Acquisition in CDMA systems using parallel interference cancellation

A code acquisition scheme employing parallel interference cancellation (PIC) for DS-CDMA systems is investigated. The scheme employs PIC to remove the multiple access interference (MAI) from the synchronized users in the system. The interference cancelled signal is used to acquire the code phase of a new unsynchronized user entering the system. The performance of the new scheme is compared to the conventional method (of using the received signal to perform acquisition) in terms of the probabilities of detection (P_d) and false alarm (P_fa). From simulation results, it is found that the proposed scheme outperforms the conventional method by producing higher values of P_d for a particular value of P_fa. A mathematical expression is derived for evaluating P_d at each stage of the PIC and is verified with the simulation results.