Beamforming with imperfect channel state information

摘要

Disclosed herein is a system and method for downlink beamforming that takes into account imperfect channel state information (CSI) at the transmitter when determining the steering vector used in the beamforming process. The steering vector is calculated to increase the ratio of the average power of a desired signal component to the sum of the interference power of other wireless terminals, referred to as the signal-to-leakage ratio. By accounting for imperfect CSI when calculating the steering vector, the bit-error rate for a given signal-to-noise ratio is decreased. Also disclosed is a power allocation method that improves performance of the system by increasing the signal-to-interference-plus-noise ratio for all of the wireless terminals currently communicating with the base station. The power allocation similarly decreases the bit-error rate for a given signal-to-noise ratio, especially at high signal-to-noise ratios.