Analysis of performance measures of forward CDMA link with non-linear devices in the signal path
V. Sorokine, Sedki Younis · 2002
We investigate the performance of the forward link in IS-95 CDMA systems in the presence of non-linear devices in the signal path. One possible measure of this performance is the Walsh power ratio (WPR) a new concept developed at Qualcomm Inc. The importance of the WPR as a system performance measure is signified by the fact that the symbol error rate (SER) due to non-linearities, is a function of the WPR. We prove that for an "all-ones" input data stream in the forward link, the WPR does not depend on the empty Walsh channel number. We derive a general formula for the WPR and "all-ones" user sequences for Walsh functions of an arbitrary length. We investigate the effect of cascading non-linear devices on the WPR. These results can be used as guidelines in the practical design of mobile telephone receivers. We also present simulation results that illustrate our theoretical findings.