Accurate techniques to evaluate CDMA bit error rates in multipath channels with imperfect power control

In this paper, a simplified expression for the improved Gaussian approximation (SEIGA) is presented for accurately evaluating direct sequence code division multiple access (DS-CDMA) bit error rates in multipath channels and systems with imperfect power control. Previous techniques for evaluating bit error rate performance of these systems can lead to overly optimistic results under a variety of conditions, particularly when directional or adaptive antennas are used at the base station. In this paper, we demonstrate the accuracy of these new techniques for evaluating bit error rates in both narrowband and wideband multipath channels and illustrate these techniques by providing a system example in which adaptive antennas are applied to CDMA cellular radio systems