Free Space Optical Communication Link Performance Based on Various Transmission Schemes Over Gamma-Gamma Distribution Channel

Due to massive growth in telecommunication systems, the required services such as reliable quality of service, secured connectivity, and low cost of technology by the users have always been a major concern that requires attention. Free space optical systems have recently been known to be an option that can proffer solutions to these problems. However, these systems rely on atmospheric weather which is prone to several degradations. This study assesses how different modulation methods perform on free space optics using the gamma-gamma channel model to determine the feasibility of the systems' communication link performance. The results show an increase in the average signal-to-noise ratio (SNR) with a decrease in the average bit error rate (BER). Based on the analytical results at the highest link range of 5200, the received bit error rate of BPSK, DPSK, and OOK was about 0.048, 0.060, and 0.140 observed at the strong fading strength when at an average SNR of 30 dB. It was deducted that the system performance degrades as the strength of channel fading fluctuates between weak, moderate, and strong levels of turbulence.