Positioning and association rules for transparent flying relay stations

Transparent flying relay stations (FlyRSs), represented by transparent relays mounted on unmanned aerial vehicles (UAVs), have the potential to improve cellular network’s capacity and coverage at little extra complexity and energy cost, especially when compared with non-transparent relays. As the transparent relays do not transmit reference signals, they do not lend themselves easily to channel estimation. This makes solving the problems of user association and positioning of transparent FlyRSs much harder. We propose a solution enabling an efficient association of users to the FlyRSs and determining suitable positions of the FlyRSs. Surprisingly, this can be done knowing neither the qualities of the channels linking the FlyRSs and the users nor the users’ location information. Our approach involves the users being grouped into clusters based on the channels to nearby static base stations via agglomerative hierarchical clustering. Then, 3D positions of one FlyRS per cluster are determined by deep neural networks. The proposal improves the users’ sum capacity with respect to existing solutions that rely on the knowledge of users’ positions.