Wireless LAN (WLAN) channels are frequently accessed using IEEE 802.11 protocols. The 802.11 standard provides several radio frequency bands for use in Wi-Fi communications, each divided into a multitude of frequency channels numbered at 5 MHz spacing (except in the 45/60 GHz band, where they are 0.54/1.08/2.16 GHz apart) between the centre frequency of the channel. The standards allow for channels to be bonded together into wider channels for faster throughput.
802.11ah operates in sub-gigahertz unlicensed bands. There are two main bands in use, with Europe mainly using 860 MHz, and the rest of the world mostly using 900 MHz.
Each world region supports different sub-bands, and the channel numbers depend on the starting frequency on the sub-band it belongs to. Therefore there is no global channel numbering plan, and the channel numbers are incompatible between world regions (and even between sub-bands of a same world region). However, for the purposes of illustration, the following table lists all the worldwide permitted frequencies with the channel numbers assigned to the region with the largest number of permitted frequencies, the United States.
Indonesia permits use in the 920âÂÂ923 MHz band, however only with 250 kHz channels, below the minimum 1 MHz required for 802.11ah.
14 channels are designated in the 2.4 GHz range, spaced 5 MHz apart from each other except for a 12 MHz space before channel 14. The abbreviation F<sub>0</sub> designates each channel's fundamental frequency.
Interference happens when two networks try to operate in the same band, or when their bands overlap. The two modulation methods used have different characteristics of band usage and therefore occupy different widths:
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). The consideration of spacing stems from both the basic bandwidth occupation (described above), which depends on the protocol, and from attenuation of interfering signals over distance. In the worst case, using every fourth or fifth channel by leaving three or four channels clear between used channels causes minimal interference, and narrower spacing still can be used at further distances. The "interference" is usually not actual bit-errors, but the wireless transmitters making space for each other. Interference resulting in bit-error is rare. The requirement of the standard is for a transmitter to yield when it decodes another at a level of 3 dB above the noise floor, or when the non-decoded noise level is higher than a threshold P<sub>th</sub> which, for Wi-Fi 5 and earlier, is between -76 and -80 dBm.
As shown in the diagram, bonding two 20 MHz channels to form a 40 MHz channel is permitted in the 2.4 GHz bands. These are generally referred to by the centres of the primary 20 MHz channel and the adjacent secondary 20 MHz channel (e.g. 1+5, 9+13, 13âÂÂ9, 5âÂÂ1). The primary 20 MHz channel is used for signalling and backwards compatibility, the secondary is only used when sending data at full speed.
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. However, not in the original specification, under newer frequency allocations from the FCC, it falls under the Citizens Broadband Radio Service band. This allows for unlicensed use, under Tier 3 GAA rules, provided that the user doesn't cause harmful interference to Incumbent Access users or Priority Access Licensees and accepts all interference from these users, and also follows all the technical requirements in CFR 47 Part 96 Subpart E.
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.
The division into 5 MHz channels consumes all eight possible channel numbers, and so (unlike other bands) it is not possible to infer the width of a channel from its number. Instead each wider channel shares its channel number with the 5 MHz channel just above its mid frequency:
and so on.
In Japan since 2002, 80 MHz of spectrum from 4910 to 4990 MHz has been available for both indoor and outdoor use, once registered.
Until 2017, an additional 60 MHz of spectrum from 5030 to 5090 MHz was available for registered use, however it has since been re-purposed and can no longer be used.
50 MHz of spectrum from 4940 to 4990 MHz (WLAN channels 20âÂÂ26) are in use by public safety entities in the United States. Within this spectrum there are two non-overlapping channels allocated, each 20 MHz wide. The most commonly used channels are 22 and 24.
Source:
In 2007, the FCC (United States) began requiring that devices operating in the bands of 5.250âÂÂ5.350 GHz and 5.470âÂÂ5.725 GHz must employ dynamic frequency selection (DFS) and 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 5.470âÂÂ5.725 GHz band to avoid interference with Terminal Doppler Weather Radar (TDWR). In FCC parlance, these restrictions are now referred to collectively as the Old Rules. 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, in Publication Number 905462. This FCC publication eliminates the ability for manufacturers to have devices approved or modified under the Old Rules in phases; the New Rules apply in all circumstances
Source:
The UK's Ofcom regulations for unlicensed use of the 5 GHz band is similar to Europe, except that DFS is not required for the frequency range 5.725âÂÂ5.850 GHz and the SRD maximum mean e.i.r.p is 200 mW instead of 25 mW.
Additionally, 5.925âÂÂ6.425 GHz is also available for unlicensed use, as long as it is used indoors with an SRD of 250 mW.
Germany requires DFS and TPC capabilities on 5.250âÂÂ5.350 GHz and 5.470âÂÂ5.725 GHz as well; in addition, the frequency range 5.150âÂÂ5.350 GHz is allowed only for indoor use, leaving only 5.470âÂÂ5.725 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.
European standard EN 301 893 covers 5.15âÂÂ5.725 GHz operation, and v2.1.1 has been adopted. 6 GHz can now be used.
Austria adopted Decision 2005/513/EC directly into national law.
Japan's use of 10 and 20 MHz-wide 5 GHz wireless channels is codified by Association of Radio Industries and Businesses (ARIB) document STD-T71, Broadband Mobile Access Communication System (CSMA). Additional rule specifications relating to 40, 80, and 160 MHz channel allocation has been taken on by Japan's Ministry of Internal Affairs and Communications (MIC).
In Brazil, the use of TPC is required in the 5.150âÂÂ5.350 GHz and 5.470âÂÂ5.725 GHz bands is required, but devices without TPC are allowed with a reduction of 3 dB. DFS is required in the 5.250âÂÂ5.350 GHz and 5.470âÂÂ5.725 GHz bands, and optional in the 5.150âÂÂ5.250 GHz band.
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 5250âÂÂ5350 MHz and 5470âÂÂ5725 MHz 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 FCC paragraph 15.407(h)(2). Also as per AS/NZS 4268 B3 and B4, transmitters designed to operate in any part of 5250âÂÂ5350 MHz and 5470âÂÂ5725 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).
New Zealand regulation differs from Australian.
In the Philippines, the National Telecommunications Commission (NTC) allows the use of 5150 MHz to 5350 MHz and 5470 MHz to 5850 MHz frequency bands indoors with an effective radiated power (ERP) not exceeding 250 mW. Indoor Wireless Data Network (WDN) equipment and devices shall not use external antenna. All outdoor equipment/radio station whether for private WDN or public WDN shall be covered by appropriate permits and licenses required under existing rules and regulations.
Singapore regulation requires DFS and TPC to be used in the 5.250âÂÂ5.350 GHz band to transmit more than 100 mW effective radiated power (EIRP), but no more than 200 mW, and requires DFS capability on 5.250âÂÂ5.350 GHz below or equal to 100 mW EIRP, and requires DFS and TPC capabilities on 5.470âÂÂ5.725 below or equal to 1000 mW EIRP. Operating 5.725âÂÂ5.850 GHz above 1000 mW and below or equal to 4000 mW EIRP shall be approved on exceptional basis.
In South Korea, the Ministry of Science and ICT has public notices. ì 고ÃÂÂ짠ìÂÂëÂÂÃÂÂê³ ê°Âì¤Ã ì ìÂÂë 무ì êµÂì© 무ì ì¤ë¹Âì 기ì 기ì¤Â, Technical standard for radio equipment for radio stations that can be opened without reporting. They allowed 160 MHz channel bandwidth from 2018 to 2016âÂÂ27.
China MIIT expanded allowed channels to add UNII-1, 5150âÂÂ5250 MHz, UNII-2, 5250âÂÂ5350 MHz (DFS/TPC), similar to European standards EN 301.893 V1.7.1. China MIIT expanded allowed channels to add U-NII-3, 5725âÂÂ5850 MHz.
Indonesia allows use of the band with maximum EIRP of () and maximum bandwidth of , and the band with the same maximum EIRP and maximum bandwidth of for indoor use. Outdoors, use of the band with maximum EIRP of () is allowed, with a maximum bandwidth of .
In exercise of the powers conferred by sections 4 and 7 of the Indian Telegraph Act, 1885 (13 of 1885) and sections 4 and 10 of the Indian Wireless Telegraphy Act, 1933 (17 of 1933) and in supersession of notification under G.S.R. 46(E), dated 28 January 2005 and notification under G.S.R. 36(E), dated 10 January 2007 and notification under G.S.R. 38(E), dated 19 January 2007, the Central Government made the rules, called the Use of Wireless Access System including Radio Local Area Network in 5 GHz band (Exemption from Licensing Requirement) Rules, 2018. The rules include criteria like 26 dB bandwidth of the modulated signal measured relative to the maximum level of the modulated carrier, the maximum power within the specified measurement bandwidth, within the device operating band; measurements in the 5725âÂÂ5875 MHz band are made over a bandwidth of 500 kHz; measurements in the 5150âÂÂ5250 MHz, 5250âÂÂ5350 MHz, and 5470âÂÂ5725 MHz bands are made over a bandwidth of 1 MHz or 26 dB emission bandwidth of the device. No licence shall be required under indoor and outdoor environment to establish, maintain, work, possess or deal in any wireless equipment for the purpose of low power wireless access systems. Transmitters operating in 5725âÂÂ5875 MHz, all emissions within the frequency range from the band edge to 10 MHz above or below the band edge shall not exceed an EIRP of ; for frequencies 10 MHz or greater above or below the band edge, emission shall not exceed an EIRP of .
The 802.11p amendment published on 15 July 2010, specifies WLAN in the licensed band of 5.9 GHz (5.850âÂÂ5.925 GHz).
The Wi-Fi Alliance has introduced the term WiâÂÂFi 6E to identify and certify IEEE 802.11ax devices that support this new band, which is also used by Wi-Fi 7 (IEEE 802.11be).
Initialisms (precise definition below):
On 23 April 2020, the FCC voted on and ratified a Report and Order to allocate 1.2 GHz of unlicensed spectrum in the 6 GHz band (5.925âÂÂ7.125 GHz) for Wi-Fi use.
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).
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 EIRP 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.
The FCC may issue a ruling in the future on a third class of very low power devices such as hotspots and short-range applications.
In November 2020, the Innovation, Science and Economic Development (ISED) of Canada published "Consultation on the Technical and Policy Framework for Licence-Exempt Use in the 6 GHz Band". They proposed to allow licence-exempt operations in the 6 GHz spectrum for three classes of radio local area networks (RLANs):
For indoor and outdoor use. Maximum EIRP of 36 dBm and maximum power spectral density (PSD) of 23 dBm/MHz. Should employ Automated Frequency Coordination (AFC) control.
For indoor use only. Maximum EIRP of 30 dBm and maximum PSD of 5 dBm/MHz.
For indoor and outdoor use. Maximum EIRP of 14 dBm and maximum PSD of -8 dBm/MHz.
ECC Decision (20)01 from 20 November 2020 allocated the frequency band from 5945 to 6425 MHz (corresponding almost to the US U-NII-5 band) for use by low-power indoor and very-low-power devices for Wireless Access Systems/Radio Local Area Networks (WAS/RLAN), with a portion specifically reserved for rail networks and intelligent transport systems.
On January 20, 2026, the Ministry of Communications, Government of India, through a Gazette notification, has officially de-licensed the lower portion of the 6 GHz spectrum (from 5925 MHz to 6425 MHz) for the Use of Low Power and Very Low Power Wireless Access System.
For indoor use only. Maximum EIRP of 30 dBm and maximum PSD of 11 dBm/MHz.
For indoor and outdoor use. Maximum EIRP of 14 dBm and maximum PSD of 1 dBm/MHz.
Since July 2020, the UK's Ofcom permitted unlicensed use of the lower 6 GHz band (5945 to 6425 MHz, corresponding to the US U-NII-5 band) by Low Power indoor and Very Low Power indoor and mobile Outdoor device.
In April 2021, Australia's ACMA opened consultations for the 6 GHz band. The lower 6 GHz band (5925 to 6425 MHz, corresponding to the US U-NII-5 band) was approved for 250 mW EIRP indoors and 25 mW outdoors on March 4, 2022. From 1 October 2025 the approved range was increased by 160 MHz to 5925âÂÂ6585 MHz, allowing for an additional 160 MHz / 320 MHz channel in the 6 GHz band for Wi-Fi use. The ACMA intends to allocate the 6585âÂÂ7100 MHz portion of the band to mobile telephony use, but is delaying that allocation while it monitors spectrum arrangements in other major markets that drive the manufacturing of mobile network equipment, potentially allowing for additional spectrum to be allocated to Wi-Fi at a later date.
This is in line with the following ACMA decisions on the future of the upper 6 GHz spectrum in Australia published in the December 2024 consultation outcomes paper:
⢠Add 6425âÂÂ6585 MHz to the LIPD class licence to support RLAN (Radio Local Area Network) use. This work is intended to be implemented as part of our task to remake the instrument prior to its sunsetting in October 2025. We are aiming to consult on updates to the LIPD class licence in early 2025.
⢠Plan for 6585âÂÂ7100 MHz in defined population areas for potential WA WBB (Wide Area Wireless Broadband) use, but not commence implementation of these arrangements until certainty around progress towards international equipment markets can be provided. This planning will include determination of defined areas in consultation with stakeholders.
⢠Once defined areas have been determined, make provision for apparatus licensed access in 6585âÂÂ7100 MHz outside those areas to enable the deployment of local area WBB services (either IMT or RLAN-based technologies).'
For indoor use only. Maximum EIRP of 250 mW. The power spectral density must not be greater than 12.5 mW EIRP per 1 MHz.
For indoor and outdoor use. Maximum EIRP of 25 mW. The power spectral density must not be greater than 1.25 mW EIRP per 1 MHz.
In September 2022, the Ministry of Internal Affairs and Communications announced amendments to the ministerial order and notices related to the Radio Act.
For indoor use only. Maximum EIRP of 200 mW.
For indoor and outdoor use. Maximum EIRP of 25 mW.
Since August 2023, Taiwan's NCC permitted unlicensed use of the lower 6 GHz band (5945 to 6425 MHz, corresponding to the US U-NII-5 band) by Low Power indoor and Very Low Power indoor and mobile Outdoor device.
In December 2022, Russian State Commission for Radio Frequencies authorised 6 GHz operation for low-power indoor (LPI) use with transmitter power control (TPC) limited to maximum EIRP of 200 mW and maximum PSD of 10 mW/MHz, and very low power (VLP) indoor and mobile outdoor use with maximum EIRP of 25 mW and maximum PSD of 1.3 mW/MHz.
In May 2023, Singapore's IMDA will amend its Regulations to allocate the radio frequency spectrum 5,925 MHz â 6,425 MHz for Wi-Fi use in Singapore.
On May 23, 2024, the Philippines' National Telecommunications Commission (NTC) is considering the use of 5925 MHz to 6425 MHz frequency bands indoors with an effective radiated power (ERP) not exceeding 250 mW and outdoors with an effective radiated power not exceeding 25 mW. On July 5, 2024, the NTC has released Memorandum Circular No. 002-07-2024, allowing 6 GHz Wi-Fi use, with the added restriction that the use on unmanned aircraft systems is prohibited.
The 802.11aj standards, also known as WiGig, operate in the spectrum.
The 802.11ad/aj/ay standards, also known as WiGig, operate in the V band unlicensed ISM band spectrum.
Indonesia allows the use of the band with maximum EIRP of (), and maximum bandwidth of , for indoor use.