Efficient User Scheduling Algorithm for Enhancing Zero-Forcing Beamforming in MIMO Broadcast Channels

Changeui SHIN  Hyunsung GO  Seungwon CHOI  

IEICE TRANSACTIONS on Communications   Vol.E94-B    No.10    pp.2908-2911
Publication Date: 2011/10/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E94.B.2908
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Wireless Communication Technologies
MU-MIMO,  user selection,  multiuser channels,  Diversity methods,  Broadcast channels,  

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This letter presents a novel user scheduling algorithm that provides a maximum sum-rate based on zero-forcing beamforming (ZFBF) in multiple-input multiple-output (MIMO) systems. The proposed technique determines primary user pairs in which the sum-rate exceeds a predetermined threshold. To determine the threshold, we define the maximum-sum-rate criterion (MSRC) derived from the extreme value theory (EVT). Applying the MSRC in ZFBF-based user scheduling, we find that the performance of the proposed method is comparable to that of the exhaustive searching scheme which has a greater computational load. Through computer simulations, we show that the proposed method outperforms the very well-known correlation-based method, semi-orthogonal user selection (SUS), yielding a sum rate that is about 0.57 bps/Hz higher when the transmit SNR is 10 dB with perfect CSI at BS and the numbers of users and transmit antennas in a cell are 100 and 4, respectively.