Analysis and evaluation of multi-access OCDMA systems in next generation network

Abstract

Optical Code Division Multiple Access(OCDMA)systems suffer from some constraints, which in turn limit their performances such as multiple access interference(MAI) that is increasingly proportional to bit error rate(BER).Spectral amplitude coding(SAC) OCDMA scheme is able to diminish MAI requiring a good choice for address signature and detection technique.To suppress this obstacle,this thesis is devoted to propose novel unidimensional and multidimensional codes characterized by high auto-correlation and zero cross-correlation features termed as One Dimensional-Identity Column/Row Shifting Matrix(1D-ICSM and (RSM)codes,Two Dimensional-Half Spectral Spatial Zero Cross Correlation(2D-HSSZCC)code,2D-Cyclic Shift(2D-CS)code and Three Dimensional-Single Weight Zero Cross Correlation(3D-SWZCC)code.These codes have demonstrated their abilities in terms of high system performance optimized through outperforming traditional SAC-OCDMA systems.The 1D systems assign the spectral encoding,2D systems specify the spectral encoding for the first component while the second component is specified by either spatial encoding or temporal encoding presented by proposed 2D-HSSZCC code and 2D-CS code,respectively and finally,3DSWZCC code is devoted to carry out spectral,temporal and spatial encoding fields,consecutively.All these proposed codes use spectral direct detection(SDD)and have ZCC property.The reason for transition from 1D through 2D and 2D through 3D is due to problem, creates in the first scheme,can be solved by using more developer scheme.These problems include;long code length,high number of fiber optics and time skew. Ultimately,it can say that proposed codes have added optimizations to conventional OCDMA systems,for instance; increase data rate and cardinality,economize received power and optical bandwidth,generate high signal-to-noise ratio(SNR)and low BER,extent fiber optic at high distances.Therefore, these improvements qualify proposed codes even be candidates to satisfy optical communication requirements.