IJPAM: Volume 21, No. 2 (2005)


Vidhyacharan Bhaskar$^1$, Kondo Hloindo Adjallah$^2$, Laurie L. Joiner$^3$
$^1$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
$^{2}$Institute of Computer Science and Engineering of Troyes
Universite de Technologie de Troyes
12 Rue Marie Curie, Troyes Cedex, 10010, FRANCE
$^{3}$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