Frazão, Luís Alexandre LopesFuentes, Daniel Alexander LopesCorreia, Luís Filipe JesusCosta, Nuno Alexandre Ribeiro daPereira , António Manuel de JesusOrtigoso, Ana Rita Lameiro2025-11-192025-11-192025-10-31http://hdl.handle.net/10400.8/14678Catastrophic events are often unpredictable, making the reuse of existing infrastructures crucial to developing alternative communication strategies that minimise their impact on public communication and the timely dissemination of official alerts. The advent of smart cities, characterised by dense and geographically distributed IoT networks, offers significant potential for such reuse. Furthermore, in post-disaster contexts, uncertainty and panic can endanger public safety and hinder rescue operations, particularly in a hyperconnected world where communication failures and misinformation can intensify these risks. This dissertation presents HaLert, a resilient smart city architecture based on a Wi- Fi HaLow IEEE 802.11s mesh network, enabling rapid resource reallocation to support an emergency communication system for exchanging text, location, image, audio, and video between citizens and authorities. The system also delivers verified, emotionaware information through Armando, a chatbot integrating Retrieval-Augmented Generation (RAG) with cumulative context tracking. Network monitoring and configuration are facilitated by Software-Defined Networking (SDN) via a LoRa controlledflooding mesh network. A prototype of HaLert architecture was implemented and tested in real urban indoor and outdoor scenarios. Results show that despite environmental impacts on latency (15–54.8 ms) and throughput (134–726 Kbps upload, 117–682 Kbps download), the Wi-Fi HaLow network remained stable, while the LoRa network achieved a 94.96% average message success rate.engPost-disaster communicationSmart CityIEEE 802.11ahWi-Fi HaLowIEEE 802.11sLoRaLTFHMeshSDNLLMConversational generative AIRAGmaster thesis204052742