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arXiv · 2605.25047

Design of APSK Constellations Approaching the Communication-Sensing Pareto Boundary for ISAC

Yujie Shao·Min Qiu·Ming-Chun Lee·Yu-Chih Huang·Jinhong Yuan
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Abstract

We propose a semi-analytical design framework for amplitude phase shift keying (APSK) signaling for integrated sensing and communication (ISAC), focusing on i.i.d. uniform discrete input distributions for practicality and analytical tractability. First, we establish APSK design criteria in which communication performance is measured by the gap to capacity and linked to the minimum Euclidean distance, while sensing performance is characterized by the symbol-energy variance. Based on these criteria, we develop a structured APSK construction whose key parameters follow explicit scaling laws. Then we prove that this construction achieves a constant gap to capacity independent of the signal-to-noise ratio. Building upon this foundation, we further construct a parametric APSK family that bridges the communication-optimal and sensing-optimal designs, with the communication and sensing (C&S) tradeoff controlled by the number of rings and energy allocation among rings. Simulation results show that the resulting APSK family achieves C&S performance very close to the Pareto boundary achieved with time-independent, circularly symmetric, and otherwise unconstrained continuous input distributions.

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Yujie Shao, Min Qiu, Ming-Chun Lee, Yu-Chih Huang, Jinhong Yuan. 2026-05-24. Design of APSK Constellations Approaching the Communication-Sensing Pareto Boundary for ISAC. https://arxiv.org/abs/2605.25047

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