Optical CDMA system using spatial AMI coding scheme and coset representative

In this paper, the utilizations of spatial alternate mark inversion (AMI) coding scheme and coset representative are investigated in time-spreading wavelength-hopping optical code division multiple access systems. The carrier hopping prime code is utilized as signature sequence whose out of phase autocorrelation is zero and the cross-correlation is at most one. Predicated upon the zero autocorrelation sidelobes property of the carrier hopping prime code, we exploit the spatial AMI coding scheme to the trellis run-length limited code from one-dimension into two-dimension. To enhance the error correcting capability of the proposed trellis code, coset representative is imposed on the trellis to further enlarge the free distance. Since the multiple access interference and beat noise are the main deteriorating factors in system performance which will bring about the error floor effect, our proposed coding scheme with larger coding gain can further effectively alleviate the adverse impacts. Aside from the multiple access interference and beat noise, some of the detrimental effects in system performance are also taken into account, which include thermal noise, shot noise and relative intensity noise.