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Regulatory Channel Selections

The WLAN bands are divided up into channels, with each local regulatory agency defining what is permitted for use in its area. This section defines the major regulatory domain regulations regarding power, antennas, and other compliance requirements.

North American Domain Channel Scheme

In the North American (NA) domain, the 2.4-GHz band ranges from 2.400 GHz to 2.4835 GHz; the 5-GHz band ranges from 5.150 to 5.825 GHz. Both bands are divided into channel schemes, which vary by regulatory domain.

2.4 GHz (NA)

In the NA channel scheme for 2.4 GHz, 11 channels are identified. As previously mentioned, these channels are 22 MHz wide, and the center of each channel is separated from the adjacent channel center by only 5 MHz. The lower channel is centered at 2.412 GHz (channel 1) with the upper channel (channel 11) centered at 2.462 GHz. (See Table 3-2.)

5 GHz (NA)

The 5-GHz band in the NA domain is divided into four segments. The UNII1 band runs from 5.150 GHz to 5.250 GHz and is divided into four channels. The UNII2 band runs from 5.250 GHz to 5.350 GHz and is also divided into four channels. The UNII3 band starts at 5.725 GHz and ends at 5.825 GHz and also has a total of four channels. Between 5.470 and 5.725 GHz lie the newer channels permitted by the inclusion of 802l.11h (an additional 11 channels).

ETSI Domain Channel Scheme

In Europe, the regulations are quite a bit different and hence not just power levels differ from the NA domain, but also some of the permitted frequency usage.

2.4 GHz (ETSI)

In the ETSI channel scheme, 13 channels are identified. The lower 11 channels are identical to the NA channel scheme, with two additional channels. These channels are centered at 2.467 GHz and 2.472 GHz.

5 GHz (ETSI)

With the recent addition channels to the NA domain, the ETSI domain now shares the same frequencies. However, there are some differences in permitted power levels and adherence to DFS and TPC that must followed.

Japan Channel Scheme

In Japan, some changes were made to the 2.4-GHz band permitting more frequency usage; however, the 5-GHz band has some stricter regulations.

2.4 GHz (Japan)

The Japan 2.4-GHz band originally supported only a single channel, centered at 2.484 GHz, and that channel was noninteroperable with any other country. A few years ago, the Japan TELEC opened up the rest of the 2.4-GHz band, permitting operation on the same 13 channels as the ETSI domain, while still keeping the single upper channels as 2.484 GHz, providing for a total of 14 channels.

5 GHz (Japan)

Japan has taken a much more restrictive role in the 5-GHz area than other regulatory domains. They only permit operation from 5.150 GHz to 5.250 GHz with four channels located at 5.170 GHz, 5.190 GHz, 5.210 GHz, and 5.130 GHz. You will notice that these center frequencies differ from those used in ETSI and the NA domains.

Other Regulatory Domain Frequency Limits

Some countries have based their permitted frequency usage on a portion of one of the ETSI or NA domain specifications, resulting in a fewer number of available channels. France and Israel were two such countries; however, they have recently changed and now permit a full range of frequencies based on either the ETSI or NA domain. It is important that the installer check with the local agency to verify what is permitted in the country in which the equipment will be used.