Sensing Capacity for Integrated Sensing and Communication Systems in Low-Altitude Economy

Abstract

The burgeoning significance of the low-altitude economy (LAE) has garnered considerable interest, largely fuelled by the widespread deployment of autonomous aerial vehicles (AAVs). To tackle the challenges associated with the detection of unauthorized AAVs and the efficient scheduling of authorized AAVs, this letter introduces a novel performance metric, termed sensing capacity, for integrated sensing and communication (ISAC) systems. This metric, which quantifies the capability of a base station (BS) to detect multiple AAVs simultaneously, leverages signal-to-noise ratio (SNR) and probability of detection (PD) as key intermediate variables. Through mathematical derivations, we can derive a closed-form solution for the maximum number of AAVs that can be detected by the BS while adhering to a specific SNR constraint. An approximate solution based on PD constraints is proposed to facilitate the efficient determination of the threshold for the maximum number of detectable AAVs. To generalize the analysis, we extend our investigation to practical scenarios with closely-spaced AAVs, incorporating inter-AAV interference effects. The accuracy of this analytical approach is verified through extensive simulation results.