HaLert: A Resilient Smart City Architecture for Post-Disaster Based on Wi-Fi HaLow Mesh and SDN
Journal:
arXiv
Published Date:
Jul 10, 2025
Abstract
Events such as catastrophes and disasters are, in most cases, unpredictable.
Consequently, reusing existing infrastructures to develop alternative
communication strategies after disasters is essential to minimise the impact of
these events on the population's ability to communicate and promptly receive
alerts from authorities. In this context, the emergence of smart cities,
characterised by dense and geographically distributed IoT networks, presents
significant potential for such reuse. This work proposes HaLert, a resilient
architecture for smart cities based on a Wi-Fi HaLow IEEE 802.11s mesh network,
whose resources can be readily reallocated to support a emergency communication
system to exchange messages (including text, location, image, audio, and video)
between citizens, authorities, and between both parties. To facilitate remote
monitoring and configuration of the network, the architecture incorporates the
SDN (Software-Defined Networking) paradigm, supported by a LoRa controlled
flooding mesh network. A prototype was developed based on this architecture and
tested in a real urban scenario comprising both indoor and outdoor
environments. The results demonstrated that, despite the significant impact of
obstacles, lack of line-of-sight, and terrain slopes on the latency (average
latency between 15 and 54.8 ms) and throughput (upload bitrates between 134 and
726 Kbps and download bitrates between 117 and 682 Kbps) of the Wi-Fi HaLow
network, it remained stable and resilient, successfully providing all
functionalities associated with the HaLert architecture. The tests conducted on
the LoRa network revealed a high average message success rate of 94.96%.
