IEEE 802.11ac: The Next Evolution of Wi-Fi

IEEE has been working on the next evolution of Wi-Fi—called 802.11ac—to push throughput rates beyond the Gigabit-per-second barrier. The 802.11ac Draft 2.0 specification was released in February 2012. 802.11ac mandates operation in the 5 GHz band where there is relatively less interference and more channels are available compared to the 2.4 GHz band used by existing 802.11 a/b/g/n standards. 802.11ac uses wider bandwidth and up to eight spatial streams to achieve a maximum of 6.93 Gigabits-per-second theoretical throughput. 802.11ac also enables new use cases such as multiple HD video streams throughout the home by improving spectral efficiency.

With an ever-increasing number of Wi-Fi-enabled devices present in a typical home (i.e., higher attach rates) 802.11ac is the ideal evolution in the Wi-Fi standard, using advanced techniques that leverage spectral efficiency and higher bandwidth and ultimately providing needed performance gains.

802.11ac is fully backward compatible with 802.11n. It operates in the 5 GHz band and uses up to 160 MHz bandwidth. In addition, it uses spatial division multiple access (SDMA) techniques to enable multi-user MIMO or MU-MIMO. Operating in 5 GHz band reduces interference and antenna size requirement, allowing for smaller antenna sizes for portable devices. Leveraging wider bandwidths (20, 40, 80, and optional 160 MHz) increases data rates.

Qualcomm has demonstrated MU-MIMO PHY operation running on a prototype 802.11n module with a MU-MIMO software overlay. Results showed a 3x improvement in PHY rates compared to 802.11n. This is shown in this video.

All of the above features have been standardized in IEEE under 802.11ac which are explained in this white paper. Qualcomm Research, along with other participants, is leading the standardization efforts.