Experimental verification and comparison of polynomials and LUTs predistortion techniques

Abstract

In order to compensate for nonlinearities and memory effects introduced by power amplifiers, the digital predistortion is a widely used technique. Commonly the digital predistortion is based on polynomials derived from Volterra series or on lookup tables. Both approaches require time to find the the solution that can be applied to digital predistorter. Nevertheless, for predistorters to be actually implemented in real-time scenarios, fast convergence and low complexity is highly required. Unfortunately there does not exist a general rule for simple choice in therms of performance, convergence time and complexity. Thus in this paper a brief comparison of Volterra based series (orthogonal polynomials and simplified dynamic deviation reduction of second order) and lookup tables with cubic interpolation which are widely used schematic is provided.