Performance analysis of different detection techniques in SAC-OCDMA systems

Abstract

Optical Code Division Multiple Access (OCDMA) system is a perfect choice for satisfying high communication demand because of the all-optical processing, simplified network control, bandwidth efficiency and security of such system. One of the coding schemes of OCDMA is the Spectral Amplitude Coding OCDMA (SAC-OCDMA). This study focused on the SAC-OCDMA system, which recently received increasing attention because of its robust performance, phase insensitivity and flexible bandwidth provisioning. This study aimed to analyze the performance of SAC-OCDMA system’s codes with cross-correlation, particularly Enhanced Double Weight (EDW) and Modified Double Weight (MDW) codes, by using direct detection technique, AND subtraction detection technique as well as modified-AND subtraction detection technique. Theoretical and simulation analyses using Optisystem Version 7.0 software were performed with reference to the parameters in the ITU-T G.652 standard. Analysis results show that the use of an ideal detection technique is more efficient than using the right type of code in reducing bit error rates (BERs) as well as eliminating multiple access interference (MAI) and phase induced intensity noise (PIIN). At 100 users, the BERs of the MDW code with the AND subtraction detection technique and modified- AND subtraction detection technique are and , respectively. Whereas, the BER of EDW and MDW codes that utilized the modified-AND subtraction technique are and respectively. The performances of EDW and MDW codes present different outcomes depending on the parameter analyzed. The modified-AND subtraction detection technique shows better performance than AND subtraction and direct detection techniques. The effectiveness of a SAC-OCDMA system in long-distance transmission with only single Light Emitting Diode (LED) and one optical amplifier was also verified. In long-distance transmission, the modified-AND subtraction detection technique exhibits a better performance than the AND subtraction detection technique. For the same quality of service at a BER of , the modified-AND subtraction detection technique allows 46.98% and 24.21% longer transmission distance than the AND subtraction detection technique with MDW code and EDW code, respectively. Hence, the ideal type of detection should be the focus in SAC-OCDMA systems to reduce BER, MAI and PIIN furthermore, optimize the system greatly and effectively.