Pilot channel-aided techniques to compute the beamforming vector for CDMA systems with antenna array

In the presence of pilot channels in the reverse-link, some approaches to compute the coherent beamforming vectors for the two-dimensional Rake (2-D Rake) combiner are considered. Since the beamforming vectors are computed using the de-spread signals, the computational complexity of the approaches is lower than that of the approach which uses the received signals before despreading. It has been shown that the beamforming performance depends on the accuracy of channel parameter estimation. The approach which provides better channel parameter estimates can give a better beamforming performance. The effect of the pilot power on the performance is also presented.