Performance Improvement of Optical Pulse Position Modulation Code Division Multiple Access using Successive Interference Cancellation Technique

Multiplexing techniques are suffering from major problem known as multiple access interference (MAI). A rejection interference called successive interference cancellation (SIC) is employed in optical code division multiple access (Optical CDMA), which has the potential to reduce the effect of MAI and therefore can increase the capacity of optical CDMA systems and improve its performance. The basic principle of SIC scheme is that, detection is carried out in multiple stages and during each stage, only the most reliable symbols are selected. In subsequent stages, the interference contributed by the already detected symbols will be removed. In this project we theoretically analyzed direct sequence (DS) optical CDMA system based on SIC scheme using pulse position modulation (PPM) signaling, considering the interference between the users, imperfection cancellation occurred during the cancellation process and receiver noises. In addition, balanced detection scheme known as spectral amplitude coding (SAC) is used to suppress the overlapping between the users and reduce the receiver noises effect