Performance Evaluation of Multistage Multiuser Detector for Asynchronous DS-CDMA System

This paper presents the results related to performance evaluation of 4-stage multiuser detector for asynchronous DS-CDMA system. To meet the real-time requirements for asynchronous multiuser detection, a bit streaming, parallel interference cancellation (PIC) cascade architecture is used. An asynchronous multiuser detection involves block-based computations and matrix inversions. The paper covers iterative-based suboptimal schemes that have been used to decrease the computational complexity, eliminate the need for matrix inversions, decreases the execution time, reduces the memory requirements by making use of joint estimation and detection process that gives better performance than the independent parameter estimation method. The stages of the iteration are cascaded and bits processed in a streaming fashion. The simulation has been carried out for asynchronous DS-CDMA system by varying two parameters, i.e., number of users and number of stages. The simulation results exhibit that system gives better performance at 3rd stage and the number of users decrease with increase in signal to noise ratio (SNR).