A Hybrid Multirate Scheme for WCDMA

초록

Different kinds of Multi-rate communication systems are considered for accommodation information sources with different data rates. Drect-sequence code-division multiple access(DS/CDMA) techniqueshave attracted many attentions to be employed in such system.In this paper, three multi-rate transmission schemes in a W-CDMA system are compared. Both AWGN and multipath Rayleigh fading channels are considered. It is shown that for high data rates the spreading factor in the variable spreading factor scheme will be very small and thus the performance will be significantly degraded due to intersymbol interference. Thus variable spreading factors are used for the low and medium high data rates, and combined with multicode transmission for the highest data rates. Sumulation result shows that hybrid multirate transmission scheme is suitable for WCDMA.