Outage Performance of Dual-Hop with Wavelength Diversified UAV-Based FSO Links under Sandstorms

This paper investigates unmanned aerial vehicles (UAVs)-based free space optical (FSO) communications under sandstorm conditions, using different wavelengths of 1550 nm and 850 nm. We propose a single UAV relay model and formulate simplified closed form expression for end-to-end (E2E) outage probability. We also obtain asymptotic outage probability for the overall system. Then, we evaluate the outage performance across various parameters, including, transmitted power, visibility, receiver field of view (FOV), and optical beamwidth. Furthermore, a dynamic single UAV relay is investigated over various distances to minimize the E2E outage probability. Our findings show that the minimum E2E outage probability occurs when a single UAV relay is positioned equidistantly between the source and destination UAVs, and the E2E outage probability increases as the single UAV relay moves farther away. Besides, in sandstorm conditions, we observe that a smaller wavelength, specifically 850 nm, provides a minimum E2E outage probability, which may be beneficial for use in UAVs-based FSO links.