Auto-correlation and cross-correlation analysis of prime and walsh codes for optical CDMA networks

Abstract

Code division Multiple Access (CDMA) is a spread technology allowing many users to occupy the same frequency band at the same time. CDMA assigns unique codes to each user to differentiate it from others in the same spectrum. Optical Communication Fibers have the high bandwidth, larger capacity and high reliability by the use of broadband of the optical fiber. By combining the advantages CDMA and optical communication, the idea of allowing several users to transmit data simultaneously allocating the available bandwidth to each user called Multiple Access. CDMA users are given distinct orthogonal codes, which can be transmitted at the same time, using the same channel and the entire available frequency spectrum available. The data for multiple users are multiplexed synchronously or asynchronously. Various optical CDMA techniques employed in fiber-optic CDMA using 1-D dimensional optical orthogonal codes (OOC) and 2-D dimensional optical orthogonal codes (OOC). m-sequences, Gold codes, Prime sequences and Modified prime code sequences are some of the Two dimensional optical orthogonal codes. In this work, the performances of various Two dimensional optical orthogonal codes have been evaluated for optical CDMA system in terms of number of users and BER by considering both wavelength and time.