Integrated Communication and Remote Sensing in LEO Satellite Systems: Protocol, Architecture and Prototype

2025-08-13

AI Summary

To address the functional isolation and lack of coordination between communication and synthetic aperture radar (SAR) remote sensing in low Earth orbit (LEO) satellite systems, this paper proposes an integrated sensing and communication (ISAC) architecture. We design a unified waveform based on orthogonal time-delay–Doppler multiplexing (ODDM) and develop a joint transmission protocol compatible with 5G New Radio (NR) standards. A unified signal processing framework is established to jointly support channel estimation, interference suppression, and real-time SAR imaging. Leveraging software-defined radio (SDR), the system achieves dual-band compatibility across sub-6 GHz and millimeter-wave (mmWave) frequencies. Simulation results demonstrate superior performance in the sub-6 GHz band, while an mmWave SDR prototype successfully validates real-time SAR imaging and data transmission to user equipment. To the best of our knowledge, this work presents the first LEO satellite ISAC system featuring shared RF front-end hardware and deep integration at both waveform and protocol levels.

Technology Category

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

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Data management and stream processing for Web, mobile and wireless applications
• Search and Retrieval-Augmented AI: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• Security and Privacy: Large-scale security measurements

Abstract

In this paper, we explore the integration of communication and synthetic aperture radar (SAR)-based remote sensing in low Earth orbit (LEO) satellite systems to provide real-time SAR imaging and information transmission. Considering the high-mobility characteristics of satellite channels and limited processing capabilities of satellite payloads, we propose an integrated communication and remote sensing architecture based on an orthogonal delay-Doppler division multiplexing (ODDM) signal waveform. Both communication and SAR imaging functionalities are achieved with an integrated transceiver onboard the LEO satellite, utilizing the same waveform and radio frequency (RF) front-end. Based on such an architecture, we propose a transmission protocol compatible with the 5G NR standard using downlink pilots for joint channel estimation and SAR imaging. Furthermore, we design a unified signal processing framework for the integrated satellite receiver to simultaneously achieve high-performance channel sensing, low-complexity channel equalization and interference-free SAR imaging. Finally, the performance of the proposed integrated system is demonstrated through comprehensive analysis and extensive simulations in the sub-6 GHz band. Moreover, a software-defined radio (SDR) prototype is presented to validate its effectiveness for real-time SAR imaging and information transmission in satellite direct-connect user equipment (UE) scenarios within the millimeter-wave (mmWave) band.

Problem

• Integrate communication and SAR sensing in LEO satellites
• Design ODDM-based architecture for dual-function transceiver
• Develop 5G-compatible protocol for joint channel estimation and imaging

Innovation

• ODDM waveform for integrated communication and SAR
• 5G NR-compatible protocol with downlink pilots
• Unified signal processing for sensing and imaging