Study on Number of Selected Antennas in Massive MIMO using Block Diagonalization

Massive multi-user multiple input multiple output (MU-MIMO) improves the system channel capacity by facilitating transmissions between a base station and multiple user terminals (UT). Block diagonalization (BD) has been proposed to realize MU-MIMO in the downlink. We have proposed an antenna selection method to reduce the number of nulls for users other an intended user through the BD algorithm. In this paper, the optimal number of selected antennas in the proposed method is investigated in terms of the throughput performance, when considering the efficiency of the medium access control (MAC).