Information Technology Reference
In-Depth Information
TABLE 13.2
IEEE 802.11 DSSS/OFDM Channel Plan for 2.4 GHz
2.4 GHz
Center freq.
US &
Europe
Japan
channel
(MHz)
Canada
(ETSI)
Spain
France
(MKK)
1
2412
X
X
X
2
2417
X
X
X
3
2422
X
X
X
4
2427
X
X
X
5
2432
X
X
X
6
2437
X
X
X
7
2442
X
X
X
8
2447
X
X
X
9
2452
X
X
X
10
2457
X
X
X
X
X
11
2462
X
X
X
X
X
12
2467
X
X
X
13
2472
X
X
X
14
2484
X
because it has a center frequency of 5180 MHz (mathematically, f
c
5000
5 *
36
5180 MHz), and is the first 20 MHz channel in the 5150 to 5250 lower ISM
band. Some manufacturers have created their own relative channel numbers, but
they may create more confusion in the future than they avoid in the present.
By contrast, FHSS uses 79 frequency channels in North America and Europe,
with 1 MHz spacings, allowing 26 collocated networks. Other countries use this
same standard, or additional variations that conform to local frequency coordina-
tion schemes. In Japan, for example, 23 hopping channels are provided.
In the 2.4 GHz band, transmit power for both FHSS and DSSS can be a rather
ample 1 Watt (or 4-W effective radiated power [EIRP]) in the United States,
although a transmit power of 100 mW or less must also be supported. Europe lim-
its this to 100 mW EIRP. As with many other types of shared-band communications,
regulatory agencies require the transmitter power to be the lowest necessary to
maintain communication. The 5 GHz bands each have differing power outputs,
depending on a number of factors, that range from about 40 mW to 800 mW (0.8
W) with up to a 6-dBi antenna.
Bluetooth IEEE 802.15.1 WLAN Operation
Another wireless innovation that is becoming a favorite is called
Bluetooth
. The
Bluetooth technology is intended for short-range use as a cable replacement. For
