CSI Feedback Reduction Method for Downlink Multiuser MIMO Transmission Using Dense Distributed Antenna Selection


IEICE TRANSACTIONS on Communications   Vol.E101-B    No.2    pp.426-433
Publication Date: 2018/02/01
Publicized: 2017/08/22
Online ISSN: 1745-1345
DOI: 10.1587/transcom.2017ISP0014
Type of Manuscript: Special Section PAPER (Special Section on Recent Progress in Antennas and Propagation in Conjunction with Main Topics of ISAP2016)
Category: MIMO
multiuser multiple input multiple output (MU-MIMO),  antenna selection,  wireless LAN (WLAN),  distributed antenna system (DAS),  channel state information (CSI),  

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This paper proposes a novel method of reducing channel state information (CSI) feedback by using transmit antenna selection for downlink multiuser multiple input multiple output (DL-MU-MIMO) transmission in dense distributed antenna systems. It is widely known that DL-MU-MIMO transmission achieves higher total bit-rate by mitigating inter-user interference based on pre-coding techniques. The pre-coding techniques require CSI between access point (AP) and multiple users. However, overhead for CSI acquisition degrades the transmission efficiency of DL-MU-MIMO transmission. In the proposed CSI feedback reduction method, AP first selects the antenna set that maximizes the received power at each user, second it skips the sequence of CSI feedback for users whose signal to interference power ratio is larger than a threshold, and finally it performs DL-MU-MIMO transmission to multiple users by using the selected antenna set. To clarify the proposed method, we evaluate it by computer simulations in an indoor scenario. The results show that the proposed method can offer higher transmission efficiency than the conventional DL-MU-MIMO transmission with the usual CSI feedback method.