Comparative Analysis of OCFHC/QCC and ZCC Based OCDMA System in Underwater Channel

In this work, the performance of one coincidence frequency hopping code/quadratic congruence code (OCFHC /QCC) based optical code division multiple access (OCDMA) system is compared to zero cross-correlation (ZCC) based OCDMA system in the underwater channel. The influence of beam divergence, turbulence, and attenuation is considered while evaluation of the performance in underwater channel. The different water types which have been used for the analysis are pure sea, clear ocean, and coastal water. In the analysis, it has been evaluated and observed that the performance of OCFHC/QCC based OCDMA system is superior to ZCC based OCDMA system under certain conditions. It is also perceived that when multiple access interference (MAI) dominates in OCFHC/QCC based systems then ZCC performs comparatively better than OCFHC/QCC based OCDMA system. For OCFHC/QCC seven user system, P_E=10^{-9} is achieved with P_T=6 and 16 dBm in pure sea and clear ocean, respectively. Correspondingly, P_E=10^{-9} is possible with ZCC code when P_T=5 and 15 dBm in the same water types. In the coastal water, the performance of both codes is not good.