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Simplified CapacityBased User Scheduling Algorithm for Multiuser MIMO Systems with Block Diagonalization
Yuyuan CHANG Kiyomichi ARAKI
Publication
IEICE TRANSACTIONS on Communications
Vol.E94B
No.10
pp.28372846 Publication Date: 2011/10/01
Online ISSN: 17451345 Print ISSN: 09168516 Type of Manuscript: PAPER Category: Wireless Communication Technologies Keyword: MIMO, multiuser diversity, block diagonalization, user scheduling algorithm, simplification, Gramschmidt orthogonalization,
Full Text: FreePDF(637.9KB)
Summary:
In multipleinput multipleoutput (MIMO) systems, the multiuser MIMO (MUMIMO) systems have the potential to provide higher channel capacity owing to multiuser and spatial diversity. Block diagonalization (BD) is one of the techniques to realize MUMIMO systems, where multiuser interference can be completely cancelled and therefore several users can be supported simultaneously. When the number of multiantenna users is larger than the number of simultaneously receiving users, it is necessary to select the users that maximize the system capacity. However, computation complexity becomes prohibitive, especially when the number of multiantenna users is large. Thus simplified user scheduling algorithms are necessary for reducing the complexity of computation. This paper proposes a simplified capacitybased user scheduling algorithm, based on analysis of the capacitybased user selection criterion. We find a new criterion that is simplified by using the properties of GramSchmidt orthogonalization (GSO). In simulation results, the proposed algorithm provides higher sum rate capacity than the conventional simplified normbased algorithm; and when signaltonoise power ratio (SNR) is high, it provides performance similar to that of the conventional simplified capacitybased algorithm, which still requires high complexity. Fairness of the users is also taken into account. With the proportionally fair (PF) criterion, the proposed algorithm provides better performance (sum rate capacity or fairness of the users) than the conventional algorithms. Simulation results also shows that the proposed algorithm has lower complexity of computation than the conventional algorithms.

