In this paper, an interference cancellation (IC) scheme for a multirate VPG DS/CDMA system is evaluated in a multipath fading mobile channel and is designed to accommodate the multimedia sources of varying data-rate requirements. In the this scheme, the strongest user with high-rate transmission will benefit from the multiple access interference (MAI) reduction of the weaker users, which yields more clean estimates in the next cancellation stage. From the numerical results, the proposed scheme outperforms the conventional SIC scheme under the condition of the approximately identical decoding delay at the cost of the hardware burden.

This letter is concerned with a performance analysis of a VPG DS/CDMA acquisition system employing a reference filter based on the statistical evaluation of the decision threshold. The probabilities of detection and false alarm are derived, and the mean acquisition time is evaluated as a measure of the system performance. From the results, it is shown that in the performance analysis of the parallel acquisition system with reference filtering, the statistical evaluation of the decision threshold seems more appropriate than the approximation of the decision threshold adopted in other acquisition schemes.