Analysis of the Relationship between Multipath Fading and Optimum Subcarrier Spacing for Generalized MC DS-CDMA Systems

Generalized multicarrier direct sequence code-division multiple-access (MC DS-CDMA) system is a model which includes a number of specific MC DS-CDMA schemes by varying the normalized subcarrier spacing. In the generalized MC DS-CDMA scheme, for a given system bandwidth and a given channel environment, there exists an optimum subcarrier spacing, which results in a minimum bit error rate. In this paper, as an extension of a previous study, detailed analysis on the variation of the optimum normalized subcarrier spacing for the generalized MC DS-CDMA in multipath Nakagami-m fading channels is performed. The results show that the optimum subcarrier spacing is almost independent of the variation of the fading parameter when the number of subcarriers is small. On the contrary, it is observed that the fading parameter has a clear effect on the settling of the optimum subcarrier spacing for large number of subcarriers