Combined OFDM-CDMA Configuration for MultimediaWireless Applications

This paper analyses the applicability of OFDM modulation when combined with CDMA for multimedia wireless systems operating in an indoor environment. We demonstrate the motivations and benefits deriving from this combination. Particular emphasis is given to channel equalisation techniques, designed to face different problems arising in the up-link and in the down-link. In particular, an equalisation technique based on channel inversion, combined with carrier interleaving and adaptive suppression of noisy carriers, is proposed in the down-link, while a pre-equalisation approach is used in the up-link. The analysis provides both BER performance and computational cost of the most important procedures that are to be implemented within multimedia terminals. The computational cost analysis is carried out using commercial DSP platforms.