HAPS-enabled Downlink Coverage Enhancement in Islands and Maritime Areas

2026-07-26

AI Summary

This study addresses the coverage limitations of High-Altitude Platform Stations (HAPS) in island and near-shore regions, where the absence of terrestrial infrastructure and shadowing effects from island structures degrade signal quality. For the first time, it integrates the shadowed Rician channel for onshore users with the conventional Rician channel for offshore users to establish a comprehensive coverage evaluation framework under a hybrid channel environment. The work proposes a low-complexity approximation algorithm to efficiently analyze downlink coverage performance in large-scale HAPS networks and uncovers the coupled influence of user distance from the island and HAPS deployment density on coverage. Simulation results demonstrate that judicious optimization of HAPS density or deployment strategy can substantially enhance communication reliability in remote maritime areas.

Abstract

Non-terrestrial networks (NTNs) are poised to play a critical role in next-generation mobile communications, offering enhanced flexibility, improved line-of-sight (LoS) conditions, and overcoming the limitations of terrestrial networks (TNs). Among NTN platforms, high altitude platform stations (HAPSs) have emerged as a promising solution to provide Internet connectivity to underserved regions, including rural areas, islands, and maritime zones, where traditional infrastructure deployment is costly and challenging to deploy. In this paper, we investigate the feasibility of large-scale HAPS deployment to connect island and maritime users, considering real-world shadowing effects on part of HAPSs caused by the presence of island building clusters. We first analyze the coverage performance of onshore (island) and offshore (remote sea) users, in which the channels between HAPSs and the user follow the shadowed Rician distributions and Rician distributions, respectively. Next, we introduce an evaluation method for nearshore users in a hybrid channel environment with HAPSs, and propose approximations that can reduce computational complexity. Based on the simulation results, we discuss how the distance from the island boundary (i.e. the relative remoteness of maritime users) affects coverage performance under different HAPS densities. We also emphasize the importance of choosing a balanced HAPS density or an advanced HAPS deployment scheme.

Problem

• HAPS
• coverage enhancement
• maritime areas
• islands
• non-terrestrial networks

Innovation

• HAPS
• shadowed Rician channel
• maritime coverage
• hybrid channel modeling
• non-terrestrial networks