we propose a new DPD method requiring only a single feedback path. In this new structure, the proposed technique first estimates the dual-band PA characteristics using the single feedback path. The DPD parameters are then extracted from the estimated PA characteristics. Computer simulation demonstrates that the proposed technique can achieve comparable performance with the conventional dual-feedback DPD, with significantly reduced hardware complexity.