What is IEEE 802.11ac ? - Explained

IEEE 802.11ac is the successor of 802.11n wireless networking specification released after the 802.11n.

1. Technology

IEEE 802.11ac allows to achieve high speed wireless network transfer by using only 5GHz wireless bands. There were two versions of IEEE 802.11 ac versions got released named Wave 1 and Wave 2 which introduced into the market in 2013 and 2016. Wave 1 version of 802.11 ac can transmit data a speed of 1.3 Gbps theoretically in physical layer and Wave 2 is capable of transmitting data at a speed of 2.34Gbps theoretically in physical layer.


1.1 Bandwidth

To get to such high speed from the 802.11n, there were couple of implementations that IEEE carried out to enhance the transfer technology in 802.11ac. In 802.11ac, the bandwidth between two channels is 80MHz in Wave 1 and 160MHz in wave 2. Which allows the channels to communicate with less interference and maximize the speed. The channel bandwidth in the previous version of 802.11n wireless network standard it was 40MHz bandwidth in-between two channels.


Wave 1Wave 2
Speed1.3Gbps2.34Gbps
Bandwidth Between Channels80MHz160MHz

1.2 MIMO

802.11ac supports MIMO spatial streams up to 8 which is twice as in 802.11n (previous standard). By using multiple MIMO the possibility of serving to multiple clients got to possible which is upto four simultaneous downlink clients.


2. Modulation

There are wide range of modulation techniques used in the 802.11ac wireless networks compared with 802.11 type wireless network standard. The wide range of modulation types enables to operate in multiple ranges and multiple types of maximum speeds.


MCS index
Spatial Streams
Coding Rate
Data Rate in Mbit/s
20 MHz channels40 MHz channels80 MHz channels160 MHz channels
800 ns GI400 ns GI800 ns GI400 ns GI800 ns GI400 ns GI800 ns GI400 ns GI
01BPSK1/26.57.213.51529.332.558.565
11QPSK1/21314.4273058.565117130
21QPSK3/419.521.740.54587.897.5175.5195
3116-QAM1/22628.95460117130234260
4116-QAM3/43943.38190175.5195351390
5164-QAM2/35257.8108120234260468520
6164-QAM3/458.565121.5135263.3292.5526.5585
7164-QAM5/66572.2135150292.5325585650
81256-QAM3/47886.7162180351390702780
91256-QAM5/6N/AN/A180200390433.3780866.7
02BPSK1/21314.4273058.565117130
12QPSK1/22628.95460117130234260
22QPSK3/43943.38190175.5195351390
3216-QAM1/25257.8108120234260468520
4216-QAM3/47886.7162180351390702780
5264-QAM2/3104115.62162404685209361040
6264-QAM3/4117130.3243270526.558510531170
7264-QAM5/6130144.427030058565011701300
82256-QAM3/4156173.332436070278014041560
92256-QAM5/6N/AN/A360400780866.715601733.4
03BPSK1/219.521.740.54587.897.5175.5195
13QPSK1/23943.38190175.5195351390
23QPSK3/458.565121.5135263.3292.5526.5585
3316-QAM1/27886.7162180351390702780
4316-QAM3/4117130243270526.558510531170
5364-QAM2/3156173.332436070278014041560
6364-QAM3/4175.5195364.5405N/AN/A1579.51755
7364-QAM5/6195216.7405450877.597517551950
83256-QAM3/42342604865401053117021062340
93256-QAM5/6260288.95406001170130023402600
04BPSK1/22628.85460117.2130234260
14QPSK1/25257.6108120234260468520
24QPSK3/47886.8162180351.2390702780
3416-QAM1/2104115.62162404685209361040
4416-QAM3/4156173.232436070278014041560
5464-QAM2/3208231.2432480936104018722080
6464-QAM3/42342604865401053.2117021062340
7464-QAM5/6260288.85406001170130023402600
84256-QAM3/4312246.86487201404156028083120
94256-QAM5/6N/AN/A72080015601733.231203466.8

3. 802.11ac Types

There are multiple types of 802.11ac wireless networks available in the market to support more devices possible. Since there are devices which uses 2.4GHz still with 802.11n, most of manufactures used multiple types of 802.11ac and manufactures devices accordingly to make more sales.

Type2.4 GHz band (Mbit/s)config (40 MHz)5 GHz band (Mbit/s)config 80 MHz
AC450--4331 stream @ MCS 9
AC6001501 Stream @ MCS 74331 stream @ MCS 9
AC7503002 Streams @ MCS 74331 stream @ MCS 9
AC10003002 Streams @ MCS 76502 stream @ MCS 7
AC12003002 Streams @ MCS 78672 stream @ MCS 9
AC13004002 Streams @ MCS 98672 stream @ MCS 9
AC1300--1,3003 stream @ MCS 9
AC13504503 Streams @ MCS 78672 stream @ MCS 9
AC14504503 Stream @ MCS 79753 stream @ MCS 7
AC16003002 Stream @ MCS 71,3003 stream @ MCS 9
AC17504503 Stream @ MCS 71,3003 stream @ MCS 9
AC19006003 Stream @ MCS 91,3003 stream @ MCS 9
AC22004503 Stream @ MCS 71,7333 stream @ MCS 9
AC23006004 Stream @ MCS 71,6255 stream @ MCS 7
AC23506004 Stream @ MCS 71,7334 stream @ MCS 9
AC26008004 Stream @ MSC 91,7334 stream @ MCS 9
AC30004503 Stream @ MCS 71,300+1,3003 stream @ MCS 9x2
AC315010004 Stream @ 1024-QAM2,1674 stream @ 1024-QAM
AC32006003 Stream @ MCS 91,300+1,3003 stream @ MCS 9x2
AC50006004 Stream @ MCS 72,167+2,1674 stream @ 1024-QAM x 2
AC530010004 Stream @ 1024-QAM2,167+2,1674 stream @ 1024-QAM x 2