ImOK: A Civilian Emergency Messaging Framework [abstract] (PDF)
Vivian Ha, Alan Kaplan, and David I. August
Proceedings of the 2026 IEEE Global Humanitarian Technology Conference (GHTC), October 2026.
Reviewers Choice Award - Track: Technologies for Disaster Mitigation, Response and Climate Resilience.

One of the first actions survivors take after a disaster strikes is to try to contact their families and friends to let them know their status. However, a disaster can wipe out or severely impact commercial communication infrastructure, making it impossible for people to communicate. This paper introduces a low-cost, low-bandwidth messaging framework called ImOK that integrates a user-friendly Wi-Fi captive portal with amateur radio-based communication. ImOK enables users to connect to a local Wi-Fi hotspot and submit short messages to a server, which are then encoded, and transmitted over amateur radio frequencies. A receiving station then decodes the messages and deliver them to recipients via an email gateway. We have implemented and tested a prototype that demonstrates the viability of the ImOK framework. By leveraging low-cost hardware, open source software and amateur radio technologies, this work demonstrates a practical approach to enabling communication during disasters, specifically to support emergency messaging when conventional communication infrastructure is unavailable.