Site-Specific and Frequency-Dependent Channel Characterization and MIMO Performance in FR3

TL;DR

This paper characterizes the propagation and MIMO performance of the FR3 frequency band (7-24 GHz) using site-specific ray-tracing simulations, revealing its intermediate behavior and the importance of large-array MIMO for effective deployment.

Contribution

It provides a detailed analysis of FR3 propagation and MIMO performance across various environments and frequencies, emphasizing the role of antenna scaling.

Findings

FR3 exhibits intermediate propagation characteristics between sub-6 GHz and mmWave bands.

Effective spatial multiplexing is achievable in FR3 with appropriate antenna array scaling.

Large-array MIMO architectures significantly enhance performance in FR3 deployments.

Abstract

Next-generation wireless systems aim to enable on-demand connectivity through dynamic spectrum utilization. Motivated by this vision, this paper investigates the propagation characteristics and MIMO performance of the upper mid-band, spanning approximately 7-24 GHz and unofficially referred to as FR3. Using site-specific ray-tracing (RT) simulations based on the Sionna framework, we analyze indoor and outdoor environments at representative frequencies across FR1, FR3, and FR2, including 3.5, 7, 10, 14, 20, 24, and 28 GHz, under both single-antenna and multi-antenna configurations. The results show that FR3 exhibits intermediate propagation behavior between sub-6 GHz and millimeter-wave bands while sustaining effective spatial multiplexing and favorable spectral efficiency. Furthermore, large-array analysis indicates that performance gains in FR3 are closely tied to antenna scaling, highlighting the importance of large-size or large-aperture MIMO architectures for practical deployments.