Matrix computations (3rd ed.)
Zero-forcing methods for downlink spatial multiplexing in multiuser MIMO channels
IEEE Transactions on Signal Processing
Low complexity user selection algorithms for multiuser MIMO systems with block diagonalization
IEEE Transactions on Signal Processing
Sum capacity of the vector Gaussian broadcast channel and uplink-downlink duality
IEEE Transactions on Information Theory
On the optimality of multiantenna broadcast scheduling using zero-forcing beamforming
IEEE Journal on Selected Areas in Communications
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This letter presents a novel method of user selection in a downlink multi-user multiple input multiple output (MU-MIMO) system employing the precoding procedures of zero forcing or block diagonalization (BD). The proposed technique utilizes the cross-entropy method (CEM) in order to maintain a performance level comparable to that of the full search (FS) method with reasonable complexity. With the CEM, the proposed system can select multiple users at once instead of selecting a single user at each step. From various computer simulations, it has been verified that the proposed method exhibits nearly 98 % of the sum-rate compared to the FS method, which implies that the proposed method far outperforms conventional methods such as semi-orthogonal user selection (SUS) or the capacity-based suboptimal user selection (CBSUS) algorithm. Compared to CBSUS, the proposed technique enhances the sum-rate by approximately 1.1 bps/Hz with about half the complexity when each user is equipped with two receiving antennas. In the case where each user is equipped with a single antenna, the proposed method outperforms the method of SUS by about 0.3 bps/Hz, at the expense of a complexity increase of $$O(2M)$$ O ( 2 M ) times.