Introduction
With features of flexible deployment and high agility, drones have attracted great attention in wireless communication fields. Drones have the capability to establish light-of-sight (LoS) wireless links for devices in harsh environments, such as emergency situation and areas without communication infrastructure [1]–[3]. Therefore, drones are widely applied as aerial base stations (BS) to support the current terrestrial communication, integrating as the coexisting drone-terrestrial network (CDTN) [4]. However, the LoS wireless links established by drones are easily blocked, which severely reduces the transmission performance.