Analysis of adaptive multistage interference cancellation for CDMA using an improved Gaussian approximation

The proposed use of code division multiple access (CDMA) for cellular telephone has sparked considerable research interest in techniques to improve the capacity of CDMA systems. We consider a simple model for adaptive multistage interference cancellation within a (direct sequence spread spectrum) CDMA system, and seek to develop an accurate analytical expression for performance of this system. Previous work on interference cancellation has relied heavily on simulation techniques or a simple Gaussian approximation, which can lead to optimistic bit error rate (BER) results. This paper presents an analytical expression for the BER of an adaptive multistage interference canceller, using an improved Gaussian approximation for multiple access interference (MAI). The performance of the resulting BER expression is compared with simulation results. The analytical framework presented can also be used to evaluate the performance of multistage interference cancellation in arbitrary fading environments