Study to integrate Delay-Tolerant Network protocols in IoT LEO constellations for flood prevention

In the era of the Internet of Things (IoT) the development of Direct-to-Satellite IoT (DtS-IoT) applications are becoming increasingly relevant. These applications are based on enabling IoT devices to communicate directly with satellites. In this scenario, LEO satellites can provide global IoT service coverage, becoming essential to connect devices in remote areas. As an example, the deployment of NarrowBand-IoT (NB-IoT) service is being actively investigated with the apparition of Non-Terrestrial Network (NTN) and DtS-IoT concepts. Although some initiatives propose seamless and ubiquitous service, these features may not be required for IoT applications. This relaxes the requirements in the satellite constellation architecture, enabling it to be more sparse. The connection between sensors, satellites and ground segment becomes intermittent and discontinuous in these non-dense architectures. Delay/Disruptive-tolerant protocols are essential to coexist with this network characteristics. Unfortunately, traditional IoT protocols have not been designed with this delay-tolerant feature. This work tackles this challenge by integrating Delay-Tolerant Network protocols with NB-IoT architecture. Specifically, the integration is based on interconnecting the Bundle Protocol and IP traffic through a novel interface. This development has been divided in three phases: (1) The definition of an architecture and protocol stack to tackle NTN IoT scenarios with discontinuities, (2) the analysis from simulated data of the resulting protocol stack in a realistic scenario based on flooding prevention, and (3) the implementation and validation of it in a laboratory testbed. The proposed case study uses a Direct-to-Satellite IoT architecture to create an early warning flooding detection system. The simulation results provide insights of the achieved performance with these architectures when servicing hundreds of sensing nodes.