Below are the MCS values for 802.11ac for different channel bandwidth and spacial streams.
Spatial Streams | VHT MCS Index | Modulation | Coding Rate | 20 MHz Data Rates (Mb/s) | 40 MHz Data Rates (Mb/s) | 80 MHz Data Rates (Mb/s) | 160 MHz / 80+80 MHz Data Rates (Mb/s) |
| 800ns GI | 400ns GI | 800ns GI | 400ns GI | 800ns GI | 400ns GI | 800ns GI | 400ns GI |
1 | 0 | BPSK | 1/2 | 6.5 | 7.2 | 13.5 | 15.0 | 29.3 | 32.5 | 58.5 | 65.0 |
| 1 | QPSK | 1/2 | 13.0 | 14.4 | 27.0 | 30.0 | 58.5 | 65.0 | 117.0 | 130.0 |
| 2 | QPSK | 3/4 | 19.5 | 21.7 | 40.5 | 45.0 | 87.8 | 97.5 | 175.5 | 195.0 |
| 3 | 16-QAM | 1/2 | 26.0 | 28.9 | 54.0 | 60.0 | 117.0 | 130.0 | 234.0 | 260.0 |
| 4 | 16-QAM | 3/4 | 39.0 | 43.3 | 81.0 | 90.0 | 175.5 | 195.0 | 351.0 | 390.0 |
| 5 | 64-QAM | 2/3 | 52.0 | 57.8 | 108.0 | 120.0 | 234.0 | 260.0 | 468.0 | 520.0 |
| 6 | 64-QAM | 3/4 | 58.5 | 65.0 | 121.5 | 135.0 | 263.3 | 292.5 | 526.5 | 585.0 |
| 7 | 64-QAM | 5/6 | 65.0 | 72.2 | 135.0 | 150.0 | 292.5 | 325.0 | 585.0 | 650.0 |
| 8 | 256-QAM | 3/4 | 78.0 | 86.7 | 162.0 | 180.0 | 351.0 | 390.0 | 702.0 | 780.0 |
| 9 | 256-QAM | 5/6 | n/a | n/a | 180.0 | 200.0 | 390.0 | 433.3 | 780.0 | 866.7 |
2 | 0 | BPSK | 1/2 | 13.0 | 14.4 | 27.0 | 30.0 | 58.5 | 65.0 | 117.0 | 130.0 |
| 1 | QPSK | 1/2 | 26.0 | 28.9 | 54.0 | 60.0 | 117.0 | 130.0 | 234.0 | 260.0 |
| 2 | QPSK | 3/4 | 39.0 | 43.3 | 81.0 | 90.0 | 175.5 | 195.0 | 351.0 | 390.0 |
| 3 | 16-QAM | 1/2 | 52.0 | 57.8 | 108.0 | 120.0 | 234.0 | 260.0 | 468.0 | 520.0 |
| 4 | 16-QAM | 3/4 | 78.0 | 86.7 | 162.0 | 180.0 | 351.0 | 390.0 | 702.0 | 780.0 |
| 5 | 64-QAM | 2/3 | 104.0 | 115.6 | 216.0 | 240.0 | 468.0 | 520.0 | 936.0 | 1040.0 |
| 6 | 64-QAM | 3/4 | 117.0 | 130.0 | 243.0 | 270.0 | 526.5 | 585.0 | 1053.0 | 1170.0 |
| 7 | 64-QAM | 5/6 | 130.0 | 144.4 | 270.0 | 300.0 | 585.0 | 650.0 | 1170.0 | 1300.0 |
| 8 | 256-QAM | 3/4 | 156.0 | 173.3 | 324.0 | 360.0 | 702.0 | 780.0 | 1404.0 | 1560.0 |
| 9 | 256-QAM | 5/6 | n/a | n/a | 360.0 | 400.0 | 780.0 | 866.7 | 1560.0 | 1733.0 |
3 | 0 | BPSK | 1/2 | 19.5 | 21.7 | 40.5 | 45.0 | 87.8 | 97.5 | 175.5 | 195.0 |
| 1 | QPSK | 1/2 | 39.0 | 43.3 | 81.0 | 90.0 | 175.0 | 195.0 | 351.0 | 390.0 |
| 2 | QPSK | 3/4 | 58.5 | 65.0 | 121.5 | 135.0 | 263.0 | 292.5 | 526.5 | 585.0 |
| 3 | 16-QAM | 1/2 | 78.0 | 86.7 | 162.0 | 180.0 | 351.0 | 390.0 | 702.0 | 780.0 |
| 4 | 16-QAM | 3/4 | 117.0 | 130.0 | 243.0 | 270.0 | 526.5 | 585.0 | 1053.0 | 1170.0 |
| 5 | 64-QAM | 2/3 | 156.0 | 173.3 | 324.0 | 360.0 | 702.0 | 780.0 | 1404.0 | 1560.0 |
| 6 | 64-QAM | 3/4 | 175.5 | 195.0 | 364.5 | 405.0 | n/a | n/a | 1579.5 | 1755.0 |
| 7 | 64-QAM | 5/6 | 195.0 | 216.7 | 405.0 | 450.0 | 877.5 | 975.0 | 1755.0 | 1950.0 |
| 8 | 256-QAM | 3/4 | 234.0 | 260.0 | 486.0 | 540.0 | 1053.0 | 1170.0 | 2106.0 | 2340.0 |
| 9 | 256-QAM | 5/6 | 260.0 | 288.9 | 540.0 | 600.0 | 1170.0 | 1300.0 | n/a | n/a |
4 | 0 | BPSK | 1/2 | 26.0 | 28.9 | 54.0 | 60.0 | 117.0 | 130.0 | 234.0 | 260.0 |
| 1 | QPSK | 1/2 | 52.0 | 57.8 | 108.0 | 120.0 | 234.0 | 260.0 | 468.0 | 520.0 |
| 2 | QPSK | 3/4 | 78.0 | 86.7 | 162.0 | 180.0 | 351.0 | 390.0 | 702.0 | 780.0 |
| 3 | 16-QAM | 1/2 | 104.0 | 115.6 | 216.0 | 240.0 | 468.0 | 520.0 | 936.0 | 1040.0 |
| 4 | 16-QAM | 3/4 | 156.0 | 173.3 | 324.0 | 360.0 | 702.0 | 780.0 | 1404.0 | 1560.0 |
| 5 | 64-QAM | 2/3 | 208.0 | 231.1 | 432.0 | 480.0 | 936.0 | 1040.0 | 1872.0 | 2080.0 |
| 6 | 64-QAM | 3/4 | 234.0 | 260.0 | 486.0 | 540.0 | 1053.0 | 1170.0 | 2106.0 | 2340.0 |
| 7 | 64-QAM | 5/6 | 260.0 | 288.9 | 540.0 | 600.0 | 1170.0 | 1300.0 | 2340.0 | 2600.0 |
| 8 | 256-QAM | 3/4 | 312.0 | 346.7 | 648.0 | 720.0 | 1404.0 | 1560.0 | 2808.0 | 3120.0 |
| 9 | 256-QAM | 5/6 | n/a | n/a | 720.0 | 800.0 | 1560.0 | 1733.3 | 3120.0 | 3466.7 |
5 | 0 | BPSK | 1/2 | 32.5 | 36.1 | 67.5 | 75.0 | 146.3 | 162.5 | 292.5 | 325.0 |
| 1 | QPSK | 1/2 | 65.0 | 72.2 | 135.0 | 150.0 | 292.5 | 325.0 | 585.0 | 650.0 |
| 2 | QPSK | 3/4 | 97.5 | 108.3 | 202.5 | 225.0 | 438.8 | 487.5 | 877.5 | 975.0 |
| 3 | 16-QAM | 1/2 | 130.0 | 144.4 | 270.0 | 300.0 | 585.0 | 650.0 | 1170.0 | 1300.0 |
| 4 | 16-QAM | 3/4 | 195.0 | 216.7 | 405.0 | 450.0 | 877.5 | 975.0 | 1755.0 | 1950.0 |
| 5 | 64-QAM | 2/3 | 260.0 | 288.9 | 540.0 | 600.0 | 1170.0 | 1300.0 | 2340.0 | 2600.0 |
| 6 | 64-QAM | 3/4 | 292.5 | 325.0 | 607.5 | 675.0 | 1316.3 | 1462.5 | 2632.5 | 2925.0 |
| 7 | 64-QAM | 5/6 | 325.0 | 361.1 | 675.0 | 750.0 | 1462.5 | 1625.0 | 2925.0 | 3250.0 |
| 8 | 256-QAM | 3/4 | 390.0 | 433.3 | 810.0 | 900.0 | 1755.0 | 1950.0 | 3510.0 | 3900.0 |
| 9 | 256-QAM | 5/6 | n/a | n/a | 900.0 | 1000.0 | 1950.0 | 2166.7 | 3900.0 | 4333.3 |
6 | 0 | BPSK | 1/2 | 39.0 | 43.3 | 81.0 | 90.0 | 175.5 | 195.0 | 351.0 | 390.0 |
| 1 | QPSK | 1/2 | 78.0 | 86.7 | 162.0 | 180.0 | 351.0 | 390.0 | 702.0 | 780.0 |
| 2 | QPSK | 3/4 | 117.0 | 130.0 | 243.0 | 270.0 | 526.5 | 585.0 | 1053.0 | 1170.0 |
| 3 | 16-QAM | 1/2 | 156.0 | 173.3 | 324.0 | 360.0 | 702.0 | 780.0 | 1404.0 | 1560.0 |
| 4 | 16-QAM | 3/4 | 234.0 | 260.0 | 486.0 | 540.0 | 1053.0 | 1170.0 | 2106.0 | 2340.0 |
| 5 | 64-QAM | 2/3 | 312.0 | 346.7 | 648.0 | 720.0 | 1404.0 | 1560.0 | 2808.0 | 3120.0 |
| 6 | 64-QAM | 3/4 | 351.0 | 390.0 | 729.0 | 810.0 | 1579.0 | 1755.0 | 3159.0 | 3510.0 |
| 7 | 64-QAM | 5/6 | 390.0 | 433.3 | 810.0 | 900.0 | 1755.0 | 1950.0 | 3510.0 | 3900.0 |
| 8 | 256-QAM | 3/4 | 468.0 | 520.0 | 972.0 | 1080.0 | 2106.0 | 2340.0 | 4212.0 | 4680.0 |
| 9 | 256-QAM | 5/6 | 520.0 | 577.8 | 1080.0 | 1200.0 | n/a | n/a | 4680.0 | 5200.0 |
7 | 0 | BPSK | 1/2 | 45.5 | 50.6 | 94.5 | 105.0 | 204.8 | 227.5 | 409.5 | 455.0 |
| 1 | QPSK | 1/2 | 91.0 | 101.1 | 189.0 | 210.0 | 409.5 | 455.0 | 819.0 | 910.0 |
| 2 | QPSK | 3/4 | 136.5 | 151.7 | 283.5 | 315.0 | 614.3 | 682.5 | 1228.5 | 1365.0 |
| 3 | 16-QAM | 1/2 | 182.0 | 202.2 | 378.0 | 420.0 | 819.0 | 910.0 | 1638.0 | 1820.0 |
| 4 | 16-QAM | 3/4 | 273.0 | 303.3 | 567.0 | 630.0 | 1228.5 | 1365.0 | 2457.0 | 2730.0 |
| 5 | 64-QAM | 2/3 | 364.0 | 404.4 | 756.0 | 840.0 | 1638.0 | 1820.0 | 3276.0 | 3640.0 |
| 6 | 64-QAM | 3/4 | 409.5 | 455.0 | 850.5 | 945.0 | n/a | n/a | 3685.5 | 4095.0 |
| 7 | 64-QAM | 5/6 | 455.0 | 505.6 | 945.0 | 1050.0 | 2047.5 | 2275.0 | 4095.0 | 4550.0 |
| 8 | 256-QAM | 3/4 | 546.0 | 606.7 | 1134.0 | 1260.0 | 2457.0 | 2730.0 | 4914.0 | 5460.0 |
| 9 | 256-QAM | 5/6 | n/a | n/a | 1260.0 | 1400.0 | 2730.0 | 3033.3 | 5460.0 | 6066.7 |
8 | 0 | BPSK | 1/2 | 52.0 | 57.8 | 108.0 | 120.0 | 234.0 | 260.0 | 468.0 | 520.0 |
| 1 | QPSK | 1/2 | 104.0 | 115.6 | 216.0 | 240.0 | 468.0 | 520.0 | 936.0 | 1040.0 |
| 2 | QPSK | 3/4 | 156.0 | 173.3 | 324.0 | 360.0 | 702.0 | 780.0 | 1404.0 | 1560.0 |
| 3 | 16-QAM | 1/2 | 208.0 | 231.1 | 432.0 | 480.0 | 936.0 | 1040.0 | 1872.0 | 2080.0 |
| 4 | 16-QAM | 3/4 | 312.0 | 346.7 | 648.0 | 720.0 | 1404.0 | 1560.0 | 2808.0 | 3120.0 |
| 5 | 64-QAM | 2/3 | 416.0 | 462.2 | 864.0 | 960.0 | 1872.0 | 2080.0 | 3744.0 | 4160.0 |
| 6 | 64-QAM | 3/4 | 468.0 | 520.0 | 972.0 | 1080.0 | 2106.0 | 2340.0 | 4212.0 | 4680.0 |
| 7 | 64-QAM | 5/6 | 520.0 | 577.8 | 1080.0 | 1200.0 | 2340.0 | 2600.0 | 4680.0 | 5200.0 |
| 8 | 256-QAM | 3/4 | 624.0 | 693.3 | 1296.0 | 1440.0 | 2808.0 | 3120.0 | 5616.0 | 6240.0 |
| 9 | 256-QAM | 5/6 | n/a | n/a | 1440.0 | 1600.0 | 3120.0 | 3466.7 | 6240.0 | 6933.3 |
Note:
- Modulation and coding set (MCS) is much simpler in 802.11ac than compared to 802.11n.
- 802.11ac has only 10 MCS values irrespective of channel width and spatial streams unlike 802.11n.
- The fields ’n/a’ are some combinations of modulation, coding and channel width that doesn’t work.
- 802.11ac transmit beam forming requires that all spatial streams be modulated identically.
- 802.11ac first wave devices have up to 3SS (spatial streams).
Mandatory and Optional PHY features of 802.11ac
- VHT frame format support - mandatory
- 20, 40 and 80MHz channel support - mandatory
- Single-Stream operation MCS 0-7 - mandatory
- BCC (Binary Convolutional Coding) - mandatory
- 160MHz and 80+80Mhz channel operations - optional
- Single-stream operation MCS 8 and 9 - optional
- 2, 3 and 4 stream support (4SS - wave 2) - optional
- 5-8 stream support - optional (not likely to be implemented anytime soon)
- Short Guard interval (400ns) - optional (though optional but is widely supported)
- LDPC (Low density parity check code) - optional
- STBC (Space time block coding) - optional
- TxBF (transmit beamforming) - optional
- Support for MCS 8 and 9 (256 QAM) - optional
Guard Interval: it is the space between symbols being transmitted. The guard interval is there to eliminate inter-symbol interference which is referred to as ISI. ISI happens when echoes or reflections from one symbol interfere with another. Adding time between symbol transmission allows these echoes and reflections to settle in before the next symbol is transmitted. Default value for guard interval in 802.11 is 800 ns.
