On the Performance of the Scheduling Scheme for MU-MIMO BC System With Two-Stage Feedback

Multi-user Multiple Input Multiple Output (MU-MIMO) broadcast channel (BC) deployed with multiple transmit antennas at the base station (BS) and multiple receive antennas at each user is considered. The channel state information (CSI) from each user is quantized at the user side and the CSI at the transmitter (CSIT) required to obtain the throughput for the system is obtained in terms of the feedback bits only. The main objective is to reduce the feedback load. Transmitter architecture is proposed based on the zero-forcing beam forming (ZFBF) semi-orthogonal user selection (SUS) algorithm. In the proposed system, a two-stage feedback scheme is used along with the SUS scheduling algorithm so as to minimize the feedback load. The Maximum expected SINR combiner (MESC) is exploited so that only a limited number of users convey their feedback. These methods efficiently eliminate users from transmission in feedback and scheduling process, resulting in optimum use of scarce resources. The simulation results bring us to a conclusion that SUS user selection method gives significant reduction in feedback bits and the required effective throughput is achieved.