Performance analysis of multistage linear groupwise successive interference cancellation via graphical approach

The performance of the multistage linear groupwise successive interference canceller (GSIC) in long-code direct sequence-code division multiple access (DS-CDMA) systems is analyzed in this research. We adopt a graphical approach to calculate the conditional mean and variance of the output signal of the receiver at an arbitrary stage. The computation of such statistics involves the evaluation of high order moments of large size matrices and, therefore, has a very high complexity, which increases exponentially with the number of stages of the receiver. The solution of this problem via graph theory allows very accurate evaluation of the conditional mean and variance. Simulation results show that the proposed method is able to estimate the bit error probability (BEP) with high accuracy.