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Bài giảng Lecture 6 WLAN Standards and Organizations
Wireless LAN Standards and Organizations (1 September, 2006) February 2005 Copyright 2005 Al Rights reserved Objectives Upon completion of this chapter you will be able to: q Define what regulations the FCC creates q Explain what the ISM and UNII bands are and how they are used q Define the different 802.11 standards and drafts as set forth by the IEEE q Describe the competing technologies for wireless LANs February 2005 Copyright 2005 Al Rights reserved FCC Regulations q The FCC manages civilian, State and local government usage of the radio spectrum Code of Federal Regulations, Title 47 (CFR 47) Part 15 http://www.accesss.gpo.gov/nara/cfr/cfr-table-search.html The FCC has authority to enforce the use of the radio spectrum, however, they generally 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 February 2005 Copyright 2005 Al Rights reserved Industrial, Scientific and Medical (ISM) q There are three license free ISM Bands 915 MHz ISM Band 902-928 MHz 915 MHz ± 13 MHz at speeds up to 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 Al RightsUNII Copyright 2005 of the reserved February 2005 ISM and UNII Spectra February 2005 Copyright 2005 Al Rights reserved Unlicensed National Information Infrastructure (UNII) q 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 February 2005 Copyright 2005 Al Rights reserved ISM and UNII Spectra February 2005 Copyright 2005 Al Rights reserved Unlicensed National Information Infrastructure (UNII) February 2005 Copyright 2005 Al Rights reserved Unlicensed National Information Infrastructure (UNII) Lower Band Middle Band Upper Band February 2005 Copyright 2005 Al Rights reserved Radiated Power Limits q 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 q 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 Copyright 2005 Al Rights reserved February 2005 10 The IEEE Standards Process q 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 q 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 February 2005 Copyright 2005 Al Rights reserved 20 The IEEE Standards Process Voting q A final draft version is submitted to the committee which will discuss, review and vote on the proposed standard q 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 q 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 q The standard may then be forwarded to the International Organization for Standardization (ISO) for approval and publication as an international standard February 2005 Copyright 2005 Al Rights reserved 21 LAN/MAN Standards Committee February 2005 Copyright 2005 Al Rights reserved 22 802.11 Task and Study Groups February 2005 Copyright 2005 Al Rights reserved 23 802.11 Task and Study Groups Contd February 2005 Copyright 2005 Al Rights reserved 24 802.11 q IEEE 802.11 Standard 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 MHz apart The US support the first 11 channels Employ both Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping spread spectrum (FHSS) Both operate at and Mbps grouper.ieee.org/groups/802/11/ February 2005 Copyright 2005 Al Rights reserved 25 802.11b q IEEE 802.11b Supplement Published in Sept 1999 Employs Direct Sequence Spread Spectrum (DSSS) with DBPSK/DQPSK and CCK coding Operates in the 2.4 GHz ISM band 14 channels (channels 1-14) spaced MHz apart The US support the first 11 channels Supported data rates are 1, 2, 5.5, 11 MBps DBPSK = Mbps DQPSK = 2, 5.5 and 11 MBps 250 -300 Feet 32 Users /Access Point grouper.ieee.org/groups/802/11/ reserved Copyright 2005 Al Rights February 2005 26 802.11a q IEEE 802.11a Supplement Published in Sept 1999 802.11a employs Orthogonal Frequency Division Multiplexing (OFDM) Operates in the 5.0 GHz UNNI bands 200 channels ( channels 1-199) spaced 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 February 2005 Copyright 2005 Al Rights reserved 27 802.11g q IEEE 802.11g Standard Approved in June, 2003 Operates in the 2.4 GHz ISM band Employs Orthogonal Frequency Division Multiplexing (OFDM) Supported data rates are 6, 9, 12, 18, 24, 36, 48, 54 MBps Backward compatible with 802.11b Automatically switches to DQPSK February 2005 Copyright 2005 Al Rights reserved 28 Wireless Networking Standards Contd February 2005 Copyright 2005 Al Rights reserved 29 Major Organizations February 2005 Copyright 2005 Al Rights reserved 30 WI-FI Alliance q Interoperability was a concern among 802.11 vendors q 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 q 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) q http:/www.wi-fi.org February 2005 Copyright 2005 Al Rights reserved 31 European Telecommunications Standards Institute (ETSI) q ETSI is Europe's IEEE equivalent q Publishes HiperLAN and HiperLAN/2 standards q Attempts are being made to unify 802.11a and HiperLAN/2 - called "5UP“ February 2005 Copyright 2005 Al Rights reserved 32 Wireless LAN Association (WLANA) q The Wireless LAN Association is a non-profit educational trade association WLANA provides a clearinghouse of information about wireless local area applications issues and trends It serves as a resource to customers and prospects of wireless local area products and wireless personal area products and to industry press and analysts February 2005 Copyright 2005 Al Rights reserved 33 End of Presentation February 2005 Copyright 2005 Al Rights reserved 34 ... 36 technical Societies q The IEEE Standards Association administers the standards process within the IEEE The American National Standards Institute (ANSI) accredits the IEEE and oversees the standards. .. and oversees the standards process Many IEEE standards become ANSI standards q The Computer Society is responsible for the IEEE 802 series of standards through its LAN/MAN Standards Committee... Operates in the 5.0 GHz UNNI bands 200 channels ( channels 1-199) spaced 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