Internally channel-coded framed time-hopping fiber-optic CDMA communications

Due to the low cardinality of optical orthogonal codes (OOCs) with a correlation value of 1, the capability of an internal channel-coding scheme cannot be applied effectively for an increasing number of simultaneous users in a typical fiber-optic code division multiple-access (FO-CDMA) system. In this paper, we consider applying the internal channel-coding scheme to the framed time-hopping (FTH) FO-CDMA system. Due to the extremely high cardinality of the spreading sequence in FTH FO-CDMA, the technique highlights the ability of the internal channel-coding scheme to increase the effective number of users in an FO-CDMA system. For the FTH FO-CDMA system, we only consider a Poisson noise-limited channel and do not take into account the physical fiber-optic channel impairments. Our simulation and analytical results show that, due to the large cardinality of spreading codes, the capability of the internal channel-coding technique to increase the maximum number of simultaneous users becomes more obvious in the FTH FO-CDMA system.