Multi-Mode High Altitude Platform Stations (HAPS) for Next Generation Wireless Networks

TL;DR

This paper proposes a multi-mode high altitude platform station (HAPS) system that adaptively switches between modes to reduce energy consumption and extend loitering time, supporting next-generation wireless networks with passive and active communication modes.

Contribution

It introduces a novel multi-mode HAPS architecture with adaptive switching to optimize energy use and enhance functionality for future wireless applications.

Findings

Multi-mode HAPS reduces energy consumption compared to single-mode systems.

Passive RIS mode extends loitering time significantly.

Case study validates efficiency of the multi-mode approach.

Abstract

The high altitude platform station (HAPS) concept has recently received notable attention from both industry and academia to support future wireless networks. A HAPS can be equipped with 5th generation (5G) and beyond technologies such as massive multiple-input multiple-output (MIMO) and reconfigurable intelligent surface (RIS). Hence, it is expected that HAPS will support numerous applications in both rural and urban areas. However, this comes at the expense of high energy consumption and thus shorter loitering time. To tackle this issue, we envision the use of a multi-mode HAPS that can adaptively switch between different modes so as to reduce energy consumption and extend the HAPS loitering time. These modes comprise a HAPS super macro base station (HAPS-SMBS) mode for enhanced computing, caching, and communication services, a HAPS relay station (HAPS-RS) mode for active communication, and a HAPS-RIS mode for passive communication. This multimode HAPS ensures that operations rely mostly on the passive communication payload, while switching to an energy-greedy active mode only when necessary. In this article, we begin with a brief review of HAPS features compared to other non-terrestrial systems, followed by an exposition of the different HAPS modes proposed. Subsequently, we illustrate the envisioned multi-mode HAPS, and discuss its benefits and challenges. Finally, we validate the multi-mode efficiency through a case study.