STTC-SD with LMMSE multi-user detection for WCDMA downlink

In this paper we analyze the performance of space time trellis coded-scrambling diversity (STTC-SD) scheme for WCDMA downlink, when a linear minimum mean squared error multi-user detection (LMMSE-MUD) receiver is used. STTC-SD scheme for CDMA systems was introduced in (S. Thirukkumaran and K.K. Pang, 2004) and was shown to perform better than conventional STTC scheme under low system loads. At high system loads, the STTC-SD scheme suffers excessively from multiple access interference. In this paper we show that, by using a LMMSE-MUD receiver, this problem can be rectified so that STTC-SD scheme performs significantly better than standard STTC scheme at all system loads.