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Main Authors: Vanspranghels, Emiel, Cui, Zhuangzhuang, Pollin, Sofie
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2601.07489
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author Vanspranghels, Emiel
Cui, Zhuangzhuang
Pollin, Sofie
author_facet Vanspranghels, Emiel
Cui, Zhuangzhuang
Pollin, Sofie
contents FR3 ($\approx$7-24 GHz), also referred to as the upper mid-band, has recently emerged as promising spectrum for 6G; however, its propagation and MIMO characteristics vary significantly with frequency and environment, and spectrum availability may be intermittent due to incumbents. Using site-specific ray tracing (Sionna RT) in representative indoor and outdoor scenarios, we evaluate 7, 10, 14, 20, and 24 GHz under SISO and MIMO configurations. The results show that FR3 exhibits propagation characteristics intermediate between sub-6 GHz and mmWave bands while supporting meaningful spatial multiplexing, albeit with strong site dependence. Motivated by these findings, we propose a fully digital frequency-adaptive multi-band MIMO architecture that repurposes ADCs/DACs and baseband processing resources across FR3 subbands via switching, enabling dynamic trade-offs between bandwidth (spectrum gain) and antenna consolidation (MIMO gain) under availability and channel constraints. Simulation results demonstrate that exploiting additional spectrum is often optimal, while adaptive resource repurposing becomes beneficial when subbands are unavailable or when multiplexing gains are concentrated at specific frequencies.
format Preprint
id arxiv_https___arxiv_org_abs_2601_07489
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Frequency-Adaptive Multi-Band Architecture for Upper Mid-Band MIMO Systems
Vanspranghels, Emiel
Cui, Zhuangzhuang
Pollin, Sofie
Information Theory
Systems and Control
FR3 ($\approx$7-24 GHz), also referred to as the upper mid-band, has recently emerged as promising spectrum for 6G; however, its propagation and MIMO characteristics vary significantly with frequency and environment, and spectrum availability may be intermittent due to incumbents. Using site-specific ray tracing (Sionna RT) in representative indoor and outdoor scenarios, we evaluate 7, 10, 14, 20, and 24 GHz under SISO and MIMO configurations. The results show that FR3 exhibits propagation characteristics intermediate between sub-6 GHz and mmWave bands while supporting meaningful spatial multiplexing, albeit with strong site dependence. Motivated by these findings, we propose a fully digital frequency-adaptive multi-band MIMO architecture that repurposes ADCs/DACs and baseband processing resources across FR3 subbands via switching, enabling dynamic trade-offs between bandwidth (spectrum gain) and antenna consolidation (MIMO gain) under availability and channel constraints. Simulation results demonstrate that exploiting additional spectrum is often optimal, while adaptive resource repurposing becomes beneficial when subbands are unavailable or when multiplexing gains are concentrated at specific frequencies.
title Frequency-Adaptive Multi-Band Architecture for Upper Mid-Band MIMO Systems
topic Information Theory
Systems and Control
url https://arxiv.org/abs/2601.07489