A new scheme on time-diversity atmospheric OCDMA system over atmospheric turbulence channels

In this paper, we propose a new scheme of time-diversity system using Optical Code Division Multiple Access (OCDMA) in free space optical (FSO) communication. Our design is a fully-optical communication system which facilitates synthesizing the time-diversity signals. We found that it can effectively minimize the influence of scintillation caused by atmospheric turbulence. We analyze the bit error rate performance of the OCDMA time-diversity scheme through atmospheric turbulence channel. We not only consider the intensity scintillation, but also consider scintillation temporal-frequency. We present the theoretical analysis which is based on lognormal model. And validate the performance of the proposed scheme through simulation. It shows that under some circumstance the bit error rate (BER) can be improved by a few orders of magnitude using the OCDMA time-diversity scheme to compensate for the scintillation.