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6.3 Frequency Range
WLAN uses the frequency range around 2.4 GHz in the ISM
band or, alternatively, the frequency range at 5 GHz.
The frequency range used in your WLAN depends on the
settings of your WLAN access point.
A WLAN in the 2.4-GHz frequency band works in the same
band as Bluetooth, DECT, microwave devices, video bridg-
es and baby monitors. This means that interference may
occur within WLANs operated in the vicinity of such devic-
es. Generally the only adverse effects are to the transmis-
sion rate; aborted connections and data losses are rare.
WLAN in the 5-GHz frequency band is subject to less inter-
ference, as these radio frequencies are used much less of-
ten.
In both frequency ranges, the European regulation author-
ities have designated certain channels for WLAN. A chan-
nel can have a bandwidth of 20 MHz (throughput up to
130 Mbit/s) or 40 MHz (throughput of up to 300 Mbit/s).
Channels located directly next to each other may overlap
and result in mutual interference. For instance, if several
WLANs are operated close to each other in the 2.4-GHz fre-
quency range with a bandwidth of 20 MHz, a distance of
at least five channels should be left empty between each
two channels used. This means that if channel 1 is select-
ed for one WLAN, the channels 6 through 13 can be select-
ed for a second WLAN. This maintains the minimum dis-
tance between channels.
Should interference in a WLAN persist, the first step
should be to select a different channel. If your WLAN ac-
cess point is equipped with an autochannel function, you
can automatically have it search for the WLAN channel in
your frequency range that is subject to the least interfer-
ence. For more instructions, see the section “WLAN Con-
nection Is Not Established” from page 42.
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