EURASIP Journal on Applied Signal Processing 
Volume 2002 (2002), Issue 8, Pages 757-770
doi:10.1155/S1110865702000914

Chip-Level Channel Equalization in WCDMA Downlink

Kari Hooli,1 Markku Juntti,1 Markku J. Heikkilä,2 Petri Komulainen,2 Matti Latva-aho,1 and Jorma Lilleberg2

 1Centre for Wireless Communications, P.O. Box 4500 FIN-90014, University of Oulu, Finland
2Nokia Mobile Phones, P.O. Box 50, Oulu 90571, Finland
Received 14 August 2001; Revised 7 March 2002

Abstract

The most important third generation (3G) cellular communications standard is based on wideband CDMA (WCDMA). Receivers based on TDMA style channel equalization at the chip level have been proposed for a WCDMA downlink employing long spreading sequences to ensure adequate performance even with a high number of active users. These receivers equalize the channel prior to despreading, thus restoring the orthogonality of users and resulting in multiple-access interference (MAI) suppression. In this paper, an overview of chip-level channel equalizers is delivered with special attention to adaptation methods suitable for the WCDMA downlink. Numerical examples on the equalizers′ performance are given in Rayleigh fading frequency-selective channels.