List of WLAN channels

From Wikipedia, the free encyclopedia
Jump to: navigation, search

This list of WLAN channels is the set of legally allowed Wireless LAN channels using IEEE 802.11.

The 802.11 workgroup currently documents use in three distinct frequency ranges, 2.4 GHz, 3.6 GHz and 4.9/5.0 GHz bands.[1] Each range is divided into a multitude of channels. Countries apply their own regulations to both the allowable channels, allowed users and maximum power levels within these frequency ranges. In some countries, such as the United States, licensed Amateur Radio operators may use some of the channels at much higher power for long distance wireless access.

Contents

2.4 GHz (802.11b/g/n) [edit]

Graphical representation of Wireless LAN channels in 2.4 GHz band

There are 14 channels designated in the 2.4 GHz range spaced 5 MHz apart (with the exception of a 12 MHz spacing before Channel 14).[2]

Interference Concerns [edit]

As the protocol requires 16.25 to 22 MHz of channel separation[citation needed], adjacent channels overlap and will interfere with each other. Leaving 3 or 4 channels clear between used channels is recommended to avoid interference.[3] The exact spacing required depends on the protocol and data rate selected as well as the electromagnetic environment where the equipment is used.

When two or more 802.11b transmitters are operated in the same airspace, their signals must be attenuated by -50dBr and/or separated by 22 MHz to prevent interference.[2] This is due to fact that the DSSS algorithm transmits data logarithmically along a 20 MHz bandwidth. The remaining 2 MHz gap is used as a Guard Band to allow sufficient attenuation along the edge channels.

Note: The 40 MHz bands in the diagram above are labelled with their centre channel numbers, the management interface of many WiFi devices labels these bands with the centre channel of one of the 20 MHz bands they overlap plus an Up or Down notation to specify the other half of the band i.e.: Channel 3 = Channel 1+Upper, or Channel5+Lower and Channel 11 = Channel 9+Upper or Channel 13+Lower.

Countries apply their own regulations to both 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 Network operators should consult their local authorities as these regulations may be out of date as they are subject to change at any time.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.

Channel Frequency
(MHz)		 North America
[4]		 Japan[4] Most of worldA
[4][5][6][7][8]
1 2412 Yes Yes YesD
2 2417 Yes Yes YesD
3 2422 Yes Yes YesD
4 2427 Yes Yes YesD
5 2432 Yes Yes Yes
6 2437 Yes Yes Yes
7 2442 Yes Yes Yes
8 2447 Yes Yes Yes
9 2452 Yes Yes Yes
10 2457 Yes Yes Yes
11 2462 Yes Yes Yes
12 2467 NoB Yes Yes
13 2472 NoB Yes Yes
14 2484 No 11b onlyC No

^A There are only 11 allowable channels in Spain & France.

^B In the USA, 802.11 operation in the channels 12 and 13 is actually allowed under low powered conditions. The 2.4 GHz Part 15 band in the US allows spread-spectrum operation as long as the 50-dB bandwidth of the signal is within the range of 2,400–2,483.5 MHz[9] which wholly encompasses both channels 12 and 13. A Federal Communications Commission (FCC) document clarifies that only channel 14 is forbidden and furthermore low-power transmitters with low-gain antennas may legally operate in channels 12 and 13.[10] However, channels 12 and 13 are not normally used in order to avoid any potential interference in the adjacent restricted frequency band, 2,483.5–2,500 MHz,[11] which is subject to strict emission limits set out in 47 CFR §15.205.[12]

In Canada, 12 channels are available for use, 11 of which at full power and the other (channel 12) is transmit power limited. However, few devices have a method to enable a lower powered channel 12[opinion].

^C Channel 14 is valid only for DSSS and CCK modes (Clause 18 a.k.a. 802.11b) in Japan. OFDM (i.e., 802.11g) may not be used. (IEEE 802.11-2007 §19.4.2)

^D Outdoor use of channels 1–4 is not allowed in Israel, although indoor use is permitted.[13]

3.6 GHz (802.11y) [edit]

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. Please see IEEE 802.11y for details.

Countries apply their own regulations to both the allowable channels, allowed users and maximum power levels within these frequency ranges.

Channel Frequency
(MHz)		 United States
5 MHz 10 MHz 20 MHz
131 3657.5 Yes No No
132 3662.5 Yes No No
132 3660.0 No Yes No
133 3667.5 Yes No No
133 3665.0 No No Yes
134 3672.5 Yes No No
134 3670.0 No Yes No
135 3677.5 Yes No No
136 3682.5 Yes No No
136 3680.0 No Yes No
137 3687.5 Yes No No
137 3685.0 No No Yes
138 3689.5 Yes No No
138 3690.0 No Yes No

4.9 GHz (802.11y) Public Safety WLAN [edit]

50 MHz of spectrum from 4940 MHz to 4990 MHz (WLAN channels 20–26) are in use by public safety entities in the United States. Within this spectrum space, there are two non-overlapping channels allocated, both with a width of 20 MHz. The most commonly used channels are 22 and 26.

5 GHz (802.11a/h/j/n)[14] [edit]

Countries apply their own regulations to both 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.

European standard EN 301 893 covers 5.15-5.725 GHz operation, and v1.7.1 is in force.

In 2007 the FCC (United States) began requiring that devices operating on 5.250–5.350 GHz and 5.470–5.725 GHz must employ dynamic frequency selection (DFS) and transmit power control (TPC) capabilities. This is to avoid interference with weather-radar and military applications.[15] 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) systems.[16] This statement eliminated the use of channels 120, 124, and 128. Channels 116 and 132 may be used, so long as they are separated by more than 30 MHz (center-to-center) from a TDWR located within 35 km of the device. There are now at least five relevant KDBs about operation in 5 GHz radar bands.

Germany requires dynamic frequency selection (DFS) and transmit power control (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 only allowed for indoor use, leaving only 5.470-5.725 GHz for outdoor and indoor use.[17]

Since this is the German implementation of EU-Rule 2005/513/EC, similar regulations must be expected throughout the European Union.[18][19]

Austria adopted Decision 2005/513/EC directly into national law.[20] The same restrictions as in Germany apply, only 5.470-5.5725 GHz is allowed to be used outdoor and indoor.

South Africa simply copied the European regulations.[21]

Japan no longer allows 34, 38, 42, and 46 channels for connecting J52 supported old APs. Authorization to use these channels expired in May 2012.

In Brazil, the TPC use in 5.150–5.725 MHz band is optional. DFS is required only in 5.470–5.725 MHz band.[22]

Australian DFS channels also require TPC, or the maximum allowed power is cut in half.[8] As per AS/NZS 4268 B1 and B2, transmitters designed to operate in any part of 5250–5350 MHz and 5470–5725 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 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).

Channel Frequency
(MHz)		 United States Europe Japan Singapore China Israel Korea Turkey Australia South Africa Brazil
40/20 MHz[23] 40/20 MHz[citation needed] 40/20 MHz[24] 10 MHz 40/20 MHz[25] 20 MHz 20 MHz[7] 20 MHz[26] 40/20 MHz[27] 40/20 MHz[8] 40/20 MHz[21] 40/20 MHz[22]
183 4915 No No No Yes No No No No No No No No
184 4920 No No Yes Yes No No No No No No No No
185 4925 No No No Yes No No No No No No No No
187 4935 No No No Yes No No No No No No No No
188 4940 No No Yes Yes No No No No No No No No
189 4945 No No No Yes No No No No No No No No
192 4960 No No Yes No No No No No No No No No
196 4980 No No Yes No No No No No No No No No
7 5035 No No No Yes No No No No No No No No
8 5040 No No No Yes No No No No No No No No
9 5045 No No No Yes No No No No No No No No
11 5055 No No No Yes No No No No No No No No
12 5060 No No No No No No No No No No No No
16 5080 No No No No No No No No No No No No
34 5170 No No Client only[clarification needed] No Yes No Yes Yes Indoors No Indoors Indoors
36 5180 Yes Indoors Yes No Yes No Yes Yes Indoors Yes Indoors Indoors
38 5190 No No Client only No Yes No Yes Yes Indoors No Indoors Indoors
40 5200 Yes Indoors Yes No Yes No Yes Yes Indoors Yes Indoors Indoors
42 5210 No No Client only No Yes No Yes Yes Indoors No Indoors Indoors
44 5220 Yes Indoors Yes No Yes No Yes Yes Indoors Yes Indoors Indoors
46 5230 No No Client only No Yes No Yes Yes Indoors No Indoors Indoors
48 5240 Yes Indoors Yes No Yes No Yes Yes Indoors Yes Indoors Indoors
52 5260 DFS Indoors/DFS/TPC DFS/TPC No Yes No Yes Yes Indoors DFS/TPC Indoors Indoors
56 5280 DFS Indoors/DFS/TPC DFS/TPC No Yes No Yes Yes Indoors DFS/TPC Indoors Indoors
60 5300 DFS Indoors/DFS/TPC DFS/TPC No Yes No Yes Yes Indoors DFS/TPC Indoors Indoors
64 5320 DFS Indoors/DFS/TPC DFS/TPC No Yes No Yes Yes Indoors DFS/TPC Indoors Indoors
100 5500 DFS[16] DFS/TPC DFS/TPC No No No No Yes DFS/TPC DFS/TPC Yes DFS
104 5520 DFS[16] DFS/TPC DFS/TPC No No No No Yes DFS/TPC DFS/TPC Yes DFS
108 5540 DFS[16] DFS/TPC DFS/TPC No No No No Yes DFS/TPC DFS/TPC Yes DFS
112 5560 DFS[16] DFS/TPC DFS/TPC No No No No Yes DFS/TPC DFS/TPC Yes DFS
116 5580 DFS[16] DFS/TPC DFS/TPC No No No No Yes DFS/TPC DFS/TPC Yes DFS
120 5600 No[28] DFS/TPC DFS/TPC No No No No Yes DFS/TPC No Yes DFS
124 5620 No[28] DFS/TPC DFS/TPC No No No No Yes DFS/TPC No Yes DFS
128 5640 No[28] DFS/TPC DFS/TPC No No No No Yes DFS/TPC No Yes DFS
132 5660 DFS[16] DFS/TPC DFS/TPC No No No No No DFS/TPC DFS/TPC Yes DFS
136 5680 DFS[16] DFS/TPC DFS/TPC No No No No No DFS/TPC DFS/TPC Yes DFS
140 5700 DFS[16] DFS/TPC DFS/TPC No No No No No DFS/TPC DFS/TPC Yes DFS
149 5745 Yes SRD (25 mW)[29] No No Yes Yes No Yes No Yes No Yes
153 5765 Yes SRD (25 mW)[29] No No Yes Yes No Yes No Yes No Yes
157 5785 Yes SRD (25 mW)[29] No No Yes Yes No Yes No Yes No Yes
161 5805 Yes SRD (25 mW)[29] No No Yes Yes No Yes No Yes No Yes
165 5825 Yes SRD (25 mW)[29] No No Yes Yes No Yes No Yes No Yes

See also [edit]

In Japan, authorization to use channels 34, 38, 42 and 46 expired in May 2012, seven years after channels 36, 40, 44 and 48 were initially allowed. ARIB STD T-71v5_2 clause 5.3.8.3.3 lists permitted channels.

References [edit]

  1. ^ "IEEE 802.11-2007: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications". IEEE. 2007-03-08. 
  2. ^ a b "IEEE 802.11-2012: 16.4.6 - PMD Operating Specifications, General". IEEE. 2013-05-15. 
  3. ^ "Change the WiFi Channel Number to Avoid Interference". 
  4. ^ a b c IEEE 802.11-2007 — Table 18-9
  5. ^ France: "WLAN regulatory update". 2003-02-03. 
  6. ^ Spain: http://web.archive.org/web/20080206082504/http://www.mityc.es/Telecomunicaciones/Secciones/Espectro/cnaf/
  7. ^ a b Israel: "צו הטלגרף האלחוטי (אי תחולת הפקודה) (מס' 2), התשס"ו – 2005" (in hebrew). 
  8. ^ a b c Australia: "Radiocommunications (Low Interference Potential Devices) Class Licence 2000". comlaw.gov.au. Retrieved 2011-03-28. 
  9. ^ 47 CFR §15.247
  10. ^ "TCB workshop on unlicensed devices". October 2005. p. 58. 
  11. ^ NTIA comments to the FCC ET Docket 03-108, footnote 88
  12. ^ http://edocket.access.gpo.gov/cfr_2004/octqtr/pdf/47cfr15.205.pdf
  13. ^ "Cisco Enterprise Mobility 4.1 Design Guide, Chapter 3: WLAN Radio Frequency Design Considerations". p. 3. 
  14. ^ IEEE 802.11-2007 Annex J modified by amendments k, y and n.
  15. ^ FCC 15.407 as of June 23, 2011 – hallikainen.com / See paragraph 'h'
  16. ^ a b c d e f g h i FCC Publication - 443999 D01 Approval of DFS UNII Devices v01
  17. ^ Bundesnetzagentur Vfg 7/2010 / See footnote 4 and 5 (german only)
  18. ^ 2005/513/EC: Commission Decision of 11 July 2005 on the harmonised use of radio spectrum in the 5 GHz frequency band for the implementation of wireless access systems
  19. ^ 2007/90/EC: Commission Decision of 12 February 2007 amending Decision 2005/513/EC on the harmonised use of radio spectrum in the 5 GHz frequency band for the implementation of Wireless Access Systems
  20. ^ Information der Obersten Fernmeldebehörde - Drahtlose lokale Netzwerke (WAS, WLAN, RLAN)(german only)
  21. ^ a b Frequency assignments for unlicensed devices / See page 14
  22. ^ a b "Brazil: Resolução nº 506, de 01/07/2008, publicado no Diário Oficial de 07/07/2008, atualizado em 24/11/2010 (in Brazilian Portuguese)". p. 33. 
  23. ^ FCC 15.407 as of April 9, 2013 – hallikainen.com
  24. ^ 802.11-2007 Japan MIC Released the new 5 GHz band (W56). Bureau Veritas — ADT. Retrieved 2008-02-23. 
  25. ^ "IDA Singapore: Spectrum Management Handbook". May 2011. p. 30. 
  26. ^ Korea Frequency Distribution Table 2008.12.31 (in Korean)
  27. ^ KISA MESAFE ERİŞİMLİ TELSİZ CİHAZLARI (KET) YÖNETMELİĞİ Resmi Gazete 10.03.2010 Madde 8 - Genişband veri iletim sistemleri (in Turkish)
  28. ^ a b c "Elimination of interference to Terminal Doppler Weather Radar (TDWR)". Retrieved 2012-12-27. 
  29. ^ a b c d e "Relating to the use of Short Range Devices (SRD)". ECC. October 9, 2012. Retrieved 2013-02-08. 
Retrieved from "http://en.wikipedia.org/w/index.php?title=List_of_WLAN_channels&oldid=556352197"