IEEE 802.11 ax is a type of WLAN in the IEEE 802.11 set of types of WLANs. It is designed to improve overall spectral efficiency especially in dense deployment scenarios. It is still in a very early stage of development, but is predicted to have a top speed of around 10 Gb/s (as tested by Huawei), it works in 2.4 and/or 5 GHz, in addition to MIMO and MU-MIMO it introduces OFDMA technique to improve spectral efficiency and also higher order 1024 QAM modulation support for better throughputs. Though the nominal data rate is just 37% higher comparing with 802.11ac, the new amendment will allow achieving 4X increase of user throughput thanks to more efficient spectrum usage. It is due to be publicly released in 2019.
