High Power Amplifier Linearization Using Zernike Polynomials in a LTE Transmission

Digital predistortion (DPD) is a highly cost- effective technique to linearize high power amplifiers (HPAs) in wireless applications. The polynomial-type behavioral models are widely used both for HPAs and predistorters, but they often suffer from the numerical instability when high order nonlinearities are included. In this paper, we propose a new polynomial predistorter model considering the use of a orthogonal polynomial model based on a Zernike polynomial basis which is very robust and stable when classical identification techniques are applied. Computer simulations in a LTE uplink transmission confirm the predistorter computed with the Zernike polynomial model provides improvements in adjacent channel leakage ratio (ACLR) with stability and moderate complexity in the DPD coefficient estimation.