Date Added: Aug 2012
The problem of transmit beamforming design for multicast wireless system is considered in this paper. The authors focus on the robust long-term transmit beamforming design with only imperfect knowledge of the channel covariance from two view points: minimizing total transmission power with prescribed Signal-to-Noise Ratio (SNR) constraints at the receivers and maximizing the minimum SNR to achieve the relative max-min fairness. Only infrequent feedback is required from the users in such an algorithm. Furthermore, the algorithm shows great tolerance of imperfect Channel State Information (CSI) on both transceiver sides.