Analysis of the relationship between multipath fading and optimum subcarrier spacing for generalized MC DS-CDMA systems

Abstract

Generalized multicarrier direct sequence code-division multiple-access (MC DS-CDMA) system is amodel which includes a number of specific MC DS-CDMA schemes by varying the normalizedsubcarrier spacing. In the generalized MC DS-CDMA scheme, for a given system bandwidth and agiven channel environment, there exists an optimum subcarrier spacing, which results in a minimumbit error rate. In this paper, as an extension of a previous study, detailed analysis on the variation ofthe optimum normalized subcarrier spacing for the generalized MC DS-CDMA in multipathNakagami-m fading channels is performed. The results show that the optimum subcarrier spacing isalmost 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 theoptimum subcarrier spacing for large number of subcarriers.