Transmit beamforming scheme for multi-antenna multicasting system with limited-rate feedback

Multicast beamforming is a challenging problem in wireless networks due to different channel conditions of users. The data rate of a multicast group is dominated by the achievable data rate of the worst case user. Beamforming in multicasting system can provide better performance by maximizing the minimum Signal to Noise Ratio over all receivers in a multi-antenna system. In this paper, we focus on transmit beamforming in multi-group multicasting system where the CSIT is obtained via codebook based limited-rate feedback. The optimization problem is formulated considering the quantization distortion in the feedback process. Simulation results also show that the proposed scheme can substantially enhance the average minimum received SINR among the receivers and can approach the performance of transmit beamforming with perfect CSIT with increasing feedback bits.