Research On Concurrent Dual-Band Digital Predistortion Technology

The multi-standards/multi-networks coexisting situation proposes pressing needs for the linearity of the power amplifiers transmitting concurrent dual-band signals. To guarantee the quality of dual-band communication systems, corresponding linearization technologies must be applied to compensate for the nonlinear distortion of power amplifiers. The concurrent dual-band digital predistortion technique developed in recent years can effectively compensate for this kind of nonlinear distortion. At present, the concurrent dual-band digital predistortion technique which can compensate for the nonlinear distortion produced by the wideband power amplifiers or the concurrent dual-band power amplifiers transmitting concurrent dual-band signals has become a hot research spot at home and abroad. This paper focuses on the concurrent dual-band digital predistortion technique which aims to the wideband power amplifiers and concurrent dual-band power amplifiers transmitting concurrent dual-band signals for further research. In this paper, the research includes the following several aspects.1. The dual-band nonlinear distortion and its classification are introduced, the existing concurrent dual-band digital predistortion structures and dual-band digital predistortion models are summarized, and several commonly used evaluation criterions to evaluate the model accuracy and predistortion effect are also given.2. A new concurrent dual-band digital predistortion structure with only one upconvertion unit is proposed for the linearization of power amplifiers transmitting concurrent dual-band signals. With the comparison of the2D-DPD structure and the conventional single-band DPD structure, the advantages and disadvantages and the application situations of the concurrent dual-band digital predistortion structure with only one upconvertion unit are summarized.3. By extending the conventional DDR model to the concurrent dual-band mode, the DB-DDR model which is suitable for concurrent dual-band digital predistortion is derived, and the SDB-DDR model is introduced by substituting the three summations of DB-DDR model for two ones. Simulation and test results verify that these two concurrent dual-band digital predistortion models have the superiority in both model complexity and predistortion effect.4. A new DB-TLBMP model used for concurrent dual-band digital predistortion is proposed. This model is derived by extending the conventional TLBMP model to concurrent dual-band mode. The experimental results confirm that the DB-TLBMP model has higher model accuracy and better predistortion effects.