Multiuser MIMO User Selection Schemes Using Block Diagonalization

Block diagonalization (BD) is a classical and practical interference cancelation precoding algorithm in MU-MIMO system. But once BD is used, the user number can be supported simultaneously by the base station is limited by the ratio of the numbers of transmit and receive antennas. In this paper, some existed lower complexity user selected schemes are discussed. These schemes are all based on capacity as the performance measure. However, there is an inherent drawback in these algorithms. Since the BS always selected the same users based on capacity or the correlation of the users in each time slot, it may not guarantee the quality-of-service of a single user. In order to ensure fairness in some systems, we improve the existed algorithms and propose the round-robin user selection algorithms.