I. Introduction

II. A Quick Glance at IEEE 802.11ax
A. Key Technologies for 802.11ax
B. Standardization Process

III. PHY Enhancements
A. PHY Enhancements Overview
B. New Modulation Technologies
C. New Coding Strategy
D. New Subcarrier Division Mechanism
E. Enhanced Multiple Access
F. Enhancement for Channel Bonding
G. PPDU

IV. MU-MAC Enhancements
A. Introduction of MU-MAC in WLANs
B. UL OFDMA Based Random Access Rule
C. UL Hybrid MU-MAC
D. Downlink MU-MAC
E. Cascaded MU-MAC
F. Overall Access Scenes for IEEE 802.11ax

V. Spatial Reuse Enhancements
A. Introduction to Spatial Reuse Enhancements
B. SR Framework in IEEE 802.11ax
C. BSS Color Mechanism
D. Enhanced NAV Mechanism
E. OBSS_PD Based SR Mechanism
F. SRP Based SR Mechanism

VI. Other Technologies
A. TWT and Service Time Reservation
B. Power Efficiency Enhancements

VII. Simulation Platform and Performance Evaluation
A. Overview of Simulation Platform for WLANs
B. Introduction of Proposed SLISP
C. Performance Evaluation for Single BSS
D. Performance Evaluation for High-Dense Deployed Multiple BSS
E. Conclusion and Discussion

VIII. Conclusions and Perspectives
A. Conclusions
B. Future Perspectives of Beyond IEEE 802.11ax