Throughput enhancement in WCDMA using the generalized rake receiver

In a multipath fading channel, when there are many interfering CDMA signals, the multipath causes loss of orthogonality between different signals leading to intracell interference. The Generalized RAKE receiver, proposed recently in the literature, is based on the concept that this interference is not white but colored. Therefore, unlike the conventional RAKE receiver, GRAKE tries to match to the channel as well as whiten the interference. The GRAKE gives a typical improvement of 1–3 dB in SNR for a moderate increase in complexity. In this paper, we quantify the benefits of using the GRAKE in place of the RAKE in a WCDMA downlink under realistic conditions as specified in the 3GPP standards. The comparison is made both in the presence and absence of channel coding. After performing channel coding, the block error rate and hence the system throughput is evaluated for both receivers in a 144 kbps test case. It is demonstrated that the GRAKE provides significant improvement in BER performance, which translates to higher data throughput, as well as increased capacity. © 2005 Taylor & Francis Group, LLC.