Abstract
A novel free space optics (FSO) communication system based on integration of two different multiplexing techniques i.e., orbital angular momentum (OAM) multiplexing and optical code division multiple access (OCDMA), are proposed in this paper for enhancing the transmission capacity. Four distinct OAM beams are used; each transporting 10 Gbps information of three different OCDMA channels. These channels are assigned with diagonal permutation shift (DPS) code. Various atmospheric conditions are considered in evaluating the performance of our suggested design in FSO communication system. These weather conditions are snowy and dusty in addition to the average intensity rainfall rates in Saudi Arabia cities (Riyadh and Jeddah) and Indian cities (Hyderabad, Pune, Chennai, and Mumbai). Received optical power (ROP), Quality (Q) factor, maximum FSO link range, and eye diagrams are used for evaluating the performance. The simulation results show successful transmission of 4 OAM x 3 OCDMA channels x 10 Gbps = 120 Gbps overall capacity with good ROP, Q-factor, and BER values. The maximum FSO link range achieved is 600 m under wet snow (WS), 140 m under dry snow (DS), and 400, 132, and 52 m, respectively, under low dust (LD), medium dust (MD), and heavy dust (HD) storms. Consequently, this proposed FSO transmission model is suggested to be used as high-speed connectivity for end users in adverse weather conditions.