HAPS-RIS-assisted IoT Networks for Disaster Recovery and Emergency Response: Architecture, Application Scenarios, and Open Challenges

TL;DR

This paper introduces a HAPS-RIS-assisted IoT communication system designed to restore connectivity during disasters, featuring a novel active RIS architecture that significantly improves data rates and energy efficiency in high-altitude emergency scenarios.

Contribution

It proposes a dynamically adjustable active RIS architecture for HAPS-assisted IoT networks, addressing the double path loss issue of passive RIS at high altitudes.

Findings

Active RIS architecture improves data rates and energy efficiency.

Simulation shows 20-30 Mbps gain with 1 dB increase in ground-station power.

HAPS-RIS is effective for resilient IoT backhaul in disaster scenarios.

Abstract

Reliable and resilient communication is essential for disaster recovery and emergency response, yet terrestrial infrastructure often fails during large-scale natural disasters. This paper proposes a High-Altitude Platform Station (HAPS) and Reconfigurable Intelligent Surfaces (RIS)-assisted Internet of Things (IoT) communication system to restore connectivity in disaster-affected areas. Distributed IoT sensors collect critical environmental data and forward it to nearby gateways via short-range links, while the HAPS-RIS system provides backhaul to these gateways. To overcome the severe double path loss of passive RIS at high altitudes, we propose a dynamically adjustable sub-connected active RIS architecture that can reconfigure the number of elements connected to each power amplifier through switching mechanisms. Simulation results demonstrate substantial gains in downlink and uplink data rates, as well as system energy efficiency, compared with conventional passive RIS schemes. Moreover, a 1 dB increase in ground-station transmit power yields approximately 20-30 Mbps improvement in gateway data rates. These findings confirm that HAPS-RIS technology offers an effective and energy-efficient approach for resilient IoT backhaul in 6G non-terrestrial networks, particularly in line-of-sight (LoS)-dominant HAPS-ground backhaul scenarios.