Taming Aerial Communication with Flight-Assisted Smart Surfaces in the 6G Era: Novel Use Cases, Requirements, and Solutions

Aerial communication is gradually taking an assertive role within common societal behaviors by means of unmanned aerial vehicles (UAVs), high-altitude platforms (HAPs), and fixed-wing aircrafts (FWAs). Such devices can assist general operations in a diverse set of heterogeneous applications, such as video surveillance, remote delivery, and connectivity provisioning in crowded events and emergency scenarios. Given their increasingly higher technology penetration rate, telco operators started looking at the sky as a new potential direction to enable a three-dimensional (3D) communication paradigm. However, designing flying mobile stations involves addressing a daunting number of challenges, such as an excessive onboard control overhead, variable battery drain, and advanced antenna design. To this end, the newly born smart surfaces technology may come to help: reconfigurable intelligent surfaces (RISs) may be flexibly installed on board to control the terrestrial propagation environment from an elevated viewpoint by involving low-complex and battery-limited solutions. In this article, we focus on identifying the key optimization aspects to be considered when designing RIS-based aerial networks, and in particular the associated control architecture, by shedding light on novel use cases, corresponding requirements, and potential solutions.