Numerically stable Digital Predistortion Model for Over-the-Air MIMO transmission

Abstract

Digital Predistortion technique is the most economical and reliable technique among all the linearization techniques available. This paper adduces the idea of linearization based on piecewise polynomial or essential spline functions as an integral solution to the MIMO nonlinearity and compares with the Crossover Memory polynomial model. MIMO nonlinearity is strongly coupled together due to the combined effect of PA nonlinearity and crosstalk. For the proof of concept, the method is implemented over the air on 2X2 MIMO, and simulation is performed for 4X4, 8X8, 16X16 MIMO System. Numerical evaluation of the technique is exhibited in terms of NMSE, BER, and EVM., while numerical stability is presented in terms of Condition number and Dispersion coefficient.