A Spatial Sigma-Delta Approach to Mitigation of Power Amplifier Distortions in Massive MIMO Downlink
In massive multiple-input multiple-output (MIMO) downlink systems, the physical implementation of the base stations (BSs) requires the use of cheap and power-efficient power amplifiers (PAs) to avoid high hardware cost and high power consumption. However, such PAs usually have limited linear amplifi...
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2025-01-01
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| author | Yatao Liu Mingjie Shao Wing-Kin Ma |
| author_facet | Yatao Liu Mingjie Shao Wing-Kin Ma |
| author_sort | Yatao Liu |
| collection | DOAJ |
| description | In massive multiple-input multiple-output (MIMO) downlink systems, the physical implementation of the base stations (BSs) requires the use of cheap and power-efficient power amplifiers (PAs) to avoid high hardware cost and high power consumption. However, such PAs usually have limited linear amplification ranges. Nonlinear distortions arising from operation beyond the linear amplification ranges can significantly degrade system performance. Existing approaches to handle the nonlinear distortions, such as digital predistortion (DPD), typically require accurate knowledge, or acquisition, of the PA transfer function. In this paper, we present a new concept for mitigation of the PA distortions. Assuming a uniform linear array (ULA) at the BS, the idea is to apply a Sigma-Delta (<inline-formula><tex-math notation="LaTeX">$\Sigma \Delta$</tex-math></inline-formula>) modulator to spatially shape the PA distortions to the high-angle region. By having the system operating in the low-angle region, the received signals are less affected by the PA distortions. To demonstrate the potential of this spatial <inline-formula><tex-math notation="LaTeX">$\Sigma \Delta$</tex-math></inline-formula> approach, we study the application of our approach to the multi-user MIMO-orthogonal frequency division modulation (OFDM) downlink scenario. A symbol-level precoding (SLP) scheme and a zero-forcing (ZF) precoding scheme, with the new design requirement by the spatial <inline-formula><tex-math notation="LaTeX">$\Sigma \Delta$</tex-math></inline-formula> approach being taken into account, are developed. Numerical simulations are performed to show the effectiveness of the developed <inline-formula><tex-math notation="LaTeX">$\Sigma \Delta$</tex-math></inline-formula> precoding schemes. |
| format | Article |
| id | doaj-art-be0d47366ba24111a3307882f95a0787 |
| institution | DOAJ |
| issn | 2644-1322 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IEEE |
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| series | IEEE Open Journal of Signal Processing |
| spelling | doaj-art-be0d47366ba24111a3307882f95a07872025-08-20T03:09:32ZengIEEEIEEE Open Journal of Signal Processing2644-13222025-01-01690091610.1109/OJSP.2025.358974711091482A Spatial Sigma-Delta Approach to Mitigation of Power Amplifier Distortions in Massive MIMO DownlinkYatao Liu0https://orcid.org/0000-0002-6647-5768Mingjie Shao1https://orcid.org/0000-0003-0659-5765Wing-Kin Ma2https://orcid.org/0000-0001-7314-3537Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong SAR, ChinaState Key Laboratory of Mathematical Sciences, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, ChinaDepartment of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong SAR, ChinaIn massive multiple-input multiple-output (MIMO) downlink systems, the physical implementation of the base stations (BSs) requires the use of cheap and power-efficient power amplifiers (PAs) to avoid high hardware cost and high power consumption. However, such PAs usually have limited linear amplification ranges. Nonlinear distortions arising from operation beyond the linear amplification ranges can significantly degrade system performance. Existing approaches to handle the nonlinear distortions, such as digital predistortion (DPD), typically require accurate knowledge, or acquisition, of the PA transfer function. In this paper, we present a new concept for mitigation of the PA distortions. Assuming a uniform linear array (ULA) at the BS, the idea is to apply a Sigma-Delta (<inline-formula><tex-math notation="LaTeX">$\Sigma \Delta$</tex-math></inline-formula>) modulator to spatially shape the PA distortions to the high-angle region. By having the system operating in the low-angle region, the received signals are less affected by the PA distortions. To demonstrate the potential of this spatial <inline-formula><tex-math notation="LaTeX">$\Sigma \Delta$</tex-math></inline-formula> approach, we study the application of our approach to the multi-user MIMO-orthogonal frequency division modulation (OFDM) downlink scenario. A symbol-level precoding (SLP) scheme and a zero-forcing (ZF) precoding scheme, with the new design requirement by the spatial <inline-formula><tex-math notation="LaTeX">$\Sigma \Delta$</tex-math></inline-formula> approach being taken into account, are developed. Numerical simulations are performed to show the effectiveness of the developed <inline-formula><tex-math notation="LaTeX">$\Sigma \Delta$</tex-math></inline-formula> precoding schemes.https://ieeexplore.ieee.org/document/11091482/Massive MIMOMIMO-OFDMnonlinear distortionpower amplifiersigma-delta modulationsymbol-level precoding |
| spellingShingle | Yatao Liu Mingjie Shao Wing-Kin Ma A Spatial Sigma-Delta Approach to Mitigation of Power Amplifier Distortions in Massive MIMO Downlink IEEE Open Journal of Signal Processing Massive MIMO MIMO-OFDM nonlinear distortion power amplifier sigma-delta modulation symbol-level precoding |
| title | A Spatial Sigma-Delta Approach to Mitigation of Power Amplifier Distortions in Massive MIMO Downlink |
| title_full | A Spatial Sigma-Delta Approach to Mitigation of Power Amplifier Distortions in Massive MIMO Downlink |
| title_fullStr | A Spatial Sigma-Delta Approach to Mitigation of Power Amplifier Distortions in Massive MIMO Downlink |
| title_full_unstemmed | A Spatial Sigma-Delta Approach to Mitigation of Power Amplifier Distortions in Massive MIMO Downlink |
| title_short | A Spatial Sigma-Delta Approach to Mitigation of Power Amplifier Distortions in Massive MIMO Downlink |
| title_sort | spatial sigma delta approach to mitigation of power amplifier distortions in massive mimo downlink |
| topic | Massive MIMO MIMO-OFDM nonlinear distortion power amplifier sigma-delta modulation symbol-level precoding |
| url | https://ieeexplore.ieee.org/document/11091482/ |
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