Руководство По Проектированию для Cisco Cisco Aironet 350 Mini-PCI Wireless LAN Client Adapter
3-3
Enterprise Mobility 4.1 Design Guide
OL-14435-01
Chapter 3 WLAN Radio Frequency Design Considerations
RF Basics
802.11b/g Operating Frequencies and Data Rates
Ratified in September 1999, the 802.11b standard operates in the 2.4 GHz spectrum and supports data
rates of 1, 2, 5.5, and 11 Mbps. 802.11b enjoys broad user acceptance and vendor support. 802.11b
technology has been deployed by thousands of enterprise organizations, which typically find its speed
and performance acceptable for their current applications.
rates of 1, 2, 5.5, and 11 Mbps. 802.11b enjoys broad user acceptance and vendor support. 802.11b
technology has been deployed by thousands of enterprise organizations, which typically find its speed
and performance acceptable for their current applications.
The 802.11g standard, which was ratified in June 2003, operates in the same spectrum as 802.11b and
is backward-compatible with the 802.11b standard. 802.11g supports the additional data rates of 6, 9,
12, 18, 24, 36, 48, and 54 Mbps.
is backward-compatible with the 802.11b standard. 802.11g supports the additional data rates of 6, 9,
12, 18, 24, 36, 48, and 54 Mbps.
lists the various 802.11b/g channel frequencies and specifies whether a regulatory agency
allows their use in their domain. Note that not all of these frequencies are available for use in all
regulatory domains.
regulatory domains.
1
Israel allows channels 1 through 13 indoors.
2
Japan requires a special license for channel 14.
802.11a Operating Frequencies and Data Rates
Operating in the unlicensed portion of the 5 GHz radio band, 802.11a is immune to interference from
devices that operate in the 2.4 GHz band, such as microwave ovens, many cordless phones, and
Bluetooth (a short-range, low-speed, point-to-point, personal-area-network wireless standard). Because
the 802.11a standard operates in a different frequency range, it is not compatible with existing 802.11b
or 802.11g-compliant wireless devices, but it does mean that 2.4-GHz and 5-GHz equipment can operate
in the same physical environment without interference.
devices that operate in the 2.4 GHz band, such as microwave ovens, many cordless phones, and
Bluetooth (a short-range, low-speed, point-to-point, personal-area-network wireless standard). Because
the 802.11a standard operates in a different frequency range, it is not compatible with existing 802.11b
or 802.11g-compliant wireless devices, but it does mean that 2.4-GHz and 5-GHz equipment can operate
in the same physical environment without interference.
Table 3-2
Operating Frequency Range for 802.11b and 802.11g
Channel
Identifier
Identifier
Center
Frequency
Frequency
FCC (America) ESTI (EMEA)
TELEC (Japan)
MOC (Israel
Outdoor)
Outdoor)
1
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
X
6
2437
X
X
X
X
7
2442
X
X
X
X
8
2447
X
X
X
X
9
2452
X
X
X
X
10
2457
X
X
X
X
11
2462
X
X
X
X
12
2467
X
X
X
13
2472
X
X
X
14
2
2484
X