Digital Predistortion Using Lookup Tables With Linear Interpolation and Extrapolation: Direct Least Squares Coefficient Adaptation

In this paper, we present a method to implement digital predistortion (DPD) memory models using lookup tables (LUTs) with linear interpolation and extrapolation. We introduce the required set of basis functions to describe this model. The DPD output is expressed as a linear combination of these basi...

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Bibliographic Details
Published in:IEEE transactions on microwave theory and techniques Vol. 65; no. 3; pp. 980 - 987
Main Authors: Molina, Albert, Rajamani, Kannan, Azadet, Kamran
Format: Journal Article
Language:English
Published: New York IEEE 01.03.2017
The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subjects:
Adaptation
Adaptation models
automatic gain control
Basis functions
cellular base station
Computational modeling
digital predistortion (DPD) adaptation
Extrapolation
Gain control
Interpolation
Least squares
lookup table (LUT)
Lookup tables
Mathematical models
nonlinear distortion
Polynomials
power amplifiers (PAs)
Predistortion
Table lookup
ISSN:0018-9480, 1557-9670
Online Access:Get full text
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Summary:In this paper, we present a method to implement digital predistortion (DPD) memory models using lookup tables (LUTs) with linear interpolation and extrapolation. We introduce the required set of basis functions to describe this model. The DPD output is expressed as a linear combination of these basis functions and we show how to directly estimate the LUT entries using least squares. We show how this model achieves lower complexity at similar or better performance compared to polynomial models translated to LUTs with interpolation or models based on LUTs without interpolation whose coefficients are adapted directly. We refer to this model as the direct adaptation of LUTs with interpolation/extrapolation (DLUTI). In this paper we also introduce the composite memory polynomial model: a new polynomial model which is a hybrid between the generalized memory polynomial and the dynamic deviation reduction models. This model is used as a starting point to generate the final LUT-based model.
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ISSN:0018-9480
1557-9670
DOI:10.1109/TMTT.2016.2627562