A Square-Root-Based Memory Polynomial Model for Concurrent Dual-Band Digital Predistortion

In this letter, a novel 2-D square-root-based memory polynomial behavioral model is proposed. A new set of square-root-based basic functions is adopted to describe the characteristic of the predistorter. Since the proposed model has only two nested summations, the number of coefficients of the proposed model is greatly reduced compared with models which have three nested summations. The experimental results show that the proposed model can reduce the coefficients by more than 66.7% compared with the 2-D digital predistortion (2D-DPD) model. Moreover, the proposed model can achieve better adjacent channel power ratio (ACPR) performance. Compared with the 2D-DPD model and the simple online coefficient update model, the proposed model can improve the normalized mean-square error by 11 dB. Compared with the 2-D modified memory polynomial model, the proposed model can obtain similar ACPR performance with a shorter running time.