Adaptive Interference-Aware Receiver for Multiuser MIMO Downlink Transmission in IEEE 802.11ac Wireless LAN Systems

Minjoon KIM  Yunho JUNG  Jaeseok KIM  

IEICE TRANSACTIONS on Communications   Vol.E99-B    No.8    pp.1884-1893
Publication Date: 2016/08/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.2015EBP3505
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
interference mitigation,  multiuser multiple-input multiple-output (MU-MIMO),  multiuser detection (MUD),  IEEE 802.11ac,  

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This paper presents an adaptive interference-aware receiver for multiuser multiple-input multiple-output (MU-MIMO) downlink systems in wireless local area network (WLAN) systems. The MU-MIMO downlink technique is one of the key techniques that are newly applied to WLAN systems in order to support a very high throughput. However, the simultaneous communication of several users causes inter-user interference (IUI), which adversely affects receivers. Therefore, in order to prevent IUI, a precoding technique is defined at the transmitter based on feedback from the receiver. Unfortunately, however, the receiver still suffers from interference, because the precoding technique is prone to practical errors from the feedback quantization and subcarrier grouping scheme. Whereas ordinary detection schemes are available to mitigate such interference, such schemes are unsuitable because of their low performance or high computational complexity. In this paper, we propose an switching algorithm based on the norm ratio between an effective channel matrix for the desired signal and that of the interfering signals. Simulation results based on the IEEE 802.11ac standard show that the proposed algorithm can achieve near-optimal performance with a 70% reduction in computational complexity.