Performance Analysis of Various coding Techniques in Optical Code Division Multiple Access System

Abstract: Optical code division multiple access system (OCDMA) exploits the advantages of CDMA and Optical communication. It has been gaining importance with increasing demands of high speed and large capacity for communication in optical networks. OCDMA encoding/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. This paper presents performance analysis of two important OCDMA coding techniques namely – 1-D and 2-D codes. Firstly performance analysis of various 1-D codes namely Walsh Hadamard codes (WHC), Optical orthogonal codes (OOC) and Zero cross correlation (ZCC) has been carried out. Secondly performance analysis of 2-D Wavelength/Time (W/T) codes has been carried out. The performance metrics on which the various codes performance has been measured are: different data formats (NR and RZ), increasing fiber distance, amount of received power, increasing the bit rate and number of simultaneous active user. Simulated results show that among 1-D codes ZCC codes provides the best overall performance over OOC and WHC. 1-D codes provide low bit error rate (BER) but they possess high temporal length. To overcome this, 2-D codes have been used which have higher cardinality than 1-D code