IEEE 802.11ac
Encyclopedia
IEEE 802.11ac is a wireless computer network
ing standard of 802.11 currently under development which will provide high throughput Wireless Local Area Networks (WLAN) below 6 GHz (what is commonly known as the 5 GHz band).
Theoretically, this specification will enable multi-station WLAN throughput of at least 1 Gigabit per second and a maximum single link throughput of at least 500 megabit per second (500 Mbit/s). This is accomplished by extending the air interface concepts embraced by 802.11n: wider RF bandwidth (up to 160 MHz), more MIMO
spatial streams (up to 8), multi-user MIMO
, and high-density modulation (up to 256 QAM
).
On January 20, 2011, the Initial Technical Specification Draft 0.1 was confirmed by IEEE 802.11 TGac.
Standard finalization is anticipated in late 2012, with final 802.11 Working Group approval in late 2013. According to a study, devices with the 802.11ac specification are expected to become common by 2015 with an estimated 1 billion spread around the world.
As of September 2011, there are no consumer devices implementing the draft specification.
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
ing standard of 802.11 currently under development which will provide high throughput Wireless Local Area Networks (WLAN) below 6 GHz (what is commonly known as the 5 GHz band).
Theoretically, this specification will enable multi-station WLAN throughput of at least 1 Gigabit per second and a maximum single link throughput of at least 500 megabit per second (500 Mbit/s). This is accomplished by extending the air interface concepts embraced by 802.11n: wider RF bandwidth (up to 160 MHz), more MIMO
MIMO
In radio, multiple-input and multiple-output, or MIMO , is the use of multiple antennas at both the transmitter and receiver to improve communication performance. It is one of several forms of smart antenna technology...
spatial streams (up to 8), multi-user MIMO
Multi-user MIMO
In radio, multi-user MIMO is a set of advanced MIMO, multiple-input and multiple-output , technologies that exploit the availability of multiple independent radio terminals in order to enhance the communication capabilities of each individual terminal...
, and high-density modulation (up to 256 QAM
Quadrature amplitude modulation
Quadrature amplitude modulation is both an analog and a digital modulation scheme. It conveys two analog message signals, or two digital bit streams, by changing the amplitudes of two carrier waves, using the amplitude-shift keying digital modulation scheme or amplitude modulation analog...
).
On January 20, 2011, the Initial Technical Specification Draft 0.1 was confirmed by IEEE 802.11 TGac.
Standard finalization is anticipated in late 2012, with final 802.11 Working Group approval in late 2013. According to a study, devices with the 802.11ac specification are expected to become common by 2015 with an estimated 1 billion spread around the world.
As of September 2011, there are no consumer devices implementing the draft specification.
New technologies
- Wider channel bandwidths
- 80 MHz and 160 MHz channel bandwidths (vs. 40 MHz maximum in 802.11n)
- 80 MHz mandatory for stations (STAs), 160 MHz optional
- 80 MHz and 160 MHz channel bandwidths (vs. 40 MHz maximum in 802.11n)
- More MIMOMIMOIn radio, multiple-input and multiple-output, or MIMO , is the use of multiple antennas at both the transmitter and receiver to improve communication performance. It is one of several forms of smart antenna technology...
spatial streams- Support for up to 8 spatial streams (vs. 4 in 802.11n)
- Multi-user MIMOMulti-user MIMOIn radio, multi-user MIMO is a set of advanced MIMO, multiple-input and multiple-output , technologies that exploit the availability of multiple independent radio terminals in order to enhance the communication capabilities of each individual terminal...
(MU-MIMO)- Multiple STAs, each with one or more antennas, transmit or receive independent data streams simultaneously
- “Space Division Multiple Access” (SDMASpace-division multiple accessSpace-Division Multiple Access is a channel access method based on creating parallel spatial pipes next to higher capacity pipes through spatial multiplexing and/or diversity, by which it is able to offer superior performance in radio multiple access communication systems...
): streams not separated by frequency, but instead resolved spatially, analogous to 11n-style MIMO
- “Space Division Multiple Access” (SDMA
- Downlink MU-MIMOMulti-user MIMOIn radio, multi-user MIMO is a set of advanced MIMO, multiple-input and multiple-output , technologies that exploit the availability of multiple independent radio terminals in order to enhance the communication capabilities of each individual terminal...
(one transmitting device, multiple receiving devices) included as an optional mode
- Multiple STAs, each with one or more antennas, transmit or receive independent data streams simultaneously
- Modulation
- 256-QAMQuadrature amplitude modulationQuadrature amplitude modulation is both an analog and a digital modulation scheme. It conveys two analog message signals, or two digital bit streams, by changing the amplitudes of two carrier waves, using the amplitude-shift keying digital modulation scheme or amplitude modulation analog...
, rate 3/4 and 5/6, added as optional modes (vs. 64-QAMQuadrature amplitude modulationQuadrature amplitude modulation is both an analog and a digital modulation scheme. It conveys two analog message signals, or two digital bit streams, by changing the amplitudes of two carrier waves, using the amplitude-shift keying digital modulation scheme or amplitude modulation analog...
, rate 5/6 maximum in 802.11n)
- 256-QAM
- Other elements/features
- Single sounding and feedback format for beamforming (vs. multiple in 802.11n)
- MAC modifications (mostly to support above changes)
- Coexistence mechanisms for 20/40/80/160 MHz channels, 11ac and 11a/n devices
New scenarios and configurations
The single-link and multi-station enhancements supported by 802.11ac enable several new WLAN usage scenarios, such as simultaneous streaming of HD video to multiple clients throughout the home, rapid synchronization and backup of large data files, wireless display, large campus/auditorium deployments, and manufacturing floor automation.Example configurations
All rates assume 256-QAM, rate 5/6:| Scenario | Typical Client Form Factor | PHY Link Rate | Aggregate Capacity |
|---|---|---|---|
| 1-antenna AP Wireless access point In computer networking, a wireless access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, Bluetooth or related standards... , 1-antenna STA, 80MHz |
Handheld | 433 Mbit/s | 433 Mbit/s |
| 2-antenna AP Wireless access point In computer networking, a wireless access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, Bluetooth or related standards... , 2-antenna STA, 80MHz |
Tablet, Laptop | 867 Mbit/s | 867 Mbit/s |
| 1-antenna AP Wireless access point In computer networking, a wireless access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, Bluetooth or related standards... , 1-antenna STA, 160MHz |
Handheld | 867 Mbit/s | 867 Mbit/s |
| 2-antenna AP Wireless access point In computer networking, a wireless access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, Bluetooth or related standards... , 2-antenna STA, 160MHz |
Tablet, Laptop | 1.73 Gbit/s | 1.73 Gbit/s |
| 4-antenna AP Wireless access point In computer networking, a wireless access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, Bluetooth or related standards... , 4 1-antenna STAs, 160MHz (MU-MIMO Multi-user MIMO In radio, multi-user MIMO is a set of advanced MIMO, multiple-input and multiple-output , technologies that exploit the availability of multiple independent radio terminals in order to enhance the communication capabilities of each individual terminal... ) |
Handheld | 867 Mbit/s to each STA | 3.47 Gbit/s |
| 8-antenna AP Wireless access point In computer networking, a wireless access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, Bluetooth or related standards... , 160MHz (MU-MIMO Multi-user MIMO In radio, multi-user MIMO is a set of advanced MIMO, multiple-input and multiple-output , technologies that exploit the availability of multiple independent radio terminals in order to enhance the communication capabilities of each individual terminal... ) -- 1 4-antenna STA -- 1 2-antenna STA -- 2 1-antenna STAs |
Digital TV, Set-top Box, Tablet, Laptop, PC, Handheld |
3.47 Gbit/s to 4-antenna STA 1.73 Gbit/s to 2-antenna STA 867 Mbit/s to each 1-antenna STA |
6.93 Gbit/s |
| 8-antenna AP Wireless access point In computer networking, a wireless access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, Bluetooth or related standards... , 4 2-antenna STAs, 160MHz (MU-MIMO Multi-user MIMO In radio, multi-user MIMO is a set of advanced MIMO, multiple-input and multiple-output , technologies that exploit the availability of multiple independent radio terminals in order to enhance the communication capabilities of each individual terminal... ) |
Digital TV, Tablet, Laptop, PC | 1.73 Gbit/s to each STA | 6.93 Gbit/s |