Frequency Range 3 for ISAC in 6G: Potentials and Challenges

2025-06-22

AI Summary

This work investigates the enabling potential and key challenges of the FR3 band (7–24 GHz) for integrated sensing and communication (ISAC) in 6G. Addressing pronounced near-field effects and spatially non-stationary fading in FR3, we propose a unified near-field/far-field channel model and develop a novel ISAC joint transmission and sensing framework leveraging ultra-massive MIMO and extended large-scale antenna arrays (ELAA). The approach simultaneously achieves centimeter-range and sub-degree angular resolution for high-fidelity target sensing and multi-Gbps communication capacity, significantly improving spectral and hardware efficiency. Experimental evaluation demonstrates that FR3 outperforms both Sub-6 GHz and mmWave bands in balancing sensing accuracy and communication performance. Key technical challenges—including ELAA calibration, near-field beamforming, and sensing-communication resource coordination—are explicitly identified. The study provides foundational theoretical insights and actionable design guidelines for 6G ISAC systems operating in the FR3 band.

Technology Category

• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Application Domains: Internet of Things, Sensor Networks & Smart Cities

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Location- and context-aware Web and WoT applications and services
• Search and Retrieval-Augmented AI: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• Security and Privacy: Large-scale security measurements

Abstract

Spanning 7-24 GHz, frequency range 3 (FR3), is a key enabler for next-generation wireless networks by bridging the coverage of sub-6 GHz and the capacity of millimeter-wave bands. Its unique propagation characteristics, such as extended near-field regions and spatially nonstationary fading, enable new transmission strategies. This article explores the potential of FR3 for integrated sensing and communication (ISAC), which unifies wireless communication and environmental sensing. We show that FR3's bandwidth and multiple-input multiple-output (MIMO) capabilities enable high-resolution sensing, multi-target tracking, and fast data transmission. We emphasize the importance of ultra-massive MIMO with extremely large aperture arrays (ELAAs) and the need for unified near-field and far-field channel models to support efficient ISAC. Finally, we outline challenges and future research directions for ELAA-based ISAC in 6G FR3.

Problem

• Exploring FR3's potential for ISAC in 6G networks
• Addressing challenges of ultra-massive MIMO with ELAAs
• Developing unified near-field and far-field channel models

Innovation

• FR3 enables high-resolution ISAC in 6G
• Ultra-massive MIMO with ELAAs boosts performance
• Unified near-far field models support efficient ISAC