Impact of Background Dense Multipath Components on Multi-Band Fusion ISAC Systems

TL;DR

This paper analyzes how dense multipath components affect multi-band fusion ISAC systems, demonstrating that multi-band processing improves estimation accuracy and system robustness in DMC scenarios.

Contribution

It provides a novel analysis of DMC impact on multi-band ISAC, including CRB-based limits and a new estimator's performance evaluation.

Findings

Multi-band processing reduces estimation error in DMC scenarios.

System resilience is significantly improved with multi-band fusion.

Numerical results validate the effectiveness of the proposed estimator.

Abstract

Multi-band sensing has emerged as a key enabler of integrated sensing and communication (ISAC), one of the six primary usage scenarios defined for IMT-2030 (6G). The introduction of frequency range 3 (FR3, 7-24 GHz), comprising non-contiguous sub-bands across a wide frequency span, further reinforces the importance of multi-band operation. In such scenarios, frequency-dependent clutter, collectively referred to as dense multipath components (DMC), must be carefully considered. Building on prior literature and our experimental observations, this paper analyzes the impact of DMC on multi-band fusion ISAC systems by investigating Cram\'er-Rao bound (CRB)-based fundamental limits and the performance of our proposed multi-band estimator. Numerical results show that multi-band processing, especially in DMC-dominated scenarios, can substantially reduce estimation error and boost system resilience when channel statistics vary.