On the Fundamental Tradeoff of Joint Communication and QCD: The Monostatic Case

TL;DR

This paper explores the fundamental tradeoff between communication efficiency and quickest change detection in monostatic ISAC systems, proposing a novel adaptive coding strategy and analyzing its optimality and practical performance.

Contribution

It introduces the JCCS strategy that dynamically adapts coding based on real-time feedback, providing a new framework for analyzing communication-detection tradeoffs in ISAC.

Findings

Characterizes the rate-delay region using mutual information and KL divergence.

Demonstrates the asymptotic optimality of the proposed detection algorithm.

Provides insights into optimal tradeoffs for binary and MIMO Gaussian channels.

Abstract

This paper investigates the fundamental tradeoff between communication and quickest change detection (QCD) in integrated sensing and communication (ISAC) systems under a monostatic setup. We introduce a novel Joint Communication and quickest Change subblock coding Strategy (JCCS) that leverages feedback to adapt coding dynamically based on real-time state estimation. The achievable rate-delay region is characterized using state-dependent mutual information and KL divergence, providing a comprehensive framework for analyzing the interplay between communication performance and detection delay. Moreover, we provide a partial converse demonstrating the asymptotic optimality of the proposed detection algorithm within the JCCS framework. To illustrate the practical implications, we analyze binary and MIMO Gaussian channels, revealing insights into achieving optimal tradeoffs in ISAC system design.