An important component of wireless network performance optimization is channel planning.
IEEE defines 14 channels available for use in 802.11b and 802.11g wireless networks. In the US and Canada the available channels for use are 1 (2.401 GHz) through 11 (2.448 GHz). Outside the US channels 13 and 14 are also available for use. Each of the 11 channels are 5 MHz apart and each defined frequency is the center of a 22 MHz wide channel. This leaves only 3 non-overlapping channels 1 (2.401-2.423 GHz), 6 (2.426-2.448 GHz), and 11 (2.451-2.473 GHz).
Using a low cost 2.4 GHz spectrum analyzer , a visual representation of the 3 non-overlapping channels is shown below. A red shaded box that is 22 MHz wide is centered at channels 1, 6, 11.
(Data collected at a T-Mobile hotspot)
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The above three non-overlapping channels (1, 6, 11) can be deployed using the cell layout below. This scenario maximizes channel reuse and minimizes interference from adjacent access points.
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Enterprises usually deploy high end managed wireless LAN networks, that have RF management features for automating channel planning.
Home and small business users will have to manually configure access points for design above if they are deploying several access points or are in an environment with other neighboring access points.
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Filed under: WLAN Design