802.11u Channels

What is 802.11u?

802.11u is an amendment to the Wi-Fi standard that enables enhanced interworking with external networks like cellular or public hotspots.

Does 802.11u define new wireless channels?

No, 802.11u uses existing Wi-Fi channels in the 2.4 GHz, 5 GHz, and newer 6 GHz bands.

How does 802.11u interact with Wi-Fi channels?

It helps devices discover and select networks but depends on the underlying Wi-Fi standard for channel use.

What frequency bands can 802.11u operate on?

It can operate on any Wi-Fi band supported by the device, including 2.4 GHz, 5 GHz, and 6 GHz bands.

Can 802.11u help with roaming across channels?

Yes, 802.11u assists fast network discovery and selection, aiding seamless roaming even when switching channels.

What role do channels play in 802.11u network discovery?

Devices scan available channels to find access points that support 802.11u capabilities.

Is Dynamic Frequency Selection (DFS) required by 802.11u?

DFS requirements depend on the Wi-Fi band and regulatory rules, not directly on 802.11u.

How does 802.11u affect channel interference management?

It does not directly manage interference but better network selection helps devices avoid congested channels.

Can 802.11u work with 20 MHz, 40 MHz, or wider channels?

Yes, it works with whatever channel widths the underlying Wi-Fi standard supports.

Does 802.11u require specific channels for operation?

No, 802.11u operates over any legal Wi-Fi channels in the device’s region.

How do regulatory domains impact 802.11u channel use?

Local regulations control which channels are available; 802.11u complies with these when selecting networks.

Can 802.11u improve performance in crowded channels?

Indirectly, by helping devices choose less congested networks on different channels.

What information do devices get about channels via 802.11u?

Devices learn about network capabilities but not direct control over channels from 802.11u itself.

Does 802.11u influence transmit power or channel width?

No, these parameters are managed by lower-layer Wi-Fi standards, not 802.11u.

What tools assist with channel planning for 802.11u networks?

Standard Wi-Fi tools like spectrum analyzers and site surveys are used for channel planning.

Does 802.11u support 6 GHz Wi-Fi channels?

Yes, it can operate over any Wi-Fi channels supported by the device, including 6 GHz.

How does channel selection affect 802.11u’s interworking features?

Efficient channel use ensures reliable connectivity, which improves the interworking experience.

Can devices using 802.11u auto-select channels?

Yes, channel auto-selection is a function of the Wi-Fi radio, not 802.11u directly.

Does 802.11u affect the physical layer channel characteristics?

No, 802.11u operates at a higher protocol layer focused on network discovery and selection.

Topics in this section,

Channel Number (MHz)

Center Frequency (MHz)

Frequency Range

DFS Required

1

2412

2401 – 2423

No

2

2417

2406 – 2428

No

3

2422

2411 – 2433

No

4

2427

2416 – 2438

No

5

2432

2421 – 2443

No

6

2437

2426 – 2448

No

7

2442

2431 – 2453

No

8

2447

2436 – 2458

No

9

2452

2441 – 2463

No

10

2457

2446 – 2468

No

11

2462

2451 – 2473

No

12

2467

2456 – 2478

No (region dependent)

13

2472

2461 – 2483

No (region dependent)

14

2484

2473 – 2495

No (Japan only)

Channel Number (MHz)

Center Frequency (MHz)

Frequency Range

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

Yes

149

5745

5735 – 5755

No

153

5765

5755 – 5775

No

157

5785

5775 – 5795

No

161

5805

5795 – 5815

No

165

5825

5815 – 5835

No

  • channel widths

Band Name

Frequency Range (GHz)

Frequency Range (MHz)

Channels

2.4 GHz Band

2.400 – 2.485

2400 – 2485

1 – 14 (region dependent)

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