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IEEE 802.11 Overview (2)
Wireless LANs2020
รศ. ดร. อนันต์ ผลเพิ.มAssoc. Prof. Anan Phonphoem, Ph.D.
[email protected] Wireless Network Group (IWING Lab)
http://iwing.cpe.ku.ac.thComputer Engineering Department
Kasetsart University, Bangkok, Thailand
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Outline• IEEE 802 Standards• IEEE 802.11 Overview• IEEE 802.11 Services• History and present of IEEE 802.11History and present of IEEE 802.11
IEEE 802.11 Family
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Modified from https://www.makeuseof.com/tag/understanding-common-wifi-standards-technology-explained/
Typical Throughput
20 Mbps 5 Mbps 20 Mbps 130 Mbps 500 Mbps
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IEEE 802.11 FamilyTask Group Descriptions802.11c Improves interoperability802.11d Multiple Regulatory Domains (Improve Roaming; New
country)802.11e Quality of Service (QoS); prioritizing voice or video 802.11f Inter-Access Point Protocol (IAPP)802.11h Supports measuring and managing the 5-GHz radio
signals in 802.11a802.11i Enhanced Security (repairs WEP weakness)802.11j Extensions for Japan 802.11k Passing specific radio frequency health and
management data to higher-level management apps.
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IEEE 802.11 Family• IEEE 802.11p - WAVE - Wireless Access for the Vehicular Env. (e.g.
ambulances and passenger cars) (working - 09?) • IEEE 802.11r - Fast roaming (08) • IEEE 802.11s - Mesh Networking, Extended Service Set (ESS) • IEEE 802.11T - Wireless Performance Prediction (WPP) – (cancel ?)• IEEE 802.11u - Interworking with non-802 networks (for example,
cellular) (proposal evaluation - March 2010?) • IEEE 802.11v - Wireless network management (early stages - 2010?) • IEEE 802.11w - Protected Management Frames (early stages - 2009?) • IEEE 802.11y - 3650-3700 MHz Operation in the U.S. (2008)
(from 802.11a to 3.7 GHz)• IEEE 802.11z: Extensions to Direct Link Setup (DLS) (September 2010)
http://en.wikipedia.org/wiki/IEEE_802.11
On the way• IEEE 802.11aa: Robust streaming of Audio Video Transport Streams
(~ March 2012)• IEEE 802.11ac: Very High Throughput <6 GHz (~ December 2012)
• 802.11n improvement• better modulation scheme (expected ~10% throughput increase)• wider channels (80 or even 160 MHz)• multi user MIMO
• IEEE 802.11ad: Very High Throughput 60 GHz (~ Dec 2012)• IEEE 802.11ae: QoS Management (~ Dec 2011)• IEEE 802.11af: TV Whitespace (~ Mar 2012)• IEEE 802.11ah: Sub 1Ghz (~ July 2013)• IEEE 802.11ai: Fast Initial Link Setup (~ Sep 2014)
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http://en.wikipedia.org/wiki/IEEE_802.11
Intelligent Wireless Network Group (IWING)
CPE Department, Kasetsart University
Wireless System Roadmap
http://www.dolcera.com/wiki/index.php?title=Image:Roadmap.jpg
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WLAN standards will emphasize throughput, QoS, security & management…
200620052004Past
Security
Radio
QoS
Other
Wi-Fi802.11b 802.11g
802.11a
802.11n
WME(eDCF) 802.11e
WEP WPA(TKIP)
802.11i(AES)
802.1x
CiscoCCXv1 CCXv2 CCXv3
•Migration to dual-band•Faster data rates with .11n
•VoIP & streaming support
•Strong AES encryption•Port-based authentication
•Cisco interoperability•Measurements & regulatory
802.11d 802.11h
802.11k
History: WLAN Technology Roadmap
By Randy Kendzior, Dell, Inc.September 24, 2004
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WLA
N
Wi-Fi802.11b 802.11g
802.11a
802.11n11 Mbps 100+ Mbps
54 Mbps
Incr
easi
ng R
ange
and
Mob
ility
èWWAN
GSMGPRS 115 kbps
WCDMA(UMTS)EDGE HSPDA
384 kbps 2 MbpsCDMA20001xRTT 1xEV-DV1xEV-DO
144 kbps 2.4 Mbps 3.1 Mbps
2007+200620052004Past
WPA
N
Bluetooth1.1
Bluetooth1.2
BluetoothEDR
Zigbee802.15.4 UWB
802.15.3a
Zigbee802.15.4’
3 Mbps
250 Kbps 1 Mbps
100 Mbps+NG UWB
480 Mbps
Bluetooth2.x1 Mbps
BWA
WiMAX802.16a 802.16e
MobileFi802.20
2-60 Mbps
History: Wireless Technology Roadmap
By Randy Kendzior, Dell, Inc.September 24, 2004
Wireless evolution (2011)
10http://electronicdesign.com/article/communications/Wireless-Companies-Follow-The-Roadmap-Past-4G-And-On-.aspxLouis E. Frenzel, June 01, 2011
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IEEE 802.11 Standards
802.11 (’99)MAC +
2Mbps PHY
802.11a (’99)54 Mbps
5GHz PHY
802.11b (’99)11 Mbps
2.4GHz PHY
PHY
Published
802.11g54 Mbps
2.4GHz PHY
802.11nHigh
Throughput(>100 Mbps)
802.11eQoS802.11i
Security
802.11f Inter AP
802.11hDFS & TPC
Currentwork
MAC
802.11kRRM
Studygroups
802.11rFast Roam
802.11sMesh
802.11TTest
Methods
802.11uWIEN SG
APF SG
802.11pWAVE
CBP SG
802.11vWNM
802.11mMaint
By Peng Yan, Tampere University of Technology, 12/4/2005
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History: 802.11 Legacy• 1997: First standard
• Standard name: IEEE 802.11-1997• Updated: IEEE 802.11-1999 • Starting Point for “Standard-based WLAN”
• Radio and infrared medium• For 2 Mbps: (fallback to 1 Mbps – Noisy): Direct sequence
Spread Spectrum (DSSS) modulation• For 1-2 Mbps Frequency Hopping Spread Spectrum (FHSS)• Both DSSS and FHSS operate in ISM band 2.4 GHz
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802.11b• 802.11b-1999• Range 50 – 100 m. (depends on obstacles)• Omni-directional antenna• Indoor / Outdoor / Point-to-point (high-gain
external antennas)• Max throughput of 11 Mbps• fallback 5.5, 2 and 1 Mbps
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802.11b• Attenuation: Metal, Thick walls, Water, etc.• ISM Band 2.4 GHz• DSSS• CSMA/CA• 14 overlapping channels• Different channels for different countries• 3 simultaneously channels• E.g. 1, 6, and 11
802.11b Channels
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http://www.air-stream.org/channel_802_11b
Japan
12 & 13Not for US
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802.11a• 2001 (802.11a-1999) • Max throughput of 54 Mbps• Typical throughput around 20 Mbps• ISM Band 5 GHz• OFDM• CSMA/CA
802.11a• 12 nonoverlapping channels, • 8 dedicated to indoor• 4 to point to point • Not widely deployed (US. / Japan)• 802.11b popularity• Less range / More attenuation• Lack of roll back compatibility (now support a,b,and g)• In Europe considering HiperLan2
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Unlicensed National Information Infrastructure (U-NII)
• Radio frequency spectrum used by 802.11a devices• U-NII Low (U-NII-1) • 5.15-5.25 GHz • Require use of an integrated antenna• Power limited to 50mW• U-NII Mid (U-NII-2) • 5.25-5.35 GHz • Allow for a user-installable antenna (radar avoidance)• Power limited to 250mW
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Unlicensed National Information Infrastructure (U-NII)
• U-NII Upper (U-NII-3)• 5.725 to 5.825 GHz• Sometimes referred to as U-NII / ISM due to overlap
with the ISM band• Allow for a user-installable antenna• Power limited to 1W• U-NII Worldwide• 5.47-5.725 GHz• Both outdoor and indoor (radar avoidance)• Power limited to 250mW
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Unlicensed National Information Infrastructure (U-NII)
20http://www.revolutionwifi.net/revolutionwifi/2014/04/impact-of-fcc-5-ghz-u-nii-report-order.html
http://hctamerica.com/radio-wireless/u-nii-3-transition-requirement-postponed-by-the-fcc/50 mW 250 mW 1 W250 mW
802.11a Channels
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http://transition.fcc.gov/pshs/techtopics/techtopics10.html
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802.11g• 3rd quarter 2003• ISM Band 2.4 GHz • Max throughput of 54 Mbps (Net 24.7 Mbps)• Fully backwards compatible with 802.11b• OFDM• CSMA/CA
802.11g Channels• Same as 802.11b
23http://en.wikipedia.org/wiki/802.11g
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802.11n• Established in Sep 2003• 2 Competing Alliances (for the draft 802.11n)
• Task group n synchronization (TGn Sync)• World Wide Spectrum Efficiency (WWiSE)
• Both agree on the usage of multiple input multiple output (MIMO) antenna technology • Mostly differences on channel bandwidth allocation, PHY
(OFDM) and MAC• Max throughput (MAC SAP) ≥ 100 Mbps
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Status 802.11n• June 2007 Draft 2.0 (Official à device)
• Draft N, Pre-N• May08 Draft 4.0, Jan09 Draft 7.0, May09 Draft 10.0 (Working)
• Qualcomm introduces “WCN1312” (June 2009)• Single-Chip 802.11n Wireless LAN Solution for Handsets and Mobile
Devices• 2.4 GHz, data rates up to 72 Mbps
• Published Oct 2009• Data rates up to 600 Mbps
• Achieved with max of four spatial streams using a 40 MHz-wide channel
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MIMO
• MIMO encoder • divides 108 Mbps à 2 x 54 Mbps Stream• One antenna / stream on same radio channel
MIMO-OFDM based IEEE802.11n
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http://www.merl.com/areas/images/adaptation.jpg
MCS: modulation and coding schemes
Example of Max data rates
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MCSindex
Spatialstreams
Modulationtype
Codingrate
Data rate (Mbit/s)
20 MHz channel 40 MHz channel
800 ns GI 400 ns GI 800 ns GI 400 ns GI
0 1 BPSK 1/2 6.50 7.20 13.50 15.001 1 QPSK 1/2 13.00 14.40 27.00 30.009 2 QPSK 1/2 26.00 28.90 54.00 60.0010 2 QPSK 3/4 39.00 43.30 81.00 90.00
15 2 64-QAM 5/6 130.00 144.40 270.00 300.00
21 3 64-QAM 2/3 156.00 173.30 324.00 360.00
31 4 64-QAM 5/6 260.00 288.80 540.00 600.00
GI: Guard interval
http://en.wikipedia.org/wiki/802.11n
Modulation Type
29QPSK (4-PSK)
BPSK (2-PSK)
QAM
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802.11n Channel Bandwidth
• TGn Sync uses 40 MHz channels in the 5 GHz spectrum, the same one used by 802.11a•WWiSE prefers 20 MHz channels in the 2.4
GHz consistently used 802.11b/g spectrum
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Application Comparison• 802.11a/b/g focus on computer networking• 802.11n interests on broad communication and
entertainment areas• Consumer applications like HDTV• Streaming video• Regular use for today J
Non-overlapping Channels (2.4 GHz)
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http://en.wikipedia.org/wiki/List_of_WLAN_channels
802.11 comparison
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Family 802.11 802.11b 802.11a 802.11g 802.11nFrequency 2400-2483.5 MHz 2400-2483.5Hz 5150-5250 MHz
5250-5350 MHz5725-5825 MHz
2400-2483.5 MHz 2.4GHz and 5 GHz
Band ISM ISM UNII ISM ISM, UNIIBandwidthAllocation
83.5 MHz 83.5 MHz 300 MHz 83.5 MHz Same
Number of Channels
FHSS: 79 chDSSS: 3 or 6
3 12 3 Same as 802.11b/a/g
Channel Width 20 MHz 20 MHz 20 MHz 20 MHz 20 MHz or40MHz
Standard year Jun. 1997 Sep. 1999 Sep. 1999 Jun. 2003 Oct. 2009
Modified from http://transition.fcc.gov/pshs/techtopics/techtopics10.html
802.11 comparison
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Family 802.11 802.11b 802.11a 802.11g 802.11nAllowable
MIMO streams1 1 1 1 4
Max PHY rate 2 Mbps 11 Mbps 54 Mbps 54 Mbps 144 MbpsUp to 600 Mbps
Data Throughput
<1.2 Mbps < 5 Mbps < 32 Mbps < 32 Mbps <80Mbps, 11g<160 Mbps, 11a
Fall-back Data Rate /
Stream (Mbps)
1, 2 1, 2, 5.5, 11 6, 9, 12, 18, 24, 36, 48, 54
6, 9, 12, 18, 24, 36, 48,
54
20MHz: 7.2, 14.4, 21.7, 28.9, 43.3, 57.8, 65,
72.2
40MHz:15, 30, 45, 60, 90, 120,
135, 150
802.11 comparison
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Family 802.11 802.11b 802.11a 802.11g 802.11nMAC CSMA/CA CSMA/CA CSMA/CA CSMA/CA CSMA/CA
ModulationTechnology
FHSSDSSS
DSSS OFDMDSSS
OFDMDSSS
OFDM/OFDMAWith MIMO
Max. Power(normal)
1000mw(30mw)
1000mw(30mw)
50, 250, 1000mw
1000 mw Same
Modulation BPSK BPSK,QPSK, CCK
BPSK, QPSK, 16 - 64 QAM
CCK, QAM Same
Modified from http://transition.fcc.gov/pshs/techtopics/techtopics10.html
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802.11 Wi-Fi• Specification defined by IEEE
(not compatibility guarantee)• A special group, Wi-Fi Alliance• Group of manufacturers• Test compatibility• Guarantee interoperability (by issue Wi-Fi Trademark)• Start with 802.11b
à Dual band/Tri mode (a, b, or g) or more à n• Security standard Wi-Fi Protected Access (WPA)
802.11 ac• Draft (Dec. 2012)• Approved (Jan 2014)• 5 GHz band, 80MHz Channel (160 MHz optional)• Multi-station throughput: ³ 1 Gbps• A single link throughput: ³ 500 Mbps• Higher Throughput• Wider RF bandwidth (up to 160 MHz)• More MIMO spatial streams (up to 8)• High-density modulation (up to 256-QAM).
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http://en.wikipedia.org/wiki/IEEE_802.11ac
Wireless Speed
38http://www.cisco.com/c/en/us/products/collateral/wireless/aironet-3600-series/white_paper_c11-713103.html
Constellation Density2
Channel Bandwidth1
# of Spatial Streams3
Example Configuration assume 256-QAM, rate 5/6
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Scenario Typical clientform factor PHY link rate
Aggregatecapacity(speed)
One-antenna AP, one-antenna STA, 80 MHz Handheld 433 Mbit/s 433 Mbit/s
Two-antenna AP, two-antenna STA, 80 MHz Tablet, laptop 867 Mbit/s 867 Mbit/s
One-antenna AP, one-antenna STA, 160 MHz Handheld 867 Mbit/s 867 Mbit/s
Three-antenna AP, three-antenna STA, 80 MHz Laptop, PC 1.27 Gbit/s 1.27 Gbit/s
Two-antenna AP, two-antenna STA, 160 MHz Tablet, laptop 1.69 Gbit/s 1.69 Gbit/s
Four-antenna AP, four one-antenna STAs, 160 MHz(MU-MIMO) Handheld 867 Mbit/s to each STA 3.39 Gbit/s
•Eight-antenna AP, 160 MHz (MU-MIMO) one four-antenna STA•one two-antenna STA•two one-antenna STAs
Digital TV, Set-top Box,Tablet, Laptop, PC, Handheld
•3.39 Gbit/s to four-antenna STA•1.69 Gbit/s to two-antenna STA•867 Mbit/s to each one-antenna STA
6.77 Gbit/s
Eight-antenna AP, four 2-antenna STAs, 160 MHz(MU-MIMO)
Digital TV, tablet, laptop, PC 1.69 Gbit/s to each STA 6.77 Gbit/s
https://en.wikipedia.org/wiki/IEEE_802.11ac
Multiuser MIMO (MU-MIMO)• 802.11n• Multiple spatial streams à 1
single add.• Wireless Hub• Single-User MIMO (SU-MIMO)
• 802.11ac• AP transmits multiple frames
à different clients• at the same time and over the
same frequency spectrum• Wireless Switch (downlink) • Multiuser MIMO (MU-MIMO)
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Null Steering Technique
802.11ad• The Wireless Gigabit Alliance (WiGig)• Unlicensed 60 GHz frequency band• Specification version 1.0 WiGig: Dec 2009• WiGig tri-band enabled devices• 2.4, 5 and 60 GHz bands• Data rates up to 7 Gbit/s• = 8 antenna 802.11ac • = 50 * highest 802.11n rate
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http://en.wikipedia.org/wiki/IEEE_802.11ac
802.11 comparison
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https://solutionsreview.com/wireless-network/802-11ad-what-is-it-and-when-will-we-see-it/
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802.11e•MAC Enhancements for Quality of Service
in the capabilities and efficiency of the protocol• VoIP, Video conferencing, Movie, …
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IEEE 802.11i• Weakness reports in the WEP • Create a larger number of initialization vectors for
encryption• Dropping “WEP2”•à Change to Temporal Key Integrity Protocol (TKIP)• a key retains its security over a period of time• Need 802.1x• Authenticating method • Some weaknesses (man-in-the-middle interception)
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