An analysis of the eigenbeamformer technique in a simulated WCDMA network

In this paper, we present an analysis of the eigenbeamformer (EB) technique in WCDMA cells using the single antenna transmission technique and the two-antenna space-time transmit diversity (STTD) technique [Siavash M. Alamouti, IEEE Journals of Select Areas in Communications, Vol. 16 No. 8, October 1998, p. 1451-1458] as the references and utilizing the dedicated physical channel (DPCH) for speech service as the traffic model. The EB [3GPP TSG RAN WG1#23, Orlando, USA, February 18-22, 2002] is a closed loop beamforming technique, with terminal assisted feedback, designed for multiple Tx-antennas, where the data is transmitted via orthogonal eigenbeams. The beams are pre-calculated at each terminal by long-term integration of the correlation matrix that is diagonalized, and the eigenvectors of this correlation matrix are sent to the base station, which then creates the beams for each terminal respectively. STTD is an open loop diversity scheme given by the orthogonal Alamouti matrix. EB is a candidate for four transmit (Tx) antenna diversity extension, and STTD is a well-known diversity technique in the 3GPP release ´99 specifications. We show some system performance results using a dynamic network simulator: the effect of some important non-idealities are included in the assumptions and they are expected to cause some degradation in performance e.g. because of the increased interference.