A recent technical paper from Cisco covers all salient points surrounding 802.11ac, the fifth generation of Wi-Fi. The paper includes a full technology explanation and overview, covering drivers for 802.11ac and differences between the new standard and the previous 802.11n Wi-Fi spec.
Other sections of the paper cover topics including: standards-based beamforming; RTS/CTS with bandwidth indication; channelization and 80+80 MHz; MU-MIMO; radio resource management and WIPS effects; compatibility; and when to upgrade to 802.11ac.
View/Download the technical paper here.