BER Performance of Underwater Wireless SAC-OCDMA System using MQC codes

Abstract

In this paper, we investigate the bit error rate (BER) performance of underwater wireless spectral-amplitude-coding optical code division multiple access (SAC-OCDMA) system by using modified quadratic congruence (MQC) codes as the user address sequence. As MQC codes have fixed in-phase cross-correlation value, a balanced detection is used so that multi-user interference (MUI) can be minimized. The phase-induced intensity noise (PIIN), shot noise and thermal noise have been taken into account for the BER calculation of the system. The BER performance of the proposed system is evaluated regarding various system parameters such as optical signal power, link distance, inclination angle and number of simultaneous users. There are different types of seawater such as pure sea water, clear ocean water and coastal ocean water. The dependency of the BER performance of the system on various seawater channels has also been investigated in this paper. It is seen that, if pure sea water is used as the system channel, the system gives the best performance.