Vidhyacharan Bhaskar, Kondo Hloindo Adjallah, Laurie L. Joiner
Departement Genie des Systemes d'Information
et de Telecommunication
Universite de Technologie de Troyes
12 Rue Marie Curie, Troyes Cedex, 10010, FRANCE
E-mail: Vidhyacharan.Bhaskar@utt.fr
Institute of Computer Science and Engineering of Troyes
Universite de Technologie de Troyes
12 Rue Marie Curie, Troyes Cedex, 10010, FRANCE
Department of Electrical and Computer Engineering
University of Alabama in Huntsville
Huntsville, AL 35899, USA

Abstract.In wideband code division multiple access (W-CDMA) systems, inter-symbol interference (ISI) introduced by multipath propagation can be significant due to large multipath delays. In the presence of multipath, each signal is subjected to frequency-selective fading and the orthogonality condition is distorted due to increased cross-correlation between the signature waveforms of the different users. In this paper, we study a subspace-based signature waveform estimation for downlink W-CDMA systems that provides estimates of the multiuser channels by exploiting the second-order statistics of the transmitted signal at the base station. We employ multiple antennas at the receiver to estimate the signature waveforms for overloaded systems. A zero-forcing equalizer and a matched-filter detector are employed to estimate the received signal constellations. Simulations are performed to evaluate the effectiveness of the algorithm. 26A33

Received: November 22, 2004

AMS Subject Classification:

Key Words and Phrases: signature waveform, signal subspace, noise subspace, capacity

Source: International Journal of Pure and Applied Mathematics
ISSN: 1311-8080
Year: 2005
Volume: 21
Issue: 2