Integrating HAPS, LEO, and Terrestrial Networks: A Cost-Performance Study for IoT Connectivity

TL;DR

The paper evaluates High-Altitude Platform Stations (HAPS) and Low Earth Orbit (LEO) satellites as IoT non-terrestrial networks and compares them to terrestrial deployments, focusing on erasure probability, LR-FHSS performance, and economic viability. It introduces a unified system-model that jointly accounts for geometric deployment, terrestrial and non-terrestrial channel models, and a LR-FHSS-based access mechanism, then analyzes both standalone and hybrid architectures. Key findings show that HAPS can effectively complement sparse terrestrial networks and improve satellite-based performance in certain scenarios, while cost analyses indicate HAPS and LEO have comparable total costs over a 20-year horizon depending on scale. The work highlights the value of hybrid architectures for robust IoT connectivity in remote areas and points to future research in diversity techniques, HAPS mobility, and coordinated multi-satellite reception to further enhance performance and resilience.

Abstract

This work evaluates the potential of High-Altitude Platform Stations (HAPS) and Low Earth Orbit (LEO) satellites as alternative or complementary systems to enhance Internet of Things (IoT) connectivity. We first analyze the transmission erasure probability under different connectivity configurations, including only HAPS or LEO satellites, as well as hybrid architectures that integrate both aerial/spatial and terrestrial infrastructures. To make the analysis more realistic, we considered movement of LEO satellites regarding a fixed region, elevation angle between gateway and devices, and different fading models for terrestrial and non-terrestrial communication. We also analyze LR-FHSS (Long-Range Frequency Hopping Spread Spectrum) random access uplink technology as a potential use case for IoT connectivity, showing the scalability impact of the scenarios. The simulation results demonstrate that HAPS can effectively complement sparse terrestrial networks and improve the performance of satellite-based systems in specific scenarios. Furthermore, considering the deployment and operational costs, respectively, CAPEX and OPEX, the economic analysis reveals that although HAPS exhibits higher costs, these remain within a comparable order of magnitude to LEO and terrestrial deployments. In addition, specific use cases, such as natural disasters, transform HAPS into a competitive technology for conventional infrastructures.

Figures (6)

• Figure 1: The illustration of the proposed architectures comprises TNs and NTNs networks, as well as the Ground Station and the Network Server components.
• Figure 2: The illustration of the NTN network geometry, which is composed by the device coordinates $(x_i,y_i, z_i)$, elevation angle $\alpha$, altitude $h$ and the distance $d_S$.
• Figure 3: Heat map of the erasure probability over the area where devices are deployed for all proposed scenarios.
• Figure 4: Erasure probability violin graph for all proposed scenarios. Wider graphs represent a higher density of that probability and the white line shows the median.
• Figure 5: Success probability as a function of the number of devices for all proposed scenarios.