Bridging Technical Capability and User Accessibility: Off-grid Civilian Emergency Communication
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 Z\"urich 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.
Cite
@article{arxiv.2509.22568,
title = {Bridging Technical Capability and User Accessibility: Off-grid Civilian Emergency Communication},
author = {Karim Khamaisi and Oliver Kamer and Bruno Rodrigues and Jan von der Assen and Burkhard Stiller},
journal= {arXiv preprint arXiv:2509.22568},
year = {2025}
}