Robust MMSE Beamforming for Multiuser MISO Systems With Limited Feedback

This letter considers minimum mean square error beamforming (MMSEBF) for the downlink of a multiuser multiple-input single-output (MISO) system with limited feedback, where the transmitter only has quantized information regarding the direction of the channel. We present an improved approach which is robust to the channel uncertainties arising from the quantization errors and the lack of channel magnitude information. Simulation results show that the proposed robust MMSEBF scheme provides improved performance over the conventional beamforming schemes in limited feedback systems.