On the Fundamental Tradeoff of Joint Communication and Quickest Change Detection

In this study, we investigate the tradeoff between communication rate and quickest change detection (QCD) in integrated sensing and communication. We establish a joint problem for QCD, utilizing constant subblock-composition codes and a modified CuSum detection rule, named subblock CuSum (SCS). This approach provides an inner bound for the tradeoff between communication rate and change point detection delay in low false alarm scenarios. Our findings show that SCS is asymptotically optimal for certain code classes.

I. Introduction

Next-generation wireless networks aim for efficient commu-nication and sensing within limited resources, a key feature of Integrated Sensing and Communication (ISAC) systems [1], [2]. ISAC combines sensing and communication functionali-ties, using shared resources like frequency bands and hardware to improve efficiency and reduce costs [3], [4]. This approach positions ISAC as a crucial technology for future applications such as localization, autonomous vehicles, and healthcare [3], [5], [6]. Some important directions in ISAC research focuses on the trade-off between information rate and sensing accu-racy, which includes information rate vs. mean-squared error (MSE) for channel state estimation [7], [8] and information rate vs. target detection probability [9]–[12]. Secrecy metrics are also considered in [13], [14], with various surveys and overviews discussing these aspects in [6], [15]–[17].