IEEE 802.11ac
IEEE 802.11ac is a wireless networking standard in the 802.11 set of protocols, providing high-throughput wireless local area networks on the 5 GHz band. The standard was developed in the IEEE Standards Association from 2008 through 2013 and published in December 2013. The standard has been retroactively labelled as Wi-Fi 5 by Wi-Fi Alliance.
The specification has multi-station throughput of at least 1 gigabit per second and single-link throughput of at least 500 megabits per second. This is accomplished by extending the air-interface concepts embraced by 802.11n: wider RF bandwidth, more MIMO spatial streams, downlink multi-user MIMO, and high-density modulation.
The Wi-Fi Alliance separated the introduction of ac wireless products into two phases, named "Wave 1" and "Wave 2". From mid-2013, the alliance started certifying Wave 1 802.11ac products shipped by manufacturers, based on the IEEE 802.11ac Draft 3.0. Subsequently in year 2016, Wi-Fi Alliance introduced the Wave 2 certification, which includes additional features like MU-MIMO, 160 MHz channel width support, support for more 5 GHz channels, and four spatial streams. It meant Wave 2 products would have higher bandwidth and capacity than Wave 1 products.
New technologies
New technologies introduced with 802.11ac include the following:- Extended channel binding
- * Optional 160 MHz and mandatory 80 MHz channel bandwidth for stations; cf. 40 MHz maximum in 802.11n.
- More MIMO spatial streams
- * Support for up to eight spatial streams
- Downlink multi-user MIMO
- * Multiple STAs, each with one or more antennas, transmit or receive independent data streams simultaneously.
- ** Space-division multiple access : streams not separated by frequency, but instead resolved spatially, analogous to 11n-style MIMO.
- * Downlink MU-MIMO included as an optional mode.
- Modulation
- * 256-QAM, rate 3/4 and 5/6, added as optional modes.
- * Some vendors offer a non-standard 1024-QAM mode, providing 25% higher data rate compared to 256-QAM
- Other elements/features
- * Beamforming with standardized sounding and feedback for compatibility between vendors
- * MAC modifications
- * Coexistence mechanisms for 20, 40, 80, and 160 MHz channels, 11ac and 11a/n devices
- * Adds four new fields to the PPDU header identifying the frame as a very high throughput frame as opposed to 802.11n's high throughput or earlier. The first three fields in the header are readable by legacy devices to allow coexistence
Features
Mandatory
- Borrowed from the 802.11a/802.11g specifications:
- * 800 ns regular guard interval
- * Binary convolutional coding
- * Single spatial stream
- Newly introduced by the 802.11ac specification:
- * 80 MHz channel bandwidths
Optional
- Borrowed from the 802.11n specification:
- * Two to four spatial streams
- * Low-density parity-check code
- * Space–time block coding
- * Transmit beamforming
- * 400 ns short guard interval
- Newly introduced by the 802.11ac specification:
- * five to eight spatial streams
- * 160 MHz channel bandwidths
- * 80+80 MHz channel bonding
- * MCS 8/9
New scenarios and configurations
With the inclusion of USB 3.0 interface, 802.11ac access points and routers can use locally attached storage to provide various services that fully utilize their WLAN capacities, such as video streaming, FTP servers, and personal cloud services. With storage locally attached through USB 2.0, filling the bandwidth made available by 802.11ac was not easily accomplished.
Example configurations
All rates assume 256-QAM, rate 5/6:| Scenario | Typical client form factor | PHY link rate | Aggregate capacity |
| One-antenna AP, one-antenna STA, 80 MHz | Handheld | 433 Mbit/s | 433 Mbit/s |
| Two-antenna AP, two-antenna STA, 80 MHz | Tablet, laptop | 867 Mbit/s | 867 Mbit/s |
| One-antenna AP, one-antenna STA, 160 MHz | Handheld | 867 Mbit/s | 867 Mbit/s |
| Three-antenna AP, three-antenna STA, 80 MHz | Laptop, PC | 1.27 Gbit/s | 1.27 Gbit/s |
| Two-antenna AP, two-antenna STA, 160 MHz | Tablet, laptop | 1.69 Gbit/s | 1.69 Gbit/s |
| Four-antenna AP, four one-antenna STAs, 160 MHz | Handheld | 867 Mbit/s to each STA | 3.39 Gbit/s |
Eight-antenna AP, 160 MHz
| Digital TV, Set-top Box,Tablet, Laptop, PC, Handheld |
| 6.77 Gbit/s |
| Eight-antenna AP, four 2-antenna STAs, 160 MHz | Digital TV, tablet, laptop, PC | 1.69 Gbit/s to each STA | 6.77 Gbit/s |
Wave 1 vs. Wave 2
Wave 2, referring to products introduced in 2016, offers a higher throughput than legacy Wave 1 products, those introduced starting in 2013. The maximum physical layer theoretical rate for Wave 1 is 1.3 Gbit/s, while Wave 2 can reach 2.34 Gbit/s. Wave 2 can therefore achieve 1 Gbit/s even if the real world throughput turns out to be only 50% of the theoretical rate. Wave 2 also supports a higher number of connected devices.Data rates and speed
Several companies are currently offering 802.11ac chipsets with higher modulation rates: MCS-10 and MCS-11, supported by Quantenna and Broadcom. Although technically not part of 802.11ac, these new MCS indices are expected to become official in the 802.11ax standard, the successor to 802.11ac.160 MHz channels, and thus the throughput might be unusable in some countries/regions due to regulatory issues that allocated some frequencies for other purposes.
Advertised Speeds
802.11ac-class device wireless speeds are often advertised as AC followed by a number, that number being the highest link rates in Mbit/s of all the simultaneously-usable radios in the device added up. For example, an AC1900 access point might have 600 Mbit/s capability on its 2.4 GHz radio and 1300 Mbit/s capability on its 5 GHz radio. No single client device could connect and achieve 1900 Mbit/s of throughput, but separate devices each connecting to the 2.4 GHz and 5 GHz radios could achieve combined throughput approaching 1900 Mbit/s. Different possible stream configurations can add up to the same AC number.| Type | 2.4 GHz band Mbit/s | 2.4 GHz band config | 5 GHz band Mbit/s | 5 GHz band config |
| AC450 | - | - | 433 | 1 stream @ MCS 9 |
| AC600 | 150 | 1 stream @ MCS 7 | 433 | 1 stream @ MCS 9 |
| AC750 | 300 | 2 streams @ MCS 7 | 433 | 1 stream @ MCS 9 |
| AC1000 | 300 | 2 streams @ MCS 7 | 650 | 2 streams @ MCS 7 |
| AC1200 | 300 | 2 streams @ MCS 7 | 867 | 2 streams @ MCS 9 |
| AC1300 | 400 | 2 streams @ 256-QAM | 867 | 2 streams @ MCS 9 |
| AC1300 | - | - | 1,300 | 3 streams @ MCS 9 |
| AC1350 | 450 | 3 streams @ MCS 7 | 867 | 2 streams @ MCS 9 |
| AC1450 | 450 | 3 streams @ MCS 7 | 975 | 3 streams @ MCS 7 |
| AC1600 | 300 | 2 streams @ MCS 7 | 1,300 | 3 streams @ MCS 9 |
| AC1700 | 800 | 4 streams @ 256-QAM | 867 | 2 streams @ MCS 9 |
| AC1750 | 450 | 3 streams @ MCS 7 | 1,300 | 3 streams @ MCS 9 |
| AC1900 | 600 | 3 streams @ 256-QAM | 1,300 | 3 streams @ MCS 9 |
| AC2100 | 800 | 4 streams @ 256-QAM | 1,300 | 3 streams @ MCS 9 |
| AC2200 | 450 | 3 streams @ MCS 7 | 1,733 | 4 streams @ MCS 9 |
| AC2300 | 600 | 4 streams @ MCS 7 | 1,625 | 3 streams @ 1024-QAM |
| AC2400 | 600 | 4 streams @ MCS 7 | 1,733 | 4 streams @ MCS 9 |
| AC2600 | 800 | 4 streams @ 256-QAM | 1,733 | 4 streams @ MCS 9 |
| AC2900 | 750 | 3 streams @ 1024-QAM | 2,167 | 4 streams @ 1024-QAM |
| AC3000 | 450 | 3 streams @ MCS 7 | 1,300 + 1,300 | 3 streams @ MCS 9 x 2 |
| AC3150 | 1000 | 4 streams @ 1024-QAM | 2,167 | 4 streams @ 1024-QAM |
| AC3200 | 600 | 3 streams @ 256-QAM | 1,300 + 1,300 | 3 streams @ MCS 9 x 2 |
| AC5000 | 600 | 4 streams @ MCS 7 | 2,167 + 2,167 | 4 streams @ 1024-QAM x 2 |
| AC5300 | 1000 | 4 streams @ 1024-QAM | 2,167 + 2,167 | 4 streams @ 1024-QAM x 2 |
Products
Commercial routers and access points
Quantenna released the first 802.11ac chipset for retail Wi-Fi routers and consumer electronics on November 15, 2011. Redpine Signals released the first low power 802.11ac technology for smartphone application processors on December 14, 2011. On January 5, 2012, Broadcom announced its first 802.11ac Wi-Fi chips and partners and on April 27, 2012, Netgear announced the first Broadcom-enabled router. On May 14, 2012, Buffalo Technology released the world’s first 802.11ac products to market, releasing a wireless router and client bridge adapter. On December 6, 2012, Huawei announced commercial availability of the industry's first enterprise-level 802.11ac Access Point.Motorola Solutions is selling 802.11ac access points including the AP 8232. In April 2014, Hewlett-Packard started selling the HP 560 access point in the controller-based WLAN enterprise market segment.
Commercial laptops
On June 7, 2012, it was reported that Asus had unveiled its ROG G75VX gaming notebook, which would be the first consumer-oriented notebook to be fully compliant with 802.11ac.Apple began implementing 802.11ac starting with the MacBook Air in June 2013, followed by the MacBook Pro and Mac Pro later that year.
, Hewlett-Packard incorporates 802.11ac compliance in laptop computers.
Commercial handsets (partial list)
| Vendor | Model | Release Date | Chipset | Notes |
| HTC | One | March 22, 2013 | BCM4335 | First 802.11ac-enabled handset announced February 19, 2013 |
| Samsung | Galaxy S4 | April 26, 2013 | BCM4335 | |
| Samsung | Galaxy Note 3 | September 25, 2013 | BCM4339 | Subsequent Devices Include 802.11ac |
| LG | LG Nexus 5 | October 2013 | BCM4339 | BCM4339 is the updated version of the BCM4335 |
| Nokia | Lumia 1520 | November 2013 | WCN3680 | First 802.11ac-enabled Windows Phone |
| Nokia | Lumia Icon | February 20, 2014 | WCN3680 | Lumia 930 is Europe version of the same phone, also with 802.11ac |
| HTC | One | March 25, 2014 | WCN3680 | |
| Samsung | Galaxy S5 | April 11, 2014 | BCM4354 | |
| LG | G2 | September 18, 2013 | AWL9581 | |
| LG | G3 | May 23, 2014 | BCM4339 | |
| Amazon.com | Fire Phone | July 25, 2014 | WCN3680 | |
| Samsung | Galaxy S5 Prime/SM-G906S | June 18, 2014 | QCA6174 | |
| Samsung | Galaxy Alpha | September 7, 2014 | E702A7 | |
| Apple | iPhone 6/Plus | September 19, 2014 | BCM4345 | First 802.11ac-enabled iOS devices |
| Motorola | Nexus 6 | October 16, 2014 | BCM4356 | |
| Samsung | Galaxy Note 4 | October 10, 2014 | BCM4358 | |
| Samsung | Galaxy Note 5 | August 21, 2015 | BCM4359 |
Commercial tablets
| Vendor | Model | Release Date | Chipset | Notes |
| Microsoft | Surface Pro 3 | June 20, 2014 | Avastar 88W8897 | 802.11ac-enabled touchscreen computing device |
| Apple | iPad Air 2 | October 24, 2014 | Broadcom BCM4350 | First 802.11ac-enabled iOS tablet device |
| Nexus 9 | November 3, 2014 | Nvidia Tegra K1 | 2x2 MIMO |