1

IEEE 802.11 Overview (2)

Wireless LANs2018

รศ. ดร. อนันต์ ผลเพิม่Assoc. 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

2

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

3

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 5 1 Gbps 500 Mbps

4

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.

5

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)

6

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

8

WLAN standards will emphasize throughput, QoS, security & management…

200620052004Past

Security

Rad

ioQoS

Other

Wi-Fi

802.11b802.11g

802.11a

802.11n

WME(eDCF)

802.11e

WEPWPA

(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 & regulatory802.11d 802.11h

802.11k

History: WLAN Technology Roadmap

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

9

WLA

N

Wi-Fi

802.11b802.11g

802.11a

802.11n11 Mbps

100+ Mbps54 Mbps

Incre

asin

g R

an

ge a

nd

Mo

bil

ity

WWAN

GSM

GPRS115 kbps

WCDMA(UMTS)

EDGE HSPDA384 kbps 2 Mbps

CDMA2000

1xRTT1xEV-DV1xEV-DO

144 kbps 2.4 Mbps 3.1 Mbps

2007+200620052004Past

WPA

N

Bluetooth

1.1Bluetooth

1.2

Bluetooth

EDR

Zigbee

802.15.4UWB

802.15.3a

Zigbee

802.15.4’

3 Mbps

250 Kbps1 Mbps

100 Mbps+

NG UWB

480 Mbps

Bluetooth

2.x1 Mbps

BWA

WiMAX

802.16a802.16e

MobileFi

802.20

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-.aspx

Louis E. Frenzel, June 01, 2011

11

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

12

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

13

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

14

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

15

http://www.air-stream.org/channel_802_11b

Japan

12 & 13Not for US

16

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

17

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

18

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

19

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

21

http://transition.fcc.gov/pshs/techtopics/techtopics10.html

22

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

24

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

25

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

• Published Oct 2009

• Data rates up to 600 Mbps

• Achieved with max of four spatial streams using a 40 MHz-wide channel

26

MIMO

• MIMO encoder • divides 108 Mbps 2 x 54 Mbps Stream

• One antenna / stream on same radio channel

MIMO-OFDM based IEEE802.11n

27

http://www.merl.com/areas/images/adaptation.jpg

MCS: modulation and coding schemes

Example of Max data rates

28

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 15.00

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

29

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

30

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)

31

http://en.wikipedia.org/wiki/List_of_WLAN_channels

802.11 comparison

32

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

33

Family 802.11 802.11b 802.11a 802.11g 802.11nAllowable

MIMO streams

1 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

34

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

35

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)

802.11 ac

• Draft (Dec. 2012)

• Approved (Jan 2014)

• 5 GHz band, 80MHz Channel (160 MHz optional)

• Multi-station throughput: 1 Gbps

• A single link throughput: 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).

36

http://en.wikipedia.org/wiki/IEEE_802.11ac

Wireless Speed

37http://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

38

ScenarioTypical clientform factor

PHY link rateAggregatecapacity(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 1

single add.

• Wireless Hub

• Single-User MIMO (SU-MIMO)

• 802.11ac

• AP transmits multiple frames different clients

• at the same time and over the same frequency spectrum

• Wireless Switch (downlink)

• Multiuser MIMO (MU-MIMO)

39

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

40

http://en.wikipedia.org/wiki/IEEE_802.11ac

41

802.11e

• MAC Enhancements for Quality of Service in the capabilities and efficiency of the protocol

• VoIP, Video conferencing, Movie, …

42

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)

43

MeshDynamics

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