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

2025-09-26

AI Summary

Large-scale crises frequently disrupt cellular and internet infrastructure, depriving civilians of reliable communication, coordinated rescue operations, and access to trustworthy information. To address this, we propose a decentralized civilian emergency communication system that synergizes LoRa’s physical-layer resilience with mobile-device usability: it leverages the 868 MHz LongFast long-range wireless protocol to establish infrastructure-free peer-to-peer networking; incorporates lightweight identity authentication, local message broadcasting, and community-driven governance. Field evaluations in urban Zurich achieved a 1.2 km communication range and 92% end-to-end message delivery rate; functionality was validated via requirements-driven system assessment. Our core contribution is the first integration—within a lightweight, deployable civilian framework—of physical-layer robustness, application-layer usability, and socio-technical trust governance, yielding an offline-capable, scalable, and governable communication foundation.

Technology Category

• Multiagent Systems: Agent Communication
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Application Domains: Internet of Things, Sensor Networks & Smart Cities

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Security and Privacy: Large-scale security measurements
• Responsible Web: Measurement, analysis, and circumvention of Web censorship

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.

Problem

• Bridging technical capability with user accessibility
• Enabling off-grid communication during infrastructure failure
• Integrating resilient networks with crisis-tailored applications

Innovation

• Integrates low-power long-range network with smartphone app
• Enables decentralized off-grid civilian emergency communication
• Uses 868 MHz band achieving 1.2 km communication range