ZyXEL Communications NWA5121-N User Manual page 67

Chapter 7 Wireless
In the 2.4 GHz spectrum, each channel from 1 to 13 is broken up into discrete 22 MHz segments
that are spaced 5 MHz apart. Channel 1 is centered on 2.412 GHz while channel 13 is centered on
2.472 GHz.
Figure 41 An Example Three-Channel Deployment
Three channels are situated in such a way as to create almost no interference with one another if
used exclusively: 1, 6 and 11. When an AP broadcasts on any of these three channels, it should not
interfere with neighboring APs as long as they are also limited to same trio.
Figure 42 An Example Four-Channel Deployment
However, some regions require the use of other channels and often use a safety scheme with the
following four channels: 1, 4, 7 and 11. While they are situated sufficiently close to both each other
and the three so-called "safe" channels (1,6 and 11) that interference becomes inevitable, the
severity of it is dependent upon other factors: proximity to the affected AP, signal strength, activity,
and so on.
Finally, there is an alternative four channel scheme for ETSI, consisting of channels 1, 5, 9, 13. This
offers significantly less overlap that the other one.
Figure 43 An Alternative Four-Channel Deployment
NWA5120 Series User's Guide
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