WiFi is a mature technology that continues to evolve offering new enhancements like higher speed, extended range and reduced power consumption. These enhancements will help satisfying the increasing demand in mobile data. The new amendment to the IEEE 802.11 standard – 802.11ac – will offer three times the speed, twice the range, and longer battery life when compared with 802.11n. The main goal of the new 802.11ac standard is to significantly increase the aggregate and user throughputs in WLANs. The target aggregate throughput is above 1 Gbps and the target user throughput is above 500 Mbps. Existing 802.11 technologies operate in the 2.4 GHz band (802.11b/g/n) and the 5 GHz band (802.11a/n). 802.11ac operates only in the 5GHz band, but supports backward compatibility with other 802.11 technologies operating in the same band (802.11a/n). To achieve these target throughputs, 802.11ac relies on a number of improvements in both the PHY and the MAC layers. The PHY improvements include these new features:
- Increased bandwidth per channel (80 MHz mandatory, 160 MHz and 80+80 MHz optional)
- Increased number of spatial streams (up to 8)
- Higher‐order modulation (256 QAM)
- Multi‐User Multiple Input Multiple Output (MU‐MIMO)
The Media Access Control (MAC) layer includes many of the improvements that were first introduced in 802.11n. One notable enhancement is the larger maximum size (1 MB) of aggregate MAC Protocol Data Units (MPDUs), resulting in higher throughputs thanks to reduced overhead.
802.11ac will offer higher speed, extended range and lower power consumption compared with previous generations. It is anticipated we will see that a rapid adoption and very strong industry support for integrated 802.11n/ac radios in a relatively short time.
The FCC recent notice of proposed rulemaking (NPRM) brings additional 195 MHz to be used for WiFi in the 5 GHz band. This will allow more wideband channels (80/160 MHz) and higher capacity.