Performance Analysis of FSO for Different Modulation Techniques under Atmospheric Turbulence with Pointing Errors

Free space optics (FSO) gained significant importance for extremely large bandwidth, unlicensed spectrum and low power secure communication. Despite the advantages, it is deeply impacted due to fog weather conditions and atmospheric turbulence. In this paper, different modulation schemes under the presence of pointing errors which are induced due to misalignment and atmospheric turbulence channels are analyzed. Under this channel condition, 16-PPM provided better performance compared to the other schemes, the performance is evaluated under weak to strong turbulence channel is also analyzed, the performance of FSO degrades with the influence of pointing errors. The performance of the system is evaluated in bit error rate (BER). This forms the basis for adaptive modulation technique according to channel condition.