PERFORMANCE ANALYSIS OF SAC-OCDMA BASED MULTIPLEXED-FSO SYSTEM OVER GAMMA-GAMMA FADING USING ZCC OPTICAL CODE

The free space optics (FSO) and spectral amplitude coding-optical code division multiple access (SAC-OCDMA) systems have become two important areas for research in communication engineering. To utilize the advantages of both techniques, performance analysis of the SAC-OCDMA-based multiplexed-FSO system over gamma-gamma fading using zero cross-correlation optical code (ZCCOC) under the influence of atmospheric turbulence of different levels is presented in this paper. The system proposed here is simulated. The performance has been evaluated for four users with a data rate of 1 Gbps in terms of bit error rate (BER), Q-factor, received power, and with the aid of eye diagrams. This presented system minimizes the effect of multiple access interference noise (MAIN) and phase intensity induced noise (PIIN). For the designed system, optimal link range limits are identified and system performance is compared under different weather conditions. Moreover, the proposed communication system is also investigated for change in transmitted source power, receiver aperture diameter, and beam divergence values to find the optimal performance limits of these design parameters. Simulation results prove that the system presented here performs reliably up to sufficient long link range values ranging from 100 m to 9,000 m under extremely turbulent and clear weather conditions, respectively. Additionally, the system performs reliably without any significant amount of distortion with a low source power level of less than 10 dBm. Results also show that the system performs to a satisfactory level with 0 dBm, 15 cm, and 3 mrad as limiting values for the design parameters: transmitted source power, receiver aperture diameter, and beam divergence, respectively, under specified FSO distance values and atmospheric weather conditions.