Sensitivity of feedback channel delay on transmit adaptive array

The investigation into the effect of various feedback errors on system performance can help the robust feedback channel design and transmission of exact feedback channel information as well. We address the algorithm that determines space combining weight vector maximizing received signal power at the mobile on a frequency flat fading channel and investigate the performance degradation by the feedback channel delay in the FDD/CDMA systems employing transmit beamforming. We observe the effect of feedback channel delay corresponding to the number of transmit antennas and the temporal/spatial correlation of channel. The results show that performance is more sensitive to feedback delay with the larger number of antennas when fading at the transmit antennas are not spatially correlated.