Adaptive Precoder Selection for Multicast/Broadcast Service in MIMO-OFDMA Systems

The multicast/broadcast service (MBS) has emerged as a key technology for delivering multimedia contents in wireless networks.The development of orthogonal frequency division multiplexing access (OFDMA) and multiple-input multiple-output (MIMO) communications have provided a high-throughput air interface for delivering the multimedia contents in MBSs. To further improve the spectral efficiency for MIMO communications, the technique of precoding can be applied to tailor the signals to the current downlink channel quality. However, due to the broadcasting nature of MBSs, link adaptation and precoder selection for individual user is infeasible. A fixed precoding scheme where the transmitter simply uses identical precoding matrices is commonly adopted for MBS transmissions in existing systems. In this paper, we propose an effective adaptive precoder selection scheme with low complexity based on precoder training and user feedback. Simulation results show that the proposed scheme effectively improves the performance of received SINR measured at the mobile stations (MSs).