Sustaining Dynamic Traffic in Dense Urban Areas with High Altitude Platform Stations (HAPS)

The impact of information and communication technologies (ICT) on global energy consumption is increasing every year, and the consumption of equipment for telecommunications accounts for a significant portion of it. Specifically, more than 50\% of the total energy consumption of ICT is issued from the radio access networks (RANs), due mainly to the rapid penetration of data-intensive applications and the increasing heterogeneity, dynamicity, and unpredictability of traffic. To tackle these high-demanding problems, RAN densification through the installation of additional base stations (BSs) in high demand areas is conventionally used. However, this leads to inefficient energy use and over-provisioning issues. To increase the energy efficiency and mitigate the environmental effects of the RANs, various techniques such as sleep scheduling and cell switch-off have been widely studied in the literature. However, their practical use remains questionable. In this context, high altitude platform stations (HAPS) emerged as a novel paradigm-shift recently. HAPS may be used to complement RANs and sustain their services in densely populated areas, where traffic can peak unpredictably. Due to their wide coverage areas, substantial communication payloads, and green energy model, HAPS super macro base stations (SMBSs) are capable of handling the massive and dynamic mobile data traffic of ground users. In this paper, we show how HAPS-SMBSs can complement RANs and serve the dynamic and unpredictable traffic demands of users in an energy efficient manner. Through the simulation of a case study, we demonstrate the superior performance of a HAPS-SMBS compared to the conventional RAN densification method in addition to its advantages of being environmentally friendly and socially acceptable.