Design and simulation of 2D wavelength x time hybrid codes for OCDMA systems

Abstract

In recent years, Optical Code Division Multiple Access (OCDMA) has become an interesting research area in optical communication technologies. Optical code division multiple access is proposed as a natural solution to achieving asynchronous and high-speed connectivity in a local area network (LAN) environment. Optical CDMA is shown to be competitive with other networking technologies such as F/WDMA and TDMA, but has the benefit of more flexibility, simpler protocols, and no need for centralized network control. OCDMA encoding or decoding process provides a high level of security which is directly implemented in the physical layer. In OCDMA, type of coding technique plays a major factor that influencing its performance. A new two dimensional (2D) Wavelength x Time Hybrid code is proposed to enhance the capacity and performance of the OCDMA system. 2D Wavelength x Time Hybrid code is designed by using 1D Modified Double Weight (MDW) and 1D Flexible Cross Correlation (FCC). These two codes are chosen because of capability to suppress multiple access interference (MAI) and reduced the PIIN. The numerical results reveal that the value of time spreading (spatial) code length, N is the major impact on the cardinality of the system. The performance of the system can be enhanced by exploiting the number of N rather than the value of wavelength encoding (spectral) code length, M.