A Novel Low-Overhead Channel Sounding Protocol for Downlink Multi-User MIMO in IEEE 802.11ax WLAN

Toshihisa NABETANI  Narendar MADHAVAN  Hiroki MORI  Tsuguhide AOKI  

IEICE TRANSACTIONS on Communications   Vol.E101-B   No.3   pp.924-932
Publication Date: 2018/03/01
Online ISSN: 1745-1345
Type of Manuscript: PAPER
Category: Terrestrial Wireless Communication/Broadcasting Technologies
channel sounding protocol,  DL-MU-MIMO,  IEEE 802.11ax,  wireless LANs,  

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The next generation wireless LAN standard IEEE 802.11ax aims to provide improved throughput performance in dense environments. We have proposed an efficient channel sounding mechanism for DL-MU-MIMO that has been adopted as a new sounding protocol in the 802.11ax standard. In this paper, we evaluate the overhead reduction in the 802.11ax sounding protocol compared with the 802.11ac sounding protocol. Sounding is frequently performed to obtain accurate channel information from the associated stations in order to improve overall system throughput. However, there is a trade-off between accurate channel information and the overhead incurred due to frequent sounding. Therefore, the sounding interval is an important factor that determines system throughput in DL-MU-MIMO transmission. We also evaluate the effect of sounding interval on the system throughput performance using both sounding protocols and provide a comparative analysis of the performance improvement.