  The new IEEE 802.11 standard, IEEE 802.11ax, has the challenging goal of
serving more Uplink (UL) traffic and users as compared with his predecessor
IEEE 802.11ac, en- abling consistent and reliable streams of data (average
throughput) per station. In this paper we explore several new IEEE 802.11ax UL
scheduling mechanisms and compare between the maximum throughputs of
unidirectional UDP Multi Users (MU) triadic. The evaluation is conducted based
on Multiple-Input-Multiple-Output (MIMO) and Orthogonal Frequency Division
Multiple Acceess (OFDMA) transmission multiplexing format in IEEE 802.11ax vs.
the CSMA/CA MAC in IEEE 802.11ac in the Single User (SU) and MU modes for 1, 4,
8, 16, 32 and 64 stations scenario in reliable and unreliable channels. The
comparison is conducted as a function of the Modulation and Coding Schemes
(MCS) in use. In IEEE 802.11ax we consider two new flavors of ac- knowledgment
operation settings, where the maximum acknowledgment windows are 64 or 256
respectively. In SU scenario IEEE 802.11ax throughputs outperform IEEE 802.11ac
by about 64% and 85% in reliable and unreliable channels respectively. In
MU-MIMO scenario IEEE 802.11ax throughputs outperform IEEE 802.11ac by up to
263% and 270% in reliable and unreliable channels respectively. Also, as the
number of stations increases, the advantage of IEEE 802.11ax in terms of the
access delay also increases.
