BIT ERROR-PROBABILITY ANALYSIS FOR FRAMES WCDMA DOWNLINK RECEIVERS

The wide-band code-division multiple-access (WCDMA) concept FMA2 devel oped in the European Future Radio Wide-Band Multiple-Access Systems (F RAMES) project supports variable-data-rate transmission. The data rate can be altered by changing either the spreading factor or by using mu ltiple spreading codes in parallel. In order to facilitate flexible ch anging of the data rate, variable-length orthogonal Walsh codes are us ed for channel separation, followed by the scrambling code. Optional s hort scrambling codes can be used if interference suppression is used. In this paper, the downlink performance of the FMA2 system using both the conventional RAKE and LMMSE-RAKE receivers is studied, According to the numerical results, the performance of the conventional RAKE rec eivers is significantly degraded at the highest data rates, whereas th e LMMSE-RAKE performs well in those cases also.