Fundamental Performance Limits of Non-Coherent ISAC: A Data-Aided Sensing Perspective

TL;DR

This paper analyzes the fundamental limits of non-coherent ISAC systems, comparing pilot sensing and data-aided sensing schemes, and reveals significant performance gains of DAS over PS through asymptotic analysis.

Contribution

It provides a novel asymptotic performance analysis of DAS and PS schemes in non-coherent ISAC, highlighting the advantages of DAS in SNR and scaling rate.

Findings

DAS achieves a 3 dB SNR gain in low-SNR regimes.

DAS has faster performance scaling at high SNR.

Asymptotic expressions quantify the performance benefits of DAS.

Abstract

In this paper, we investigate a bistatic multiple-input multiple-output (MIMO) integrated sensing and communication (ISAC) system over block-fading channels, focusing on the scenario where the sensing and communication receivers (Rxs) are co-located. Under the assumption of unknown channel state information (CSI) at the Rx, two schemes are considered: pilot sensing (PS) and data-aided sensing (DAS). The communication rate-sensing distortion functions for both schemes are characterized. For the DAS scheme, a closed-form asymptotic expression for the sensing distortion is derived by using random matrix theory (RMT). The asymptotic performance analysis explicitly quantifies the significant gains of the DAS scheme, revealing a strict $3$ dB effective SNR improvement in the low-SNR regime and a strictly faster performance scaling rate in the high-SNR limit compared to the PS scheme.