Abstract
For capacity enhancement of free space optics (FSO) communication, a new model based on using four Laguerre-Gaussian (LG) beams, each carries four different users use optical code division multiplexing (OCDMA) techniques, is proposed. Additionally, the permutation vector (PV) codes that have zero cross correlation with direct detection (DD) technique are assigned to the OCDMA system. Each user carries 10 Gbps information data, so the overall capacity is 4 LG beams × 4 users (OCDMA) × 10 Gbps = 160 Gbps. Furthermore, the proposed model is simulated under the effects of different attenuations caused by different weather conditions and the performance is studied. The conducted results reveal successful transmission of 13 km under clear air (CA), 1.75 km under heavy haze (HH), 1.1 km under heavy rain (HR), and 0.9 km under heavy fog (HF) with an overall system capacity of 160 Gbps. These results were obtained with an acceptable log bit error rate (BER) less than −9 and quality (Q)-factor nearly 6.