Experimental Evaluation of FSO Link: Impact of Pointing Error on OFDM System Performance

This paper presents an experimental and simulation study of Orthogonal Frequency Division Multiplexing (OFDM) over Free-Space Optical (FSO) links under atmospheric turbulence induced by temperature and wind variations. We investigate the impact of pointing error (PE) on OFDM system power loss and Bit Error Ratio (BER) for Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK) and Quadrature Amplitude Modulation (QAM) for 16 and 64 symbols. Results show BER degradation in higher-order modulations due to PE. Additionally, the study indicated that geometric losses had a greater influence than PE in short-distance links, accounting for 99.9% of losses for the smallest observed PE and 84% for the largest.