Lecture 6 WLAN Standards and Organizations.ppt

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Wireless LAN
Standards and Organizations
(1 September, 2006)
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Define what regulations the FCC creates
●
Explain what the ISM and UNII bands are and
how they are used
●
Define the different 802.11 standards and
drafts as set forth by the IEEE
●
Describe the competing technologies for
wireless LANs
Objectives
Upon completion of this chapter you will be able to:
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FCC Regulations
●
The FCC manages civilian, State and local
government usage of the radio spectrum.
✔
Code of Federal Regulations, Title 47 (CFR 47) Part 15.
/>✔
The FCC has authority to enforce the use of the radio
spectrum, however, they generally do not unless a

complaint is received.
✔
The FCC specifies the Power limits for 802.11.
✔
The FCC certifies equipment two major ways:
☛
As a component – mix and match.
☛
As a System – Cannot mix and match
✔
Read: "Regulations Affecting 802.11 Deployment" by Tim Pozar
Note: The National Telecommunication and Information Administration (NTIA) works with
the Interdepartmental Radio Advisory Committee (IRAC) to manage the federal use of the
radio spectrum.
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Industrial, Scientific and Medical (ISM)
●
There are three license free ISM Bands.
✔
915 MHz ISM Band
☛
902-928 MHz
☛
915 MHz 13 MHz at speeds up to 1 Mbps
☛
Home phones, game systems and home Cameras
☛
Garage door openers and Automotive security systems
☛

Cards are expensive – about $800
☛
Largely abandoned
✔
2.4 GHz ISM Band
☛
Used by 802.11, 802.11b/g
☛
2.400-2.4835 GHz
☛
2.400 +-5MHz
☛
Only 2.400-2.4835 are used
☛
Microwave ovens and baby monitors
✔
5.8 GHz ISM Band
☛
Used by 802.11a
☛
5.725 – 5.875
☛
150 MHz bandwidth
☛
Not to be confused with Band 3 of the UNII
±

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ISM and UNII Spectra

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Unlicensed National Information Infrastructure
(UNII)
●
Three Bands frequency bands make up the UNII.
✔
Lower Band (UNII-1)
☛
5.15 - 5.25 GHz
☛
Maximum output power: FCC = 50 mW, IEEE= 40 mW
☛
Reserved for indoor operation only
☛
Four non-overlapping channels separated by 20 MHz
✔
Middle Band (UNII-2)
☛
5.25 - 5.35 GHz
☛
Maximum output power: FCC = 250 mW, IEEE= 200 mW
☛
Reserved for indoor/outdoor operation only
☛
Four non-overlapping channels separated by 20 MHz
✔
Upper Band(UNII-3)
☛
5.725 - 5.825 GHz

☛
Maximum output power: FCC = 1000 mW, IEEE= 800 mW
☛
Reserved for outdoor operation only
☛
Four non-overlapping channels separated by 20 MHz
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ISM and UNII Spectra
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Unlicensed National Information Infrastructure (UNII)
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Lower Band
Middle Band
Upper Band
Unlicensed National Information Infrastructure
(UNII)
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Radiated Power Limits
●
The FCC enforces rules regarding power radiated by antenna
elements.
✔
Equivalent Isotropically Radiated Power (EIRP) is the
actual power radiated by the antenna which also takes into
account the gain of the antenna.
●

2.4 GHz Point-to-Multipoint (PtMP)
✔
PtMP links have a central antenna and two or more remote
antennas.
✔
The central antenna is normally an omnidirectional antenna.
✔
The FCC limits the EIRP in the 2.4GHz band to 4000mW (4
Watts).
✔
The intentional radiator may vary depending upon the
antenna gain.
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2.4 GHz PtMP Radiated Power Limits
●
The maximum EIRP allowed by the FCC is 4 Watt. This assumes a 6
dBI antenna gain with an Intentional Radiator of 1 Watt.
●
As the antenna gain in increased the intentional radiator power must
be reduced to maintain the 4 watt EIRP.
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Radiated Power Limits
For a 2.4 GHz Point-to-Multipoint (PtMP) Link
36
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5.8 GHz UNII GHz Point-to-Multipoint (PtMP)
●

The 5.8 GHz UNII band PtMP power rules are as follows:
✔
The maximum power of the IR in the UNII-1 Band is 40 mW
which means the maximum EIRP must be 160mW assuming an
antenna gain of 6
✔
The maximum power of the IR in the UNII-2 Band is 200 mW
which means the maximum EIRP must be 800 mW assuming an
antenna gain of 6.
✔
The maximum power of the IR in the UNII-3 Band is 800 mW
which means the maximum EIRP must be 3200 mW assuming an
antenna gain of 6.
●
The 1:1 rule (similar to the 2.4 GHz band) applies to the 5.8
GHz band in that for each 1 dB of antenna gain the intentional
Radiator must be reduced by 1 dB.