Bhaskar, Vidhyacharan; Adjallah, Kondo Hloindo; Joiner, Laurie L. Subspace based channel estimation for downlink W-CDMA. (English) Zbl 1084.94507 Int. J. Pure Appl. Math. 21, No. 2, 139-149 (2005). Summary: 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. MSC: 94A40 Channel models (including quantum) in information and communication theory 94A13 Detection theory in information and communication theory 62H12 Estimation in multivariate analysis 62H15 Hypothesis testing in multivariate analysis Keywords:signal subspace; noise subspace; capacity; signature waveforms PDFBibTeX XMLCite \textit{V. Bhaskar} et al., Int. J. Pure Appl. Math. 21, No. 2, 139--149 (2005; Zbl 1084.94507)