Joint Scheduling and Precoding Scheme in MU-MIMO System with Limited Feedback

We consider a MIMO broadcast channel where both the transmitter and receivers are equipped with multiple antennas. A novel joint scheduling and precoding scheme based on the limited feedback is proposed. In the proposed scheme, each receiver feeds back the index which indicates the preferable precoding vector in a predefined codebook and one scalar denoting the quantization error. By using the feedback information from each receiver, the transmitter generates a unitary precoding matrix and schedules users whose channels can match the precoding matrix well according to the scheduling function. This paper explores the scheduling function based on the minimal chordal distance between the generated precoding vector and the quantized preferable precoding vector. Simulation results are exhibited to indicate that the proposed scheme can provide further system performance improvement than other MU-MIMO schemes without increasing the feedback load and avoid the scheduling failure at the transmitter.