Dual-Domain Convergence Criterion for Iterative Digital Predistortion Coefficient Optimization in E-Band mmWave Systems

Citation: Tatiana Krasik, "Dual-Domain Convergence Criterion for Iterative Digital Predistortion Coefficient Optimization in E-Band mmWave Systems", Universal Library of Engineering Technology, Volume 03, Issue 02.

Copyright: This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This letter presents a dual-domain convergence criterion methodology for iterative digital predistortion (DPD) coefficient optimization in E-band (71-86 GHz) mmWave production automated test environments (ATE). Existing stopping criteria rely on a single measurement domain: received signal level (RSL) stability [10] or coefficient delta norms [1]. Both work at low modulation orders. Neither is sufficient at 256QAM. In practice, RSL convergence consistently precedes mean square error (MSE) stabilization at the demodulator, producing a false convergence window during which premature termination yields a miscalibrated radio. The proposed methodology requires both an RF-domain RSL stability condition and a baseband MSE threshold to be satisfied simultaneously before the loop may exit, augmented by a bounded safety exit counter guaranteeing finite execution time. The criterion is formalized for E-band backhaul systems and illustrated numerically under representative production ATE parameters.

Keywords: Digital Predistortion, DPD, Convergence Criterion, E-Band, mmWave, Automated Test, 256QAM, Measurement Methodology.

https://doi.org/10.70315/uloap.ulete.2026.0302010