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IEEE 802.11 Overview (2)

Wireless LANs December 2011 – March 2012

รศ. ดร. อนันต ์ผลเพิม่ Assoc. Prof. Anan Phonphoem, Ph.D.

anan.p@ku.ac.th

Intelligent Wireless Network Group (IWING Lab)

http://iwing.cpe.ku.ac.th

Computer 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 802.11 History and present of IEEE 802.11

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IEEE 802.11 Family

Standards Band (GHz)

Raw Throughput Typical Throughput

802.11 2.4 2 Mbps (Legacy) 1 Mbps

802.11a 5 54 Mbps 20 Mbps

802.11b 2.4 11 Mbps 5 Mbps

802.11g 2.4 54 Mbps 20 Mbps

802.11n 2.4 / 5 300, 600 Mbps 130 Mbps

802.11ac < 6 1 Gbps ?

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IEEE 802.11 Family

Task Group Descriptions

802.11c Improves interoperability

802.11d 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 802.11a

802.11i 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…

2006 2005 2004 Past

Secu

rity

R

ad

io

Qo

S

Oth

er

Wi-Fi

802.11b 802.11g

802.11a

802.11n

WME (eDCF)

802.11e

WEP WPA

(TKIP) 802.11i

(AES)

802.1x

Cisco

CCXv1 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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WL

AN

Wi-Fi

802.11b 802.11g

802.11a

802.11n 11 Mbps

100+ Mbps 54 Mbps

Incre

asin

g R

an

ge a

nd

Mo

bil

ity

WW

AN

GSM

GPRS 115 kbps

WCDMA (UMTS)

EDGE HSPDA 384 kbps 2 Mbps

CDMA2000

1xRTT 1xEV-DV 1xEV-DO

144 kbps 2.4 Mbps 3.1 Mbps

2007+ 2006 2005 2004 Past

WP

AN

Bluetooth

1.1 Bluetooth

1.2

Bluetooth

EDR

Zigbee

802.15.4 UWB

802.15.3a

Zigbee

802.15.4’

3 Mbps

250 Kbps 1 Mbps

100 Mbps+

NG UWB

480 Mbps

Bluetooth

2.x 1 Mbps

BW

A

WiMAX

802.16a 802.16e

MobileFi

802.20

2-60 Mbps

History: Wireless Technology Roadmap

By Randy Kendzior, Dell, Inc.September 24, 2004

Wireless evolution (2011)

10 http://electronicdesign.com/article/communications/Wireless-Companies-Follow-The-Roadmap-Past-4G-And-On-.aspx

Louis 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

802.11g 54 Mbps

2.4GHz PHY

802.11n High

Throughput (>100 Mbps)

802.11e QoS 802.11i

Security

802.11f Inter AP

802.11h DFS & TPC

Current work

MAC

802.11k RRM

Study groups

802.11r Fast Roam

802.11s Mesh

802.11T Test

Methods

802.11u WIEN SG

APF SG

802.11p WAVE

CBP SG

802.11v WNM

802.11m Maint

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 & 13 Not 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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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

22 http://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 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

• 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 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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MCS index

Spatial streams

Modulation type

Coding rate

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 15.00

1 1 QPSK 1/2 13.00 14.40 27.00 30.00

9 2 QPSK 1/2 26.00 28.90 54.00 60.00

10 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

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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

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 802.11n Frequency 2400-2483.5 MHz 2400-2483.5Hz 5150-5250 MHz

5250-5350 MHz 5725-5825 MHz

2400-2483.5 MHz 2.4GHz and 5 GHz

Band ISM ISM UNII ISM ISM, UNII Bandwidth Allocation

83.5 MHz 83.5 MHz 300 MHz 83.5 MHz Same

Number of Channels

FHSS: 79 ch DSSS: 3 or 6

3 12 3 Same as 802.11b/a/g

Channel Width 20 MHz 20 MHz 20 MHz 20 MHz 20 MHz or 40MHz

Standard year July 1997 Sep. 1999 Sep. 1999 March 2002 started

Expected in October 2008

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 802.11n Max PHY rate 2 Mbps 11 Mbps 54 Mbps 54 Mbps 144 Mbps

Up to 600 Mbps

Data Throughput

<1.2 Mbps < 5 Mbps < 32 Mbps < 32 Mbps <80Mbps, 11g <160 Mbps,

11a Fall-back Data Rate

1, 2 1, 2, 5.5, 11 6, 9, 12, 18, 24, 36, 48, 54

1, 2, 5.5, 11 NG WiFi

MAC CSMA/CA CSMA/CA CSMA/CA CSMA/CA CSMA/CA Modulation Technology

FHSS DSSS

DSSS OFDM DSSS

OFDM DSSS

OFDM/OFDMA With 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

Dual band/Tri mode (a, b, or g) or more n

• Security standard Wi-Fi Protected Access (WPA)

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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”

• 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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Since 2002, www.meshdynamics.com/MDPerformanceAnalysis.html