Cram\'er-Rao Bounds for Integrated Sensing and Communications in Pinching-Antenna Systems

TL;DR

This paper derives fundamental sensing limits for pinching-antenna systems in integrated sensing and communications, showing they can achieve high resolution with fewer resources, guiding future system design.

Contribution

It introduces closed-form Cramér-Rao bounds for PAS-based ISAC, revealing performance advantages and providing practical design insights.

Findings

Achieves centimeter-level ranging accuracy.

Attains sub-degree angular resolution.

Uses fewer hardware resources than traditional arrays.

Abstract

Pinching-antenna systems (PASs) have recently emerged as a flexible, cost-effective route to large-scale antenna deployments envisioned for integrated sensing and communications (ISAC). This paper establishes the fundamental sensing limits of a bistatic PAS link by deriving closed-form Cram\'er-Rao lower bounds for the joint estimation of range and direction when a target is illuminated by pinching antennas placed along a dielectric waveguide and observed by a uniform linear array receiver. By rigorously preserving the amplitude and phase variations of each pinching antenna, as well as exploiting their non-uniform deployment, we gain valuable insights into the performance gain of PASs over conventional antenna arrays. Numerical results validate that the PAS-based ISAC can achieve centimeter-level ranging and sub-degree angular resolution with significantly fewer hardware resources than conventional uniform linear arrays. The derived bounds provide practical design guidelines for next-generation PAS-enabled ISAC systems.