WLAN Frequency Bands and Channels for IEEE 802.11 WiFi Networks

The IEEE 802.11 standards, which define WiFi protocols, operate across multiple frequency bands, each divided into channels with varying regulations by country. These bands include 2.4 GHz, 3.6 GHz, 4.9 GHz, 5 GHz, 5.9 GHz, 60 GHz, and 900 MHz. Regulations govern allowable channels, users, and power levels, with some bands requiring Dynamic Frequency Selection (DFS) and Transmit Power Control (TPC) to avoid interference with radar and other systems. This summary outlines key frequency bands, channel assignments, and regulatory considerations.

2.4 GHz Band (802.11b/g/n/ax)

The 2.4 GHz band, spanning 2.400–2.483.5 MHz (or 2.400–2.497 GHz in Japan), is widely used for 802.11b/g/n/ax. It includes 14 channels spaced 5 MHz apart, with channel 14 having a 12 MHz gap. Channels are 20 MHz wide, with 40 MHz bonding available in 802.11n/ax. Overlap between adjacent channels causes interference, so non-overlapping channels (e.g. 1, 6, 11) are recommended, requiring 16.25–22 MHz separation for OFDM (802.11g/n/ax).

Interference Concerns: 802.11b uses DSSS/CCK, requiring 22 MHz separation and -50 dBr attenuation between transmitters to avoid interference. OFDM-based 802.11g/n/ax requires 16.25–22 MHz separation. A 2 MHz guard band helps attenuate edge-channel interference.

Regulatory Notes:

• Most countries allow channels 1–13; channel 14 is restricted to 802.11b (DSSS/CCK) in Japan.
• In the USA, channels 12–13 are permitted under low-power conditions (FCC Part 15, 2.400–2.483.5 MHz). Channel 14 is forbidden to avoid interference with the restricted 2.483.5–2.500 MHz band.
• In Canada, channel 12 is power-limited; channels 1–11 are at full power.

2.4 GHz Channel Table

3.6 GHz Band (802.11y)

The 3.6 GHz band (3655–3695 MHz) is a licensed band in the USA, primarily for 802.11y, supporting public safety and private networks. It offers a 40 MHz band, divisible into 5 MHz, 10 MHz, or 20 MHz channels.

3.6 GHz Channel Table

Note: Licensed operation; consult local regulations for power levels and usage.

4.9 GHz Band (802.11y)

The 4.9 GHz band (4940–4990 MHz) is reserved for public safety in the USA, supporting 802.11y. It provides 50 MHz of spectrum with two non-overlapping 20 MHz channels (22 and 26).

4.9 GHz Channel Table

Note: Restricted to public safety entities; consult local regulations.

5 GHz Band (802.11a/h/j/n/ac/ax)

The 5 GHz band (5.15–5.825 GHz) is used by 802.11a/h/j/n/ac/ax, offering 20, 40, 80, and 160 MHz channels. It is divided into U-NII bands (1, 2A, 2C, 3) with varying regulations:

• U-NII-1 (5.15–5.25 GHz): Primarily indoor use; no DFS/TPC required in most regions.
• U-NII-2A (5.25–5.35 GHz): Requires DFS/TPC in most regions to avoid radar interference.
• U-NII-2C (5.47–5.725 GHz): Requires DFS/TPC; expanded channel availability post-2015 FCC rules.
• U-NII-3 (5.725–5.825 GHz): Outdoor/indoor use; no DFS in some regions.

Regulatory Notes:

• USA: DFS/TPC required for 5.25–5.35 GHz and 5.47–5.725 GHz (FCC “New Rules” since June 2016, enabling 80/160 MHz channels).
• Europe: 5.15–5.35 GHz indoor only; 5.47–5.725 GHz requires DFS/TPC (EN 301 893 v1.8.1).
• Japan: Channels 34, 38, 42, 46 expired in 2012; 10 MHz channels (7–11) available.
• China: Expanded to include 5.15–5.35 GHz with DFS/TPC (MIIT, 2012).
• Singapore: DFS/TPC required for 5.25–5.35 GHz above 100 mW; 5.15–5.35 GHz indoor only.
• Brazil: DFS required for 5.47–5.725 GHz; TPC optional for 5.15–5.725 GHz.
• Australia/New Zealand: DFS/TPC required for 5.25–5.35 GHz and 5.47–5.725 GHz (AS/NZS 4268).

5 GHz Channel Table (Selected Channels)

Note: DFS/TPC requirements vary; consult local regulations for power limits and usage restrictions.

5.9 GHz Band (802.11p)

The 5.9 GHz band (5.850–5.925 GHz) is a licensed ITS band for 802.11p (WAVE), used for vehicular communication systems. Channels are 10 MHz wide, with some regions supporting 20 MHz.

5.9 GHz Channel Table

60 GHz Band (802.11ad/ay)

The 60 GHz band (57–71 GHz) is used by 802.11ad/ay (WiGig), offering high-throughput, short-range communication with 2.16 GHz channels. Four channels are defined globally, with additional channels in some regions (e.g. USA, Europe).

60 GHz Channel Table

900 MHz Band (802.11ah)

The 900 MHz band (e.g. 902–928 MHz in the USA) is used by 802.11ah for low-power, long-range IoT applications. Channel widths vary (1, 2, 4, 8, 16 MHz) depending on region.

900 MHz Channel Example (USA)

Note: Channel assignments vary by region; consult local regulations.

Summary

IEEE 802.11 Wi-Fi operates across multiple frequency bands, each with specific channel plans and regulatory requirements. The 2.4 GHz band offers 14 channels but requires careful channel selection to avoid interference. The 3.6 GHz and 4.9 GHz bands are licensed for specific uses in the USA. The 5 GHz band provides wider channels (up to 160 MHz) with DFS/TPC requirements in many regions. The 5.9 GHz band supports vehicular communications, while 60 GHz and 900 MHz bands cater to high-throughput and IoT applications, respectively. Network operators must verify local regulations for allowable channels and power levels, as these vary globally and may change.

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