A survey of performance improvement methods for free-space optical communication systems

Free-space optical communication (FSO) is a line-of-sight (LOS) technology that enables data transmission based on the propagation of light in free space. Compared to radio frequency (RF) communication systems, FSO ones provide high data rates, unregulated bandwidth, high security, and low power. Therefore, FSO systems are rapidly gaining interest as an effective means of transferring data at high rates over short distances. However, FSO still faces many challenges, including weather-dependent atmospheric attenuation, atmospheric turbulence, and misalignment fading (or pointing error). In this paper, we present some of the exciting research approaches that have been suggested to evaluate and improve the performance of FSO systems. The principle as well as the advantages and disadvantages of each improvement method will be analyzed. In addition, we outline some future research challenges and opportunities.