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Main Authors: Wu, Yibo, Gustavsson, Ulf, Valkama, Mikko, Amat, Alexandre Graell i, Wymeersch, Henk
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2402.16577
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author Wu, Yibo
Gustavsson, Ulf
Valkama, Mikko
Amat, Alexandre Graell i
Wymeersch, Henk
author_facet Wu, Yibo
Gustavsson, Ulf
Valkama, Mikko
Amat, Alexandre Graell i
Wymeersch, Henk
contents The use of up to hundreds of antennas in massive multi-user (MU) multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) poses a complexity challenge for digital predistortion (DPD) aiming to linearize the nonlinear power amplifiers (PAs). While the complexity for conventional time domain (TD) DPD scales with the number of PAs, frequency domain (FD) DPD has a complexity scaling with the number of user equipments (UEs). In this work, we provide a comprehensive analysis of different state-of-the-art TD and FD-DPD schemes in terms of complexity and linearization performance in both rich scattering and line-of-sight (LOS) channels and with antenna crosstalk. We propose a novel low-complexity FD convolutional neural network (CNN) DPD. We also propose a learning algorithm for any FD-DPDs with differentiable structure. The analysis shows that FD-DPD, particularly the proposed FD CNN, is preferable in LOS scenarios with few users, due to the favorable trade-off between complexity and linearization performance. On the other hand, in scenarios with more users or isotropic scattering channels, significant intermodulation distortions among UEs degrade FD-DPD performance, making TD-DPD more suitable. The proposed learning algorithm allows FD-DPDs to outperform TD-DPD optimized by indirect learning architecture under antenna crosstalk.
format Preprint
id arxiv_https___arxiv_org_abs_2402_16577
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Time vs. Frequency Domain DPD for Massive MIMO: Methods and Performance Analysis
Wu, Yibo
Gustavsson, Ulf
Valkama, Mikko
Amat, Alexandre Graell i
Wymeersch, Henk
Signal Processing
The use of up to hundreds of antennas in massive multi-user (MU) multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) poses a complexity challenge for digital predistortion (DPD) aiming to linearize the nonlinear power amplifiers (PAs). While the complexity for conventional time domain (TD) DPD scales with the number of PAs, frequency domain (FD) DPD has a complexity scaling with the number of user equipments (UEs). In this work, we provide a comprehensive analysis of different state-of-the-art TD and FD-DPD schemes in terms of complexity and linearization performance in both rich scattering and line-of-sight (LOS) channels and with antenna crosstalk. We propose a novel low-complexity FD convolutional neural network (CNN) DPD. We also propose a learning algorithm for any FD-DPDs with differentiable structure. The analysis shows that FD-DPD, particularly the proposed FD CNN, is preferable in LOS scenarios with few users, due to the favorable trade-off between complexity and linearization performance. On the other hand, in scenarios with more users or isotropic scattering channels, significant intermodulation distortions among UEs degrade FD-DPD performance, making TD-DPD more suitable. The proposed learning algorithm allows FD-DPDs to outperform TD-DPD optimized by indirect learning architecture under antenna crosstalk.
title Time vs. Frequency Domain DPD for Massive MIMO: Methods and Performance Analysis
topic Signal Processing
url https://arxiv.org/abs/2402.16577