A joint scheduling and precoding scheme based on sum chord distance in MU-MIMO system with limited feedback

In this paper, we propose a joint scheduling and precoding scheme in MU-MIMO downlink channel with limited feedback. Each user feeds back the index which indicates the channel direction in a predefined codebook and one scalar denoting the quantization error. With the feedback information, the base station schedules the first user with the minimal quantization error. And then it schedules the users with the metric based on the sum of two chord distances. Compared with the traditional joint scheduling and precoding based on ZF-CI, our proposed scheme can restrain the performance loss caused by quantization error and reduce the feedback. Further, the sum rate is greatly improved as SNR increases. Simulation results are exhibited to verify its effectiveness.