Continuous-Aperture Array-Based ISAC Over Fading Channels

TL;DR

This paper introduces a novel continuous-aperture array framework for integrated sensing and communications over fading channels, providing new beamforming designs and performance analysis that outperform traditional methods.

Contribution

It develops a continuous operator-based signal model and analyzes three beamforming strategies, including a Pareto-optimal design, for CAPA-based ISAC systems.

Findings

Closed-form expressions for sensing rate and communication rate are derived.

High-SNR asymptotic analysis reveals multiplexing and diversity gains.

Numerical results show superior performance over traditional array-based ISAC.

Abstract

A framework of continuous-aperture array (CAPA)-based integrated sensing and communications (ISAC) under a fading communication channel is proposed. A continuous operator-based signal model is developed, and the statistics of the communication channel gain are characterized via Landau's eigenvalue theorem. On this basis, the performance of the CAPA-based ISAC system is analyzed by considering three continuous beamforming designs: i) the sensing-centric (S-C) design that optimizes sensing performance, ii) the communication-centric (C-C) design that optimizes communication performance, and iii) the Pareto-optimal design that balances the sensing-communication trade-off. For the S-C and C-C design, closed-form expressions for the sensing rate (SR), ergodic communication rate (CR), and outage probability are derived, and high-signal-to-noise ratio asymptotic analysis is conducted to obtain the multiplexing and diversity gains. For the Pareto-optimal design, the Pareto-optimal beamformer achieving the Pareto boundary is derived, and the achievable SR-CR region is characterized. Numerical results demonstrate that the proposed CAPA-ISAC scheme outperforms both conventional spatially discrete arrays-based ISAC and CAPA-based frequency-division sensing and communications.