Link Budget Profile for Infrared FSO Link with Aerial Platform Rahul Bosu and Shanthi Prince Abstract This paper investigates the implementation of infrared (IR) free-space optical (FSO) communication to enhance the data transmission capacity to aerial platforms. As such, the study introduces a geometrical model of establishing an FSO link between a base station (BS) and an unmanned surveillance aerial vehicle (USAV) drifting along an inclined straight track using the Gaussian beam theory. The analytical analysis along with the MATLAB simulation envisages that the optimum received power required to ensure FSO link availability along the track depends on the track inclination angle, separation distance between BS-USAV and the source beam divergence angle for covering the track. Based on the received power, the error rate performance of the OOK-FSO system is illustrated for data rates ranging from 100 to 300 Mbps and is observed to improve with a reduction in the beam coverage length. Finally, the link budget analysis is incorporated for gauging the theoretical power limited link range of BS-USAV FSO system in different weather conditions. Based on the analytical study, the proposed system model can enact continual FSO communication between BS and USAV moving over an inclined straight track. Keywords Free-space optical communication · Laser beams · Optical propagation · Infra-red surveillance · Unmanned aerial vehicle · Link budget 1 Introduction Free-space optical (FSO) communication is essentially a line-of-sight (LOS) tech- nology that employs infrared (IR) beam [1, 2] as a carrier and is the preferred option for wireless accessing technique in areas where the applications of RF systems are limited or restricted, like: hospitals, aerial vehicles, and military applications [3]. As R. Bosu (B ) · S. Prince SRM Institute of Science & Technology, Kattankulathur, Tamil Nadu, India e-mail: rohulbosu.g@ktr.srmuniv.ac.in S. Prince e-mail: shanthi.p@ktr.srmuniv.ac.in © Springer Nature Singapore Pte Ltd. 2020 V. Janyani et al. (eds.), Optical and Wireless Technologies, Lecture Notes in Electrical Engineering 546, https://doi.org/10.1007/978-981-13-6159-3_12 101