Fundamental Limits of 1-bit ISAC Systems: Capacity Region and Optimal Power Control

2026-04-14

AI Summary

This study investigates the fundamental trade-off between communication and sensing performance in integrated sensing and communication (ISAC) systems under 1-bit quantization over Gaussian fading channels. Employing information-theoretic tools, the work characterizes the capacity region when channel state information is available at the receiver, revealing that no performance compromise is necessary between communication and sensing under 1-bit quantization. It further demonstrates that rotationally symmetric constant-modulus input distributions simultaneously achieve both communication and sensing capacities. When channel state information is also available at the transmitter, the paper proposes an optimal power control strategy that adaptively adjusts according to sensing priority; the solution continuously transitions from water-filling to uniform power allocation, offering practical design insights for real-world ISAC systems.

Technology Category

• Constraint Satisfaction and Optimization: Satisfiability
• Machine Learning: Calibration & Uncertainty Quantification
• Search and Optimization: Mixed Discrete/Continuous Search

Application Category

• Security and Privacy: Large-scale security measurements
• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization
• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems

Abstract

This paper investigates the fundamental limits of integrated sensing and communication (ISAC) systems with 1-bit receiver quantization. We analyze a Gaussian fading ISAC channel with separate communication and monostatic sensing links, where both communication and sensing receivers are equipped with 1-bit quantizers. When the communication channel state information (CSI) is available at the receiver, we characterize the communication-sensing capacity region of 1-bit ISAC channel and show that no trade-off exists between communication and sensing performance. In particular, both communication and sensing capacities can be simultaneously achieved by a constant-amplitude input distribution with a specific rotational symmetry. For the scenario where communication CSI is also available at the transmitter, we formulate a weighted optimization problem that balances communication and sensing rates in 1-bit ISAC channel under an average power constraint and then derive the corresponding optimal power control policy. The results demonstrate how the optimal power control policy evolves with the weighting parameter, transitioning from a communication-centric water-filling structure to a more uniform allocation as sensing becomes increasingly prioritized.

Problem

• 1-bit quantization
• ISAC
• capacity region
• power control
• fundamental limits

Innovation

• 1-bit quantization
• ISAC
• capacity region
• optimal power control
• rotational symmetry