Wi-Fi / WLAN channels, frequencies and bandwidths
- Wi-Fi / WLAN / 802.11b, 802.11g channels, their channel frequencies and bandwidth allocations around the globe, spectral mask and summary of which channels can be used together for WLAN solutions.
This IEEE 802.11 standard for WLANs tutorial is split into several pages each of which addresses different aspects of IEE 802.11 / Wi-Fi operation and technology:
[1] IEEE 802.11 standard tutorial[2] IEEE 802.11a
[3] IEEE 802.11b
[4] IEEE 802.11e
[5] IEEE 802.11g
[6] IEEE 802.11n
[6] IEEE 802.11af White-Fi
[7] 802.11 Wi-Fi channels and frequencies
The IEEE 802.11 Wi-Fi / WLAN standards set the attributes for the different channels that may be used. These attributes enable different Wi-Fi modules to talk to each other and effectively set up a WLAN. To ensure that WLAN solutions operate satisfactorily, parameters such as the RF signal centre frequencies, channel numbers and the bandwidths must all be set..
The 802.11b, 802.11g, and 802.11n standards all used the 2.4 GHz ISM (industrial, scientific and medical band). This is a licence free band for which individual users are not required to have a licence. As the band is available for WLAN solutions, virtually globally, this means that items such as laptops that use Wi-Fi are able to be used in many countries.
802.11 channel basics
There is a total of fourteen channels defined for use by Wi-Fi 802.11 for the 2.4 GHz ISM band. Not all of the channels are allowed in all countries: 11 are allowed by the FCC and used in what is often termed the North American domain, and 13 are allowed in Europe where channels have been defined by ETSI. The WLAN / Wi-Fi channels are spaced 5 MHz apart (with the exception of a 12 MHz spacing between the last two channels).
The 802.11 WLAN standards specify a bandwidth of 22 MHz and a 25 MHz channel separation, although nominal figures for the bandwidth of 20 MHz are often given. The 20 / 22 MHz bandwidth and channel separation of 5 MHz means that adjacent channels overlap and signals on adjacent channels will interfere with each other.
The 22 MHz channel bandwidth holds for all standards even though 802.11b WLAN standard can run at variety of speeds: 1, 2, 5.5, or 11 Mbps and the newer 802.11g standard can run at speeds up to 54 Mbps. The differences occur in the RF modulation scheme used, but the WLAN channels are identical across all of the applicable 802.11 standards.
When using Wi-Fi to provide WLAN solutions for offices, general use hotspots, or for any WLAN applications, it is necessary to ensure that parameters such as the channels are correctly set to ensure the required performance is achieved.
Wi-Fi WLAN channel frequencies
The table given below provides the frequencies for the total of fourteen WLAN / Wi-Fi channels that are available around the globe. Not all of these WLAN / Wi-Fi channels are available for use in all countries.
Channel Number | Lower Frequency |
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