Influence of atmospheric scintillation on performance of wireless optical CDMA system

Two dimensional atmosphere wireless optical CDMA communication system with Mary PPM(pulse position modulation)signal format is presented and studied．With the factors of multiuser interference，avalanche photodiode (APD) noise and thermal noise taken into account，the influence of atmospheric scintillation on the bit error rate(BER) of two dimensional wireless optical CDMA communication system was analyzed in detail. The results indicate that the atmospheric scintillation is an important factor for the bit error rate of two dimensional wireless optical CDMA systems. High speed communication can be realized in wireless optical CDMA systems if the logarithm variance of the scintillation is small enough (for example，σ2s=0.1). Otherwise，if the logarithm variance is too big(σ2s≥0.2),it will be difficult to communicate with limited receiving power. In this case, some improving methods，such as channel coding technology，need to be used to improve the BER performance of 2D optical CDMA communication system.