Open Access

Multicarrier Block-Spread CDMA for Broadband Cellular Downlink

EURASIP Journal on Advances in Signal Processing20042004:354827

Received: 6 March 2003

Published: 7 September 2004


Effective suppression of multiuser interference (MUI) and mitigation of frequency-selective fading effects within the complexity constraints of the mobile constitute major challenges for broadband cellular downlink transceiver design. Existing wideband direct-sequence (DS) code division multiple access (CDMA) transceivers suppress MUI statistically by restoring the orthogonality among users at the receiver. However, they call for receive diversity and multichannel equalization to improve the fading effects caused by deep channel fades. Relying on redundant block spreading and linear precoding, we design a so-called multicarrier block-spread- (MCBS-)CDMA transceiver that preserves the orthogonality among users and guarantees symbol detection, regardless of the underlying frequency-selective fading channels. These properties allow for deterministic MUI elimination through low-complexity block despreading and enable full diversity gains, irrespective of the system load. Different options to perform equalization and decoding, either jointly or separately, strike the trade-off between performance and complexity. To improve the performance over multi-input multi-output (MIMO) multipath fading channels, our MCBS-CDMA transceiver combines well with space-time block-coding (STBC) techniques, to exploit both multiantenna and multipath diversity gains, irrespective of the system load. Simulation results demonstrate the superior performance of MCBS-CDMA compared to competing alternatives.

Keywords and phrases

multicarrier CDMAbroadband cellular systemfrequency-selective fading channelsequalizationMIMOspace-time block coding

Authors’ Affiliations

Wireless Research, Interuniversity MicroElectronics Center (IMEC), Leuven, Belgium
Electrical Engineering, Mathematics and Computer Science, Delft University of Technology (TUDelft), Delft, The Netherlands
Department of Electrical Engineering (ESAT), Katholieke Universiteit Leuven (KULeuven), Leuven, Belgium
Interuniversity MicroElectronics Center (IMEC), Leuven, Belgium


© Petré et al. 2004