802.11ac Channels

What are channels in 802.11ac?

Channels in 802.11ac refer to frequency ranges in the 5 GHz band used for wireless communication, supporting wider bandwidths than 802.11a.

How many channels are available in 802.11ac?

802.11ac supports up to 24 or more channels in the 5 GHz band, depending on regulatory domains and channel widths.

What frequency bands does 802.11ac use?

Primarily the 5 GHz band, with channel bandwidths of 20, 40, 80, and optionally 160 MHz.

What are channel widths in 802.11ac?

802.11ac supports 20 MHz, 40 MHz, 80 MHz, and 160 MHz channel widths for higher throughput.

Why does 802.11ac support wider channels?

Wider channels allow higher data rates by transmitting more data simultaneously.

Are 802.11ac channels overlapping?

Yes, depending on the channel width used, especially for 40 MHz and wider, some channel overlap occurs.

What is Dynamic Frequency Selection (DFS) in 802.11ac?

DFS enables APs to detect radar signals and switch channels to avoid interference in certain 5 GHz bands.

What is Transmit Power Control (TPC) in 802.11ac?

TPC manages transmission power to minimize interference and meet regulatory limits.

How are 802.11ac channels numbered?

Channels are numbered similarly to 802.11a (e.g., 36, 40, 44), but with support for wider bandwidths that combine adjacent channels.

What are typical 802.11ac channel widths and their bandwidths?

  • 20 MHz: standard width

  • 40 MHz: combines two adjacent 20 MHz channels

  • 80 MHz: combines four adjacent 20 MHz channels

  • 160 MHz: combines eight adjacent 20 MHz channels (rarely used)

Why is channel planning important in 802.11ac?

To minimize interference, optimize throughput, and ensure effective use of wider channels.

Are all 5 GHz channels available globally for 802.11ac?

No, availability depends on local regulations, especially for DFS-required channels.

Can 802.11ac devices auto-select channels?

Yes, devices typically scan and select channels to avoid congestion and interference.

What tools help with 802.11ac channel planning?

Spectrum analyzers, Wi-Fi scanners, site survey tools, and WLAN controllers.

How does channel bonding affect interference in 802.11ac?

Channel bonding increases throughput but can cause more interference due to wider channels overlapping.

What happens if two APs use overlapping 80 MHz channels?

They may experience significant co-channel interference, reducing network performance.

Can 802.11ac operate outdoors?

Yes, but subject to regulatory restrictions and often with DFS and TPC enabled.

What is the typical range of 802.11ac?

Similar to 802.11a, usually 30–50 meters indoors, varying with environment and channel width.

Topics in this section,

Channel Number (MHz)

Center Frequency (MHz)

Frequency Range (MHz)

DFS Required

36

5180

5170 – 5190

No

40

5200

5190 – 5210

No

44

5220

5210 – 5230

No

48

5240

5230 – 5250

No

52

5260

5250 – 5270

Yes

56

5280

5270 – 5290

Yes

60

5300

5290 – 5310

Yes

64

5320

5310 – 5330

Yes

100

5500

5490 – 5510

Yes

104

5520

5510 – 5530

Yes

108

5540

5530 – 5550

Yes

112

5560

5550 – 5570

Yes

116

5580

5570 – 5590

Yes

120

5600

5590 – 5610

Yes

124

5620

5610 – 5630

Yes

128

5640

5630 – 5650

Yes

132

5660

5650 – 5670

Yes

136

5680

5670 – 5690

Yes

140

5700

5690 – 5710

Yes

144

5720

5710 – 5730

No

  • channel widths

Band Name

Frequency Range (GHz)

Frequency Range (MHz)

Channels

UNII-1

5.150 – 5.250

5150 – 5250

36, 40, 44, 48

UNII-2 (DFS)

5.250 – 5.350

5250 – 5350

52, 56, 60, 64

UNII-2 Extended (DFS)

5.470 – 5.725

5470 – 5725

100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 144

UNII-3

5.725 – 5.825

5725 – 5825

149, 153, 157, 161, 165

  • Reference links