DS-CDMA is a dominant player in the world of wireless telecommunications, emerging as the standard of choice in 3G UMTS (Universal mobile telecommunications system). Here, DS-CDMA is also referred to as WCDMA (wideband CDMA). In this work, we introduce a novel multicarrier chip-shaping filter at the transmitter, replacing the usual root-raised cosine chip shape filter in WCDMA systems. At the receiver side, a corresponding frequency-based processing is proposed, where chips are separated into their N carrier components, and then recombined in order to minimize interference and noise while exploiting frequency diversity gains. Our performance analysis assumes system parameters and channel models consistent with UMTS WCDMA standards, and results show that the frequency-based WCDMA physical layer offers a 5 dB-performance gain at P(/spl epsiv/)=10/sup -2/ (uncoded transmission) over a traditional time-based WCDMA system with RAKE reception.