Spreading code set dependent decorrelator performance in an AWGN channel at the fraction of chip user delay offsets

The CDMA system performance is studied with a decorrelating detector in an additive white Gaussian noise channel. Different degrees of chip-synchronism between users are taken into consideration. Either random or Gold codes of length 31 are used as spreading codes. Furthermore, orthogonal Hadamard codes of length 32 are used. For Gold codes different code set selection criteria are examined. Performance results between these criteria show clear differences. However, the overall performance seems to be more dependent on the delay offset than the code phase optimization criterion. For orthogonal codes only delay offsets larger than a quarter of the chip cause severe performance losses.