Determining Memory Polynomial Model Parameters from Those of Complex p-th Order Inverse for Designing Predistorter

Michiharu NAKAMURA  Eisuke FUKUDA  Yoshimasa DAIDO  Keiichi MIZUTANI  Takeshi MATSUMURA  Hiroshi HARADA  

IEICE TRANSACTIONS on Communications   Vol.E104-B    No.11    pp.1429-1440
Publication Date: 2021/11/01
Publicized: 2021/06/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.2020EBP3155
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
behavioral model,  memory polynomial,  digital predistorter (DPD),  non-linear power amplifier,  linearlizer,  

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Non-linear behavioral models play a key role in designing digital pre-distorters (DPDs) for non-linear power amplifiers (NLPAs). In general, more complex behavioral models have better capability, but they should be converted into simpler versions to assist implementation. In this paper, a conversion from a complex fifth order inverse of a parallel Wiener (PRW) model to a simpler memory polynomial (MP) model is developed by using frequency domain expressions. In the developed conversion, parameters of the converted MP model are calculated from those of original fifth order inverse and frequency domain statistics of the transmit signal. Since the frequency domain statistics of the transmit signal can be precalculated, the developed conversion is deterministic, unlike the conventional conversion that identifies a converted model from lengthy input and output data. Computer simulations are conducted to confirm that conversion error is sufficiently small and the converted MP model offers equivalent pre-distortion to the original fifth order inverse.