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arXiv · 2509.22568

Bridging Technical Capability and User Accessibility: Off-grid Civilian Emergency Communication

Karim Khamaisi·Oliver Kamer·Bruno Rodrigues·Jan von der Assen·Burkhard Stiller
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Abstract

During large-scale crises disrupting cellular and Internet infrastructure, civilians lack reliable methods for communication, aid coordination, and access to trustworthy information. This paper presents a unified emergency communication system integrating a low-power, long-range network with a crisis-oriented smartphone application, enabling decentralized and off-grid civilian communication. Unlike previous solutions separating physical layer resilience from user layer usability, our design merges these aspects into a cohesive crisis-tailored framework. The system is evaluated in two dimensions: communication performance and application functionality. Field experiments in urban Zürich demonstrate that the 868 MHz band, using the LongFast configuration, achieves a communication range of up to 1.2 km with 92% Packet Delivery Ratio, validating network robustness under real-world infrastructure degraded conditions. In parallel, a purpose-built mobile application featuring peer-to-peer messaging, identity verification, and community moderation was evaluated through a requirements-based analysis.

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Karim Khamaisi, Oliver Kamer, Bruno Rodrigues, Jan von der Assen, Burkhard Stiller. 2025-09-29. Bridging Technical Capability and User Accessibility: Off-grid Civilian Emergency Communication. https://arxiv.org/abs/2509.22568

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