Performance Analysis of Linear MUDs and MMSE Precoding in WCDMA over Nonlinear channels

A composite of wide band code division multiple access (WCDMA) signals, transmitted by the base station, has a large peak to average power ratio (PAPR). This large PAPR causes nonlinear distortion (NLD) at the output of the base station high power amplifier (HPA), which results in performance degradation of mobile receivers. This paper analyzes fficts of HPA nonlinearity on the symbol error rate (SER) of three dffirent receivers: linear decorrelating detector (LDD), MMSE detector (which both are complicated multi user detectors (MUDil, and a simple matched filter. Only in the third case, an MMSE precoding is also used in the base station trarusmitter. Simulation results validate the analysis. Moreover, in both flat and frequency selective chnnnels, the third case have more performance degradation against NLD rather than the other two receivers on the other hand the advantage of that is providing much simpler mobile receivers.

Keywords:

HPA nonlinearity , PAPR , WCDMA , MMSE Precoding , Linear Decorrelating detector (LDD) , MMSE detector