Optimization of CDMA signature sequences in multipath channels

We consider the problem of finding good signature sequences for interference avoidance in a CDMA multipath channel, for a given known channel state. We consider two cases. In the first case, we optimize the transmit powers as well as the signature sequences of the users; the optimality of the set is measured by the effective total squared correlation which is related to achievable SIR. In the second case, we assume fixed received powers and optimize the signature sequences. In this case we consider two optimality criteria: total minimum mean square estimation error, and information theoretic sum capacity. For all three cost functions, we derive iterative algorithms for sequentially updating the users signature sequences.