Symbol-Level Precoding for Integrated Sensing and Covert Communication

TL;DR

This paper introduces a symbol-level precoding waveform design for integrated sensing and covert communication, enhancing security and sensing performance without extra resources, and robustly handling imperfect channel information.

Contribution

It proposes a novel SLP-based waveform design that achieves covert communication and sensing simultaneously, with a low-complexity optimization algorithm for practical implementation.

Findings

Achieves superior covertness and sensing performance.

Maintains high reliability for legitimate users.

Demonstrates robustness with imperfect channel information.

Abstract

Integrated sensing and communication (ISAC) systems have emerged as a promising solution to improve spectrum efficiency and enable functional convergence. However, ensuring secure information transmission while maintaining high-quality sensing performance remains a significant challenge. In this paper, we investigate an integrated sensing and covert communication (ISCC) system, in which a base station (BS) simultaneously serves multiple downlink users and senses malicious targets that may act as both potential eavesdroppers (Eves) and wardens. We propose a novel symbol-level precoding (SLP)-based waveform design for ISCC that achieves covert communication intrinsically, without requiring additional transmission resources such as artificial noise. The proposed design integrates symbol shaping to enhance reliability for legitimate users and noise shaping to obscure transmission activities from the targets. For imperfect channel state information (CSI), the framework incorporates bounded uncertainty models for user channels and target angles, yielding a more robust design. The resulting ISCC waveform optimization problem is non-convex; to address this, we develop a low-complexity proximal distance algorithm (PDA) with closed-form updates under both PSK and QAM modulations. Simulation results demonstrate that the proposed method achieves superior covertness and sensing-communication performance with negligible degradation compared to traditional beamforming and conventional SLP approaches without noise-shaping mechanisms.