Computationally Stable MIMO Digital Predistortion for Power Amplifier based on Orthogonal Polynomial

Abstract

This study introduces orthogonal polynomials, a useful tool for simulating power amplifier behaviour and linearizing utizing Digital Predistortion (DPD). The numerical stability of the system is improved by using an orthogonal polynomial basis. The representation is compared to the conventional polynomial in terms of numerical stability for the $4\times 4$ MIMO system. LTE-OFDM signals were used to test the performance of the proposed DPD. The observed ACPR and NMSE of the OFDM signal were enhanced from −29 dB to −50 dB and from −8 dB to −35 dB by adopting the suggested DPD linearization topology.