DESIGN AND IMPLEMENTATION OF IMPROVED SUPERIMPOSED CYCLIC OPTICAL ORTHOGONAL CODES (SCOOC) BASED OPTICAL ENCODER/DECODER STRUCTURE FOR 1GBPS OPTICAL CDMA SYSTEM

• Main Authors: GURJIT KAUR, NEENA GUPTA
• Format: Article
• Language: English
• Published: Taylor's University 2010-12-01
• Series: Journal of Engineering Science and Technology
• Subjects: Optical code division multiple access; Bit error rate; Encoder; Decoder
• Online Access: http://jestec.taylors.edu.my/Vol%205%20Issue%204%20December%2010/Vol_5_4_391_399_Gurjit%20Kaur.pdf

In this paper, an improved form of two dimensional optical orthogonal codes is introduced for optical CDMA system by using just six lasers. This new technique not only reduces the length of the code but also improves the bit error rate (BER) performance of the system. The uniqueness of this coding architecture is that the two adjacent codes are not only different by their time slots but have different wavelength combination as well. The encoder and decoder structure has been designed with the help of filters and optical delay lines. An OCDMA system at 1 Gbps bit rate is designed for above codes and performance is evaluated and compared for various parameters i.e. number of simultaneous users, bit error rate, quality factor. The OCDMA system can accommodate 25 users for permissible BER of 10-9, with -15db received power at 1 Gbps bit rate respectively. If received power is kept low i.e. -22db, the OCDMA system can support 16 users with extremely low BER of 1.58e-41 for 1G bps bit rate.