Wireless LAN / Wi-Fi WiFi frequency bands UHF (300 MHz - 3000 MHz) and higher - Super High Frequency so UHF/SHF
900 MHz (802.11ah)
802.11ah operates in sub-gigahertz unlicensed bands. While it is referred to as "900 MHz" it actually covers various bands including the 700 MHz band, 800 MHz band (including the European Short Range Device - SRD - SRD860 band allocations) and 900 MHz band. Each world region supports different sub-bands, and the channels number depends on the starting frequency of the sub-band it belongs to. Thus, there is no global channels numbering plan, and the channels numbers are incompatible between world regions (and even between sub-bands of a same world region).
It is important to note that the 902-928 MHz band is allocated to numerous other services, including 33cm amateur radio band, cordless telephone systems, vehicle transponder systems, train and railroad telemetry systems and unlicensed frequency hopping spread spectrum (FHSS) business radio systems as well as being an ISM (FCC Rules Part 18).
The following sub-bands are defined in the 802.11ah specifications:
|Australia||915–920 MHz||1, 2, 4|
|920–928 MHz||1, 2, 4, 8|
|779–787 MHz||1, 2, 4, 8|
|Europe||863–868 MHz||1, 2|
|Korea||917.5–923.5 MHz||1, 2, 4|
|915–924 MHz||1, 2, 4, 8|
|924–928 MHz||1, 2, 4|
|Singapore||866–869 MHz||1, 2|
|920–925 MHz||1, 2, 4|
|Taiwan||839–848.5 MHz||1, 2, 4|
|United States||902–904 MHz||1, 2|
|904–920 MHz||1, 2, 4, 8, 16|
|920–928 MHz||1, 2, 4, 8|
2.4 GHz (802.11b/g/n/ax)
Includes 802.11b, 802.11g, 802.11n, 802.11ax wireless specification. Look at 2.45 GHz or 2450 MHz center frequency on a SDR waterfall or spectrum analyzer and you'll see the insanity.
The 2.4 GHz band is extremely congested in many areas with numerous devices using this frequency band, including high power ISM devices, cordless telephones, Bluetooth, analog and digital wireless video link systems (video senders), baby monitors, wireless intercoms, wireless microphone systems, short-range data and audio/video link systems of various power output levels and bandwidths...along with dozens of other uses.
The availability of the 5 GHz band for WLAN / WiFi applications, the 900 MHz band and/or the 5.8 GHz band for cordless telephones and the 1.9 GHz / 1900 MHz DECT band for cordless telephones, wireless intercoms (many use FRS frequencies at considerably lower power levels), baby monitors, business cordless phone PBX systems, etc. means that some of the interference on 2.4 GHz could be eliminated with careful planning and frequency/channel use coordination among local users.
|Channel||F0 (MHz)|| Frequency|
Nations apply their own RF emission regulations to the allowable channels, allowed users and maximum power levels within these frequency ranges. Network operators should consult their local authorities as these regulations may be out of date as they are subject to change at any time. Most of the world will allow the first thirteen channels in the spectrum.
To guarantee no interference in any circumstances the Wi‑Fi protocol requires 16.25 to 22 MHz of channel separation. The remaining 2 MHz gap is used as a guard band to allow sufficient attenuation along the edge of the band. This guardband is mainly used to accommodate older routers with modem chipsets prone to full channel occupancy, as most modern Wi‑Fi modems are not prone to excessive channel occupancy. In 22 MHz channel width situations, there is 3 MHz free/unused spectrum between NON-overlapping channels, this is not called "guard band" but channel spacing.
While overlapping frequencies can be configured at a location and will usually work, it can cause interference resulting in slowdowns, sometimes severe, particularly in heavy use. Certain subsets of frequencies can be used simultaneously at any one location without interference (see diagrams for typical allocations):
However, the exact spacing required when the transmitters are not colocated depends on the protocol, the data rate selected, the distances and the electromagnetic environment where the equipment is used.
The overall effect is that if there is considerable overlap between adjacent channels transmitters they will often interfere with each other. However, using every fourth or fifth channel by leaving three or four channels clear between used channels can cause less interference than sharing channels.
3.65 GHz (802.11y)
Except where noted, all information taken from Annex J of IEEE 802.11y-2008
This range is documented as only being allowed as a licensed band in the United States. 3.6 GHz band license required.
A 40 MHz band is available from 3655 to 3695 MHz. It may be divided into eight 5 MHz channels, four 10 MHz channels, or two 20 MHz channels, as follows:
|5 MHz||10 MHz||20 MHz|
5 GHz (802.11a|a/802.11h|h/802.11j|j/802.11n|n/802.11ac|ac/IEEE 802.11ax|ax
|Template:Yes||MAY be used without restrictions.|
|Template:No||SHOULD NOT be used.|
|Template:Yes||MUST be used indoor only.|
|Template:Yes||MUST be used with DFS regardless indoor or outdoor.|
|Template:Yes||MUST comply with SRD requirements regardless indoor or outdoor.|
|Template:Yes||MUST be used with DFS and indoor only.|
|Template:Yes||MUST be used with TPC and indoor only.|
|Template:Yes||MUST be used with DFS and TPC.|
|Template:Yes||MUST be used with DFS, TPC and comply with SRD requirements.|
|Template:Yes||MUST be used with DFS, TPC and indoor only.|
|Template:Nonfree||MUST be used only after registration.|
|Template:Unknown||Information not available or defined.|
In 2007, the Federal Communications Commission began requiring that devices operating in the bands of 5.250–5.350 GHz and 5.470–5.725 GHz must employ dynamic frequency selection (DFS) and automatic transmit power control (TPC) capabilities.
This is to avoid interference with weather-radar and military applications. In 2010, the FCC further clarified the use of channels in the 5.470–5.725 GHz band to avoid interference with Terminal Doppler Weather Radar (TDWR) a type of weather radar system that operates in the same frequency band. On 10 June 2015, the FCC approved a "new" ruleset for 5 GHz device operation (called the "New Rules"), which adds 160 and 80 MHz channel identifiers, and re-enables previously prohibited DFS channels.
Germany requires DFS and TPC capabilities on 5.250–5.350 GHz and 5.470–5.725 GHz as well; in addition, the frequency range 5.150–5.350 GHz is allowed only for indoor use, leaving only 5.470–5.725 GHz for outdoor and indoor use.
Since this is the German implementation of EU Rule 2005/513/EC, similar regulations must be expected throughout the European Union.
The same restrictions as in Germany apply, only 5.470–5.725 GHz is allowed to be used outdoor and indoor.
In Brazil, the TPC use in 5.150–5.725 GHz band is optional. DFS is required only in the 5.470–5.725 GHz band.
As of 2015, some of the Australian channels require DFS to be utilised (a significant change from the 2000 regulations, which allowed lower power operation without DFS). As per AS/NZS 4268 B1 and B2, transmitters designed to operate in any part of 5250–5350 GHz and 5470–5725 GHz bands shall implement DFS in accordance with sections 4.7 and 5.3.8 and Annex D of ETSI EN 301 893 or alternatively in accordance with Part 15 FCC paragraph 15.407(h)(2). Also as per AS/NZS 4268 B3 and B4, transmitters designed to operate in any part of 5250–5350 MHz and 5470–5725 MHz bands shall implement TPC in accordance with sections 4.4 and 5.3.4 of ETSI EN 301 893 or alternatively in accordance with FCC paragraph 15.407(h)(1).
Singapore regulatory – IMDA requires DFS and TPC capabilities on 5.250–5.350 GHz above 100 mW effective radiated powerand below or equal to 200 mW EIRP, requires DFS capability on 5.250–5.350 GHz below or equal to 100 mW EIRP, and requires DFS and TPC capabilities on 5.470–5.725 below or equal to 1000 mW EIRP (1 watt) Operating 5.725–5.850 GHz above 1000 mW (1 watt) and below or equal to 4000 mW (4 watts) EIRP shall be approved on exceptional basis.
In South Korea, the Ministry of Science and ICT has public notices. 신고하지 아니하고 개설할 수 있는 무선국용 무선설비의 기술기준, Technical standard for radio equipment for radio stations that can be opened without reporting. They allowed 160 MHz channel bandwidth from 2018.
China expanded allowed channels to add UNII-1, 5150–5250 GHz, UNII-2, 5250–5350 GHz (DFS/TPC), similar to European standards EN 301.893 V1.7.1.
Indonesia allows use of frequency of 5.150–5.250 GHz and 5.250–5.350 GHz for indoors use with maximum EIRP of 200 mW and frequency of 5.725–5.825 GHz with maximum EIRP of 4000 mW (4 watts) for outdoors and 200 mW for indoors.
5.9 GHz (802.11p)
The 802.11p specification was published on 15 July 2010, specifies WLAN in the licensed band of 5.9 GHz (5.850–5.925 GHz).
6 GHz (802.11ax)
On 23 April 2020, the FCC voted to allocate 1.2 GHz of unlicensed spectrum in the 6 GHz band (5.925–7.125 GHz) for Wi-Fi use. This represents a significant increase in available spectrum bandwidth for broadband wireless applications. It also provides for the possibility of moving larger networks off of the heavily congested 2.4 GHz and 5 GHz bands.
The Wi-Fi Alliance has introduced the term "Wi-Fi 6E" to identify and certify Wi-Fi devices that support this new band. Channel numbers will be defined by the IEEE's 802.11ax task group.
Low-power indoor (LPI) operation
|Band||20 MHz||40 MHz||80 MHz||160 MHz|
Note: Partial channels indicate channels that span UNII boundaries, which is permitted in 6 GHz LPI operation. Under the proposed channel numbers, the U-NII-7/U-NII-8 boundary is spanned by channels 185 (20 MHz), 187 (40 MHz), 183 (80 MHz), and 175 (160 MHz). The U-NII-6/U-NII-7 boundary is spanned by channels 115 (40 MHz), 119 (80 MHz), and channel 111 (160 MHz).
For use in indoor environments, access points are limited to a maximum effective radiated power of 30 dBm and a maximum power spectral density of 5 dBm/MHz. They can operate in this mode on all four U-NII bands (5,6,7,8) without the use of automatic frequency coordination. To help ensure they are used only indoors, these types of access points are not permitted to be connectorized for external antennas, weather-resistant, or run on battery power.
|Band||20 MHz||40 MHz||80 MHz||160 MHz|
Standard power access points are permitted indoors and outdoors at a maximum EIRP of 36 dBm in the U-NII-5 and U-NII-7 sub-bands with automatic frequency coordination (AFC).
The FCC will issue a ruling in the future on a third class of very low power devices such as hotspots and short-range applications.
Clients are limited to 24 dB below the power of the access point.
The European Commission is expected to rule on 6 GHz in early 2021. It is currently expected that EU regulations will permit operation only in the band from 5925 to 6425 MHz 5.925 GHz to 6.425 GHz (corresponding to the US U-NII-5 band) by low-power indoor and very-low-power devices.
|Band||20 MHz||40 MHz||80 MHz||160 MHz|
The UK's OFCOM is expected to generally mirror EU regulations.
60 GHz (802.11ad/ay)
The 60 GHz band 802.11ad / 802.ay also known as WiGig.This operates in the 60 GHz "V band" ISM band.
60 GHz WiGig channels Most original 802.11ad based chipset products only use channels 1–4.
There are some exceptions to this channel scheme. For example, IgniteNet (manufacturer of 60 GHz PtP and PtMP products) incorporate an option for eight 1.08GHz wide "half channels" (channels 1, 1.5, 2, 2.5, 3, 3.5, 4, and 4.5).
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