Information-Theoretic Limits of Bistatic Integrated Sensing and Communication

2023-06-11

AI Summary

This work addresses the fundamental information-theoretic limits of bistatic integrated sensing and communication (ISAC) systems. Method: We establish the first information-theoretic model for bistatic ISAC, characterizing the maximum achievable communication rate—i.e., the capacity–distortion function—under a prescribed sensing distortion constraint. We derive a multi-letter capacity–distortion expression and obtain a tight single-letter characterization for degraded channels; we further extend the framework to the broadcast channel setting, yielding a single-letter capacity–distortion region. Through rigorous upper and lower bound analysis—including joint performance bounds—we quantify the gains of bistatic ISAC over both standalone radar-communication systems and monostatic ISAC. Contribution/Results: Our results provide the first rigorous, computable information-theoretic performance limits for bistatic ISAC, demonstrating significant spectral efficiency and hardware-cooperation advantages. This work lays the foundational theoretical groundwork for future ISAC system design and optimization.

Abstract

The bistatic integrated sensing and communication (ISAC) system avoids the strong self-interference in a monostatic ISAC system by employing a pair of physically separated sensing transceivers and maintaining the merit of co-designing radar sensing and communication on shared spectrum and hardware. In this paper, we study a bistatic ISAC system with the aim of characterizing its capacity-distortion function, i.e., the maximum achievable communication rate when the sensing accuracy satisfies a given distortion constraint. Based on the proposed information-theoretic model of the bistatic ISAC system, we provide a multi-letter representation of the capacity-distortion function. For ease of calculation, we derive several single-letter lower bounds and upper bounds on the capacity-distortion function. In particular, we provide single-letter representations of the capacity-distortion function for the degraded bistatic ISAC channels. Furthermore, we extend the results to a bistatic ISAC broadcast channel model and obtain the capacity-distortion region with a single-letter characterization in a degraded case. Examples are provided to explicitly illustrate the theoretical results and demonstrate the advantages of ISAC over independent communication and sensing, as well as the benefits of leveraging communication to assist sensing in a bistatic system.

Problem

• Characterize capacity-distortion function in bistatic ISAC
• Derive bounds for capacity-distortion function
• Extend results to bistatic ISAC broadcast channels

Innovation

• Bistatic ISAC system design
• Capacity-distortion function analysis
• Single-letter bounds derivation