Conference Paper

Recent natural disasters, including severe storms, wildfires, and prolonged power outages, have highlighted the vulnerability of telecommunication infrastructures. Public Protection and Disaster Relief (PPDR) services are critical in such scenarios, requiring quick and reliable communication networks to ensure effective response and coordination. This work presents an on-demand 5G and Non-Terrestrial Network (NTN) connectivity architecture that combines an open-source non-public flying network with a proprietary Mission Critical platform (MCX), addressing the requirements of both affected civilians and First Responders. The open-source Non-Public Network (NPN) is mounted on an Unnamed Aerial Vehicle (UAV), and is built with Open5GS and IMS-based voice services using Kamailio. It provides essential services for people impacted in the disaster, including Voice over New Radio (VoNR) and QoS differentiation. The architecture also supports roaming, allowing users to authenticate via the operator's Home Network, while connecting to the local on site Visited Network using the Local Breakout approach. This reduces latency and inefficient backhauling of user-plane traffic. For PPDR teams and other disaster response teams, the MCX solution complements the NPN by providing resilient mission-critical voice, video and data services through a cloud-native microservice architecture, suitable for deployment in edge nodes on the field. Experimental results demonstrate that the proposed open-source 5G NPN can support communications in disaster scenarios, sustaining up to 32 simultaneous VoNR calls with a MOS score of 4.5, while interoperating with an MCX platform for first-responder coordination, enhancing both service availability and traffic prioritization.