802.11ac采纳的新技术

• Extended channel binding
  • Mandatory 80 MHz channel bandwidth for stations (vs. 40 MHz maximum in 802.11n), 160 MHz available optionally   (必须支持80MHz的频道宽度，可以选择支持160MHz)
• More MIMO spatial streams   (更多的空分)
  • Support for up to eight spatial streams (vs. four in 802.11n)   （支持多达8个空分）
• Multi-user MIMO (MU-MIMO)   （多用户MIMO）
  • Multiple STAs, each with one or more antennas, transmit or receive independent data streams simultaneously  （多个用户同时发送或接收数据）
    • “Space Division Multiple Access” (SDMA): streams not separated by frequency, but instead resolved spatially, analogous to 11n-style MIMO  （SDMA空分技术，不是分频）
  • Downlink MU-MIMO (one transmitting device, multiple receiving devices) included as an optional mode  （下行链路多用户：一个发送设备，多个接收设备）
• Modulation
  • 256-QAM, rate 3/4 and 5/6, added as optional modes (vs. 64-QAM, rate 5/6 maximum in 802.11n)  （使用256QAM调制解调，编码率3/4, 5/6）

• Other elements/features （其他特性）
  • Beamforming with standardized sounding and feedback for compatibility between vendors (non-standard in 802.11n made it hard for beamforming to work effectively between different vendor products)   （标准化的波束赋形技术，使不同厂商设备互相兼容）
  • MAC modifications (mostly to support above changes)    （MAC层的修改，以期支持以上特性）
  • Coexistence mechanisms for 20/40/80/160 MHz channels, 11ac and 11a/n devices     （多频道共存，和11a/n设备共存）