The 802.11ax Specification Framework delivered by the IEEE High Efficiency WLANs (HEW) Task Group (TG) in early 2016 has specified the uplink multi-user multiple-input multiple-output (UL MU-MIMO) as a key medium access control (MAC) and physical layer (PHY) technique to improve the uplink network throughout in ultra-dense networks loaded with small form factor devices. In this paper, we first show that the phase noise (PN) hardware impairment does not degrade the 802.11ax UL MU-MIMO PHY performance even with differences on the received power among the clients. In the following, we show that the effects of in-phase and quadrature (IQ) imbalance on the UL MU-MIMO PHY performance can be catastrophic, especially when it is used high-cardinality modulation schemes without uplink power control. Finally, we show that a joint implementation of an uplink power control scheme and a time-domain IQ mitigation algorithm can mitigate the dramatic effects on the 802.11ax UL MU-MIMO PHY performance due to IQ imbalance and phase noise hardware impairments in channels where the average power received per client at the access point presents a significant standard deviation.
IEEE 802.11ax: Joint Effects of Power Control and IQ Imbalance Mitigation Schemes on the Performance of OFDM Uplink Multi-User MIMO
2017-09-01
443236 byte
Conference paper
Electronic Resource
English