3.802.11 std over view
TRANSCRIPT
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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)