Channel adapted CDMA for MAI/ISI-free power optimized burst transmission with space diversity at the base station

This paper considers the uplink and the downlink of a DS-CDMA multiuser communication system based on burst transmission over frequency selective channels. The purpose is to evaluate the performance gain obtained if space diversity is introduced at the base station with an optimized set of codes. The codes are designed in order to minimize the emitted power at the mobile stations (in case of uplink transmission) or at the base station (in case of downlink transmission) while allowing the complete elimination of the intersymbol interference (ISI) and multiple-access interference (MAI) if filters matched to the total impulse responses are used at the receiver. An iterative algorithm is used to generate the codes. The comparison is made with the performances reached when a conventional set of codes is used. It is shown that the precoding scheme based on channel adapted codes significantly outperforms a system based on a conventional set of codes