Is Repeater-Assisted Massive MIMO Compatible with Dynamic TDD?

Fuente: arXiv
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Main Authors: Andersson, Martin, Chowdhury, Anubhab, Larsson, Erik G.
Format: Preprint
Published: 2025
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author Andersson, Martin
Chowdhury, Anubhab
Larsson, Erik G.
author_facet Andersson, Martin
Chowdhury, Anubhab
Larsson, Erik G.
contents We present a framework for joint amplification and phase shift optimization of the repeater gain in dynamic time-division duplex (TDD) repeater-assisted massive MIMO networks. Repeaters, being active scatterers with amplification and phase shift, enhance the received signal strengths for users. However, they inevitably also amplify undesired noise and interference signals, which become particularly prominent in dynamic TDD systems due to the concurrent downlink (DL) and uplink (UL) transmissions, introducing cross-link interference among access points and users operating in opposite transmit directions. This causes a non-trivial trade-off between amplification of desired and undesired signals. To underpin the conditions under which such a trade-off can improve performance, we first derive DL and UL spectral efficiencies (SEs), and then develop a repeater gain optimization algorithm for SE maximization. Numerically, we show that our proposed algorithm successfully calibrates the repeater gain to amplify the desired signal while limiting the interference.
format Preprint
id arxiv_https___arxiv_org_abs_2510_20998
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Is Repeater-Assisted Massive MIMO Compatible with Dynamic TDD?
Andersson, Martin
Chowdhury, Anubhab
Larsson, Erik G.
Signal Processing
We present a framework for joint amplification and phase shift optimization of the repeater gain in dynamic time-division duplex (TDD) repeater-assisted massive MIMO networks. Repeaters, being active scatterers with amplification and phase shift, enhance the received signal strengths for users. However, they inevitably also amplify undesired noise and interference signals, which become particularly prominent in dynamic TDD systems due to the concurrent downlink (DL) and uplink (UL) transmissions, introducing cross-link interference among access points and users operating in opposite transmit directions. This causes a non-trivial trade-off between amplification of desired and undesired signals. To underpin the conditions under which such a trade-off can improve performance, we first derive DL and UL spectral efficiencies (SEs), and then develop a repeater gain optimization algorithm for SE maximization. Numerically, we show that our proposed algorithm successfully calibrates the repeater gain to amplify the desired signal while limiting the interference.
title Is Repeater-Assisted Massive MIMO Compatible with Dynamic TDD?
topic Signal Processing
url https://arxiv.org/abs/2510.20998