Throughput Scaling of Uplink SDMA with Limited Feedback

In a multi-antenna system with a large number of users, combining space division multiple access (SDMA) and scheduling achieves high throughput. The implementation of joint SDMA and scheduling requires limited feedback of channel sate information (CSI) from users to a base station. In this paper, an uplink SDMA system with limited feedback and a large number of users is considered. The scaling of uplink throughput with different system parameters is analyzed. These parameters include the numbers of users, feedback bits and antennas. Our results provide guidelines for designing uplink SDMA to achieve optimum throughput scaling. For instance, in the high SNR regime, scheduling should select users with small CSI quantization error.