ABSTRACT:

A predistorter-high power amplifier (PD-HPA) pair has become a common practice in wireless Communication to compensate for nonlinear distortion due to HPA. However, the PD-HPA pair still produces severe signal distortionwhen the input signal exceeds the PD-HPA's saturation level. The effects of such distortion on bit error rate (BER) degradation in downlink direct sequence-code division multiple access signals (DS-CDMA) are analyzed. We establish which signal characteristics at the HPA input are the factors contributing to BER. Assuming that the baseband CDMA signal is characterized as a complex Gaussian process, we develop analytic expressions for theBER and the contributing factors to BER.