Iterative construction of spreading sequences in CDMA forward link

We consider an iterative algorithm to construct spreading sequences in a CDMA forward link to support users with a uniform target signal-to-interference ratio (SIR). Particular attention is given to the case when the number of users is larger than the spreading gain. We classify users into two classes, namely, overfaded users and nonoverfaded users, according to their effective noise densities. Overfaded users are allocated orthogonal "channels", and nonoverfaded users share the remaining "channels". Two adaptive algorithms are presented to construct the sequences iteratively based on the observation that the MMSE receiver weights are the same as those of the matched filter using the extended total squared correlation (ETSC) minimization sequences.