Adaptive CDMA receiver for downlink multiuser interference suppression

In code division multiple access (CDMA) mobile communication systems with time-varying multipath channels, both intersymbol interference (ISI) and multiple-access interference (MAI) must be considered. The zero-forcing (ZF) and the minimum mean-square-error block linear equalisers (MMSE-BLE) have been proposed to solve such a problem under the condition that the channel impulse response has been perfectly estimated. Presented is an MAI/ISI suppression receiver based on recursive least squares criterion. The proposed MAI/ISI suppression receiver is adaptive so that channel impulse response estimation is not necessary. Simulation results show that the performance of the proposed receiver is better than that of the existing MMSE-BLE and ZF-BLE.