Frequency Hopping Waveform Design for Secure Integrated Sensing and Communications

2025-04-14

AI Summary

To address the vulnerability of radar parameters to passive eavesdropping and the inherent trade-off between security and sensing performance in Integrated Sensing and Communication (ISAC) systems, this paper proposes a Random Frequency and Pulse Repetition Interval Agile (RFPA) waveform design. The framework integrates Channel Reciprocity-based Key Generation (CRKG) with hybrid information embedding—combining ASK, PSK, Index Modulation, and Spatial Modulation—enabling decentralized secure communication-sensing coexistence. A novel sparse matched-filter receiver is devised to jointly achieve high-accuracy Doppler and PRI estimation while ensuring low-bit-error-rate (BER) data decoding. Experimental results demonstrate a significant reduction in passive eavesdroppers’ success rate for estimating critical radar parameters; ambiguity function analysis confirms improved range-Doppler resolution and enhanced clutter suppression; and communication throughput increases substantially with markedly reduced BER.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Multiagent Systems: Agent Communication

Application Category

• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments

Abstract

We introduce a comprehensive approach to enhance the security, privacy, and sensing capabilities of integrated sensing and communications (ISAC) systems by leveraging random frequency agility (RFA) and random pulse repetition interval (PRI) agility (RPA) techniques. The combination of these techniques, which we refer to collectively as random frequency and PRI agility (RFPA), with channel reciprocity-based key generation (CRKG) obfuscates both Doppler frequency and PRIs, significantly hindering the chances that passive adversaries can successfully estimate radar parameters. In addition, a hybrid information embedding method integrating amplitude shift keying (ASK), phase shift keying (PSK), index modulation (IM), and spatial modulation (SM) is incorporated to increase the achievable bit rate of the system significantly. Next, a sparse-matched filter receiver design is proposed to efficiently decode the embedded information with a low bit error rate (BER). Finally, a novel RFPA-based secret generation scheme using CRKG ensures secure code creation without a coordinating authority. The improved range and velocity estimation and reduced clutter effects achieved with the method are demonstrated via the evaluation of the ambiguity function (AF) of the proposed waveforms.

Problem

• Enhance ISAC security via random frequency and PRI agility
• Increase bit rate with hybrid information embedding method
• Improve range and velocity estimation with novel waveforms

Innovation

• Random frequency and PRI agility (RFPA) enhances security
• Hybrid information embedding method increases bit rate
• Sparse-matched filter receiver design reduces BER