User Scheduling Algorithms for Downlink MU-MIMO System Based on the SCSI

Qiang SUN  Chen SUN  Shi JIN  Yuan ZHANG  Xiqi GAO  

IEICE TRANSACTIONS on Communications   Vol.E96-B    No.2    pp.651-655
Publication Date: 2013/02/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E96.B.651
Print ISSN: 0916-8516
Type of Manuscript: LETTER
Category: Wireless Communication Technologies
statistical channel state information,  user scheduling,  MU-MIMO,  

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In this paper, we investigate the user scheduling algorithms with statistical eigen-mode transmission (SET) for downlink multiuser multiple-input multiple-output (MU-MIMO) system by utilizing the statistical channel state information (SCSI). Given the objective of maximizing the ergodic achievable sum rate per group (EASRPG), our first proposal, the Munkres user assignment algorithm (MUAA), solves the optimal user grouping problem. Different from the conventional user grouping algorithm (e.g. max-min method), MUAA can efficiently solve the user assignment problem and acquire an optimal solution. However, some user groups of the optimal solution called “unfriendly” groups severely degrade the EASRPG by performing the multiuser SET (MU-SET) due to excessive inter-user interference. To overcome this obstacle, the MUAA with sequential iterative separation (MUAA-SIS) is proposed to find the “unfriendly” groups and switch from the MU-SET to the single-user SET. Finally, our numerical results show that MUAA-SIS offers a higher EASRPG.