Performance analysis and experimental evaluation of modulating retroreflector and UAV based free space optical transmission systems

This paper introduces a novel unmanned aerial vehicle (UAV) based free space optical (FSO) communication system that integrates differential detection with a modulating retro-reflector (MRR) to enhance performance. We provide a comprehensive analysis of the system's performance, taking into account critical factors including atmospheric path loss, non-zero boresight pointing error, atmospheric turbulence, and angle of arrival (AoA) fluctuations induced by UAV orientation fluctuations. To facilitate this analysis, we have derived the probability density function (PDF) and cumulative distribution function (CDF) for the end-to-end signal-to-noise ratio (SNR) under these channel conditions. Our study presents new closed-form solutions for pivotal performance metrics: outage probability (OP), average bit error rate (ABER), and ergodic capacity (EC), which are corroborated through Monte Carlo simulations. Additionally, we perform asymptotic analyses to gain deeper insights into the behavior of OP, ABER, and EC. A pioneering experimental setup has been constructed to empirically validate the communication performance of our proposed system. The numerical findings underscore the presented system's feasibility and the significant impact of atmospheric turbulence and pointing errors on system performance. Moreover, our experimental results indicate that the proposed system outperforms current UAV-based MRR FSO systems under identical conditions.