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802.11 standard overview

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The first 802.11 standard was published in 1997.

At the lowest layer (PHY,) : Frequency Hopping (FHSS) unlicensed 2.4 GHz

Direct Sequence Spread Spectrum (DSSS) unlicensed2.4 GHz band, and an

Infrared 316353 THz.

Basic data rate of 1 Mb/s with an optional 2 Mb/smode

Commercial infrared implementations do notexist

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1997 feedback : many products did not

provide the degree of compatibility customers

expected

Wireless Ethernet Compatibility Alliance

(WECA) in 1999

renamed the Wi-Fi Alliance (WFA) in 2003.

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802.11 std

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802.11 std

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802.11 std

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802.11 std

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802.11 PHY amandement

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802.11 OFDM PHY

802.11a

802.11g

802.11h 802.11j

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802.11a

First ext 902.11a September 1997

OFDM PHY

Up to 54 Mb/s 5 GHz band

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802.11g

2.4 GHz

DSS-compatible signaling

802.11

802.11g Up to 54 Mbps

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802.11h

Europea regulatory

5 GHz

Low interfearence Dynamic Frequency Selection and Transmit

Power Control (MAC mechanism)

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802.11j

Ratified 2004

Japanese regulatory

4,9 GHz & 5 GHz 10 MHz Channel BW

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802.11n

High Trouhput

Up to 600 Mb/s

MIMO Feature Up to 4 antennas array

Spatial Mux or beamforming

40 MHz channel (opt)

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802.11ac & ad

ITU req IMT Advanced

Very High Trouhput

> 1 Gb/s ac below 6 GHZ

ad 60 GHz

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802.11p

September 2003

Vehicular environment

5.85-5.925 GHz in USA 5.855-5.905 GHz in Europe

OFDM-based 802.11a

20 MHz, 10 MHz (opt) 27 Mb/s

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802.11y

Wide area coverage

3.65-3.7 GHz

Up to 20 W output power

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802.11 MAC amendments

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QoS Support

802.11e

HCF (Hybrid Coordinaton Function)

HCCA (HCF Controlled Channel Access)

EDCA (Enhanced Distributed Channel Access)

HCCA hasnt been implemented

EDCA support 4 traffic category EDCA variant called Wi-Fi multimedia (WMM)

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MAC efficency enhancement

802.11e&n

Transmit consecutive frame without

immediate ACK

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Direct Link Setup

802.11e&z

Need to exchange local traffic

DLS protocol

direct frame exchangebetween adjecent divices

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Handoff Support

802.11r

Handoff without loss connectivity

Device registered at neighbour AP

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Security Enhancement

802.11i&w

2001 WEP weakness known

WPA

WPA2 (final ammandement) Authenticated and encrypted management

frameDoS

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Conclusion

802.11 standard and amendements provide richfeature for wireless comm

5,10,20,40 MHz channel BW

2.4, 3.65, 4.9, 5, 60 GHz freq band New standdard and amendment open new

scenario for WLAN

But also makes it more and more difficult tomaintain a cohesive standard

802.11 will continues to expand

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802.11-2012

IEEE Std 802.11k-2008: Radio Resource Measurement of Wireless LANs

(Amendment 1)

IEEE Std 802.11r-2008: Fast Basic Service Set (BSS) Transition (Amendment

2)

IEEE Std 802.11y-2008: 36503700 MHz Operation in USA (Amendment 3)

IEEE Std 802.11w-2009: Protected Management Frames (Amendment 4)

IEEE Std 802.11n-2009: Enhancements for Higher Throughput (Amendment 5)

IEEE Std 802.11p-2010: Wireless Access in Vehicular Environments

(Amendment 6)

IEEE Std 802.11z-2010: Extensions to Direct-Link Setup (DLS) (Amendment7)

IEEE Std 802.11v-2011: IEEE 802.11 Wireless Network Management

(Amendment 8)

IEEE Std 802.11u-2011: Interworking with External Networks (Amendment 9)

IEEE Std 802.11s-2011: Mesh Networking (Amendment 10)