Performance Improvement of a SAC-OCDMA FSO System Under Climatic Conditions for Smart City Applications

SAC-OCDMA FSO (Spectral Amplitude Coding - Optical Code Division Multiple Access Free Space Optical) technology holds significant promise for optical wireless communications, offering improved security and transmission capacity. This technology presents an appealing option for numerous smart city applications, providing secure, rapid, broadband, and interference-resistant communication systems. However, its implementation faces various challenges, including weather-related attenuation in free space and Multiple Access Interference (MAI). To address these challenges, numerous optical codes and detection techniques are utilized for encoding and decoding SAC-OCDMA FSO systems. In this study, we investigate the performance of a 7-user SAC-OCDMA FSO system, initially comparing three optical codes: EDW, ZCC, and DW-ZCC. Based on our comparison, which indicates that the DW-ZCC code is the most suitable among the options, we proceed to evaluate the performance of our proposed system under different meteorological conditions. We analyze the maximum transmission range achieved under the influence of each condition by assessing the variation in Bit Error Rate (BER). The maximum ranges achieved under light fog, light rain, and wet snow conditions are determined to be 1420 m, 1564 m, and 690 m, respectively.