Universal discrete model and linear algebra representation for variant OFDM-CDMA systems

Variant Orthogonal Frequency Division Multiplexing Code Division Multiple Access (OFDM-CDMA) schemes can mitigate the hostile influence due to the frequency-selective fading while maintaining bandwidth efficiency by minimizing the frequency separation between adjacent subcarriers, therefore they are broadly considered as effective approaches for future wireless multimedia communications. In this paper, based on software-defined radio (SDR), by neglecting differentiae of both "decomposition" and spread spectral operations in each scheme, a universal discrete model for variant OFDM-CDMA systems is developed. Moreover, the corresponding linear algebra representation is addressed, which is of significance to design reconfigurable, reprogrammable, and multimode transceivers.