On the Performance of LAP-Based Multiple-Hop RF/FSO Systems

In this paper, we propose a low-altitude aerial platform (LAP) based relaying system, where two LAPs serve as relays. More specifically, the air-to-ground links are assumed to be radio frequency (RF) channels experiencing large-scale path loss and small-scale fading, while the link between the two relays is assumed to employ a free-space optical communication scheme. Based on such a setup, we derive closed-form expressions for the outage probability and optimal altitude. Our results show that the optimal altitude of the LAPs plays a crucial role in the system performance. Furthermore, pointing errors has a greater impact on the system performance than the path loss of the RF links.