Downlink processing for mitigation of intracell interference in DS-CDMA systems

We present a downlink processing algorithm which provides the necessary signal level at the output of the demodulator at the mobile station (MS). Both, the base station (BS) and MS are equipped with only one antenna. Furthermore, we presume a time division duplex (TDD) system, therefore, the complete channel is known to the BS. With this knowledge an exact representation of the downlink transmission is possible at the BS. The conventional way to create the signal for transmission in a direct sequence code division multiple access (DS-CDMA) system is to sum the weighted outputs of spread QPSK signals dedicated to the different mobiles. Contrary, we optimize the transmission signal itself to provide the demanded outputs at the mobiles. Simulation results show the superiority of the new approach.