Cdma transmission diversity apparatus

摘要

A base station includes a transmit diversity unit. The transmit diversity unit is provided with two transmission units for respective systems. Each of the transmission units produces transmission codes by coding transmission data. Each of the transmission units produces two CDMA signals by subjecting first transmission codes to spreading and 16QAM and transmits the two CDMA signals. Each of the transmission units produces two CDMA signals by subjecting second transmission codes to spreading and 16QAM and transmits the two CDMA signals. With this, time-difference diversity is implemented. Each of the transmission units codes the transmission data such that constellation points of a combined signal derived from the two CDMA signals are substantially evenly distributed. Accordingly, it is ensured that noise margin is large so that a bit error rate is improved.