Abstract
During emergencies, terrestrial base stations (BSs) often fail to support the network. In such circumstances, satellite and UAV-supported non-terrestrial networks offer the most promising platform, either as complementary network support or for increasing network capacity based on customer demand. Satellite-to-UAV communication is particularly challenging because both devices are in motion and communicate over very long distances. In this paper, we have proposed a communication system where the satellite and UAV are connected via a free-space optical (FSO) link. For the FSO link, we have considered the effects of Doppler shifts, pointing errors, and atmospheric turbulence. The performance is evaluated using the bit error rate (BER) versus signal-to-noise ratio (SNR) responses under a binary phase shift keying (BPSK) modulation scheme. The core network is supported by cluster-based flying ad hoc networks (FANETs). Performance analysis is conducted by examining the throughput of the medium access control (MAC) protocol as a function of distance and outage probability. Coverage from UAVs to mobile users is provided through a radio frequency (RF) link, considering different environmental conditions such as suburban, urban, dense urban, and high-rise urban areas.