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ITNW 1351
Chapter 8 – Wireless LAN Organizations and Standards
The Federal Communications Commission (FCC)
> independent U.S. government agency – directly responsible to Congress
o Charged with regulating interstate and international communications by radio, television,
wire, satellite, and cable
o Jurisdiction = all 50 states, the District of Columbia, and all U.S. possessions
o Mandates where on the radio frequency spectrum wireless LANs may operate and at what
power, transmission technologies, and how and where various pieces of LAN hardware may be
used
o http://www.fcc.gov
> Industrial, Scientific, and Medical (ISM) Band
o License free
o 902-MHz
* 902 MHz to 928 MHz (915 MHz +/- 13 MHz)
* Wireless home devices (phones and wireless camera systems)
* Wireless LAN equipment obsolete and expensive to replace
o 2.4-GHz
* Bound by 2.4000 GHz and 2.5000 GHz (2.4500 GHz +/- 50 MHz)
* Only 2.4000 to 2.4835 GHz used by wireless LAN devices
* Used by all 802.11, 802.11b, and 802.11g compliant devices
* Most populated space of the three bands
o 5.8-GHz
* AKA 5-GHz Band
* 150-MHz bandwidth, bound between 5.725 and 5.875 GHz)
* Not specified for use by wireless LAN devices
* Band overlaps part of the Upper UNII band which is used with wireless LANs
* Don’t confuse the two!
> Unlicensed National Information Infrastructure (UNII) Band
o Three separate 100 MHz wide bands
* All consist of four, 20 MHz wide nonoverlapping orthogonal frequency division
multiplexing (OFDM) channels
* Channels separated by 5 MHz
o 802.11 a compliant
o Lower Band
* Reserved for indoor operation only
* Bound by 5.15 GHz and 5.25 GHz
* Maximum output power = 50 mW at the intentional radiator (FCC)
* IEEE specifies 40 MW (80%) as maximum output power for 802.11a compliant radios
o Middle Band
* Used indoors and outdoors
* Bound by 5.25 GHz and 5.35 GHz
* Maximum power at intentional radiator 250 mW (FCC)
* IEEE specifies 200 mW
* Commonly used for short outdoor hops between closely spaced buildings
o Upper Band
* Reserved for outdoor links
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