Adaptive multi-rate multi-code CDMA systems

To support variable data-rates multi-code code-division multiple-access (MC-CDMA) systems have been proposed for mobile communications. They allow the support of variable source data-rates by variation of the set of spreading-sequences assigned to each user. The impact of the sequence-design on the system performance is considered. For the antifading capability and the multiuser interference performance measures are derived. We describe sequence-sets which are almost optimum with respect to these parameters and which allow each user to change its data-rate without affecting the other users.