Lecture 6 WLAN Standards and Organizations.ppt

Bài giảng Lecture 6 WLAN Standards and Organizations

Wireless LAN Standards and Organizations

(1 September, 2006)

 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:

 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

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

 Only 2.400-2.4835 are used

 Microwave ovens and baby monitors

ISM and UNII Spectra

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

ISM and UNII Spectra

Unlicensed National Information Infrastructure (UNII)

Lower Band Middle Band

Upper Band

Unlicensed National Information Infrastructure

(UNII)

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.

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

Radiated Power Limits

For a 2.4 GHz Point-to-Multipoint (PtMP) Link

36

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

Radiated Power Limits

 PtP includes a single directional transmitting

antenna and a single directional receiving antenna.

 2.4 GHz Band

 The power at the intentional radiator is limited to 1000

mW (1 Watt), however, the EIRP can increase with the

gain of the antenna

 As the antenna gain increases the Intentional Radiator power must be decreased by 1 dB for each 3dB increase in antenna gain

 This is known as the 3:1 rule

2.4 GHz PtP Radiated Power Limits

 The maximum EIRP allowed by the FCC is depends upon the

antenna gain

 For every 3 dBi above the initial 6 dBi antenna gain the FCC

mandates that the Intentional Radiator be reduced by 1 dB.

Point-to-Point Link Radiated Power Limits

Radiated Power Limits

 PtPt links for the UNII-1 and UNII-2 bands follow

exactly the same rules as the PtMP link.

 However the UNII-3 band follows a different rule

 A directional antenna gain of up to 23 dBi can be used with no reduction in transmitter power output

 For directional antenna with a gain greater than 23 dBi:

 A 1 dB reduction in peak transmitter power is required for each 1dBi in antenna gain in excess of 23 dBi

 A peak output power of 200 Watt EIRP is attainable given a 23 dBi antenna with a + 30 dBm Intentional

IEEE and 802.11

Institute of Electrical and Electronic engineers

 The American National Standards Institute (ANSI) accredits the IEEE

and oversees the standards process.

 Many IEEE standards become ANSI standards.

 The Computer Society is responsible for the IEEE 802 series of

standards through its LAN/MAN Standards Committee.

 Working Groups write standards.

 Technical Advisory Groups gives advise and makes recommendations to

the Working Groups.

The IEEE Standards Process

 The Sponsor Executive Committee (IEEE 802 SEC) has responsibility

for the general administration of the LAN/MAN standard activities.

 Anyone interested in investigating an area submits a Project

Authorization Request (PAR) to the IEEE 802.SEC.

 Project Scope

 Economic feasibility

 Market Potential

 IEEE 802 compatibility, etc.

 The SEC votes on the PAR and if approved:

 Assigns the project to an existing or new committee

 Appoints a Chairperson

 Individuals become members of the committee by meeting minimum attendance standards.

The IEEE Standards Process Voting

 A final draft version is submitted to the committee which will discuss, review and vote on the proposed standard

 The final draft standard must receive 75 percent approval.

 Any NO vote must indicate changes that should be made to the draft

to change the vote to YES

 This process continues until a 75% consensus is reached.

 Upon reaching consensus the Draft is sent to the SEC for

approval then transferred to the IEEE Standards Review

Committee.

 It is published as a standard

 The standard may then be forwarded to the International

Organization for Standardization (ISO) for approval and

LAN/MAN Standards Committee

802.11 Task and Study Groups

802.11 Task and Study Groups Contd

 The 802.11 is the base standard (ratified July 1997, updated in

1999 and reaffirmed in 2003)

All other 802.11 standards simply amend the base standard

and are identified by lower case letters such a b/a/g

 Operates in the 2.4 GHz band

 14 channels (channels 1-14) spaced 5 MHz apart

 The US support the first 11 channels

 Employ both Direct Sequence Spread Spectrum (DSSS)

 Both operate at 1 and 2 Mbps

grouper.ieee.org/groups/802/11/

 Operates in the 2.4 GHz ISM band.

 14 channels (channels 1-14) spaced 5 MHz apart

 The US support the first 11 channels

 Supported data rates are 1, 2, 5.5, 11 MBps

 Operates in the 5.0 GHz UNNI bands.

 200 channels ( channels 1-199) spaced 5 MHz apart.

 Supported data rates are 6, 9, 12, 18, 24, 36, 48 and 54

MBps.

 6, 12, and 24 are mandatory All others are optional.

 75-80 Feet

 Approved in June, 2003

 Operates in the 2.4 GHz ISM band.

 Employs Orthogonal Frequency Division

Wireless Networking Standards Contd

Major Organizations

WI-FI Alliance

 Interoperability was a concern among 802.11 vendors.

 The Wireless Ethernet Compatibility Alliance (WECA) as formed in

1999 to address Interoperability It was formed by

 3Com.Aironet(now Cisco), Intersil (formerly Harris), Lucent (now Agere), Nokia and Symbol Technology

 It now has over 150 members

 Equipment certified as compatible is branded Wi-Fi compatible Over 1500 products have been tested in the following categories:

 Wi-Fi products based on IEEE radio standards: 802.11a, 802.11b, 802.11g

in single, dual-mode (802.11b and 802.11g) or multi-band (2.4GHz and 5GHz) products.

 Wi-Fi wireless network security: WPA (Wi-Fi Protected Access) - Personal

and Enterprise, WPA2 (Wi-Fi Protected Access 2) - Personal and Enterprise

 Support for multimedia content over Wi-Fi networks: WMM (Wi-Fi

Multimedia).

European Telecommunications Standards Institute

(ETSI)

 ETSI is Europe's IEEE equivalent

 Publishes HiperLAN and HiperLAN/2 standards

 Attempts are being made to unify 802.11a and

HiperLAN/2 - called "5UP“

Wireless LAN Association

End of Presentation