Bit error rate analysis along a slanted path link between UAVs and Ground Stations

Free space optical (FSO) communications links is a promising solution for the provision of high data rate point to point communications. The FSO links due to their huge bandwidth and license free spectrum provide a viable communication solution between Unmanned Aerial Vehicles (UAVs) and fixed Ground Stations (GS). It is of great importance to characterize the quality of the optical channel with a proper model, taking into consideration the interesting challenges of the mobility and the slanted path of the optical beam in order to design a high performance communication link. In this paper we investigate the performance of a mobile link between a fixed GS and an UAV in terms of Bit Error Rate (BER) and average Signal to Noise Ratio (SNR). It deals with modelling the influence of the scintillation index and the received optical power with noise on link performance, separating the slanted path into small intervals assuming a Gaussian-beam wave. An extensive comparative analysis among different FSO configurations links considering the altitude of the UAV, the wavelength and the atmospheric conditions is provided. The results show that there is degradation at the BER over a slanted path compared to a horizontal path at the same conditions.