Performance analysis of SAC-OCDMA in free space optical medium using MD and DDW code

Abstract

Spectral amplitude coded Optical code division multiple access technique (SAC-OCDMA) has become a major area of research in optical communication. OCDMA allows multiple users to access a medium simultaneously without any contention. It has ability to operate asynchronously, provide privacy and security and to reduce multiple user interference. In this paper performance of SAC-OCDMA with Multi-diagonal (MD) code and Diagonal double weight (DDW) code with FSO communication system is presented and compared under different conditions of rain and haze. 10 simultaneous users with 5Gbps data are evaluated in the system. Effect of transmitted power and beam divergence is also studied. Results have been formulated based upon eye diagrams and values of Q- factor and BER. Simulation results show that DDW code outperforms MD code for longer distance under rain and haze conditions. DDW code is able to perform well at low input power.