Subband adaptive array for multirate multicode DS-CDMA

Recently, multicode CDMA has been adopted for multirate implementation in wideband multimedia networks. However, in such networks, the two main factors which affect system performance are multiple access interference (MAI), particularly of high data rate (HDR) users on low data rate (LDR) users, and intersymbol interference (ISI) due to multipath fading. To mitigate both MAI and ISI for multirate multicode CDMA, we propose an efficient adaptive array scheme for multirate multicode CDMA using subband signal processing. We also propose the use of the so-called cyclic prefix spread code combining with the scheme to maximize diversity gain in multipath fading environments. SINR and BER performance of 3 class users are explored by computer simulation.