Abstract:As existing adaptive algorithms need training bits and are unsuited to fast fading channel in WCDMA systems, a novel adaptive multiuser algorithm based on differential MMSE (DMMSE) criterion is presented in this paper. According to the typical characteristic of two-layered spreading modulation in the WCDMA systems, the proposed DMMSE criterion updates the weight coeffients of transversal filter by tracking the ratio of successive symbols with the same comprehansive spread sequence. Thanks to depict the multiple access interference (MAI) more properly, the proposed algritnm can suppress the MAI more effectively. Simulation results illustrate that proposed one performs better than the existed ones at the Doppler shift channel.